062-00381-010 - Control Technology, Inc.

Transcription

Control Technology Inc.
Automation Systems Training Program
2500 Series Training
Course 1
CONTROL TECHNOLOGY INC.
2500 Series Training Course 1
5734 Middlebrook Pike
Knoxville, TN 37921
Phone 865-584-0440 • Fax 865-584-5720
www.controltechnology.com
©2008-2012 Control Technology Inc., all rights reserved
This manual may contain references to brand and product names which are trade names, trademarks, and/or
registered trademarks of Control Technology Inc., Siemens® AG, Texas Instruments, Rockwell Automation, and
FasTrak Softworks. Every effort has been made to ensure the accuracy of this manual; however, errors do occur.
CTI provides the manual on an “as is” basis and assumes no responsibility for direct or consequential damages
resulting from the use of this manual. This manual is supplied without any express or implied warranty of any
kind, including but not limited to the warranties of merchantability or fitness for a particular purpose. This
manual, the products it references, and the product specifications are subject to change without notice. If you
have any comments or discover an error, please contact us by phone at 1-800-537-8398 or visit our website at
www.controltechnology.com .
Siemens®, SIMATIC® and Series 505® are registered trademarks of Siemens AG and Siemens Energy &
Automation, and TISOFT™ is a trademark of Siemens Energy and Automation. Inc. Any references herein to
“505” are intended as references to the Siemens or SIMATIC 505 product line. While Control Technology, Inc.’s
2500 series products are compatible with the SIMATIC Series 505, Siemens in no way endorses or sponsors CTI
or the 2500 series. Neither is CTI in anyway affiliated with Siemens.
WorkShop® and FTTrend® are registered trademarks of FasTrak SoftWorks, Inc.
Windows® is a registered trademark of Microsoft Corporation.
CTI Part No. 062-00381-010
Published 04/24/12
Table of Contents
Introduction ........................................................................................... 1
Understanding the 2500 Series System Architecture ..................................... 1
Hands-on Application Development ................................................................ 1
Additional Documentation ................................................................................ 2
Chapter 1. PLC Memory Architecture .............................................. 3
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
User Program Memory ........................................................................... 3
User Program Elements.......................................................................... 3
I/O Registers ............................................................................................ 4
Control Relays ........................................................................................ 4
Status Words........................................................................................... 4
Configuration Data ................................................................................ 5
Flash Memory ......................................................................................... 5
High-Speed DRAM ................................................................................. 5
Chapter 2. PLC Scan Cycle ................................................................. 7
2.1
2.2
2.3
Scan Overview ........................................................................................ 7
Discrete Scan............................................................................................ 8
Analog Scan ............................................................................................. 9
2.3.1 Cyclic Analog Tasks ...................................................................................... 9
2.3.2 Non-Cyclic Analog Tasks ........................................................................... 10
2.6
2.7
Cyclic RLL ............................................................................................. 10
PLC Scan Types .................................................................................... 10
2.7.1 Fixed Scan .................................................................................................... 11
2.7.2 Variable Scan ............................................................................................... 11
2.7.3 Variable Scan with Limit............................................................................ 11
2.8
Scan Modes ............................................................................................ 12
2.8.1 Discrete Scan Mode ..................................................................................... 12
2.8.2 Analog Scan Mode....................................................................................... 13
2.8.3 Scan Locking Mode ..................................................................................... 13
Chapter 3. 2500 Series Hardware ..................................................... 15
3.1
3.2
2500 Series System Overview ............................................................... 15
2500 Series System Components.......................................................... 17
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Chapter 4. Addressing and Memory Structure ............................... 23
4.1
Digital and Analog I/O Addressing ..................................................... 23
4.1.1 Digital Inputs and Outputs ........................................................................ 23
4.1.2 Analog Inputs and Outputs ........................................................................ 24
4.2
4.2.1
4.2.2
4.2.3
4.2.4
4.3
I/O Concepts .......................................................................................... 24
Discrete Image Register.............................................................................. 25
Word Image Register.................................................................................. 26
Normal I/O Updates.................................................................................... 26
Immediate I/O Updates .............................................................................. 26
Memory Types ....................................................................................... 27
4.3.1 Program Memory ....................................................................................... 27
4.3.2 Data Memory............................................................................................... 28
4.3.3 System Memory ........................................................................................... 28
Chapter 5. Configuration and Setup ................................................. 31
5.1
5.2
5.2.1
5.2.2
5.2.3
5.2.4
5.3
Configuration Overview ....................................................................... 31
Communications Path ........................................................................... 32
RS232 Port Details ...................................................................................... 32
Communications Setup in WorkShop ...................................................... 34
Serial Port Setup ......................................................................................... 35
Quick Connect Communications Setup .................................................... 36
PLC Configuration ................................................................................ 37
5.3.1 PLC Type Setup .......................................................................................... 37
5.3.2 PLC Memory Configuration...................................................................... 38
5.4
I/O Configuration .................................................................................. 40
5.4.1 Configuring 32-Pt Digital Input Module .................................................. 42
5.4.2 Configuring 32-Pt Digital Output Module ............................................... 43
Chapter 6. Discrete RLL Programming ........................................... 45
6.1
6.2
Introduction ........................................................................................... 45
Opening a Program ............................................................................... 46
6.2.1 Ladder Editor .............................................................................................. 47
6.2.2 Toolbar Icons............................................................................................... 48
6.3
6.4
6.4.1
6.4.2
6.4.3
6.4.4
6.4.5
6.4.6
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Insert a RLL Network........................................................................... 49
Discrete Contacts and Coils .................................................................. 50
Normally Open Contact ............................................................................. 50
Output Coil .................................................................................................. 51
Normally Closed Contact ........................................................................... 52
Series (AND) Contacts ................................................................................ 52
Parallel (OR) Contacts ............................................................................... 53
Not Coil Output ........................................................................................... 54
2500 Series Advanced C
6.4.7
6.4.8
6.4.9
6.4.10
6.5
6.6
6.7
6.8
6.9
6.10
Logical NOT Contact .................................................................................. 54
Set Coil Output ............................................................................................ 55
Reset Coil Output ........................................................................................ 55
One Shot Contact ........................................................................................ 56
Saving a Program .................................................................................. 56
Program Download ............................................................................... 57
Transfer PLC to RUN Mode ................................................................ 57
Monitor Program Status ...................................................................... 58
On-Line Edit .......................................................................................... 64
Timer and Compare Instructions ........................................................ 65
6.10.1
6.10.2
6.10.3
6.10.4
6.10.5
6.10.6
6.10.7
Motor Control or ON/OFF Station Example ........................................... 65
Creating Tag Names and Descriptors ....................................................... 66
Integer Number Format ............................................................................. 69
Timer Operation .......................................................................................... 70
Creating Timers .......................................................................................... 71
Compare Operation .................................................................................... 72
Timer and Pulse Timer Application .......................................................... 74
6.11 Counter Instructions ............................................................................. 76
6.11.1 Up Counter .................................................................................................. 76
6.11.2 Up/Down Counter ....................................................................................... 77
6.11.3 Counter Application.................................................................................... 79
6.12 Move Word and Date Compare Instructions ..................................... 80
6.12.1
6.12.2
6.12.3
6.12.4
6.12.5
Move Word Description ............................................................................. 80
Move Word Application ............................................................................. 81
Date Compare Description ......................................................................... 82
Data Representation.................................................................................... 83
Date Compare Application ......................................................................... 84
6.13 Event Drum and Load Data Constant Instructions .......................... 86
6.13.1 Load Data Constant Description ............................................................... 86
6.13.2 Event Drum Description ............................................................................. 87
6.13.3 EDRUM and LDC Application .................................................................. 92
6.14 Shift Registers ........................................................................................ 96
6.14.1
6.14.2
6.14.3
6.14.4
Bit Shift Register Description .................................................................... 96
Bit Shift Register Application .................................................................... 98
Word Shift Register Description ............................................................. 101
Word Shift Register Application ............................................................. 103
Chapter 7. PLC Program Control .................................................. 107
7.1
7.2
Program Structure .............................................................................. 107
END Instruction .................................................................................. 110
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7.3
Master Control Relay (MCR) ............................................................ 111
7.3.1 MCR Description ...................................................................................... 111
7.3.2 MCR Application ...................................................................................... 112
7.4
Jump to Jump-End.............................................................................. 113
7.4.1 Jump Description ...................................................................................... 113
7.4.2 Jump Application ...................................................................................... 114
7.5
Skip-to-Label ....................................................................................... 115
7.5.1 Skip-to-Label Description ........................................................................ 115
7.5.2 Skip-to-Label Application ........................................................................ 116
7.6
Go to Subroutine (GTS) ...................................................................... 117
7.6.1 GTS Description ........................................................................................ 117
7.6.2 GTS Application ....................................................................................... 118
7.7
TASK Instruction ................................................................................ 120
7.7.1 TASK Description ..................................................................................... 120
7.7.2 TASK Application..................................................................................... 122
Chapter 8. Data Formatting ............................................................. 125
8.1
8.2
8.2.1
8.2.2
8.2.2
8.2.3
8.2.4
8.2.5
8.2.6
8.2.7
8.3
Data Elements ...................................................................................... 125
Data Types............................................................................................ 127
Signed Integer ........................................................................................... 127
Unsigned Integer ....................................................................................... 128
Long Integer .............................................................................................. 128
Real Number ............................................................................................. 128
Hexadecimal .............................................................................................. 129
Binary Coded Decimal (BCD) ................................................................. 130
BCD to Binary Conversion ...................................................................... 131
Binary to BCD Conversion ...................................................................... 132
Analog Data.......................................................................................... 133
8.3.1 Analog-to-Digital Conversions................................................................. 133
8.3.2 Signals with 20% Offset ........................................................................... 134
Chapter 9. Math Instructions .......................................................... 137
9.1
Add and Subtract Instructions .......................................................... 137
9.1.1 ADD and SUB Descriptions ..................................................................... 137
9.1.2 ADD Application ....................................................................................... 138
9.2
Multiply Instruction ............................................................................ 141
9.2.1 Multiply Description ................................................................................. 141
9.2.2 Multiply Application................................................................................. 141
9.3
Divide Instruction ................................................................................ 143
9.3.1 Divide Description..................................................................................... 143
9.3.2 Divide Application .................................................................................... 144
9.4
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RLL Math Example Application ....................................................... 145
Chapter 10. Troubleshooting ........................................................... 147
10.1
10.2
10.3
10.3
10.4
10.5
10.6
10.7
PLC Status Words............................................................................... 147
Alarming and Status Reporting ......................................................... 148
Program Control Monitoring ............................................................ 150
PLC Status ........................................................................................... 153
I/O Status ............................................................................................. 155
Digital Input Module Status ............................................................... 156
Digital Output Module Status ............................................................ 157
Remote I/O Communications Status ................................................. 159
10.7.1 Monitoring Remote I/O Errors ................................................................ 159
10.7.2 Logging Remote I/O Error Counts .......................................................... 160
Chapter 11. Documentation ............................................................. 163
11.1 Print Dialog .......................................................................................... 163
11.2 Selection of Program Elements .......................................................... 164
11.3 Data Range and Print Setup .............................................................. 165
Appendix A. CTI Contact Information .......................................... 167
Appendix B. Replacement/Compatibility Guide ........................... 169
Appendix C. CPU Product Models ................................................. 171
Appendix D. 2500 Series Status Words .......................................... 173
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Page vi
Introduction
A good foundation is essential to a productive experience with any system.
T
he content of this course is intended for students that have experience with Automation
and Control Systems including control devices and PLCs. The student should also have
some basic knowledge of ladder or control programming and be competent using a PC
with Windows operating system.
Understanding the 2500 Series System Architecture

Basic PLC concepts

Basic system architecture and hardware description

Use of Workshop program package

PLC program loading, editing, and saving

Description and use of common instructions

Description and use of program control instructions

PLC number formats

Handling analog values in Ladder

Status words

Troubleshooting
Hands-on Application Development
The students will receive hands on experience with live training systems. Each training system
will provide a 2500 Series rack, power supply, processor, and Input/Output modules connected
to a PC Application Development Station. Upon completion, the student will be able to:

Assemble a CTI 2500 Series Automation System

Understand the PLC System operation and architecture

Write and edit a RLL (Relay Ladder Logic) program

Monitor the operation of a ladder program

Troubleshoot a CTI 2500 Series PLC
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Additional Documentation
Additional documentation is available on the CTI website at www.controltechnology.com .
This includes the following:

CTI Product Catalog

CTI Product Datasheets and User Manuals

Application Notes

CTI Replacement Guide for Siemens 505 products

Siemens SIMATIC® 505 manual set
Page 2
Chapter 1. PLC Memory Architecture
T
he CTI 2500 Series controller contains several different types of memory, each with a
specific purpose. The memory types are described in the following sections.
1.1 User Program Memory
The user program and related data is stored in battery-backed memory. As long as battery power
is present, the contents of battery-backed memory will be maintained over a power cycle. The
size of the battery backed memory is model dependent.
As an alternative, flash memory is provided on all 2500 Series CPUs for permanent storage of
user programs and configuration data. This memory replaces the optional EEPROM in the
Siemens 505 controllers.
See Appendix C for CPU Model information.
1.2 User Program Elements
The following user program elements are stored in battery-backed memory

Relay Ladder Logic (RLL) Program

Special Function Programs

Special Function Subroutines

Loop Parameters

Analog Alarm Parameters

Variable Data – 16 bit words

Constant Data – 16 bit words

Timer Counter Data

Drum Data

Shift Register Data

Table Move Data

One-Shot Instruction Data
The amount of memory allocated to the user program elements may be specified by the user as
part of the PLC configuration.
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1.3 I/O Registers
The CTI 2500 controller contains two I/O registers, which are memory areas used to hold I/O
values. The discrete I/O register contains Boolean values (0 or 1). The word I/O register contains
16 bit word values. The size of the I/O register depends on the product model. See Appendix C
for CPU model information.
An I/O register address can be used as an Input or an Output. Discrete I/O register Inputs are
assigned a designator of X; discrete I/O register Outputs are assigned a designator of Y. For
example, an Input associated with discrete I/O register address 6 would be designated as X6 and
an Output associated with discrete register address 10 would be designated as Y10.
Word I/O register Inputs are assigned a designator of WX while word I/O register Outputs are
assigned a designator of WY. For example, an Input associated with word I/O register address 16
would be designated as WX16 and an Output associated with discrete register address 20 would
be designated as WY20.
The I/O register Output values represent the last value set by the user logic or by programming
software. Unless changed by user logic or programming software, the I/O register Input values
represent the value last read from the physical I/O point associated with the I/O register address.
The I/O register locations are linked to the physical I/O modules by associating the register
address with I/O points on a particular module to a range of I/O register addresses. For example,
you could assign the 8 points of a discrete Input module to X1-X8 or assign the Outputs of
analog Output module to WY9 – WY17.
Assignment of I/O register locations to physical module I/O points, which is accomplished
within the programming package, is referred to as an I/O configuration.
1.4 Control Relays
Control Relays are used for internal storage of discrete (Boolean) data. Control Relays are not
associated with the physical I/O. Control Relays can be retentive or non-retentive. Retentive
relays hold their value over a power cycle, as long as the battery is good. The number of control
relays supported varies with the controller model. See Appendix C for CPU Model information.
1.5
Status Words
Status Words are used to provide information about the controller operation. Because Status
Words can be read by user logic, they can be used to condition the operation of the controller. In
addition, the Status Words can be accessed by user programs or supervisory control software.
See Appendix D for a description of the System Status Words.
Page 4
1.6
Configuration Data
The following configuration data is maintained in the battery backed memory:
 I/O Configuration
The I/O configuration data includes the I/O Configuration, which associates the logical
I/O addresses with the physical I/O points, and the base enable status.
 Memory Configuration
The memory configuration contains the user memory allocation for each of the user
program elements listed in Section 1.2 above.
 Profibus Configuration
The Profibus configuration includes the Profibus parameter sets, which define the
characteristics of the Profibus bus and slaves; the operational parameters, and the
Profibus I/O configuration table.
 Scan Configuration
The scan configuration includes the scan type, the scan time, the task codes per scan, the
scan watchdog value, and the analog scan time slice configuration. See Chapter 2 for a
description of the CTI 2500 CPU scan.
 Password Data
The password data includes the user password, the access level, and the enable status.
1.7 Flash Memory
Non-volatile flash memory is used to store the operating firmware for the controller. The
firmware can be updated in the field. See Appendix E for more information.
1.8 High-Speed DRAM
Because the DRAM (Dynamic Random Access Memory) is significantly faster than either
battery backed memory or flash memory, it is used to execute the operating firmware, user
program instructions, I/O registers, and Control Relays.
The contents of the DRAM are lost when power is removed and must be refreshed from nonvolatile storage during controller power up start.
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Page 6
Chapter 2. PLC Scan Cycle
T
his chapter presents the concepts of the Scan Cycle processing, when certain functions
are performed in the cycle and how to customize the scan time behavior.
2.1 Scan Overview
The controller executes most tasks in a cyclical sequential order. This order is referred to as the
controller scan. There are two major divisions to the CTI 2500 controller scan; the discrete scan
and the analog scan. The discrete scan contains elements commonly found in traditional
programmable logic controllers. The analog scan provides an execution framework better suited
to process control tasks such as PID loops and analog alarms.
Discrete
Scan
Analog
Scan
Figure 2.1 Controller Scan
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2.2 Discrete Scan
The Discrete Scan consists of three tasks. These tasks always run to completion.
Normal I/O
Update
Main
RLL
SF I/O
Figure 2.2 Discrete Scan
 Normal I/O
During the Normal I/O task, I/O register Output values are transferred to the physical I/O
and new Input values are obtained from the physical I/O and written to the I/O register.
All configured I/O points are fully updated each scan.
 RLL Execution
During the Main RLL Execution task, the Relay Ladder Logic is evaluated and executed.
The I/O register is updated with values set by the RLL. Physical I/O may be read or
written during the RLL execution by using immediate I/O instructions.
 Special Function I/O
During the Special Function I/O tasks, requests from the Special Function modules
installed in the local and remote bases are processed and requests from remote base
controller communications ports are serviced.
Page 8
2.3 Analog Scan
The Analog Scan consists of tasks that may require multiple scans to complete. Included in this
scan are the Loops, Alarms, and Special Function programs as well as communications and
diagnostic functions.
Each task in the Analog Scan is allotted a time slice in which to. Except for the diagnostic task,
whose time slice is fixed, the time allocated to each task can be configured. This allows you to
optimize the controller performance for your application.
Analog
Loops
(Cyclic)
Analog
Alarms
Runtime
Diags
Cyclic
SF
Programs
Priority
SF
Programs
Normal
SF
Programs
Ladder
SF
Sub
Network
Com
Priority
Com
Normal
Com
Ladder
SF
Sub0
Figure 2.3 Analog Scan
These analog tasks are further specified in the following sections.
2.3.1 Cyclic Analog Tasks
Cyclic tasks execute on a time interval basis, based on a user-specified sample rate. Cyclic tasks
include Analog Loops, Analog Alarms, and Cyclic Special Function (SF) programs.
As illustrated in the Figure 2.3, these cyclic tasks are executed in separate time slices. Execution
is prioritized based on how close an instance of the Loop, Alarm, or SF program is to
overrunning (scheduled for another execution before the previous execution is finished). At the
beginning of the time slice, the highest priority instance is executed first. Execution continues
until the instance completes or the time slice expires. If it completes before the time slice expires,
the next highest priority instance will be executed. If the time slice expires before an instance
completes, the instance is suspended.
When there are no more instances to be executed or when the time slice expires, the controller
begins executing the next analog task. If an instance has not completed executing before it is
scheduled to execute again, an overrun flag will be set.
Special Function programs called by Loops or Alarms will be executed during the time slice of
the task which called it. Similarly, Special Function Subroutines called by Special Function
Programs or other Special Function Subroutines shall be executed during the calling program
time slice.
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2.3.2 Non-Cyclic Analog Tasks
Non-cyclic analog tasks are triggered from ladder or are otherwise event based. They include:
 Priority and Normal SF programs
These programs are queued for execution when the SFPGM RLL box receives power
flow. The processes are executed in the order in which they are queued. There is a
separate task for priority SF programs and normal SF programs.
 RLL Requested SF Subroutines
These subroutines are queued for execution when SFSUB RLL box receives power flow.
There is a separate task for SFSUB and SFSUB0 instructions requests.
 Normal Communications
This task processes deferred requests that require several scans to complete, such as
program edit operations. These requests may originate from the local serial port, USB
port, local Ethernet port, or from Special Function modules.
 Priority Communications
This task processes all requests from the serial and USB ports that can be processed in a
single scan.
 Network Communications
This task processes all requests from the local Ethernet port, except deferred requests.
 Run-time diagnostics
Run-time diagnostics are executed continuously to ensure PLC hardware is functioning
properly. The diagnostic task executes for a maximum of 1ms per scan.
NOTE:
PID Loops, Special Function Programs, and SF Subroutines called from the RLL program that are
marked for In-Line execution are executed immediately during the RLL portion of the scan
2.6
Cyclic RLL
Cyclic RLL instructions are executed on a user-specified interval. When queued for execution, it
will interrupt any other task in the discrete scan or the analog scan. See the CTI 2500
Programming Reference Manual for additional information.
2.7
PLC Scan Types
The CTI 2500 Series controller provides three scan types: Fixed Scan, Variable Scan, and
Variable Scan with Limit.
Page 10
2.7.1 Fixed Scan
When a Fixed Scan time is selected, the controller will attempt to start a new scan when the scan
time interval specified by the user expires. All tasks in the Discrete Scan will be executed once.
Then each task in the Analog Scan will be executed at least once.
If all analog tasks have been executed within the specified scan time, the controller will re-check
all communications tasks (Normal, Priority, and Network) and process any outstanding requests
until the scan time expires. If a task is processing when it is time to start a new scan, it will be
suspended until the next scan.
If there is no work to be done, the PLC will idle until it is time to start another scan. If the total
execution time of the Discrete Scan and the first execution of the Analog Scan exceeds the fixed
time, the Scan Overrun flag is set.
NOTE:
To avoid scan overruns, you must set the Fixed Scan time to a value that allows the Discrete
Scan tasks to run to completion and all Analog Scan tasks to execute at least once based on the
configured time slices.
2.7.2 Variable Scan
When Variable Scan is selected, the controller will execute all Discrete and Analog Scan tasks
once and then immediately start a new scan. All tasks are guaranteed one execution per scan.
Variable Scan provides the fastest PLC scan time and is used in most applications.
2.7.3 Variable Scan with Limit
When this option is selected, the controller shall execute the Discrete Scan once and then begin
executing Analog tasks. Each Analog task will be guaranteed execution at least once during scan.
The PLC will continue executing the Analog Scan tasks as long as there is work to be done or
the time limit has been reached. A new scan is started when all Analog tasks are completed or
the time limit expires. The scan overrun bit is set in Status Word 1 if the total execution time for
one pass through the Discrete and Analog Scan exceeds the time limit.
NOTE:
To avoid scan overruns, you must set the Time Limit to a value that allows the Discrete
Scan tasks to run to completion and all Analog Scan tasks to execute at least once based on the
configured time slices.
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2.8
Scan Modes
Normally, the execution mode of the Discrete Scan and Analog Scan are locked together. Placing
the controller in RUN mode, places both the Discrete Scan and Analog Scan in RUN mode while
placing the controller in PROGRAM mode places both scans in PROGRAM mode.
For special application needs, it is possible to set the operating mode of the Discrete Scan and
Analog Scan separately. The following sections describe the operating modes of each scan.
2.8.1 Discrete Scan Mode
Mode
PROGRAM
Description
When the Discrete Scan is in PROGRAM mode, the RLL tasks
do not execute. However, the Normal I/O and Special Function
I/O tasks continue to operate normally.
RUN
When the PLC is in RUN mode, all Discrete Scan elements are
executing.
EDIT
This sub-mode is automatically selected when you modify an
RLL program while the controller is in RUN mode.
While the controller is in EDIT mode, you can modify the RLL
source while the non-modified RLL continues to execute. When
you change to RUN mode after editing, the RLL will be
recompiled. During this time, which can take several seconds,
the I/O will be frozen at the last state. Should the compile fail,
the controller will be placed in PROGRAM mode.
Page 12
2.8.2 Analog Scan Mode
Mode
PROGRAM
Description
RUN
When the Analog Scan is in RUN mode, all analog tasks are
running and enabled control blocks are queued for execution.
HALT
When the Analog Scan is placed in HALT mode, the Loop,
Alarm and Special Function Program/Subroutine tasks will be
suspended. However, the enabled control blocks will continue to
be queued for execution.
When the analog scan mode is changed from HALT to RUN
mode, task execution will resume.
When the Analog scan is placed in PROGRAM mode, the Loop,
Alarm, and Special Function Program/Subroutine tasks do not
execute. Nothing will be queued for execution. Other analog
tasks, including communication tasks and the diagnostics task,
continue to operate normally.
THE ANALOG SCAN CANNOT BE PLACED IN PROGRAM
MODE WHILE THE DISCRETE SCAN IS IN RUN MODE.
2.8.3 Scan Locking Mode
The Discrete Scan and Analog Scan modes are automatically locked when both scan modes are
placed in PROGRAM mode. The scan modes are automatically unlocked when the Analog Scan
is placed in RUN mode while the Discrete Scan is in PROGRAM mode. You can manually lock
and unlock the scans when both scans are in RUN mode.
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Page 14
Chapter 3. 2500 Series Hardware
CTI has been supplying high-performance I/O and communications products to
the Automation Industry for over 30 years.
T
his chapter provides an overview of the types of products and modules CTI offers for the
2500 Series. These products include Power Supplies, Racks, Remote Base Controllers,
Digital, Analog, Temperature, Pulse and Communication modules.
3.1 2500 Series System Overview
Figure 3.1 CTI 2500 Series System
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2500 Se
The 2500 Series system is composed of:
 2500 Series Base
The base is the chassis where the modules are installed. It provides the back plane and
mounting for the modules. It may be a 4, 8, or 16 slot unit. A system may have 1 Local
Base and as many as 15 remote bases. The bases without the processor module are
referred to as remote bases and contain a Remote Base Controller. The base with the CPU
module is ALWAYS base number 0 (also called the “local base”). The remote bases are
numbered from 1 to 15. No duplication is allowed. No numbering order or sequence is
required. Base numbers may be skipped as desired.
 Power Supply
The Power Supply is the first module from the left and is not assigned a slot number. The
power supply provides logic power for the 2500 Series Modules. Power for field control
devices such as relays, sensors, transmitters, actuators, etc. must be provided by external
power sources.
 CPU Module
Second module from the left and also is not assigned a slot number. The CPU runs the
Control Application, manages all IO, communications, and provides memory for data
storage. All remote bases are controlled by a CPU Module.
 Input/Output Modules
Can be inserted into any of the remaining slots. Each I/O module is assigned a slot
number corresponding to their physical location. The slots are numbered starting with 1
and increasing left to right to a maximum of 16.
 Remote Base Controller
The remote base controller or RBC is used only in remote bases and is installed in the left
slot beside the Power Supply. It controls communications on the extended I/O network or
Profibus DP. It provides the direct interface between the CPU and all the IO located in its
remote base.
CTI has a wide variety of 2500 Series modules available. This discussion is focused upon a
general description of the most commonly used modules.
Many of the Siemens SIMATIC 505 modules can be replaced by CTI 2500 Series Modules. CTI
provides several aids to assist in selecting a Siemens SIMATIC 505 module replacement from
CTI. See Appendix B for a conversion chart.
Page 16
3.2 2500 Series System Components
2500 Base or Rack
The Rack contains the Power Supply, CPU or
Base Controller and all the IO modules.
The 2500 Rack comes in three models:
 2500-R4 Four Slot Rack
 2500-R8 Eight Slot Rack
 2500-R16 Sixteen Slot Rack
Power Supply
The Power Supply provides logic power. The
RED LED indicates Input power is good. All
models have a front panel fuse.
CTI offers three power supplies:
 2510 125VDC Power Supply
 2512 75-Watt Power Supply
 2515 100-Watt Power Supply
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CPU Models
The CTI 2500 Series CPUs are direct replacements for the
Siemens SIMATIC® 505 Series 545 and 555 controllers. The
front panel will vary depending on the model.
CPU GOOD –LED indicating CPU status
RUN – LED indicating CPU operation mode. When lit, CPU
is executing user program and controlling I/O.
BATTERY GOOD – LED that indicates status of battery
used for RAM back-up
3 Digit LED – Used to display IP address and Error Codes
BATTERY – User-friendly front panel access
SD FLASH CARD – Can be used for firmware update
USB – High-speed serial port for communications with PC
programming software
ETHERNET – RJ45 connector for use with TCP/IP networks
Supports 10/100Mb data rates
RS232 – Serial port compatible with ‘Port 1’ on Siemens 505
controllers. Can be used for communications with PC
programming software, HMI devices, or PRINT Output..
PROFIBUS-DP – Provides interface for CPU to serve as
Master for Profibus-DP network.
I/O –Remote I/O channel that supports up to 15 remote bases.
CTI offers four CPU models:
 2500-C100 128K CPU
 2500-C200 256K CPU
 2500-C300 512K CPU
 2500-C400 3072K CPU
Page 18
Digital Input Modules
Typically all discrete Input modules have an LED for each Input
channel. The LEDs indicate the module is detecting an active
Input signal.
Modules are selected for Input voltage/type and number of
channels. The front panels and associated wiring vary depending
on model. Refer to the model documentation for wiring
requirements.
CTI offers the following Discrete Input modules:
 2580 16pt Isolated 120VAC Input
 2581 16pt Isolated 24VDC Input
 2582 16pt Isolated 125VDC Input
 2585 16pt TTL/Word Input
 2588-8 8pt Universal Input
 2589-A 32/16/8pt Universal Input
Digital Output Modules
Typically all discrete Output modules have an LED for each Output
channel. LEDs indicate the Output signal is active in the module.
Modules are selected for Output voltage/type, and number of
channels. The front panels and associated wiring vary according to
model. Refer to the model documentation for wiring requirements.
CTI offers these Discrete Output modules:















2590-A 16pt Isolated 120VAC Output
2590-EF 16pt Isolated 120VAC Output
2591-A 16pt Isolated 24VDC Output
2591-EF 16pt Isolated 24VDC Output
2595 16pt TTL/Word Output
2596-8 8pt DC Output
2596 16/8pt DC Output
2597 32/16/8pt DC Output
2598-8 8pt AC Output
2598 16/8pt AC Output
2599 32/16/8pt AC Output
2530 8pt Form-C Relay Output
2531 32pt Form-A Relay Output
2532 16pt Form-A Relay Output
2534 8-pt Form-C Relay Output
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Analog Input Modules
Typically one LED labeled ‘Active’ or ‘Good’ is provided for
indication that the module is powered and operating as
expected. If the LED is flashing or OFF, refer to the manual for
troubleshooting information.
Model appearance will vary slightly with module type. The
modules are selected for signal level and type, and some
modules support multiple signal ranges. Wiring and power
requirements vary with module. Refer to the appropriate
manual for information.
CTI offers these Analog Input modules
 2550-A 8ch Isolated Analog Input
 2551-A 8ch Isolated Thermocouple Input
 2552-A 8ch Isolated RTD Input
 2553-A 2ch Mag Meter Input
 2554-A 4ch Isolated High Speed Counter
 2555-A 16ch Analog Input
 2556 16ch Isolated Thermocouple Input
 2557 16ch RTD Input
 2558 8ch Analog Input
 2559-RTD 8ch RTD Input
 2559-TC 8ch Thermocouple Input
Analog Output Modules
Typically one LED labeled ‘Active’ or ‘Good’ is provided for
indication that the module is powered and operating as
expected. If the LED is flashing or OFF, refer to the manual for
troubleshooting information.
Model appearance will vary slightly with module type. The
modules are selected for signal level and type, and some
modules support multiple signal ranges. Wiring and power
requirements vary with module. Refer to the appropriate
manual for information.
CTI offers these Analog Output modules
 2560-A 8ch Isolated Analog Output
 2562 8cht Analog Output
Page 20
Special Function Modules
A Special Function (SF) module has a processor and memory.
It is capable of operation without direct PLC control and
generally runs independent of the scan cycle. In many cases it
may continue to operate even if the PLC is not running.
Typically SF modules are used for PLC interface to external
communication networks. Two examples are shown: Ethernet
Adapter and Serial Interface Adapter
The 2572/2572-A Ethernet Adapters provide an interface for
the PLC to send and/or receive data from other Ethernetcapable devices. Multiple protocols are supported for
connection to other PLC manufacturers.
The 2573-MOD Serial Interface Adapter provides 4 serial ports
to exchange data with plant floor devices. Each port can be
individually configured for a specific protocol such as Modbus
ASCII, Modbus RTU, General ASCII (GAS), or 505compatible protocols. PLC logic is used to send Output
messages and process Input messages.
CTI offers the following communications modules:
 2572 Ethernet TCP/IP Adapter
 2572-A Fast Ethernet TCP/IP Adapter
 2573-MOD Serial Interface Adapter with Modbus
 2576 DeviceNet™ Scanner

2577 Profibus Slave Adapter
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Remote Base Controllers
The Remote Base Controller (RBC) allows a CTI 2500 Series
or a SIMATIC® 505 I/O base to function as a slave node on the
I/O network. This allows the PLC to control I/O points located
some distance away from the controller.
The RBC provides the following functions:
 Compatible with CTI 2500 Series and Siemens 505
controllers and bases
 LED display shows Error and Status Codes.
 Selectable station address.
CTI provides the following Remote Base Controllers:
 2500-RIO - RS-485 Remote I/O Channel
 2500-RBC - Profibus-DP network
Page 22
Chapter 4. Addressing and Memory Structure
To maximize system flexibility, performance, and functionality, the 2500 Series
architecture uses more types of system memory than most other PLCs.
T
his chapter covers the 2500 System IO addressing, how image registers are used by the
system and the different types of memory. It is very important to understand how the
system uses memory for reading and writing IO and when various functions occur during
the scan cycle.
4.1 Digital and Analog I/O Addressing
There are two basic types of Inputs and Outputs. The first type is Digital (or Discrete) Inputs and
Outputs and the second type is Analog Inputs and Outputs. Digital I/O values are generally
represented by a single bit value while Analog I/O is represented by a word value.
NOTE:
The “n” used in these discussions refers to the address offset of each I/O point for the specified
memory type. This offset value is in the range of 1 to the maximum number of I/O points supported in
the CPU model being used.
4.1.1 Digital Inputs and Outputs
Digital Inputs are designated Xn where X indicates Input and n is the address number.
Examples: X3, X57, X120.
Digital Outputs are designated Yn where Y indicates Output and n is the address number.
Examples: Y13, Y33, Y230
Digital I/O is stored as bits with a value of a 1 (ON) or 0 (OFF).
IMPORTANT:
Digital Inputs(X) and Digital Outputs(Y) share the same memory register.
For example, X1 and Y1 reference the same memory location.
Do NOT duplicate address numbers
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4.1.2 Analog Inputs and Outputs
Analog Inputs are designated WXn where WX indicates word Input and n is the Input address.
Examples: WX5, WX42, WX127
Analog Outputs are designated WYn where WY indicates word Output and n is the Output
address.
Examples: WY3, WY61, WY211
IMPORTANT:
Analog Inputs (WX) and Analog Outputs (WY) share the same memory register.
For example, WX1 and WY1 reference the same memory location.
Do NOT duplicate address numbers
4.2 I/O Concepts
The controller uses reserved memory areas called “image registers” for storage of all Discrete
and Analog Inputs and Outputs. The image registers provide a fast-access interface between the
ladder program and the field I/O modules. The discrete image resister occupies a single bit while
each entry in the word (analog) image register is 16-bits.
The controller maintains separate image registers for Digital I/O and Analog (word) I/O
modules, but the maximum number of points is dependent on the controller model as indicated
below:
Page 24
Controller Model
Discrete I/O Points
2500-C100
2500-C200
2500-C300
2500-C400
1024
2048
8192
8192
Max Analog I/O
(16-bit channels)
1024
1024
8192
8192
During the I/O period of each PLC scan cycle, the Discrete and Analog Output values stored as a
result of the last ladder program scan are transferred from the image registers to the Output
modules. Then new Discrete and Analog Input values are read from the Input modules and
transferred to the image registers. As the ladder program executes, new values for Discrete and
Analog Outputs are written to the image registers. Then the I/O update is repeated.
Write Outputs from
Image Register to Outputs
Modules
Read Inputs from Input
Modules to Image Register
Run Ladder Program, and
update Image Register values
Communications,
Diagnostics, and
Housekeeping
Run Alarms, Loop, SFP/SFS, and
update Image Register values
Figure 4.1 PLC Scan Overview
4.2.1 Discrete Image Register
The Discrete Image Register holds the status of all Digital Inputs (X) and Outputs (Y). These
values are updated during execution of the ladder program and transferred to/from field discrete
I/O modules during the normal I/O update period of each PLC scan cycle.
As an aid in debug and troubleshooting, it is possible for the user to override a Discrete I/O point
and “force” it to the ON or OFF state. When forced, the Discrete I/O point will remain in that
state until forced to the opposite state or unforced. The forced state of each Discrete I/O point is
maintained in battery-backed memory and is not affected by PLC operational mode changes
and/or power cycles as long as the controller battery is good.
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2500 Se
4.2.2 Word Image Register
The Word Image Register holds a 16-bit value of each Analog Input (WX) and Output (WY)
channel. These contents are updated during execution of the ladder program and transferred
to/from field Analog I/O modules during the normal I/O update period of each PLC scan cycle.
It is also possible for the user to override an Analog I/O point and “force” it to a specific value.
When forced, the Analog I/O word will remain at the specified value until forced to a different
value or unforced. The forced Analog I/O word is maintained in battery-backed memory and is
not affected by PLC operational mode changes and/or power cycles as long as the controller
battery is good.
4.2.3 Normal I/O Updates
The Normal I/O Update is executed at the start of each PLC scan cycle. During this period, the
value of each Discrete and Analog Output is copied from its logical address in the image register
to its physical hardware location. Then, each Discrete and Analog Input value is transferred from
the field module to its appropriate image register address. The connection between the I/O
module hardware and image register address is specified by the controller I/O Configuration.
4.2.4 Immediate I/O Updates
The Immediate I/O Update feature allows the controller to access an I/O point multiple times in a
single RLL scan. This allows a fast-changing Input value to be monitored more often than once
per PLC scan cycle and allows the system to respond faster to changes in the process. Immediate
I/O Updates are usually used in cyclic or hardware interrupt tasks to ensure the current I/O
values are used.
I/O points associated with modules located in the local base and/or Profibus-DP stations can be
accessed via Immediate I/O instructions.
Page 26
4.3
Memory Types
2500 Series memory can be broken down to 3 main types:
1. Program Memory

L (Ladder) memory

S (Special) memory
2. Data Memory

V (Variable) memory

K (Constant) memory
NOTE:
U (User) Memory and CS (Compiled Special) Memory types used in SIMATIC 505 controllers
are not utilized in CTI 2500 Series CPUs.
3. System Memory

RLL Instruction Operation

C (Control Relay) memory

I/O Image Registers

T (Temporary) memory

Status Words
4.3.1 Program Memory
Ladder Memory
Used for RLL program storage. The CPU uses L-Memory to store both source code (RLL
instructions) and compiled code used for program execution.
Special Memory
Holds configuration data for Loops and Analog Alarms as well as Special Function
programs and subroutines
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2500 Se
4.3.2 Data Memory
V-Memory
Internal memory designed for use by PLC programmer for data storage. It is wordaddressed memory that is read/write accessible as word or bit. For instance, the result of a
math operation can be stored in V-Memory. You can enter values directly into VMemory addresses.
Examples: V200, V391, V562.4, V2001
K-Memory
Internal memory used for holding constant (unchanging) data. It is word-addressed
memory that is designated as read-only by PLC program instructions. It is possible to
write values into K-Memory addresses via programming software and HMI panels.
Examples: K13, K201, K513
4.3.3 System Memory
Discrete Image Register
Memory area reserved for holding status of Digital Inputs and Outputs. This area is
accessed as individual points (or bits) via X/Y-Memory type. Input (X) addresses are
designated as read-only by PLC program instructions.
Word Image Register
Block of memory used for storage of all Word Inputs and Outputs. Data in this memory
area can be accessed as integer or bit via WX/WY-Memory type. Word-Input (WX)
addresses are designated as read-only by PLC program instructions.
Control Relays (C-Memory)
Control Relays are single-bit internal coils and do not represent actual field I/O points.
Examples: C10, C373, C1002
T-Memory
Memory that is available to each Special Function program for temporary storage. It is
word addressed memory accessible as word or bit. This memory is 64 words in length,
and the contents are not saved when the SF program has completed running. (TISOFT
users and WorkShop releases earlier than V4.5 are limited to 16 words.)
Examples: T1, T3, T9.14
Status Words
Controller memory that holds status information pertaining to the PLC operation
These status words are used to indicate error conditions (bits) and controller data (words)
such as PLC Scan time and Real-Time Clock.
Examples: STW141, STW1.1, STW9.10, STW144
Page 28
RLL Instruction Operation
Stores information for RLL instructions that operate over multiple PLC scans
Timers/Counters
Timer (TMR, TMRF)
Discrete Control Alarm Timer (DCAT)
Motor Control Alarm Timer (MCAT)
Up Counter (CTR)
Up/Down Counter (UDC)
Drums
Drum (DRUM)
Event Drum (EDRUM)
Maskable Event Drum Discrete (MDRMD)
Maskable Event Drum Word (MDRMW)
Drum Memory is used to store the following data as 16-bit integer values:
Drum Step Preset (DSP) – Starting step
Drum Step Current (DSC) – Active step (valid when Drum operating)
Drum Count Preset (DCP) – “Counts per Step” value stored in 16 consecutive words
accessed as DRUM.STEP format (i.e., DCP1.1, DCP1.16). This memory type is valid
only for EDRUM instructions.
Drum Count Current (DCC) – Current count for active step
One-Shots
One-Shot contacts ( ↑ )
Time Set (TSET)
Date Set (DSET)
Shift Registers
Bit Shift Register (SHRB)
Word Shift Register (SHRW)
Table Move Instructions
Move Word to Table (MWTT)
Move Word from Table (MWFT)
IMPORTANT:
All instructions listed on this page must contain an address number that is unique within its
instruction group. For example, you cannot enter a Timer and Counter with the same address
(i.e. TMR1 and CTR1 in the same program is invalid).
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2500 Se
Page 30
Chapter 5. Configuration and Setup
The 2500 Series has always been recognized for ease of configuration and setup. The
only requirement for PLC communications and programming is the PC-based
programming software (WorkShop) – no additional network configuration software
and special PC hardware is needed.
T
his chapter will provide instruction on how to establish communications, setup port
parameters, configure system I/O, and start using WorkShop to help with the process.
5.1 Configuration Overview
Large PLC’s are designed with communication, PLC, program, and hardware flexibility. This
requires us to configure the system, defining what it is, what it has, and how to use it. The
configuration can be broken down into three parts:
1. Communications Path
This defines how the programming device is to communicate with the PLC
2. PLC Configuration
This defines type of PLC, Memory sizes, and scan time (On-line function)
3. I/O Configuration
This defines the 4 basic characteristics of the I/O modules:
 Module type
 Module starting address
 Module size
 Special Function Module (Yes/No)
The term Special Function Module is not related to Special Function Programs and
Subroutines.
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5.2 Communications Path
Traditionally, the most common way of establishing communications between the PLC and PC
programming software has been through the RS232 serial port. The 2500 Series CPU has a
RS232 port on the front panel.
However, new communication methods such as USB and Ethernet have now surpassed serial
ports as the preferred means of connectivity. This is due to standard cabling and abundance of
commercial products that are available. All 2500 Series CPU models contain USB and Ethernet
ports on the front panel in support of these standards.
NOTE:
The USB port on the 2500 Series CPU is essentially a high-speed serial port. Therefore, the PC
Setup for USB operation is identical to the Serial Port Setup within WorkShop. However, an
additional requirement to use the USB interface is the installation of the Windows USB Driver that
is available for free download from the CTI website ( www.controltechnology.com ).
5.2.1 RS232 Port Details
The RS232 Serial Port communications requires a grounded null modem cable with pin-outs as
shown. The wiring for this port is identical to ‘Port 1’ on the front panel of Siemens 505
controllers.
Figure 5.1 RS232 Cable Pinout
Page 32
Other communication settings (such as Baud Rate and RS422 mode) are selected via 12-position
dipswitch on CPU circuit board as shown below. These switches are read only on power-up.
Figure 5.2 CPU User Switch Settings
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2500 Se
5.2.2 Communications Setup in WorkShop
The Communication Setup defines the communications path to be used when the program
applicable to the PLC is selected and displayed in WorkShop. This establishes a link between the
PLC contents and the program in the PC. This link provides display of Comments, Tag Names,
and Descriptors that are NOT stored in the PLC memory
In the WorkShop window, select File. Then click on Communications Setup and its dialog
will appear as shown in Figure 5.3.
Figure 5.3 Communications Setup Dialog
Serial Ports
Selects serial communications between the PC and CPU. Serial communications apply to
both RS232 and USB ports. The COM Port numbers refer to the ports on the PC.
Serial TIWAY
Not used with 250 Series CPUs. TIWAY is a legacy communications network from Texas
Instruments days. Most old TIWAY networks are being replaced by Ethernet networks.
TCP/IP
Selects communications via Ethernet. The 2500 Series requires an Ethernet communication
module. You will also need the PLC’s TCP/IP address. There may also be some other system
setup requirements by the Windows OS.
FMS
Not used with 2500 Series CPUs - used with Siemens Profibus FMS networks
H1
Not used with 2500 Series CPUs - used with Siemens H1 networks
Page 34
5.2.3 Serial Port Setup
When Serial Port is selected, a dialog box appears to set communications parameters.
Figure 5.4 Serial Port Setup Dialog
The default parameters are shown. These settings work in most installations. Click the OK button
to accept.
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2500 Se
5.2.4 Quick Connect Communications Setup
The Quick Connect function is used to establish a connection to a PLC without having the PLC
program selected or displayed in WorkShop. Symbols, Tag Names, and Descriptors will NOT be
available as there will be no link established between the PLC and the program data on the PC.
This is used primarily when the PLC program is not on the PC you are using.
Select Fast PLC Setup from the File menu (as shown in Figure 5.3) and the Fast PLC
Connection Setup dialog is displayed. Click the Serial Ports button, and the Serial Port Setup
dialog appears as shown in the previous section.
Figure 5.4 Fast PLC Connection Setup Dialogs
Select communications path and click OK. Only the paths you plan to use need to be configured.
You have now set both the default programming path and the Quick Connect path. These will be
saved with WorkShop, and future changes will require reconfiguring the appropriate path.
Page 36
5.3 PLC Configuration
We will create a new program and configure the PLC from the default settings.
5.3.1 PLC Type Setup
In the WorkShop File menu, click New and the PLC Type Setup dialog box appears.
Figure 5.5 PLC Type Setup Dialog
Select PLC Type and Revision (Model) from the PLC Type Setup dialog.
The Address Documentation window displays the path where this program will be saved.
The Advanced button allows saving the program to a path other than the default Workshop
Programs path.
Click OK, and the new program screen is displayed as shown in the following figure.
Figure 5.6 New PLC Program
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5.3.2 PLC Memory Configuration
In the WorkShop toolbar, select PLC Utilities / PLC Configuration and the PLC
Configuration dialog appears. This dialog box displays the default memory configuration for the
selected PLC Type.
Figure 5.7 PLC Memory Configuration
There are two columns in the Memory Configuration screen, User and System.

User

System
– Displays the amount of each instruction type is currently configured.
- Displays the amount of memory required for the specified User instructions.
Example: We have 2K of Table memory configured. Each Table instruction requires 2 words of
memory storage during execution. Therefore, the system allocates 4K of memory for
Table instructions.
If you make a change in the memory configuration the Accept button becomes active. You must
click the Accept button before closing to save the new memory configuration. Click the Close
button.
Page 38
We want to save our work. Unfortunately we cannot save while the Yellow editing indicator is
active.
Figure 5.8 WorkShop Editing Screen
Right-click on Ladder Network1, select Delete, then select Network, and click on OK.
Click YES on displayed warning message. Click on the
to accept the deletion.
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2500 Se
We can now save the PLC configuration.
Figure 5.9 Saving New PLC Program
Click File, select Save As, and name the file Configured.FSS. After you have entered the file
name click the Save button.
5.4 I/O Configuration
The program Configured.FSS should still be open. If not, open it by clicking File/Open from
the WorkShop main menu.
.
Select PLC Utilities, then select PLC Configuration The I/O Configuration dialog appears.
Figure 5.10 I/O Configuration Dialog
Page 40
There are three columns listed in the I/O Configuration dialog. These include: Base, Enabled,
and Configured. There are 16 total bases numbered from 0 to 15. Bases 1-15 are the remote
bases. We will only be working with Base 0 (or the ‘local base’) during this training class.
Move the cursor to Base 0 and click to highlight it. Then select Edit Base, and the Edit I/O
Base dialog box appears as shown below.
Figure 5.11 Edit I/O Base Dialog
We are now ready to begin the process of configuring the I/O slots.
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5.4.1 Configuring 32-Pt Digital Input Module
In our training system, Slot 1 has a 32-Point Digital Input module. From the Edit I/O Base
dialog, highlight Slot 1 and click Edit Slot. The Edit I/O Slot dialog box appears:
Figure 5.12 Edit I/O Slot Dialog
Enter the following to configure the module:
I/O Address:
Designates Starting I/O Address (Enter 1)
Num of X Bits:
Specifies number of Digital Input points for this slot (Enter 32)
All other entries can be left at their default values.
Click OK to close dialog box.
The module is now configured to use Digital I/O addresses X1 to X32. Remember Digital Inputs
use the X memory type designator.
NOTE:
The system assumes all modules support 8, 16, or 32 channels. Therefore all module starting
addresses must be a multiple of 8 plus 1.

Example: Slot 1 is (X0) +1=1. The next Digital I/O address available is 33 (used 1 –32).

(Number of Input Channels=32)+1=33.
Digital Inputs and Outputs share the same register memory. DO NOT duplicate address numbers.
Example: We have used Digital I/O addresses 1-32. Do not assign a starting address of 1, 9, 17, or
25 to another digital module whether Input or Output.
A module may have any starting address within the above constraints. Modules need not be
sequentially addressed.
Page 42
5.4.2 Configuring 32-Pt Digital Output Module
Slot 2 in the Training System contains a 32-Point Digital Output module. From the Edit I/O
Base dialog, highlight Slot 2 and click Edit Slot. The Edit I/O Slot dialog box appears:
Figure 5.13 Edit I/O Slot Dialog
Because we used Digital I/O points 1-32 for the Digital Output Module in Slot 1, this module can
use the next group of Digital I/O points 33-64.
Enter the following to configure the module:
I/O Address:
Designates Starting I/O Address (Enter 33)
Num of Y Bits:
Specifies number of Digital Output points for this slot (Enter 32)
All other entries can be left at their default values.
Click OK to close dialog box.
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Page 44
Chapter 6. Discrete RLL Programming
The 2500 Series has a unique discrete function which is the Drum Control Block. This
single instruction provides functionality that generally requires multiple networks to
duplicate in other systems.
T
his chapter covers the main aspects of Discrete RLL programming. We will use all the
common program elements. We will create a program Off Line, load them into the PLC,
run them, and monitor their operation. We will then modify the programs using On-Line
Editing. The modified programs will then be saved to the programming device.
6.1 Introduction
Applications are developed for the 2500 Series using 505 WorkShop and other legacy
development tools such as TISOFT. WorkShop is a Windows-based development tool with builtin functionality such as FT-Trend for data analysis and an optional 2500 Series Simulator for
process simulation. To obtain more information on WorkShop and related products, visit
FasTrak online at their website www.fast-soft.com .
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6.2 Opening a Program
To open a program from the WorkShop startup screen, click File in the main toolbar and then
click Open. Select Browse to locate the previously save program Configured.FSS, select it,
verify Off Line, and click the OK button to open the program.
Figure 6.1 WorkShop Startup Screen
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6.2.1 Ladder Editor
The program opens to the Ladder Editor screen as shown below:
Figure 6.2 Ladder Editor Screen
In this step we want to enable the Toolbars that are available for our editing session. In the top
menu, click View. Click Toolbars; go to Ladder Toolbars; and enable Ladder Popup Menu
and Common Elements.
Figure 6.3 Ladder Toolbars
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6.2.2 Toolbar Icons
Descriptions for WorkShop icons are shown below:
Main Toolbar Icons
Fast PLC Connect
Create a New File
Open Program
Save Current Programs
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Coil
Page 48
6.3 Insert a RLL Network
Right-click on the rung with Program End. Select Insert then press OK from the popup box.
Figure 6.4 Insert RLL Network
A Yellow bar is displayed to indicate the location where instructions can be added.
Figure 6.5 RLL Edit Screen
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6.4 Discrete Contacts and Coils
This section describes the steps for using relay logic instructions. All instructions used in this
example are located in the Relays toolbar
6.4.1 Normally Open Contact
Add a Normally Open contact to the program by selecting Relays and then click the Open
Contact
icon
.
Now place the relay in the first block of the Yellow bar against the left rail.
Left click on C1 and change it to X1.
Page 50
6.4.2 Output Coil
Add an Output to the rung by selecting Relays and then the Coil icon
.
Add the Output by placing it in the Yellow bar near the end of the rung.
Change the address of the Coil from C1 to Y33.
Click the Check Mark
in the Main Toolbar to accept changes. You can also use F8 to enter
logic. The first RLL network is now completed.
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6.4.3 Normally Closed Contact
To add another new rung to the program, right-click the rung with Program End and select
Insert and then Network as shown in the previous section.
The next rung uses a Normally Closed contact as the first instruction. Insert this rung using
Closed Contact
addressed as X1 and Coil
addressed asY34.
6.4.4 Series (AND) Contacts
Add another rung with two Normally Open contacts in series. Address the Open Contacts as
X2 and X3, and set the Output Coil address to Y35.
Page 52
6.4.5 Parallel (OR) Contacts
Add a fourth rung with two Normally Open contacts in parallel. To do this, place the first Open
Contact against the left rail and assign it to address X4. Add the second Open Contact directly
below it and set the address to X5. Now select a Vertical Branch
from the Relays toolbar
and place it next to the X4 contact. This will connect X4 and X5 contacts.
Now add an Output Coil and assign it Y36.
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6.4.6 Not Coil Output
The fifth rung includes a Vertical Branch on both Inputs and Outputs. These are added the
same as done in the previous example. Create the network shown below using X6, X7 and X8
for the Inputs. Note that a new Output instruction, the Not Coil
Outputs. Address the standard Coil asY37 and the Not Coil as Y38.
, is used for one of the
6.4.7 Logical NOT Contact
Create another rung as shown below using an Open Contact addressed as X1, a Logical NOT
Contact
Page 54
and a Coil C1.
6.4.8 Set Coil Output
Add a new rung using an Open Contact with address X1 and a Set Coil
with address C2.
6.4.9 Reset Coil Output
Add another rung using an Open Contact with address X2 and a Reset Coil
address C2.
with
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6.4.10 One Shot Contact
The last rung includes an Open Contact with address X3 in series with a One Shot
, and
both are in parallel with an Open Contact with address C3. Then another Open Contact X4
is in series with all of that to control the Output Coil with address C3.
After this last rung is completed, ensure all changes have been entered into the program by
clicking the Enter Logic
check mark icon.
6.5 Saving a Program
Then save the file by selecting File; then Save As and save the program with the name
CONTACTS.FSS. Close the Ladder Editor by clicking on the Close icon
window.
in the edit
Congratulations, you have now configured a PLC system, written a program, and saved it Off
Line. Now you will load it into a PLC, run it, and monitor the results.
Page 56
6.6 Program Download
From the main screen in WorkShop, select File; then click Open. Make sure you have a
connection between the PC (RS232, USB, or TCP/IP) and CPU.
Figure 6.6 Program Download Menus
In the Open Program dialog box, shown in Figure 6.6, you will need to make several selections.
First, select Connect to PLC and make sure that the connection listed (COM1 in our example)
matches your connection method. If not, then press Select to choose the proper connection.
Next, select Transfer Logic to PLC and click the Browse button to locate the PLC program. In
the Open dialog box, select the program CONTACTS.FSS and click Open. Click OK to accept
the selection.
If the proper PLC connection is chosen, the selected program will now transfer to the PLC and
will be displayed in On-Line mode.
6.7 Transfer PLC to RUN Mode
To switch the PLC to RUN mode, click the RUN button
Then click Yes.
in the WorkShop main toolbar.
When the PLC enters RUN mode, the button display toggles to PROGRAM
.
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6.8 Monitor Program Status
Look at the 32-point Output card and you will notice that channels 2 and 6 are ON. This is
normal. For this example we will be using the Input switches 1 thru 8 (X1–X8) and monitoring
Outputs 1 thru 6 (Y33–Y38).
Monitor the Ladder Status by selecting Diagnostics then Ladder Status from the main toolbar.
Look at the first rung of the Ladder program. Here we have an Open contact X1 (the first switch
on the Input simulator) and an Output Y33 (channel 1 on the 32-point Output module).
Turn ON the first switch on the Input simulator. X1 and Y33 are highlighted in RED indicating
power flow. Notice that channel 1 on the 32-point Output card turns ON. Turn OFF X1.
NOTE:
The ACTIVE indicators are highlighted in this manual with a gray box to show power flow on a
black and white print. Normally there are no gray boxes on the screen.
Page 58
The second rung of ladder contains a Normally Closed contact X1 and an Output Y33. In this
rung when X1 is OFF the Output is ON. Notice that channel 2 of the Output card is ON.
Turn X1 ON. Notice that channel 2 of the Output card is OFF. Turn X1 OFF.
The third rung has two Open contacts X2 and X3 in series controlling Output Y35. In order for
the Output to be on, both X2 AND X3 have to be ON. Turn ON X2 AND X3 and notice that
channel 3 comes ON. Turn OFF X2 and X3.
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In the fourth rung are two Open contacts X4 and X5 in parallel controlling Output Y36. In order
for the Output to turn ON, either X4 OR X5 have to be ON. Turn ON X4 and notice that channel
4 of the Output module comes ON. Turn X4 OFF.
Repeat operation for Rung 4 by turning ON X5 and notice that channel 4 turns ON.
Turn X5 OFF.
Page 60
The fifth rung has 3 open contacts: X8 in series with parallel contacts X6 and X7, and two
Outputs: standard Coil Output Y37 and a Not Coil Output Y38.
By turning ON X8 AND turning ON either X6 OR X7 the Outputs turn ON. Turn ON X6 AND
X8, and notice that the Output module channel 6 turns OFF and channel 5 turns ON. Turn OFF
X6 and X8.
Turn ON X7 AND X8 and notice that channel 6 turns OFF and channel 5 turns ON. Turn OFF
X7 and X8.
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Rung 6 demonstrates the Logical Not Contact. The NOT instruction inverts the power flow to
the state opposite its current state. Notice that C1 is ON even though X1 is not turned ON.
Turn ON X1 and notice that C1 turns OFF. Turn OFF X1.
Rung 7 contains a Set Coil Output. When X1 is set ON, C2 turns ON and remains ON until C2
is turned OFF by a Reset Coil instruction.
Turn X1 ON then OFF and notice that C2 remains ON.
Page 62
Rung 8 contains a Reset Coil Output with same address C2 as the Set Coil Output in Rung 7.
Since C2 is ON (via Set Coil Output in the previous rung), the Reset Coil Output is highlighted
to show the current state of the Output.
For example, if C2 is ON (or SET), both Set Coil and Reset Coil Outputs are highlighted. If C2
is OFF (or RESET), both Set Coil and Reset Coil turn OFF. Turn X2 ON then OFF and notice
that C2 turns OFF.
Rung 9 demonstrates the operation of a One Shot contact. The One Shot instruction passes
power flow for a single scan. When the Input changes from OFF to ON, the Output turns ON for
exactly one scan. After the One Shot is executed, its Input must be OFF for at least one scan
before the instruction can be executed again. When the Input is OFF, the instruction is not
executed and there is no power flow to the Output.
X4 must
be ON before turning X3 ON and because power flows to the Output for only one scan
when X3 turns ON. The C3 contact in parallel acts as a “seal-in” to keep the Output ON once it
is turned ON by X3 transition from OFF to ON. Turning X4 OFF always turns the Output OFF.
Try the following switch settings:
Turn X3 ON then X4 ON. The Output remains OFF. Turn OFF X3 and X4.
Turn X4 ON then X3 ON. The Output turns ON.
Turn X3 OFF. The Output remains ON because it is latched by C3.
Turn X4 OFF. The Output will turn OFF.
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6.9 On-Line Edit
The 2500 Series controllers support On Line changes to the program while the CPU is in RUN
mode. This is demonstrated in this section.
Go to Network 8, simply click on the line, and type address X2. Typing an address inserts a
default Open Contact.
The network is now highlighted indicating an Edit in is progress.
Click the Enter Logic
check mark to accept the logic changes. You must confirm the
transition to Run-Time Edit Mode by selecting the Yes button in the pop-up window. Clicking
the No button will discard your changes.
When the logic changes are confirmed, the CPU enters Run-Time Edit Mode. The modified
program is stored but not executed until the PLC is transferred to RUN mode. Until then, the
original program is still running.
It is possible to make additional changes while the CPU is in Run-Time Edit Mode. All edit
functions and buttons are active.
SAFETY NOTICE:
The Run-Time Edit feature should be used only when absolutely necessary. The transfer to RUN
mode causes the CPU to compile and start execution of the modified program. The compile process
can be lengthy depending on the RLL memory used. In fact, the compile time for very large programs
(> 75K of RLL memory) can exceed 500msec.This can cause Remote Base Controllers to timeout and
possibly “bump” Outputs that could result in damage to process, machinery, and personnel.
Exit the On Line connection by selecting the Close icon
is no reason to Save the program changes.
Page 64
on the Ladder Editor screen. There
6.10 Timer and Compare Instructions
This section demonstrates operation of the Timer and Compare instructions.
6.10.1 Motor Control or ON/OFF Station Example
M1
Conv1
Conv2
M2
SS1
SS2
Figure 6.7 Motor Control Example
We have two conveyors. The logic for Conveyor1 is:
1. Conv2 must be running (SS2 closed).
2. Conv1 Overload is not tripped.
Signals
Conv1Stop
Conv1Start
Conv1OVLD
Conv1SS
Conv2SS
Conv1Run
Address
X1
X2
X3
X4
X5
Y33
Field Device
Normally Open Switch
Normally Closed Overload Contact
Open CONFIGURED.FSS program Off Line. Add RLL network as shown below.
Save As – CONVEYORS.FSS
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6.10.2 Creating Tag Names and Descriptors
Tag Names are interchangeable with the addresses, i.e. If X52 has been assigned Tag START
you may type either X52 or START when writing ladder instructions. Descriptors are tied to the
address but are not interchangeable. Descriptors are used to hold the synonyms imported from a
converted TISOFT program. If your program is converted from TISOFT, you should continue to
use only Descriptors since using both Tags and Descriptors takes up a lot of space on the screen.
A new program written in WorkShop should use only Tag Names.
Figure 6.8 Documentation Editor Icon
There are two ways to access the Documentation Editor for creating Tags and Descriptors:

The first is directly from the main toolbar. Click the Documentation button (see pointer
in Figure 6.8) or click View in the main toolbar and then select Documentation.
Fill in the information and click OK. Documentation data can also be imported into
WorkShop.
Figure 6.9 Documentation Editor
Page 66

The second way to access the Documentation Editor is to right-click on an address in the
ladder (or CTRL+L) and then selects Modify Address Doc.
Figure 6.10 Documentation Editor Access from RLL
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Addresses, Tag Names, and Descriptors can be switched ON/OFF by selecting Options; then
Program Setup from the main toolbar.
Figure 6.10 Program Setup Dialog
Select Show Addresses and Show Tags.
Using the names for our example in Figure 6.7, enter Tag Names for X1, X2, X3, and X5. The
Ladder Editor will now display both Tags and Addresses.
Save
the program as CONVEYORS.FSS.
Close the Ladder Editor screen by clicking the Close icon
Page 68
.
6.10.3 Integer Number Format
Timers and Counters hold their Preset Values (TCP) and Current Values (TCC) as signed
integers. This section describes the representation of signed integer values used by the Timers
and Counters.
Integers are whole numbers with no fractions and no decimal values.
Signed integers are stored as 16-bit words in the two’s complement format as shown. The 16-bit
format allows you to store values ranging from –32,768 to +32,767 (decimal integer values).
When bit 1 (the sign bit) is 0, the number is positive; when bit 1 is 1, the number is negative.
Most
Significant
bit
Sign
bit
Bit
#
Least
significant
bit
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
0
0
0
1
1
1
0
0
1
0
1
0
0
1
0
1
0
0
1
0
1
0
0
1
0
1
0
0
1
0
1
0
0
1
0
1
0
0
1
0
1
0
0
1
0
1
0
0
1
0
1
0
0
1
0
1
0
0
1
0
1
0
0
1
0
1
0
0
1
0
1
0
0
1
0
1
1
0
1
0
+32767
+1
00000
-1
-32768
Figure 6.11 Integer Number Format
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6.10.4 Timer Operation
The Timer instruction creates a time period. This is an “On Delay” Timer, meaning the Output
turns ON when the timer value reaches zero. There are two Timers - a fast Timer (TMRF) and a
standard Timer (TMR). A fast Timer counts in 1msec. increments, while the standard Timer
counts in 0.1 sec. increments.
Figure 6.12 Timer Instruction
WARNING:
Timer and Counter instructions use the same memory. DO NOT duplicate instruction numbers
between Timers and Counters.
The Timer times down from the Preset value (00000 to 32767) to 00000.
TCPn – holds the Preset time (as integer value)
TCCn – holds the remaining Current time (as integer value)
Enable
ON - Timer enabled
Enable
OFF – Timer disabled and sets TCC = TCP
Run
Input ON and Enable ON - Timer runs. It starts at TCP and times down to zero.
Run Input OFF and Enable ON - the Timer stops; TCC remains at the Current
If Run Input turns ON again, the Timer starts timing again from that point.
Output
value (retentive).
- turns on when remaining time (TCC) is zero.
TCP and TCC addresses are selectable as Read/Write (Unprotected) or Read-only (Protected).
The Current value is retained on power loss if the Enable is ON.
Page 70
6.10.5 Creating Timers
This section describes how to build and operate On-Delay, Off-Delay, and Pulse Timers having
Retentive and Non-Retentive values.
Open the
program CONFIGURED.FSS. Add the following logic:
Figure 6.13 Timer Examples
Save as - TIMERS.FSS.
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Download the program to the PLC by selecting File; then select Transfer-On Line; Connect to
PLC; and Transfer Logic to PLC. Run and monitor the program.
Turn the Inputs ON and OFF watching how the Timers run.
Use On Line Edit to change the Enable Inputs to the addresses shown in network headers
Run
and monitor the program. Turn the signals ON and OFF watching how the Timers operate.
Leave the program running. We will use it for the Compare example.
6.10.6 Compare Operation
The 2500 Series PLC includes the following Compare instructions:

Equal To (EQU)

Not Equal To (NEQ)

Less Than (LESS)

Less Than or Equal To (LEQ)

Greater Than (GTR)

Great Than or Equal To (GEQ)

Compare (CMP)

Indexed Matrix Compare (IMC)

Scan Matrix Compare (SMC)
We will use the Greater Than instruction for an example.
Page 72
Click the New Network button. Then click anywhere in Network 2. The New Network is
inserted above the rung you selected.
Figure 6.14 Creating New Network
Add the logic shown below to the new network:
Figure 6.15 Compare Instruction
Run the
program and watch the operation of the Compare (GTR) instruction.
As long as TCC1 is greater than 50 (100 down to 51) and X1 is active, the Output is ON. You
have created a 5 sec Pulse Timer.
Save the
program and close the Ladder Editor screen.
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6.10.7 Timer and Pulse Timer Application
We are now going to add a starting alarm horn to our CONVEYOR program. This horn will
blow for 5 seconds before the conveyor is allowed to start.
Open the program
CONVEYOR.FSS and add the following logic:
Figure 6.16 Starting Alarm Horn Logic
Save
the program. Download the program to the PLC and transfer to Run mode.
Monitor and operate the conveyor system. Y34 should be ON for 5 sec. Then Y34 turns OFF
and Y33 turns ON running the conveyor. Any of the CONV1STOP, CONV1OVLD, or
CONV2SS switches can shut down the system.
NOTE:
The One-Shot instruction was added to the start circuit to simulate a momentary contact switch.
Page 74
We will add another interlock to detect a broken belt while Conveyor1 is running. Unfortunately
this will prevent ever starting the conveyor, so we need to add a timed bypass contact around it.
The Bypass Timer should allow 5 seconds for Alarm Horn plus 3 seconds of Acceleration time
(8 seconds total).
Add CONV1SS (X4) and Bypass Timer contact (C11) into the control circuit as shown in the
following figure. Then add the Bypass Timer shown in Network 4.
Figure 6.17 Conveyor Interlocks
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6.11 Counter Instructions
There are two types of Counters in the instruction set, Up Counter and Up/Down Counter..
WARNING:
Timer and Counter instructions use the same memory. DO NOT duplicate instruction numbers
between Timers and Counters.
6.11.1 Up Counter
The Up Counter counts incoming pulses and increments its count by one for each pulse. The
Output turns ON when the Current Count (TCC) equals the Preset value (0-32767).
Figure 6.18 Up Counter
Enable
ON – the Counter Current value increments on the positive edge of the Signal Input
Enable
OFF – the Counter is reset to zero and Counter is disabled
Output
ON – when Current (TCC) value equals Count Preset TCP)
TCPn – holds the Counter Preset value
TCCn – holds the Counter Current value
The Counter Current value is retained on power loss if the Enable is ON.
Page 76
6.11.2 Up/Down Counter
The Up/Down Counter maintains a count value based on pulses from two incoming signals. It
counts up or down on the positive transition (edge trigger) of the Input signals. The Output turns
ON when the Current (TCC) value equals zero or the Preset value (0-32767).
Figure 6.19 Up/Down Counter
Enable ON – TCC increments on positive edge of Up Signal and decrements on the
edge of Down Signal. The Counter does not count above the TCP or below zero.
Enable OFF –
Z (zero
positive
TCC is reset to zero and Counter is disabled
bit) - turns ON when TCC equals zero and Enable ON
Output –
turns “ON” when TCC equals zero or TCP.
TCPn – holds the Counter Preset value
TCCn – holds the Counter Current value
The Current Count is retained on power loss if the Enable is ON.
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We will write a new program to show the operation of Counters. We will start from the
beginning to practice configuration.
From the Workshop main toolbar click File; then New; and select your PLC Type and
Revision. Now select PLC Utilities and PLC Configuration and verify the Memory
Configuration is correct.
Next, click 505 I/O and select Base 0. Click Edit Base and go through the process of
configuring I/O for each module in your system (as shown in Section 5.4). Then press the
Accept button and close the configuration screens
Create the program as shown in the following figure.
Figure 6.20 Logic Showing Operation of Counters
Save the program by selecting File, then Save As - COUNTERS.FSS.
Now Download the program down to the PLC (as shown in Section 6.4). Select File, then
Transfer → Online. Select Connect to PLC and Transfer Logic to PLC. Click OK.
When the download is complete, put the PLC in Run mode using the Workshop toolbar Run
icon. Then select Diagnostics and Ladder Status to monitor the PLC program operation.
Note the following operation for both Counters:

Signal pulses are detected only on OFF to ON transition.

If the Enable Input is OFF, the Counter is disabled and TCC is set equal to TCP.
Page 78
The Up/Down Counter has two Outputs. The instruction box Output (Y34) turns ON when
Current Count (TCC) equals zero or Preset (TCP). The Z bit address specified inside the
instruction box turns ON only when TCC equals zero.
If you would like Y34 active only when TCC = TCP, edit Network 2 to insert Normally Closed
contact C10 as shown in the following figure:
Figure 6.21 Logic for UDC Instruction Output
6.11.3 Counter Application
There is a 10-car parking garage. We want the FULL indicator (Y33) to come ON when the
garage is full. Incoming cars generate X3 (Up Count) and outgoing cars generate X4 (Down
Count). Input X5 will be the Counter Enable signal.
10 Car Parking Garage
Pay Booth
X4
Ticket Gate
X3
Figure 6.22 UDC Application Example
If you delete Network 1 from the COUNTERS.FSS program, the remaining logic performs our
application to count cars in and out and turn ON the FULL light when the garage is full.
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6.12 Move Word and Date Compare Instructions
Unfortunately, due to irregularities in the hardware that generates the input signals, we can never
guarantee that our count is always correct. Therefore, we need a way to manually enter a count
value into the Counter.
We provide thumbwheel switches and a key-locked Load button. Pressing the button (X1) will
transfer the thumbwheel value to memory location V100. We will simulate the thumbwheel
switches by entering the number into V100 and use the Move Word instruction to move the
contents of V100 into TCC2.
6.12.1 Move Word Description
The Move Word instruction copies up to 256 contiguous words from one memory location to
another. The starting memory location for the words to be moved is specified by parameter A,
and the starting memory location for their destination is specified by parameter B. All words are
copied in a single scan.
Enable
Status
Figure 6.23 Move Word Instruction
Enable
ON – Moves a constant or block of contiguous addresses (block size specified by N)
starting at address A to a block of contiguous addresses starting at address B. Output Status turns
ON at completion of every successful operation.
Enable
OFF – Instruction is disabled and Output Status turns OFF.
A – Starting Address for data to be moved (or copied) or integer constant. If a constant is
entered, that value is copied into each Destination address.
B – Starting Address for destination when data is copied
N – Number of words to copy (1-256)
Page 80
6.12.2 Move Word Application
Enter new Network 2 as shown below:
Figure 6.24 MOVW Example
Use the Data Window to monitor or enter values in any address in the PLC. It is particularly
useful when working with analog values.
Figure 6.25 Data Window Icon in Main Toolbar
Activate the Data Window by clicking on the Data Window icon as shown by the arrow in
Figure 6.25.
Figure 6.26 Data Window
Enter the address (V100) and value (6). Notice that WorkShop assigns a Data Type of Unsigned
Decimal (Integer). It can be changed when needed - right click in Value cell, select Format, and
select Data Type desired. The value is placed in V100 as soon as you enter it in the cell. This is
NOT a force. The system can change the value entered based the program logic.
Run the
program and monitor results.
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Enter different values into V100. Use X1 to move V100 into TCC2.
6.12.3 Date Compare Description
The Date Compare instruction compares the current date in the PLC internal clock registers to
the date values in a memory mask.
Enable
Status
Figure 6.27 Date Compare Instruction
Enable
ON – Compare the current date in the PLC internal clock registers to the Date mask.
When the values match, the Output Status turns ON.
Enable
DATE – Starting Address of Date Mask (uses 4 consecutive V-memory words)
Word 1: Year (BCD values 0000-0099)
Word 2: Month (BCD values 0001-0012)
Word 3: Day of Month (BCD values 0001-0031)
Word 4: Day of Week (BCD values 0001-0007)
Mask is a term for fixed data used as a reference for comparison against other changing data.
Date values can be entered and/or viewed in Data Window using the Hexadecimal data format.
Fields in the Date mask can be ignored by compare operation by entering a value of 00FF Hex
into the appropriate word. This value causes the Date Compare instruction to automatically
match” that parameter.
Page 82
6.12.4 Data Representation
The following chart shows equivalent values for Hexadecimal, Binary, Decimal, and BCD
values:
Hex
0
1
2
3
4
5
6
7
8
9
A
B
C
D
E
F
Bin.
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
Dec.
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
BCD
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
Hexadecimal format:
Hex
7
F
B
3
Binary
0
1
1
1
1
1
1
1
1
0
1
1
0
0
1
1
Bit No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Binary Coded Decimal format:
BCD
7
9
5
3
Binary
0
1
1
1
1
0
0
1
0
1
0
1
0
0
1
1
Bit No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Figure 6.28 Data Representation
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6.12.5 Date Compare Application
We want a totalizer to count the number of cars that paid to use the garage over the year. At year
end we will use this for accounting purposes. An Up Counter on the pay booth (X3) will
provide this. Since we would like to be able to read and reset the totalizer at the beginning of
each year, we will use the Date Compare instruction to detect the “start of a new year”, store
the total count from the previous year, and reset the totalizer count to zero
We must determine how to specify the event that triggers the Date Compare instruction to run.
Because we are interested in an entire year of data, the first of January will work for us.
The Date Mask will be located in V102, V103, V104, and V105.

V102 = 00FF Don’t care about Year

V103 = 0001 Compare to Month 1 (January)

V104 = 00FF Don’t care about Day of Month

V105 = 00FF Don’t care about Day of Week.

V106
Storage of year’s totalizer value
The Date Compare instruction internally uses a One-Shot contact so that it only executes once
when the Input transitions from OFF to ON.
WARNING:
You must not duplicate the address used for the Date Compare instruction with any other OneShot or Time Compare instructions.
Enter values via the Data Window. Remember to format the values as Hexadecimal.
Figure 6.29 Date Compare ‘Date Mask’ values
Page 84
Modify the program as shown below.
Figure 6.30 DCMP Application Example
Place the PLC in Run mode.
From the WorkShop main window, set the PLC Real-time Clock. Select PLC Utilities; PLC
Configuration; PLC Date/Time; and then click Set.
Set the Date to 12/31 and Time to 23:59:00.
You now have 1 minute to return to the Ladder Editor and monitor the program. At midnight,
the Totalizer count TCC1 will be moved to V106 and then it will reset to 0.
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6.13 Event Drum and Load Data Constant Instructions
This section describes the operation of the Event Drum and Load Data Constant instructions.
6.13.1 Load Data Constant Description
The Load Data Constant instruction puts a positive integer specified as parameter N into the
address specified at parameter A.
Figure 6.31 Load Data Constant Instruction
Enable
ON – Moves a positive integer (N) into memory address (A). Output Status turns ON at
completion of every successful operation.
Enable
A – Destination Address receiving integer constant; can be any writeable address
N – Positive integer (0-32767)
Page 86
6.13.2 Event Drum Description
There are two types of Drum instructions: DRUM and EDRUM. They replace other functions
known as Sequencer, Drum Switch, Time Drum, and other names. These instructions are used
for batch and repetitive processes. The DRUM instruction is time-driven and the EDRUM is both
time and event driven. We will use the EDRUM as it covers everything in the DRUM as well.
We will develop two examples: a Filter System and a Batch Paint Mixer.
The Time/Event Drum instruction (or EDRUM) moves through the programmed steps under
control of Time, Events, or both. The JOG Input forces the move to the next step on positive
edge trigger. The Drum-Controlled Coils are set to the values in the Drum Mask for the active
Drum Step.
Start
N
Jog
Drum-Controlled Coils
STEP
EVENT
COUNTS
Drum MASK
Status
USEN
ABLE
Enable
Figure 6.32 Event Drum Instruction
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INPUTS
FORMAT
DESCRIPTION
START
Binary
ON = Drum advances based on Timer/Event
OFF = Drum holds state. Event ignored.
JOG
Binary
Moves Drum to next step on positive edge trigger.
ENABLE
Binary
ON = Drum enabled
OFF = Drum reset. Moves to Preset Step
INTERNAL
FORMAT
DESCRIPTION
Instruction #
Number
Must be unique for each DRUM instruction
(includes DRUM, EDRUM, MDRMD, and
MDRMW instructions)
PRESET
Number 1-16
Specifies step the Drum goes to when Enable is
OFF (Reset).
SECS/CNT
Positive integer
0-32767
COUNTS
Positive integer
0-32767
EVENT
X, Y or C contact
Time base for Drum operation (0 – 32767)
Corresponds to .001 to 32.767 seconds.
Time-base multiplier for each step.
Time interval for each step calculated as:
COUNTS * SECS/CNT
Counts down to zero before advancing.
Controls the Step Timer.
ON = Step Timer counts down
OFF = Step Timer stops and retains current value.
CONTROLLED
COILS
Y or C coils
Memory addresses controlled by EDRUM
MASK
0 or 1 (OFF, ON)
Specifies Coil states for each Drum Step
OUTPUTS
FORMAT
DESCRIPTION
STATUS
Y or C coils
ON at the completion of the last programmed step
until Drum instruction is reset.
IMPORTANT NOTES:
The Drum-Controlled Coils ALWAYS follow the states set in the Coil Mask for the Current Step
even if the Drum is disabled (Enabled = OFF).
Your Drum must include a Step (usually the Preset Step) that puts all Drum-Controlled Coils in
safe states that will not affect the process when the Drum is disabled.
Page 88
Drum Variables:
ADDRESS
NAME
DESCRIPTION
DSPn
Drum Step Preset
DSCn
Drum Step Current
Holds the Step number the Drum is set to when
Enable OFF (reset)
Holds the active Step number.
DCPn.s
Drum Count Preset
Holds the programmed Count value for each Step.
Step numbers = 1 to 16
DCCn
Drum Count Current
Holds the Current Count value for active Step
n = Drum number; s = Step number
Time Interval Calculation using Counts/Step (CNT)
Time duration of a step is determined by Counts/Step (CNT) value.
Time Interval = SEC/CNT * CNT/STP
where: SEC/CNT is the time base for the Drum
CNT/STP is the time-base multiplier for the step
Example 1:
SEC/CNT is set to 100 msec (0.100 sec) and CNT/STP = 25
Time Interval = 0.100 * 25 = 2.5 seconds
Example 2:
SEC/CNT is set to 0 and CNT/STP = 10
When SEC/CNT = 0, time-base = 1 PLC scan-time
Time Interval = 10 scans
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We will build a simple EDRUM program to control two filters. Below is a block diagram of the
application:
F1 Online
F2 Backwash
F1 Online
F2 Standby
5 sec
10 sec
Y33
Y35
F1Backwash
F2 Online
F1 Standby
F2 Online
5 sec
10 sec
Y36
Filter
1
Y34
Y40
Y37
Black – Filtered flow
Red – Backwash flow
Filter
2
Y39
Y38
Figure 6.33 Filters Application Diagram
Page 90
Refer to Section 6.2, Open program CONFIGURED.FSS and add the following logic program
to create the Filters application:
Figure 6.33 Filters Application Logic
Save As
– FILTERS.FSS
Using the steps in Section 6.4 - Download, Run, and Monitor the program
Note the ‘ALWAYS ON’ contact (C10) created in Network 1. This contact is used as the Run
input to the DRUM so that it runs continuously.
Note that C11 is used as Enable Input and Status Output so that the DRUM resets
immediately when it completes a cycle.
Toggle the Jog Input (X1) ON/OFF and note the DRUM operation.
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6.13.3 EDRUM and LDC Application
Below is a block diagram for a Batch Paint Mixing process:
Red Y34
Base Y33
Blue Y35
Solvent Y36
LSH X1
Mixer Y39
LSL X2
Packing Y37
Drain Y38
Figure 6.34 Batch Paint Mixer Application Diagram
Additional signals:
 X3 – Start Batch
 X4 – Color: Red = 0, Blue = 1
 X5 – Jog
 C10 – Batch Run
 C11 – Batch Done
 C13 and C14 - dummy coils
Page 92
Refer to Section 6.2, Open program CONFIGURED.FSS and add the following logic program
to create the Batch Paint Mixer application:
Page 93
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Figure 6.35 Batch Paint Mixer Application Logic
Save As
– PAINT.FSS
Refer to Section 6.4 - Download, Run, and Monitor the program.
Page 94
Run the process steps listed below for both Red and Blue paint colors:
1) Batch not running – Drain (Y38) ON
2) Toggle Start Batch (X3) ON/OFF
3) Load Base to LSH1 (X1), then Mixer (Y39) ON
4) If Red (X4 = 0), add Red tint (Y34) for 5 sec., Mixer (Y39) ON and skip Blue
5) If Blue (X4=1), skip Red, add Blue tint (Y35) for 3 sec, Mixer (Y39) ON
6) Mixer (Y39) for 10 sec
7) Send to Packing (Y37) until LSL (X2), Mixer (Y39) ON
8) Load Solvent (Y36) to LSH (X1) plus 7 sec, Mixer (Y39) ON
9) Send Solvent to Drain (Y38) to LSL (X2) plus 5 sec, Mixer (Y39) ON
10) Return to Step 1 and stop
Note that Event C10 in DRUM Step 1 is used to hold the DRUM in the Reset Step until a new
batch is started. Similar logic is required for all Drums that run intermittently.
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6.14 Shift Registers
This section describes the operation of the Bit Shift Register and Word Shift Register
instructions.
6.14.1 Bit Shift Register Description
The Bit Shift Register instruction can be used to load, shift, and unload bit values based on a
Clock input leading-edge trigger.
Clock
K
Data-Out
Data-In
Enable
Figure 6.36 Bit Shift Register Instruction
Enable
OFF – Shift Register disabled and all bits are cleared including the Data_Out bit.
Enable ON – Shift Register operates.
Clock
ON – The state of Data_In bit (OFF or ON) is written into the first position of the Shift
Register on the clock positive-going edge. All bits in the Shift Register are moved down one
position. The last bit is moved to Data_Out.
Page 96
INPUTS
FORMAT
DESCRIPTION
CLOCK
Binary
Clock detected as OFF-to-ON transition.
State of Data In moved into first position in Shift
Register. All bits shifted one position.
DATA_IN
Binary
Bit state moved into first position of Shift Register
when Clock changes OFF-to-ON
ENABLE
Binary
ON = Shift Register enabled
OFF = SHRB disabled. All other inputs ignored.
INTERNAL
FORMAT
DESCRIPTION
Instruction #
Number
Must be unique for each Shift Register instruction
(includes SHRW and other SHRB instructions)
IR
C or Y
Starting bit address of Shift Register
N
Positive integer
1-1023
Length of Shift Register (in bits)
OUTPUTS
FORMAT
DESCRIPTION
DATA_OUT
Binary
Set to state (OFF or ON) of the last bit expelled
from Shift Register
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6.14.2 Bit Shift Register Application
We have a requirement to track parts attached to carriers as they move down a production line.
Below is a block diagram for the application:
Pos 1
Pos 2
Pos 3
Pos 4
Pos 5
C51 =1
C52 =0
C53 =1
C54 =1
C55 =1
Pos 6
C56 =1
Figure 6.37 Production Line Application Diagram
Description of line operation:

There are two proximity switches at Position #1.
X1 reads the presence of a carrier (Clock input)
X2 reads the presence of a part (Data_In input)

If part is detected at Pos #2 (C52), spray 3 sec of primer

If part is detected at Pos #3 (C53) spray 3 sec of paint

Use 6-bit Shift Register located at C51 - C56.
Other signals:

Page 98
X3 –
Enable/Reset
We need to build a new program for this application. Select the PLC Type and Configure I/O as
done in Chapter 5. When complete, go to the Ladder Editor and enter the logic as shown below
and on the next page:
Page 99
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Figure 6.38 Production Line Application Program
Save As
– PRODLINE.FSS
Refer to Section 6.4 - Download, Run, and Monitor the program.
Note the Shift Register operation:
When a carrier is detected (X1 OFF-to-ON):
1) State of part (X2) is shifted into the first Shift Register position. This bit value moves
down the register each time X1 detects a new carrier.
2) In Networks 2-3, 3 sec Timer for primer runs if C2 ON (when bit position #2 (C52)
set ON in register).
3) In Networks 4-5, 3 sec Timer for paint runs if C3 ON (when bit position #3 (C53) set
ON in register).
Page 100
6.14.3 Word Shift Register Description
The Word Shift Register instruction can be used to load, shift, and unload word values based
on a Clock input leading-edge trigger.
Clock
K
Status
Enable
Reset
Figure 6.39 Word Shift Register Instruction
Reset
OFF – Register contents are cleared and Status Output set OFF.
Reset ON and Enable
Status Output is OFF.
OFF – Shift Register disabled, Register contents retain values, and
Reset
ON and Enable ON – The data in address (A) is read into the Shift Register on leading
edge (OFF-to-ON) of the Clock signal. All other data in the Shift Register is moved down one
address position. Oldest data (at position N) is shifted out. Status Output turns ON for one scan
on each successful operation into the Shift Register.
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INPUTS
FORMAT
DESCRIPTION
CLOCK
Binary
Clock detected as OFF-to-ON transition.
Data in Address A moved into start of Shift Register
(Address B). All register data moved down one
position. Oldest data shifted out of Shift Register.
ENABLE
Binary
ON = Shift Register enabled
OFF = SHRW disabled. All register data retained..
RESET
Binary
ON = Shift Register activated
OFF = SHRW reset. All register data cleared.
INTERNAL
FORMAT
DESCRIPTION
Instruction #
Number
Must be unique for each Shift Register instruction
(includes SHRB and other SHRW instructions)
A
V-Memory
Address of data to be moved into the Shift Register
B
V-Memory
Starting address of the Shift Register
N
Positive integer
1-1023
Length of Shift Register (in words)
OUTPUTS
FORMAT
DESCRIPTION
STATUS
Binary
Turns ON for one scan at the completion of every
successful shift operation.
Page 102
6.14.4 Word Shift Register Application
Perform On-Line Edit to modify the existing program in PLC to create the logic as shown below
(program logic spans 3 pages).
NOTE:
Remember to assign unique Instruction numbers to One-Shots, Timers, and Shift
Registers. Go to RUN mode after completing Run-time Edit changes.
Page 103
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Page 104
Figure 6.40 Word Shift Register Application
Save As
– SHIFTREG.FSS
Page 105
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Select the Data Window icon from the main toolbar and build this chart:
Figure 6.41 ShiftReg Application Data Window
Run
the program, and watch the values move through the Bit and Word Shift Registers.
Save
the Data Template:
Select Data on main toolbar; click Save Template, name it SHIFTREG, and then Save
Close the Data Window.
Verify Data Template was saved:
Open
new Data Window.
Select Data on main toolbar; click Load Template, select SHIFTREG, and then Open
Your saved template should now be open.
Page 106
Chapter 7. PLC Program Control
his chapter will present the concept of Control Flow – techniques used to modify
program execution so that the RLL instructions are not forced to run in sequence from top
to bottom – and the effect this has on the PLC scan cycle.
T
7.1 Program Structure
Program control instructions allow movement within the program. There are basically three
types of program structure:
1) Linear – the program runs from top to bottom, running all the logic.
2) Partitioned or Semi-Structured – The program runs from top to bottom jumping over
selected portions (or partitions) of the program.
3) Structured – Each function is in a subroutine called from the ‘Kernel’ program.
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Partitioned Programming Example:
The following flow chart shows a packaging machine that packs either 6 items or 12 items
depending on a switch position. The switch controls which program section gets executed.
No
6 Pack?
Yes
Jump
6 pack control
logic
12 Pack?
No
Yes
Jump
12 pack control
logic
Figure 7.1 Partitioned Programming Example
Advantages:
1) Eliminates complicated control and enabling/disabling logic.
2) Could possibly reduce scan time depending on technique used to “jump” over unused
logic. Options are described later in this chapter.
Page 108
Structured Programming Example
The following flow chart shows the logic for the same packaging machine using a Kernel (shown
in Red) with a separate subroutine for each function.
Yes
6 Pack?
6-Pack
Subroutine
No
Yes
12 Pack?
12-Pack
Subroutine
No
Figure 7.2 Structured Programming Example
Advantages:
1) Removes the need for complicated control and enabling/disabling logic.
2) Places each function in its own code section (subroutine).
3) Breaks the program into logical blocks for easier programming.
4) Troubleshooting is easier because only the subroutine needs to be monitored to verify
machine operation. Eliminates the need to search through a long logic program.
5) Decreases scan time.
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7.2 END Instruction
Up to this point, we have been lazy by ignoring the END command. Good programming
procedure includes an END instruction to indicate the end of program logic to be executed as part
of the main RLL program. If no END is found, the PLC completes the RLL scan when it reaches
the end of configured Ladder memory.
There are 2 forms of the END command:
 Unconditional
 Conditional
If a contact is inserted in the network, the END instruction automatically becomes a Conditional
End (ENDC). This will terminate the main RLL program if the condition is TRUE.
If the END instruction is placed on a network with no inputs, it is treated as an Unconditional
End (END) and serves as the terminator for the main RLL program..
Figure 7.3 END Instruction Examples
NOTE:
If using subroutines as described in the Structured Programming Example, they must be
located after the END command to prevent them being run as part of the normal (Kernel)
program.
Page 110
7.3 Master Control Relay (MCR)
This section describes the operation of the Master Control Relay instruction.
7.3.1 MCR Description
The Master Control Relay acts as a software “Emergency Stop” switch to conditionally turn OFF
the Outputs within its Control Zone. When power flow to MCR is lost, it clears all Output coils
between the MCR and the MCR End (MCRE) instructions.
Control Zone
Figure 7.4 MCR Instructions
Power flow ON to MCR – the MCR is disabled and all Outputs work normally.
Power flow OFF to MCR – the MCR turns OFF all Outputs coils in its Control Zone.
WARNING:
Do not use the MCR to replace hard-wired Emergency Shutdowns or Personnel
Protection devices as it requires the PLC system to be fully functional to operate.
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7.3.2 MCR Application
Open program
CONFIGURED.FSS and build the following program:
Figure 7.5 MCR Application
Refer to Sections 6.4-6.5 to Download, Run, and Monitor the program
Turn X2 ON and X1 ON. Watch the logic operation.
Turn X1 OFF. Watch the logic operation.
Turn X2 OFF - wait several seconds; turn X2 ON; wait several seconds; repeat
Note the Timer1 still runs although its Output is disabled.
Page 112
7.4 Jump to Jump-End
This section describes the operation of the Jump instruction.
7.4.1 Jump Description
The Jump instruction ignores the Output coils within its Control Zone (between JMP and JMPE
instructions). This instruction allows Outputs to be duplicated with the RLL program and
updated only when specific input conditions are present.
Control zone
Figure 7.6 JMP Instruction
Power flow ON to JMP – the Jump is disabled. All logic and Outputs within the Control Zone
run normally.
Power flow OFF to JMP – the Jump operates. The Control Zone logic runs normally, but all
Outputs are not updated and are held in previous state.
NOTE:
The JMP instruction is overridden if located within a MCR Control Zone. When the
MCR instruction loses power flow, the Outputs in the JMP zone are turned OFF
regardless of the JMP state.
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7.4.2 Jump Application
Add these networks thru On-Line Edit to the MCR Application created in the last section.
Figure 7.7 JMP Application
Run
and Monitor the program
Observe the operation of Outputs in the JMP Control Zone with X4 ON and X4 OFF.
Page 114
7.5 Skip-to-Label
This section describes the operation of the Skip-to-Label instructions.
7.5.1 Skip-to-Label Description
The Skip-to-Label instructions are similar to the JMP instruction except it ignores BOTH logic
and Output coils within its Control Zone. These instructions allow Outputs to be duplicated and
controlled by different logic sections within an RLL program.
Control zone
Figure 7.8 SKP-to-LBL Instructions
Power flow OFF to SKP – the Skip-to-Label is disabled. All logic and Outputs within the
Control Zone operate normally.
Power flow ON to SKP – the Skip-to-Label operates. All logic and Outputs within the Control
Zone are bypassed and ignored.
NOTE:
If the SKP is in an MCR or JMP Control Zone, the SKP takes precedence. When
power flow is ON to SKP, all logic within the SKP-to-LBL Control Zone is bypassed
and ignored.
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7.5.2 Skip-to-Label Application
Add these networks thru On-Line Edit to the Jump Application created in the last section.
Figure 7.9 SKP-to-LBL Application
Run
and Monitor the program
Observe the operation of timers in the SKP-to-LBL Control Zone with X10 ON and X10 OFF.
Page 116
7.6 Go to Subroutine (GTS)
This section describes the operation of the Go to Subroutine instruction.
7.6.1 GTS Description
The GTS instruction directs the program to leave the main (linear) RLL program and call (or
run) the specified subroutine. When the subroutine is completed (by RTN instruction), the
program returns to the next instruction or network following the GTS instruction.
Any MCR and/or JMP that is active when SBR is called remain active while the subroutine is
executed. Likewise, any MCR and/or JMP set in a subroutine remains active in main program if
not ended within the subroutine. A SKP-to-LBL pair must be located within the same SBR.
The following rules apply to the use of subroutines:
a. The END instruction must be used to mark the end of the main program.
b. All subroutines must be entered in the ladder after the END instruction.
c. SBR – must be used to define the start of each subroutine program.
d. RTN – must be used to terminate each subroutine and return to the main program
Figure 7.10 GTS/SBR Instrucitons
Power flow ON to GTS – program control is transferred to specified subroutine number
Power flow OFF to GTS –instruction is not executed and main program continues in sequence
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7.6.2 GTS Application
Add the following networks thru On-Line Edit to the Skip-to-Label Application created in the
last section. Ensure Network 19 contains an Unconditional END.
(program continues on next page)
Page 118
Figure 7.11 GTS/SBR Application
Run and Monitor
the program.
Toggle X13 ON to call Subroutine 1.
Toggle X13 OFF to call Subroutine 2.
Observe timer runs only in the active subroutine. Since the timer in the uncalled subroutine is
inactive, we can use the same timer number in both subroutines.
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7.7 TASK Instruction
There are two Tasks in the 2500 Series PLC:
TASK1
The main RLL program
TASK2
Cyclic RLL networks are high-priority instructions that execute on the specified
time interval. The Cyclic RLL task interrupts all other PLC operations (Main
RLL, Analog Tasks, I/O Update) in order to execute when required.
7.7.1 TASK Description
The TASK instruction is entered as an unconditional RLL network output.

The RLL program is limited to one main RLL task (TASK1) and one optional Cyclic
RLL Task (TASK2). However, each task can consist of one or more segments of RLL
instructions. Each task segment is started by the TASK instruction. A task segment is
terminated by another TASK instruction or END instruction. All task segments must
be placed in front of the END instruction.

Each task executes RLL instructions in order from top to bottom as positioned in the
program.

If the first RLL network does not include a TASK instruction, TASK1 is assumed.
Therefore, all RLL instructions are executed as part of the main RLL program until a
TASK2 instruction is encountered.

The Task Cycle Time (T) applies only to the Cyclic RLL Task (TASK2). The Cycle
Time can be designated in milliseconds as a signed integer constant (0-32767) or as an
unsigned integer value (0-65535) in the specified Word Memory Address. The use of a
Word Address allows the cycle interval to be altered during run-time. If the Task
Cycle Time = 0, the default time of 10 msec is used.

If the Cyclic RLL Task consists of more than one TASK2 segment, the Task Cycle
Time (T) specified in first TASK2 instruction determines the Cyclic RLL Task
interval.
Page 120
Default Task
1
Task 2 - T entry specifies the
interrupt cycle time in msecs
T is set to 0 for Task 1 &
8.
Task 2
segment
Task 1 segment
continued
Task 2 Segment
continued
Notice the second
Task2 definition has no
time. Task 2 cycle time
is defined by the first
Task 2 instruction.
Subsequent Task 2
times are ignored.
Task 1 Segment
continued
Figure 7.12 TASK Instructions
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7.7.2 TASK Application
Open program
Figure 7.13 TASK Application
Save As
Page 122
- TASKS.FSS and Download to PLC.
Before changing PLC to Run mode:
Select PLC Utilities, PLC Configuration, Scan Time, and set Fixed Scan at 250 msec
Go to Run.
Observe the count in Task2 (V2) will be double the count in Task 1 (V1). This demonstrates that
the Cyclic Task at 125 msec is running twice as often as the main RLL program at 250 msec.
Immediate Contacts
and/or Coils are used to read or write data to I/O modules during the
scan rather than at the start of the PLC scan (as done with Normal I/O). Generally, Immediate
Contacts and Coils are used in Task2 networks.
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Page 124
Chapter 8. Data Formatting
T
his chapter describes the different types of data used in the 2500 Series CPU and how
each data type is formatted for storage.
8.1 Data Elements
Several different Data Elements are used in PLC to allow the logic instructions to access
values stored in memory. This is general information applicable to any computer.
Byte
A Byte consists of 8 contiguous bits. A Byte represents a single value.
Bit number
1
2
3
4
5
6
7
8
Most
significant
bit
Word
Least
significant
bit
A Word value consists of 2 contiguous bytes or 16 bits.
1
2
Most
significant bit
Examples:
3
4
5
6
7
8
9
1
0
1
1
1
2
1
3
1
4
1
5
1
6
Bit
number
Least
significant bit
The contents of V-Memory address V100 is a word.
The output address WY551 is a word.
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Double Word
A Double Word consists of 2 contiguous words or 32 bits.
The Double Word element represents a single value.
V200 Most Significant Word
1
2
3
4
5
6
7
8
9
1
0
1
1
1
2
1
3
1
4
1
5
1
6
1
3
1
4
1
5
1
6
Bit
number
Most
Significant Bit
V201 Least Significant Word
1
2
3
4
5
6
7
8
9
1
0
1
1
1
2
Bit
number
Least
Significant Bit
Note that the Most Significant Word is the first (or lowest) addressed word.
Page 126
8.2 Data Types
A Data Type is simply a definition of the data format of the value in a Data Element. For
instance, the data stored in a Word can represent a Signed Integer, Unsigned Integer, or BCD
value. This section describes the formats used in the 2500 Series PLC.
8.2.1 Signed Integer
Word data is most commonly stored as a 16-bit Signed Integer. The Signed Integer holds
values16- ranging from –32,768 to +32,767. This data type uses two’s complement format as
shown below. When bit 1 (the sign bit) is 0, the number is positive; when bit 1 is 1, the number is
negative.
Sign
Bit
Most
Significant Bit
Bit
#
Least
Significant Bit
1
2
3
4
5
6
7
8
9
1
0
1
1
1
2
1
3
1
4
1
5
1
6
0
0
0
1
1
1
0
0
1
0
1
0
0
1
0
1
0
0
1
0
1
0
0
1
0
1
0
0
1
0
1
0
0
1
0
1
0
0
1
0
1
0
0
1
0
1
0
0
1
0
1
0
0
1
0
1
0
0
1
0
1
0
0
1
0
1
0
0
1
0
1
0
0
1
0
1
1
0
1
0
+32767
+1
00000
-1
-32768
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8.2.2 Unsigned Integer
Word data can also be accessed as an Unsigned Integer. The Unsigned Integer holds values
ranging from 0 to 65535.
Least
Significant Bit
Most
Significant Bit
Bit
#
1
2
3
4
5
6
7
8
9
1
0
1
1
1
2
1
3
1
4
1
5
1
6
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 +65535
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
8.2.2 Long Integer
A Double Word (32-bit) value can be accessed as a Long Integer. Long Integer data is similar to
Signed Integer in that both positive and negative values are stored in sign-extended two’s
complement format as shown in Section 8.1.
8.2.3 Real Number
Real numbers are 32-bit floating point numbers stored as a Double Word value in accordance
with ANSI/IEEE Standard 754–1985 forma as shown in the following diagram. Real numbers
are not used in the 2500 Series RLL instructions. They are available for use with Loops, Alarms,
and Special Function programs.
Sign Bit
Exponent
1
Mantissa
2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Page 128
8.2.4 Hexadecimal
Hexadecimal (Hex) formatting is often used in programming because it is actually just a concise
method of representing Binary data.
Each Hexadecimal digit represent 4-bits of Binary data; which means 2 Hex digits are used to
represent one Byte, and 4 Hex digits represent one Word.
Decimal
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Example:
Bit
1
Binary
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
Hex
0
1
2
3
4
5
6
7
8
9
A
B
C
D
E
F
Hex B7C3 = Binary 1011 0111 1100 0011
2
3
0
B
1
4
5
6
7
1
7
1
8
9
10
11
1
C
0
12
13
14
15
16
0
3
1
1
No.
Hex
Bin
1
1
0
1
1
0
0
Bit numbers in this PLC are numbered 1 to 16 where Bit 1 is the most significant value
and Bit 16 is the least significant value.
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8.2.5 Binary Coded Decimal (BCD)
BCD is a legacy data format used primarily for transferring values to/from thumbwheel switches
and 7-segment LED displays using Digital I/O channels as the communications interface. BCD
uses 4-bits to represent each decimal number as shown in the following table.
Decimal
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Binary
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
BCD
0
1
2
3
4
5
6
7
8
9
None
None
None
None
None
none
Hex
0
1
2
3
4
5
6
7
8
9
A
B
C
D
E
F
Example: BCD 9364 = Binary 1001 0011 0110 0100
NOTE:
Hexadecimal is in the table only for reference. There is no direct relation between BCD
and Hex. However, there is a correlation as the binary representations for BCD 0 thru 9
is identical to Hex 0 thru 9. Although, most PLCs (including the 2500 Series) do not
support BCD values directly, it is possible to access BCD data in Hexadecimal format
because the BCD data format is identical to Hex digits 0-9
Page 130
8.2.6 BCD to Binary Conversion
When using BCD input devices such as thumbwheel switches, it is usually necessary to convert
the BCD data into binary (integer) format since most RLL instructions do not directly support
the BCD data format.
The Convert BCD to Binary instruction performs this task.
Figure 8.1 BCD to Binary Instruction
This instruction executes each scan the Input is ON:
 The value in (N) determines the number of BCD digits to convert. The number of BCD
digits are counted from the least significant digit (in Bits 13-16) to most significant
digit (in Bits 1-4) as shown below:
BCD Digit Count:
Digit 4
Digit 3
Digit 2
Digit 1
Bits 1-4
Bits 5-8
Bits 9-12
Bits 13-16
 If the Input Word Address (BCD) contains a valid BCD value (0-9) in each 4-bit segment
for the number of specified BCD digits (N), the equivalent binary integer is written to
Output Word Address (BIN) and the Output turns ON.
 If any segments in Input Word Address (BCD) marked for conversion are not valid, the
BCD-to-Binary conversion is aborted. The Output Address (BIN) is unchanged and the
Output turns OFF.
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8.2.7 Binary to BCD Conversion
When using BCD output devices such as 7-segment LED displays, it is necessary to convert
integer values into BCD format before writing the data to the display.
The Convert Binary to BCD instruction performs this task.
Figure 8.2 Binary to BCD Instruction
The CBD instruction executes each scan the Input is ON:
 The value in (BIN) is evaluated as a 16-bit signed integer.
If the value is in the positive range (0 to 32767), the BCD equivalent value is written to
Addresses (BCD) and (BCD+1) as shown below and the Output turns ON.
Each BCD digit occupies four bits and is written into two contiguous memory locations
as shown below.
Address BCD:
Address BCD+1:

Page 132
Bits 1-4
Bits 5-8
Bits 9-12
Bits 13-16
Unused
Unused
Unused
Ten
Thousands
Bits 1-4
Bits 5-8
Bits 9-12
Bits 13-16
Thousands
Hundreds
Tens
Ones
If the value in (BIN) is negative, the BCD conversion is aborted. The values in
Addresses (BCD) and (BCD+1) are unchanged and the Output turns OFF.
Example 1: V1 = 1234
MSB
0
LSB
0
0
0
MSB
1
LSB
2
3
4
Example 2: V1 = 23456
MSB
0
LSB
0
0
2
MSB
3
LSB
4
5
6
8.3 Analog Data
We have already discussed (in Chapter 4) the storage of Analog Inputs (WX) and Analog
Outputs (WY) in the Word I/O Image Register. This section describes the methods used to
perform the Analog-to-Digital conversion required to digitize those signals. We will explicitly
discuss Analog Input signals, but the same techniques are used for the Digital-to-Analog
conversion required for Analog Outputs.
8.3.1 Analog-to-Digital Conversions
The digitized Analog Input theoretically is a Signed Integer in the range of -32000 to +32000. In
reality, the A/D chip will over-range to approximately –32600 to +32600 so it is certainly
possible to see a digital value outside of the theoretical range. It should NOT go to maximums
+32767 and –32768.
A/D converters are not continuous linear devices. They convert in steps. The size of each step is
determined by the number of bits used for the conversion.
Example: A 9-bit A/D converter generates a binary number in bits 2 thru 10. Therefore, the
analog value must change by a minimum of 64 counts (see table below) before a change is
detected in the digital value. For a typical analog signal with a range of 0-32000 counts, this
equals to a change of 0.2% of the range ( 64 / 32000 ). This is the theoretical “best-case”
resolution with 9-bit conversion.
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3
2
7
6
8
1
6
3
8
4
8
1
9
2
4
0
9
6
2
0
4
8
1
0
2
4
5
1
2
2
5
6
1
2
8
6
4
3
2
1
6
8
1
2
3
4
5
6
7
8
9
10
11
12
13 14
15 16
0
0
1
1
1
1
1
1
1
-
-
-
-
4
-
2
9-bit gives ~2.0%
10-bit gives ~1.3%
11-bit gives ~0.6%
12-bit gives ~0.3%
13-bit gives ~0.2%
14-bit gives ~0.1%
15-bit gives ~0.04%
1
-
There are also variations in the A/D chip itself which can de-rate the conversion accuracy as
much as 5-10X. Add the inaccuracies in other components and the de-rating may approach 20X
the theoretical resolution. Reputable manufacturers aggressively de-rate the accuracy
specifications of modules due to these variations.
Examples:
CTI Model 2550A (12-bit mode is guaranteed 1.0% full scale.
CTI Model 2555A (14-bit mode) is guaranteed 1.0% full scale.
CTI Model 2558 (13-bit mode) is guaranteed 0.5% full scale.
CTI Model 2501 (15-bit mode) is guaranteed 0.5% full scale
(even with resolution ~10X the 2550A)
8.3.2 Signals with 20% Offset
The term 20% Offset is derived from the value used as the minimum signal level. For instance,
a 4-20ma uses 4ma (or 20%) of the full signal range as the ‘zero’ point. Commonly used 20%
Offset ranges are 4-20ma and 1-5V.
Many input circuits use 4-20ma signals for two reasons:
1) Noise Rejection – Current circuits are low impedance. Since noise is a voltage level, it is
a high-impedance signal that is shunted to Ground.
2) Open Circuit Detection – Because 4ma level is used the minimum range (or ‘zero’) point,
an input value less than 3.5ma indicates a bad circuit. Certainly, 0ma indicates an open
circuit.
A/D converters are voltage device. Current signals must be converted to voltage. This is
commonly done with a 250ohm resistor placed in parallel with the input when current mode is
selected. The voltage is then brought in as 0 to 5VDC.
Page 134
Some A/D converters have built-in compensation for 20% Offset signals. If not, the A/D
converter loses 20% of its resolution when 20% Offset signals are used. See the following
tables:
A/D Conversion with 20% Offset Compensation:
Current
0ma
4ma
12ma
20ma
Volts
0VDC
1VDC
3VDC
5VDC
% of Range
NA
0%
50%
100%
Raw Data
NA
0000
16000
32000
Range
32000
A/D Conversion without 20% Offset Compensation:
Current
0ma
4ma
12ma
20ma
Volts
0VDC
1VDC
3VDC
5VDC
% of Range
NA
0%
50%
100%
Raw Data
NA
6400
19200
32000
Range
0000
25600
When using modules with 20% Offset compensation, use the following formula to convert raw
analog signals to engineering units:
EU_Value = (Raw Data / 32000 * EU_ Range) + EU_Offset
When using modules without 20% Offset compensation, use the following equations for
converting a raw signal values:
EU_Value = (Raw Data / 25600* EU_ Range) + EU_Offset
Example:
4-20ma signal represents 400 to 700°F
Raw signal = 9014
EU_Range = 700-400 = 300°F
EU_Value = (9014-6400)/25600*300 + 400 = 430.6328°F
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Page 136
Chapter 9. Math Instructions
W
hen used within its constraints, RLL Math is very simple. It becomes very
cumbersome and awkward when pushed outside its constraints. This chapter describes
the Math instructions and demonstrates these constraints.
9.1 Add and Subtract Instructions
The Add instruction computes the Sum of two Signed Integer values, and the Subtract
instruction computes the Difference of two Signed Integers.
9.1.1 ADD and SUB Descriptions
The ADD instruction executes (R = A + B) each scan the Input is ON.
 The parameter values in A and B are evaluated as 16-bit Signed Integers.
 Contents of B can contain a Word Address or Integer constant.
 If the result is within the valid range for a Signed Integer (-32768 thru +32767), the Sum
is written to Address R and the Output turns ON.
 If the result is outside of the valid range for a Signed Integer, an overflow condition
occurs. The result is then written as the 16-bit truncated Sum (16 LSB) and the Output
turns OFF.
The Subtract instruction executes (R = A – B) each scan the Input is ON.
 The values in A and B are evaluated as 16-bit Signed Integers.
 Either A or B can contain an Integer constant. However, it is invalid for constants to be
entered in both fields.
 If the result is within the valid range for a Signed Integer (-32768 thru +32767), the
Difference is written to Address R and the Output turns ON.
 If the result is outside of the valid range for a Signed Integer, an overflow condition
occurs. The result is then written as the 16-bit truncated Sum (16 LSB) and the Output
turns OFF.
The following application example shows the operation of the Add instruction. The Subtract
instruction operation is identical.
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9.1.2 ADD Application
Open program
Figure 9.1 ADD Instruction
Save
as ADD.FSS. Download to PLC and Run.
Open Data Window.
Click Options in main toolbar, then select Program Setup, Data Window and deselect Tags, Descriptions, Time Stamp, and Status displays as shown below.
Figure 9.2 Data Window Display Selection
Page 138
Reduce image sizes to display both Ladder Editor and Data Window.
Figure 9.3 Resized Ladder Editor and Data Window
Enter addresses and data formats in Data Window as shown below. Adjust width of cells may to
display the full binary value.
Figure 9.4 Display of Data Formats
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Enter the following values: V1 = 3000, V2 = 3000
Note the result of the ADD instruction (V3) and C2 Output is ON.
Set V1 = 32766 and V2 = 1. C2 Output is ON. Note both Decimal and Binary values of V1-V3.
Set V2 = 2. C2 Output is OFF. Note both Decimal and Binary values of V1-V3.
It is possible to reconstruct the result by detecting C2 as Overrun bit, deleting Bit 1 (sign bit),
and reconstructing the result using other Math functions BUT it is extremely awkward. It is even
worse when dealing with negative numbers.
Do not add or subtract values that will give a result outside the valid range (-32768 to +32767).
If necessary, values can be scaled by a factor of 10 as long as the process can tolerate the reduced
accuracy.
Page 140
9.2 Multiply Instruction
The Multiply instruction computes the Product of two Signed Integer values and stores the result
as a Long Integer (32-bit Signed Integer).
9.2.1 Multiply Description
The Multiply instruction executes (RR = A * B) each scan the Input is ON.
 The values to multiply are read as 16-bit Signed Integers from Memory Address A and
either Word Address or constant in parameter B.
 The multiplication is completed and Product is stored as a Long Integer in Word
Addresses RR and RR+1. Address RR contains the 15 most significant bits plus sign, and
Word RR+1 holds the 16 least significant bits.
Range of Long Integer: -2,147,483, 648 thru +2,147,483,647
 Output is turned ON.
9.2.2 Multiply Application
Add the following network to the current PLC program and addresses V4-V6 to the Data
Window as shown below:
Figure 9.5 Multiply Instruction Application
Note result of the Multiply instruction is labeled RR. This indicates that it is stored in 2 words as
a 32-bit Long Integer value. In the PLC memory, this value occupies locations V6 (MSW) and
V7 (LSW).
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Set the size of V6 to display a 32- bit Signed Integer value.
Enter V4 = 32767 and V5 = 1000. Note result in V6 and C3 Output is ON.
Enter V4 = 32767 and V5 = 32767. Note that even when maximum possible values are used,
the result is valid (does not Overrun) and C3 Output is ON.
Producing a 32-bit result is very useful for computations, but the Long Integer is generally not
supported as a parameter directly in RLL Math instructions. Therefore, it must be scaled to a 16bit Integer value. You can use the Divide instruction to accomplish this, but it causes a loss of
accuracy.
Page 142
9.3 Divide Instruction
The Divide instruction performs an Integer Division operation. The results are stored as the
Quotient and Remainder as standard 16-bit Signed Integers.
9.3.1 Divide Description
The Divide instruction executes (R = A / B) each scan the Input is ON.
1. The Dividend is read from a memory address or constant based on the contents in A.
 If A contains a Word Address, the Dividend is read as a Long Integer. Word A
contains the 15 most significant bits plus sign, and Word A+1 holds the 16 least
significant bits. Otherwise, A is read as a 16-bit Signed Integer constant.=
2. The Divisor B is read as a 16-bit Signed Integer from a memory address or constant
It is invalid for both A and B to be entered as constants.
3. The Division is completed and results are stored based on the following conditions:
 If the Divisor is equal to zero, the operation is aborted. The Result Words R and
R+1 are unchanged, and the Output is turned OFF
 If the Quotient is a valid 16-bit Signed Integer, the Quotient is written to Address
R, and the Remainder to written to Address R+1. The Output is turned ON.
 If the Quotient is invalid (greater than +32767 or less than -32768), the operation
is aborted. The Result Words R and R+1 are unchanged, and Output is set OFF.
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9.3.2 Divide Application
Add the following network to the current PLC program and addresses V8-V10 to the Data
Window as shown below:
Figure 9.6 Divide Instruction Application
Set V4 = 20000, V5 = 5000, and V8 = 700.
Note there is no result in the Divide instruction result words V9 or V10. Since the result is
142,857 we have an overrun condition, the operation is aborted, and C4 Output is turned OFF.
Change V8 = 7000.
The Divide operation now completes successfully. The Result V9 (Quotient) holds 14285, V10
(Remainder) equals 5, and C4 Output is turned ON.
Remember the Divide instruction uses Integer Math, and results are truncated (not rounded).
Page 144
9.4 RLL Math Example Application
This section shows an example of RLL Math instructions to convert a standard Analog Input into
Engineering Units.
Analog Input WX1 = 4–20 mA (20% offset).
This value represents flow of 0–100.0 gph (accuracy = 0.1%)
Engineering units will be 0 to 1000 (Flow*10). Store the result in V100.
V200-V205 used
for temporary storage for Math operations.
Because decimal numbers cannot exist in Integer Math, we will compute flow in the range of
0-1000 (representing 0-100.0 gph). If this value is sent to an HMI, the HMI software must be
configured to take this value and divide by 10 to convert to a Real Number 0.0 to 100.0.
Engr Units = (Raw Data – 6400) / 25600 * Engr Units Range
If we first divide, the result will be number less than 1 and the result will be ZERO.
So we must first multiply and store as Long Integer. Then divide by 25600.
V100 = (WX1 – 6400) * 1000 / 25600
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Add the RLL network to the PLC program and addresses to the Data Window as shown below.
Figure 9.7 RLL Math Example Application
Change to Run mode.
Force different values in the range of 6400-32000 into WX1 to see flow results.
Page 146
Chapter 10. Troubleshooting
System status and diagnostic data is critical to any application. PLC Status Words
provide this information to the programmer.
T
his chapter describes some of the basic diagnostic data provided by the CPU and
techniques that can be used to analyze and troubleshooting the operation of your system
based on this data.
10.1 PLC Status Words
We can display Status Words (STW) in a Data Window and interpret the value contained in
each word. Some Status Words contain a group of bits (each with a different meaning) , and
others hold an Integer value. Appendix G of the Programming Reference Manual explains the
Status Words provided by the 2500 Series PLC.
Open program
CONFIGURED.FSS and Download program to PLC.
Open a new Data Window and add word STW1. Display as Binary value and expand the cell to
show all 16 bits as shown below:
Figure 10.1 STW1 Example
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A description of STW1 bits are shown in the following table:
Bit
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Description
Password entered
Password entered and disabled
Error in user program. See STW200 for further information
Overflow subroutine stack
Time of day failure
Special Function module communications failure
Failure in previous ladder instruction
Failure or mismatch in I/O module
Processor communication port failure
Scan overrun
Low battery
Figure 10.2 STW1 Description
In our example, Bit 15 ON indicates a Low Battery condition.
10.2 Alarming and Status Reporting
Blocks of V-Memory words are typically assigned to hold data to be transferred to/from other
system devices.
Assume V500–V599 is designated to store data to be transmitted and V500 holds 16 status bits.
In this case, we want V500 to be assigned as follows:
V500.1 = STW1.11
V500.2 = STW1.12
V500.3 = STW1.13
V500.4 = STW1.14
Page 148
We can accomplish this using the logic shown in the following program example.
Figure 10.3 Alarming and Status Reporting Example
When using this technique to send data to a HMI device, you must coordinate the HMI
configuration so the appropriate data can be broken out to generate alarm messages to the
operator screens.
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10.3 Program Control Monitoring
A routine is often needed for power-up initialization. For instance, we want to ensure Outputs are
set to a specific state whenever the PLC enters Run mode.
STW201 holds First Scan Status Flags
Bit
1
2
3
4-8
9
10
11
12
13-16
as shown in the following table:
Description
First scan after compiling an SFPGM
First scan after change from Program mode to Run mode
First scan after changing from Run-time Edit mode to Run mode
Not used
First scan after Power-up Restart with a bad battery
First scan after Power-up Restart with a good battery
First scan after a commanded Complete Restart
First scan after a commanded Partial Restart
Not used
Figure 10.4 STW201 Description
Page 150
The following example shows the logic required to initialize a motor controlled by Y33 to OFF
whenever the PLC enters Run mode following a power cycle.
We will use STW201.9 and STW201.10 since we want to initialize the motor whether the
battery is good or bad. The initialization logic is placed in a Subroutine called when STW201.9
or STW201.10 is ON.
Always use the END command to separate Subroutines from the main program.
Figure 10.5 STW201 Application Example
Ladder Network 9 ensures that Y33 is always turned OFF by the First Scan Flags.
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Many programmers prefer to generate their own First Scan Flag. This is accomplished by
entering in the following logic as the LAST network in the program. Any previously unused
non-retentive Control Relay (C) address can be used.
Figure 10.6 User Generated First Scan Flag
In this example, C100 is OFF for the first scan until it is turned ON when the last RLL network
is executed. It is then held ON until the power is cycled.
Page 152
10.3 PLC Status
PLC Status is an On-Line function meaning it can be monitored only when connected to an
active PLC. PLC Status is accessed by selecting PLC Utilities / PLC Status from the main
toolbar.
Figure 10.7 PLC Status Menu Selection
The following screen is displayed indicating no errors:
Figure 10.8 PLC Status Window
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Close the PLC Status window.
Remove the Output Module from Slot #2, and re-open the PLC Status
Status now shows a Non-Fatal Error in the I/O configuration.
window. The PLC
Figure 10.9 Non-Fatal Error Status
The cause of the I/O configuration requires further investigation as described in the next section.
Page 154
10.4 I/O Status
I/O Status
is an On-Line function that provides status for each configured I/O base. I/O Status
indicates whether each slot in the base matches the I/O configuration map.
I/O Status
is accessed by selecting PLC Utilities / PLC Utilities/ I/O Status from the main
toolbar.
Figure 10.10 I/O Status Window
You can now see that the I/O Error is caused a module mismatch in Slot #2 in Base 0 (Local
Base). The slot is reporting Empty, but a 32-point Output module has been configured in that
position.
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10.5 Digital Input Module Status
This section provides a simplified description of the operation of a typical Digital Input Module.
LED
Channel 1
LED
Channel 2
M
u
l
t
i
p
l
e
x
e
r
M
e
m
o
r
y
Chassis
Backplane
Figure 10.11 Digital Input Module Block Diagram
The signal comes in thru the screw terminals and into an input buffer/amplifier.
The Status LED for the channel is on the output of the buffer/amplifier.
The multiplexer is a switch selecting one of the inputs and sends it to the module memory.
Data is then transferred along the bus as controlled by the PLC or RBC.
LED ON
indicates the signal is getting to the Multiplexer. A failure after this point usually
affects the entire module and is detected by the module diagnostics.
LED OFF
indicates either the signal is not coming into the module or the buffer/amp for this
channel has failed. A failed buffer/amp will usually NOT be detected by the diagnostics.
Page 156
10.6 Digital Output Module Status
This section provides a description of the operation of a typical Digital Output Module. Both
solid-state and relay modules are included.
Below is a simplified block diagram of a typical solid-state Digital Output Module:
Field Power
LED
Driver
M
e
m
o
r
y
D
e
m
u
l
t
i
p
l
e
x
e
r
Driver
Driver
Driver
Typically field power
sources 4-8 outputs
Figure 10.12 Solid-State Digital Output Module Block Diagram
The Output channel Status LED is located between the Demultiplexer and the output drivers
LED ON indicates
the Output signal is getting to the driver. A problem with the field device not
operating is probably due to the fuse or other field wiring/device failure. It COULD be the
Output driver. This usually will NOT be detected by the module diagnostics.
LED OFF indicates
the Output signal is not getting to the driver. If the corresponding Y coil is
ON in the program, there is probably a failure in the module. Usually other Output signals will
be affected. This situation is usually detected by the module diagnostics.
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Below is a simplified block diagram of a typical Relay Output Module:
24VDC
Relay Coil
Power
Field Power
NC Output
D
e
m
u
l
t
i
p
l
e
x
e
r
NO Output
LED
Driver
R1
Figure 10.13 Relay Output Module Block Diagram
A Relay Output is similar to a solid-state Digital Output except there are 4 items generally not
detected by the diagnostics:

The individual drivers

The relay coils and contacts

Relay coil power

Field power
The Status LED is located on the input to the driver. Problems before the LED will usually
affect multiple channels and be detected by the diagnostics.
A field device not operating when the LED is ON probably indicates a problem with field wiring
or device, or loss of relay coil power. However, it is possible that the driver or relay has failed.
LED OFF
indicates the Output signal is not getting to the driver. If the corresponding Y coil is
ON in the program, there is probably a failure in the module. Usually other Output signals will
be affected. This situation is usually detected by the module diagnostics.
Page 158
10.7 Remote I/O Communications Status
Many system problems are caused by communication errors between the PLC and Remote I/O
Bases. All Remote I/O cable installations should adhere strictly to the recommended wiring
practices for high-speed RS-485 communication networks. Although this discussion is beyond of
this class, detailed information is available. Please contact CTI Technical Support.
Status Words STW145 and STW146 contain Communications Error Counts for the Remote
I/O system.
STW145
records the number of Receive Errors indicating “noise” on the wire.
STW146 holds
the number of Timeout Errors. This indicates a total loss of data, i.e., a
broken wire since the most recent restart.
10.7.1 Monitoring Remote I/O Errors
You may find it useful to establish a baseline for Remote I/O Communications operation as a
reference to determine future degradation of performance. This can be accomplished as follows:
With the system stable and running normally, create a Data Window and set STW145-STW148
to zero as shown below.
Return after approximately 24 hours of operation and read the counts in these Status Words.
Save these values with other system parameters. A good place for storage of this data is in the
Program Header block.
NOTE:
There should be no more than one I/O error detected (and corrected on retry) per 20,000
scans. This is approximately 15 minutes in a system with a PLC scan of 50msec. A higher
value may indicate cabling and/or interference problems. Three consecutive errors to an
RBC cause the base to be logged off and a failure bit in STW2 will be set.
Page 159
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10.7.2 Logging Remote I/O Error Counts
Communication faults often occur at random times or from odd conditions. It is difficult to stand
and watch a Data Window for error events. The following program is set up to log Remote I/O
Error Counts in15-minute intervals over a 24-hour period.
The error counts are stored in Shift Register V502-V598. Each error count entry is be
accompanied by a Hour/Minute value indicating the corresponding time period in Shift Register
V602-V698.
WARNING:
The addresses and instruction numbers used in this example are for demonstration only. If
using this logic in your program, you must change the instruction numbers and addresses to
reference ones not currently being used.
(program continues on next page)
Page 160
Figure 10.14 Remote I/O Error Count Logging Application
Page 161
2500 Se
Page 162
Chapter 11. Documentation
Every application requires documentation for future reference and explanation of the
original requirements and thought process that went in to developing the system.
T
his chapter provides a brief overview for generating a documentation package for your
application.
11.1 Print Dialog
WorkShop provides a simplified way for printing your system documentation.
The Print dialog contains two separate windows:
1. Program Elements available for printing
 Logic (RLL) and SFs
 Loops
 Alarms
 PLC Configuration
 Registers
 Documentation
 Cross Reference
2. Specific Data Range and Print Setup parameters
With your program loaded, Open the Print Dialog by selecting File / Print from the main
toolbar.
Page 163
2500 Se
11.2 Selection of Program Elements
When the Print function is opened, the following dialog opens:
Figure 11.1 Print Program Elements Selection
As a default setting, all program documentation is selected. All Program Elements, and all
configured data is a are selected to be printed. Any of the Program Elements can be selected or
de-selected using the corresponding check boxes.
The window on the right shows the range of each selected Program Element. The default
setting includes all configured data. For instance, our example shows Ladder Networks 1-7
which includes our entire RLL program. No SF Programs or SF Subroutines are shown because
none exist in our program.
Page 164
11.3 Data Range and Print Setup
When the button for one of the selected Program Elements (checkmark displayed) is pressed,
the second Print dialog appears. This window is used to enter the Data Range for the selected
Program Element and Print Setup parameters.
For example, press the Logic and SFs button. The following dialog is displayed:
Figure 11.1 Print Selection Dialog
Here you can select the range of RLL Network numbers, SF Programs, and SF Subroutines
to be printed along with Print Setup information.
Page 165
2500 Se
Page 166
Appendix A. CTI Contact Information
5734 Middlebrook Pike
Knoxville, TN 37921
Website: www.controltechnology.com
Office: 865-584-0440
Fax:
865-584-5720
Technical Support
John Ottinger
Scott Simpson
Ed Hibbard
Fred Wilson
ext 401
ext 209
ext 461
ext 270
email: [email protected]
Sales
Robert Peck
Ron Soderberg
Alan Jenkins
Perry Bright
ext. 210
ext 452
ext 450
ext 456
Inside Sales Manager
Missy Johnson
ext 281
Page 167
2500 Se
Page 168
Appendix B. Replacement/Compatibility Guide
Page 169
2500 Se
Page 170
Appendix C. CPU Product Models
The CTI 2500 Series controller is available in four models. The following table lists the
characteristics for each model.
Feature
2500-C100
User Program Memory
Discrete I/O Points
Word I/O Points
Control Relays
Retentive Control Relays
Timers/Counters
Compiled SF
Cyclic PID Loops
RLL Initiated PID Loops
Analog Alarms
Special Function Programs
Special Function Subroutines
Maximum Serial Port Data Rate
Flash O/S
Removable User Storage
128K
256K
512K
3072K
1024
2048
8192
8192
1024
1024
8192
8192
4096
32,768
32,768
32,768
1024
4096
4096
4096
1024
20,480
20,480
20,480
Yes
Yes
Yes
Yes
16
64
128
128
0
0
384
384
32
128
512
512
64
1023
1023
1023
64
1023
1023
1023
115,200 baud 115,200 baud 115,200 baud 115,200 baud
Yes
Yes
Yes
Yes
SD Card –
SD Card –
SD Card –
SD Card – Up
Up to 1GB
Up to 1GB
Up to 1GB
to 1GB
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
Yes
Yes
Yes
No
Yes
Yes
Yes
5-yr storage (0-60ºC)
3-yr continuous operation @ 25º C, 6 mos. @ 60º C
On-Board User Flash
Local Ethernet Port
USB Port
Remote I/O
Profibus-DP I/O
Battery
2500-C200
2500-C300
2500-C400
Page 171
2500 Se
Page 172
Appendix D. 2500 Series Status Words
Word: Bit
505 Description
STW 1
Bit 1
Bit 2
Bit 3
Bit 4
Bit 5
Bit 6
Misc. Status and Non-Fatal Errors
Set by SSI Instruction to inhibit HBU synch
Set to indicate Online Standby
HBU Preference Switch
Password has been entered
Password is currently disabled
User Program Error Flag
Bit 7
Bit 8
Bit 9
Bit 10
Bit 11
Subroutine Stack Overflow
Time of Day Clock Failure
TIWAY II Failure
SF Module Communications Failure
Previous RLL Instruction Failed
Bit 12
I/O Module Failure
Bit 13
Bit 14
Communications Port Failure
Scan Overrun
Bit 15
Bit 16
Battery Low
Ladder Memory Checksum Error
STW 2
Base Controller Status Remote I/O.
Corresponding bit is set to 1 if a base is:
 Failed
 Not Present
 Not Configured
 Not Enabled.
Status of DP channel slaves.
Set to 1 if slave is:
 Not Present
 Not Enabled
 Offline
 Not Configured
 Configured but Not Active
 Configured and Activated but Profibus
state is set to STOP
STW 3:
STW 9
STW 10
Dynamic Scan Time
Comments
Not used. Set to 0
Not Used. Set to 0
Not Used. Set to 0
Standard Password Only
Standard Password Only
Set ON when RLL error detected.
When set, STW200 is valid.
Subroutines nested more than 32 deep
Use TBD
Not Used
TBD.
Set ON when error detected. Set OFF
when instruction successful.
Set if any I/O module reports a failure.
I/O failure may be exhibited even if the
slot containing the module is a mismatch
or not configured.
If the base is not configured or the base
is disabled, this bit will not be set.
Failed modules in a Profibus base are not
reported in this bit by the 505.
Determine what constitutes “failure”
Set if scan time exceeds the Fixed Time
or Upper Limit Time
Set if battery is low or bad/off
This is the checksum for the “source”
ladder not the compiled ladder.
There is one bit for the local base and
each remote base controller address.
LSB (bit 16) is the local base; bit 15 is
base 1; etc.
Tested and observed the following
conditions that set the bit:
 Slave Not Present
 Slave Not Enabled
 Slave Offline
 Slave in Stop Mode
The Profibus base can be configured so
that it goes Offline if there is a
configuration error.
Scan time of previous scan.
Page 173
2500 Se
STW 11:
STW 26
I/O Module Status
Slot bit is set to 1 if any of the following
conditions is true:
 Installed Module does not match
configuration for the slot
 The slot is configured but no module is
installed in the slot.
 The slot is not configured but a module
is installed.
 Module fail is asserted and fail bit is set
Bit is set to 0 if:
 Module is configured and configuration
matches
 Slot is not configured and no module is
present
 No slots in the base are configured,
regardless of whether a module is
present. See comments.
STW 27:
STW 138
Profibus Module Status.
Provides module status for modules in a 505
base using a Profibus RBC.
The conditions for setting the bit are the same as
the I/O Module Status words.
STW 139
STW 140
STW 141
Bit 1 – 4
Bit 5 – 8
Bit 9 – 12
Bit 13 - 16
STW 142
Bit 1 – 4
Bit 5 – 8
Bit 9 – 12
Bit 13 - 16
STW 143
Bit 1 – 4
Bit 5 – 8
Bit 9 – 12
Bit 13 - 16
Page 174
Number of Forced Bits.
Current count of forced X, Y, and C.
Number of Forced Words
Current count of forced WX and WY.
BCD Time of Day – Word 1
Year – Tens
Year – Units
Month – Tens
Month - Units
Day - Tens
Day - Units
Hour - Tens
Hour - Units
Minute - Tens
Minute - Units
Second - Tens
Second - Units
LSB (bit 16) is the first slot.
STW 11 is local base. STW 12 is remote
base 1. STW 13 is remote base 2, etc.
Remote bases must be enabled and
configured before the module status will
be reported. Otherwise, all words will be
set to 0.
When an SF module is configured
without the SF indicator, this does NOT
show up as a mismatched module.
STW 127 is Station 1, STW 128 is
Station 2, etc. If a station is not a
Profibus RBC, the corresponding status
word will be set to 0.
Profibus bases must be enabled,
configured, and online before the module
status will be reported. Otherwise, all
words will be set to 0
The Profibus RBC can be configured to
go offline if there is a configuration
error. If the RBC is offline, the status
words will report all zeroes.
Count of Word forces includes words
with one or more bits forced.
STW 144
Bit 1 – 4
Bit 5 – 8
Bit 9 – 12
Bit 13 - 16
STW 145
STW 146
STW 147
STW 148
STW 149:
STW 160
STW 161
Bit 1
Bit 2
Bit 3
Bit 4
Bit 5
Bit 6
Bit 7
Bit 8
Bit 9 - 16
STW 162
Bit 1
Bit 2
Bit 3
Bit 4
Bit 5
Bit 6
Bit 7
Bit 8
Bit 9
Bit 10
Bit 11
Bit 12
Bit 13
Bit 14 - 15
Bit 16
STW 163
STW 164
STW 165
Second - Tenths
Second - Hundredths
Unused – Set to 0
Day of Week
Remote I/O Channel Receive Errors
Cumulative count of all RIO Receive Errors.
Remote I/O Channel Timeout Errors
Cumulative counts of all RIO Timeout Errors
Number of DP-related Errors
Counts all DP errors on the Profibus Channel.
This includes timeouts, etc.
Number of Token-related Errors
Counts errors related to token passingon the
Profibus channel.
Not used
SF Processor Fatal Errors
ROM Error
RAM Error
OS Error
Invalid Control Block Encountered
Diagnostic Failure
Unused
S-Memory is inconsistent
SF Program number from SF is invalid
Unused
SF Processor (Loop) Non-Fatal Errors
Port 1 Communications Error
Port 2 Communications Error
Loops are Overrunning
Analog Alarms are Overrunning
Cyclic SF programs are overrunning
Normal SF Queue is Full
Priority SF Queue is Full
Cyclic SF Queue is Full
Error Occurred during loop calculation
Error occurred during analog alarm calculation
A control Block is disabled
Attempt to execute undefined SFP or SFS
Attempt to execute restricted SFPGM from RLL
Unused
Scan-time Error
RLL Subroutine Stack Overflow
Contains the number of the subroutine that
caused a stack overflow
L memory checksum C0
Contains checksum as a 32 bit unsigned integer
Sunday = Day 1
Reset on PLC restart and power cycle
Reset on PLC restart and power cycle.
Indicates problems with cables or station
addressing/configuration.
Total failure of Profibus network, i.e.,
cable unplugged from PLC.
Set to 0
Set to 0
Set to 0
Not currently used
The checksum algorithm is a Fletcher
Checksum with two terms, C0 and C1.
Page 175
2500 Se
STW 166
STW 167
L memory checksum C1
Contains checksum as a 32-bit unsigned integer
STW 168
Dual Media RBC Status (Remote I/O)
Status of 0 indicates that the base is present and
configured with a redundant RBC
Unused
STW 169:
STW 175
STW 176
STW 177:
STW 183
STW 184
Bit 1
Bit 2-4
Bit 5 – 8
Bit 9 - 16
STW 185:
STW 191
STW 192
STW 193:
STW 199
STW 200
Page 176
The checksum shall be validated as part
of runtime diagnostics.
This checksum in on the “source” RLL,
not the compiled RLL.
LSB (bit 16) is the local base
TBD: 505 testing
Set to 0xFFFF
Redundant Power Supply Status
Status of 0 indicates that the base is present, dual
supplies are present, and they are both good.
Unused
LSN (bit 16) is the local base
Module Mismatch or Unclaimed MODFAIL
signal (Channel 0)
Unclaimed MODFAIL is not reported on
PLCs that have Profibus I/O.
Set to 1 if there is a module mismatch on any
base
Unused
Number of base with mismatch
Unused
Unused
Set to 0xFFFF
Set to 0
The highest numbered base with the a
mismatch will be indicated
Set to 0
Time in msec
Discrete Execution Scan Time
Indicates the time spent in the last discrete scan
Set to 0
COMAU PLC STATUS
Not used
User Program Error Cause
Reason Code associated with STW1/Bit 6 and STW1/Bit 11.
0 No Error
1 Uninstalled Application Referenced (Not used)
2 Attempt to unlock a semaphore that is not held (Use TBD)
3 Mismatched LOCK/UNLOCK instructions
4 Subroutine nesting level exceeded
5 Table Overflow
6 Attempt to call a non-existent subroutine
7 VME bus access failed (timeout) (Not used)
8 SFPGM has not been compiled
9 SFPGM is currently disabled
10 SFPGM type is not Normal or Priority
11 S-Memory is busy, e.g. due to an edit operation
12 Invalid context for in-line SFPGM/SFSUB
13 User-scheduled fast loop is not configured
14 User scheduled fast loop is disabled
STW 201
User Program First Scan Flags
Bit 1
First Scan After Compile
Bit 2
Bit 3
First scan after Program Mode
First scan after Edit Mode
Bit 4
Bit 5 – 8
Bit 9
First scan after Auto Recompile
Unused
First Scan following a Battery Bad Power-up
restart
First Scan following a Battery Good Power-up
restart (or power-on start)
First Scan following a Complete Restart
First Scan following a Partial Restart
Unused
Application Mode Flags
Bit 10
Bit 11
Bit 12
Bit 13 – 16
STW 202:
STW 203
STW 204:
STW 204
STW 205:
STW 206
STW 207:
STW 208
STW 210
STW 211:
STW 217
NOTE: These flags are cleared at the end
of the first Main RLL scan.
Set on first RUN or SINGLE SCAN
after RLL program is compiled.
Set on transition to PROGRAM mode
Set on first RUN mode scan after a
transition from EDIT mode.
Set when Autocompile has completed
Set to 0
Set at completion of restart
Set to 0
Always set to 0
Application Installed Flags
Always set to 0
U Memory Checksum C0
These words are currently unused.
U memory Checksum C1
Remote I/O Base Poll Enable Flag
Base 0 (local base) is in the LSB (Bit 1).
Bases corresponding to a clear bit (0) shall not
be polled.
Flags shall be set to the default of 0xFFFF after
a Clear PC or a battery bad Power Up restart (or
a power cycle with battery bad). All other
restarts leave this word unchanged.
If the user selects RUN FROM ROM (flash), the
contents of this status word shall be stored in
flash also. NOTE: Run from Flash is TBD.
Profibus Poll Enable Flags
Polling applies to remote bases. When a
base is not enabled, it will not be polled.
Bases that are enabled but not configured
will be polled in rotational sequence for
a pending task code (SF I/O).
A base that is failed but enabled and
configured will be polled once per scan
and logged-in if present and functional.
External requests for Read Base or Base
Diagnostics shall be performed
independently of this status word.
Poll bit shall be set equal to the “activated” bit
of the corresponding slave S1_Flag.
STW 218
STW 219
STW 220
Poll bits of undefined slaves shall be set to 0.
My Application ID (575 Only)
RLL Task Overrun
The overrun status of each RLL task is indicated
by a corresponding bit. Bit 1 corresponds to
Task 1. This bit is set if the task does not
complete in the user specified cycle time.
Interrupting Slots on Backplane
The contents of this word shall be established
when the interrupt occurs. The bit shall be set
for each module that has just asserted its
interrupt to the CPU. All other bits are cleared.
Unused. Set to 0
The bit remains set until cleared by
TC6A (Reset SF/LOOP errors)
Applies only to Cyclic Task (TASK2)
Unused in 2500 Series CPUs
Page 177
2500 Se
STW 221
STW 222
STW 223
STW 224
STW 225
STW 226
Bit 1
Bit 2 – 9
Bit 10
Bit 11
Bit 12 - 13
Bit 14
Bit 15
Bit 16
STW 227:
STW 228
STW 229:
STW 230
STW 231
Bit 1
Bit 2
Bit 3 – 15
Bit 16
STW 232:
STW 238
STW 239:
STW 240
STW 241:
STW 242
STW 243
Bit 1
Bit 2 – 8
Bit 9- 16
Page 178
Module Interrupt Count
Incremented any time an interrupt is received
from any interrupting module in the local base.
Spurious Interrupt Count
Binary Time of Day
Contains the relative millisecond of the current
data expressed as a 32-bit unsigned integer.
Binary Relative Day
Contains the relative day, with January 1, 1984
being day 0.
Time of Day Status
1 = Current time is prior to time reported in the
last Main RLL scan
Reserved
1 = Time is Valid (has been set)
1 = Time is synchronized over a network
Time Resolution
00 = Time Resolution is .001 second
01 = Time Resolution is .01 second
02 = Time Resolution is 0.1 second
03 = Time Resolution is 1 second
Time synchronization error. Module has lost
synchronization with network or has failed to
request synchronization by the scheduled time
No Time synchronization inputs.
Reserved
Bus Error Access Address (575 Only)
Bus Error Program Offset (575 Only)
Profibus I/O Status
DP-mode set to OPERATE
DP-mode set to CLEAR
Unused.
DP Bus Parameter Set is inactive
Profibus I/O Slave Diagnostic Status
The corresponding bit will be set to 1 if the slave
signals a diagnostic that has not been read by a
RSD RLL instruction.
CS Memory Checksum C0
Unused in 2500 Series CPUs
Incremented each time a spurious
interrupt is received.
Set for one scan when the current time is
earlier than the previous clock value.
Set to 0
Set when the PLC Clock is set to any
value. Cleared on power cycle or PowerUp Reset when the battery is bad.
Always set to 0
Always set to 01 = .01 second
Always set to 0
Always set to 0
Set to 0
Always set to 0
Always set to 0
Set to 0
Slave ID 1 is in the LSB of the first
word.
CS Memory Checksum C1
Auto Recompile Status
1 = Auto-compile enabled
Unused
Auto Recompile Count
Not used in 2500 Series CPUs

062-00381-010 - Control Technology, Inc.

Transcription

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