SH-VT250-M2, VT250A-M2 Rev C

SH-VT250-M2,
VT250A-M2
Rev C
 NDIR CO2 Dual sensor
 Needless calibration
on long-term use
 Can measure over
95% RH condition
 Applicable to humid storage,
mushroom farm and
floricultural industry
 Communication Method
RS-485 (Standard)
4~20 mA (Option)
0~5 V analog (Option)
RoHS
CO2, Temperature & Humidity Transmitter

Applications

-
Ventilation Control
-
Heat Ventilation Air Conditioning System
-
Mushroom Farming Greenhouse
-
Greenhouse and Humid Storage
-
Floricultural Industry
-
Cold storage, vegetable storage
SOHA TECH CO,.Ltd.
Suite 104, Hagye technotown A,250-3,
Hagye-dong,Nowon-gu,Seoul, Korea
TEL : +82 -2-978-0461,2,5
FAX : +82-2-978-0463
http://www.soha-tech.com
This product can be changed
for quality improvement without notification.
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SH-VT250-M2,

VT250A-M2
Rev C
Input Power :
DC 12 ~ 24 V, over 200 mA
 Features

Power consumption: Normal 40 mA, Peak 135 mA

Model:
SH-VT250 =

RS-485 Communication
SH-VT250A =
4 ~20 mA output type
SH-VT250V =
0 ~ 5 V output type
CO2 (Carbon Dioxide), Temperature,
Humidity Transmitter

Analog output tupy : 4~20 mA Current Loop (option)
: 0~5V (0ption)

Communication output: RS485

Precision Temperature and Humidity sensor

Can be connected with PLC or MICOM controller

Suitable for humid and weeping water condition

Low Cost, High Quality

IP65 Protection grade
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SH-VT250-M2,
VT250A-M2
Rev C
 CAUTION
Cautions for the installation of SH-VT250
You have to install SH-VT250 in the direction of O mark.
And don’t turn the power off when using SH-VT250.
It causes dampness inside the product.
In case of turn the power off, you have to store this product
in non-condensing condition.
When user spray agricultural pesticides, VT250 transmitter
should be covered with plastic bag
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SH-VT250-M2,
 SPECIFICATIONS

VT250A-M2
Rev C
CO2 sensor
List
Contents
Measuring method
Remarks
NDIR
Measuring Range
0~3000/5000/10,000 ppm
option
Accuracy
±2%
@10~50℃
Response time
0 ~ 80% < 30 Sec
Signal update term
Every 2.0 Seconds
Warm-up Time
@25℃ < 90Sec
Working Temp
Working Humidity

@25℃
0 ~ 50℃
( -10~50℃ Option)
0 ~ 99.9% RH
Temperature sensor
List
Contents
Measuring Range
Accuracy
-25 ~ 85℃ (RS485)
-10 ~ 50℃ (Analog)
Remarks
SH-VT250
SH-VT250A
Max.
±0.4 ℃
±0.3℃
.
Response Time

5 ~ 30 sec
Humidity sensor
List
Contents
Measuring Range
0 ~ 99.9 %RH
Accuracy
±2 %RH
Response time
8 sec
Remarks
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SH-VT250-M2,
VT250A-M2
Rev C
 Communication Protocol
1. Data Transmission Format
Byte
1
2
Contents STX
ID
Byte
15
14
Contents
3
4
5
6
7
9
CO2 Value
16
17
18
10
11
12
13
Temperature Value
19
Humidity Value

8
20
21
22
23
24
SHT
Mode Check Sum
CR
LF
Each content is displayed by ASCII type
- STX: Start Code (0x02)
- ID: Transmitter ID (Initial value : 0x00)
- CO2 Value: a number of four byte ASCII cords
- Temperature Value Display
Below zero, 9th Byte is „-„(0x2D)
Above zero, 9th Byte is Space(0x20)
12th Byte decimal point display is „.‟(0x2E)
- Humidity Value Display
17th Byte decimal point display is „.‟(0x2E)
- SHT: display condition of temperature and humidity sensors
„0‟(0x30) = normal running
„1‟(0x31) = measured temp. & humidity value error
Or temp. & humidity sensor connection error
(temp. & humidity data will be displayed former one)
- Mode: „0‟(0x30) = data transmission every 2 sec
„1‟(0x31) = data transmission when DTE needs data
(Initial value : 0x30)
- Check Sum: Sum of 1~21Byte, use low data 1Byte only
- CR: 0x0D
- LF: 0x0A
- 3, 8, 14, 19 Byte: Space (0x20)
** Compare the Check Sum after receiving 24 Byte and check the error.
** If the value of SHT is „1‟, the measured temp. & humidity values are error.
Or the connection wire of temp. & humidity has problems.
In this case , transmitted data is former measured data
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SH-VT250-M2,
VT250A-M2
Rev C
2. Set up
Byte
Contents
1
2
3
4
5
STX
ID
S
Set ID
Mode
6
7
Reserve
8
9
10
Check Sum
CR
LF
- STX: Start Code (0x02)
- ID: Transmitter ID ( if this byte set as 0x00 :every transmitter
accepts command)
- „S‟(0x53): set up Command
- Set ID: Transmitter ID set(0x00 ~ 0xFF)
- Mode: „0‟(0x30) = data transmission every 2 sec
„1‟(0x31) = data transmission only when controller request data
(Initial value : 0x30)
- Reserve
- Check Sum: Sum of 1~7Byte, use low data 1Byte only
- CR: 0x0D
- LF: 0x0A
** If user want to set Transmitter‟s ID, don‟t use 0x00. ( ID 0x00 has reserved
as automatic transmission)
If transmitter has set as some of specific ID except 0x00,
it will respond automatically when transmitter receive 0x00 Call.
This function allow you to set up transmitter, even if you don‟t know the ID.
** Notice : When many transmitter connected in parallel, if controller call ID 0x00
, every transmitter will respond.
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SH-VT250-M2,
VT250A-M2
Rev C
3. Data Command (Mode „1‟only)
Byte
Contents
1
2
3
STX
ID
R
4
5
6
7
Reserve
8
9
10
Check Sum
CR
LF
- STX: Start Code (0x02)
- ID: Terminal ID
- „R‟(0x52): Data request Command
- ID set: Terminal ID set (0x00 ~ 0xFF)
- Reserve
- Check Sum: Sum of 1~7 Byte, use low data 1 Byte only
- CR: 0x0D
- LF: 0x0A
 Modbus protocol
Modbus Address Map
Address
contents
read
Hex
Dec
(2 byte)
/write
0x64
100
CO2 Value
Read
0x66
102
Temperature Value
Read
0x68
104
Humidity Value
Read
0x6A
106
Temp. RH sensor error status
read
0x00 0x30 : Normal
0x00 0x31 : Error
0x6C
108
Device ID
read/write
(Refer to additional
description)
※ Notice:
measured values of temperature and humidity must be divided by 10
before use the data.
Ex) Read Value 253(0x00FD)
-> Real Value
25.3℃,
Read Value -123(0xFF85) -> Read Value -12.3℃,
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SH-VT250-M2,
※ When user apply Device ID writing instruction,
VT250A-M2
Rev C
DIP switch should
be set as “1” before sending instruction.
ID writing sequences are like bellows,
1. Turn off the power.
2. Set Dip S/W as “01”
3. Switch on the power.
4. Write Device ID .
5. Turn off the power again.
6. Set Dip S/W as “F” (1111).
7. Switch on the power again.
8. Device is ready to communicate as a set ID.
[DIP S/W “1”
(only No. 4 pin ON(UP))
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SH-VT250-M2,
VT250A-M2
Rev C
 Dip Switch setting method
Data transmission every 2 sec
ID 1 Setting, Data transmission when DTE needs data
ID 2 Setting, Data transmission when DTE needs data
ID 3 Setting, Data transmission when DTE needs data
|
|
|
|
|
|
ID 14 Setting, Data transmission when DTE needs data
When use ID(15 ~ 255) of which Serial communication set up
* Note: When DIP switch value is “0“ (all dip switch are Off), serial communication
setup is not available.
Other dip switch setting except “0” are available of serial communication.
Before set ID and apply new setting,
Ex)
power should be off.
1) Turn off the power
2) set dip switch (ID)
3) Switch on the power
※
Select output mode (SH-VT250A only)
output OFF
0~5V output
output OFF
4~20mA output
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SH-VT250-M2,
VT250A-M2
Rev C
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SH-VT250-M2,
VT250A-M2
Rev C
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SH-VT250-M2,
VT250A-M2
Rev C
■ Analog wiring diagram
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SH-VT250-M2,
VT250A-M2
Rev C
■ Dimension
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