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Copy No. _____
Defence Research and
Development Canada
Recherche et développement
pour la défense Canada
DEFENCE
&
DÉFENSE
Modification of the Laboratory Oil
Condition Test Rig and Wireless Data
Acquisition System to Accommodate a
Schroeder TWS-C Water Sensor
K.J. KarisAllen
FACTS Engineering Inc.
PO Box 20039
Halifax, Nova Scotia
B3R 2K9
Contract Project Manager: K.J. KarisAllen, 902-477-4062
Contract Number: W7707-063261/001/HAL
Contract Scientific Authority: R.D. Haggett, 902-427-3443
Defence R&D Canada – Atlantic
Contract Report
DRDC Atlantic CR 2007-112
July 2007
This page intentionally left blank.
Modification of the Laboratory Oil
Condition Test Rig and Wireless Data
Acquisition System to Accommodate a
Schroeder TWS-C Water Sensor
K.J. KarisAllen
PO Box 20039
Halifax, Nova Scotia
B3R 2K9
Project Manager: K.J. KarisAllen, (902) 477-4062
Contract Number: W7707-063261/001/HAL
Contract Scientific Authority: R.D. Haggett, (902) 427-3443
Contract Report
July 2007
Author
Original signed by K.J. KarisAllen
K.J. KarisAllen
Approved by
Original signed by R.D. Haggett
R.D. Haggett
Contract Scientific Authority
Approved for release by
Original signed by Ron Kuwahara for
Jim L. Kennedy
DRP Chair
Terms of release: The scientific or technical validity of this Contract Report is
entirely the responsibility of the contractor and the contents do not necessarily have
the approval or endorsement of Defence R&D Canada.
© Her Majesty the Queen as represented by the Minister of National Defence, 2007
© Sa majesté la reine, représentée par le ministre de la Défense nationale, 2007
Abstract
Over the past several years, DRDC Atlantic has embarked on a program for the evaluation of
existing technologies, as well as the development of new technologies for application in
platform specific health monitoring systems. It has been envisioned that dedicated sensor,
hardware, and software suites may be employed to provide engineering officers with real time
monitoring with respect to the performance of critical ships’ systems. Identified general
applications for dedicated monitoring systems include detecting the ingress of water in highpressure hydraulic systems, assessing the rheological properties of main machinery lubricants,
conducting rotating machinery vibration analysis, and measuring structural strain. The current
study is focused primarily on detecting the ingress of water in high-pressure hydraulic
systems. Specifically, two additional prototype sensors have been integrated into the DRDC
oil condition monitoring test apparatus, a prototype water detection sensor (TestMate TWS-C
TM
), and an oil viscosity sensor (Biode eCup TM).
A major upgrade has been conducted with respect to the hardware/software suite utilized for
the acquisition and control of the DRDC laboratory oil condition monitoring test apparatus to
accommodate the additional sensors. The upgrade includes the design and fabrication of a
custom signal conditioning board capable of supporting up to sixteen input signals from the
condition monitoring sensors. Ten of the sixteen module circuits are capable of supporting
the output signals from both internally and externally powered 4-20 mA current loop
transmitters while the remaining six modules support both single-ended referenced and
differential voltage signals. The resulting sixteen conditioned output signals are routed to a
commercially available 16-bit multifunction board for data capture and storage. The software
suite has been upgraded to include the algorithms required for the digital communication to
the multifunction board via the PC’s internal PCI bus. Modifications to the user interface
(GUI) include the display of the acquired data in a virtual instrument format, and a signal
selectable graphical presentation of an approximately two hour process history for individual
sensors. The programming code has been developed using C++ and compiled for execution
on a Windows 2000TM operating system.
Modifications to the prototype wireless hardware/software suite have also been conducted for
the acquisition of data from the sensors incorporated into a laboratory oil condition
monitoring test apparatus. The hardware and software algorithms have been configured to
support data acquisition from multiple, concurrently active, remote sensor stations. The
acquisition hardware is comprised of a general-purpose multifunction board coupled to a 433
MHz RF transceiver. Transmitted data from the remote sensor stations is received by a RF
base station and bussed to a PC data logger for storage and post processing. Two software
programs have been developed to control the functionality of the system. The first program
includes the algorithms to acquire the data from the sensors attached to an autonomous,
remotely located RF station, and transmits the data to the RF base station. The remote sensor
station program has been designed in accordance with the protocol established by the “open
architecture” TinyOS™ operating system. The second software program developed is a PC
based program, which provides a user interface to parse, analyse, and store the incoming data
packet messages. The programming code has been developed using C++ and compiled for
execution on a Windows XPTM operating system.
i
Résumé
Ces dernières années, RDDC Atlantique a entrepris un programme visant l'évaluation des
technologies existantes et le développement de nouvelles technologies destinées à des
systèmes de surveillance d'état propres à une plate-forme. On envisage d'employer des
capteurs et des matériels et logiciels spécialisés afin de doter les officiers du génie
d'instruments leur permettant de surveiller en temps réel le rendement des systèmes de navire
essentiels. Les applications générales identifiées pour les systèmes de surveillance spécialisés
comprennent la détection de l’entrée d’eau dans les systèmes hydrauliques à haute pression,
l'évaluation des propriétés rhéologiques des lubrifiants de la machine principale, l'analyse des
vibrations des machines tournantes et la mesure des tensions structurelles. La présente étude
vise principalement la détection de l’entrée d’eau dans les systèmes hydrauliques à haute
pression. En particulier, deux capteurs prototypes supplémentaires ont été intégrés à l’appareil
d’essai de surveillance de l’état de l’huile de RDDC ainsi qu’un capteur prototype de
détection d’eau (TestMate TWS-C MD) et un détecteur de viscosité de l’huile (Biode eCup MD).
Une importante mise à niveau a été apportée à la suite matérielle/logicielle d’acquisition du
dispositif d’essai de surveillance d’état de l’huile au laboratoire de RDDC afin de tenir
compte des capteurs supplémentaires. Cette mise à niveau comprend la conception et la
fabrication d’une carte de conditionnement de signal sur mesure, capable de traiter jusqu’à
seize signaux d’entrée provenant des capteurs de surveillance d’état. Dix des seize circuits de
module sont capables de traiter les signaux de sortie des deux émetteurs à boucle de courant
de 4-20 mA à alimentation interne et externe tandis que les six autres modules traitent à la fois
les signaux de tension différentielle et de référence asymétriques. Les seize signaux de sortie
conditionnés ainsi produits sont acheminés vers une carte commerciale multifonction de
16 bits pour la saisie et le stockage des données. La suite logicielle a été mise à niveau afin
d’inclure les algorithmes nécessaires à la communication numérique avec la carte
multifonction par l’intermédiaire du bus PCI interne de l’ordinateur personnel. Les
modifications à l’interface utilisateur (GUI) comprennent l’affichage des données acquises en
format Virtual Instrument (instrument virtuel), et une présentation graphique sélectionnable
par signal, offrant un historique de traitement pour chaque capteur, couvrant environ deux
heures. Le code de programmation a été développé en C++ et compilé pour exécution sur un
système d’exploitation Windows 2000MD.
Des modifications ont également été apportées au prototype de la suite logicielle/matérielle
sans fil pour l’acquisition de données des capteurs incorporés à un appareil d’essai de
surveillance d’état de l’huile en laboratoire. Les algorithmes de la suite logicielle/matérielle
ont été configurés pour permettre l’acquisition de données de multiples stations de détection à
distance simultanément actives. Le matériel d’acquisition se compose d’une carte
multifonction polyvalente couplée à un émetteur-récepteur RF de 433 MHz. Les données
transmises par les stations de détection à distance sont reçues par une station de base RF et
acheminées par bus vers un enregistreur de données d’ordinateur personnel pour stockage et
post-traitement. Deux programmes logiciels ont été développés pour commander les fonctions
du système. Le premier comprend les algorithmes utilisés pour acquérir les données des
capteurs reliés à une station RF autonome à distance et transmettre les données à la station de
base RF. Le programme de la station de détection à distance a été conçu conformément au
ii
protocole établi par le système d’exploitation TinyOSMD à « architecture ouverte ». Le second
programme logiciel développé est axé sur un ordinateur personnel, qui offre une interface
utilisateur pour parser, analyser et stocker les messages qui entrent en paquets de données. Le
code de programmation a été développé en langage C++ et compilé pour exécution sur un
système d’exploitation Windows XPMD.
iii
Executive summary
Introduction
Current practice for the assessment of the degradation/contamination sustained by hydraulic
fluids in marine platforms is to conduct an offsite analysis. In an offsite analysis, a relatively
small quantity of oil is removed from the system and sent to a laboratory. Disadvantages of
this methodology include the time lag between sampling and assessment, the fact that the
small sample volume may not be representative of the entire charge of oil, and the potential
for the introduction of error in the analysis owing to the sampling technique. Recently,
several commercial ventures have been initiated for the development of inline sensors
monitored by electronic hardware systems for the assessment of the properties of oils. These
systems have the capability of providing a real-time assessment of the entire charge of oil.
Results
the acquisition and control of the DRDC laboratory oil condition monitoring test apparatus to
accommodate the additional sensors. The upgrade includes the design and fabrication of a
custom signal conditioning board capable of supporting up to sixteen input signals from the
condition monitoring sensors. Ten of the sixteen module circuits are capable of supporting
the output signals from both internally and externally powered 4-20 mA current loop
transmitters while the remaining six modules support both single-ended referenced and
differential voltage signals. The resulting sixteen conditioned output signals are routed to a
commercially available 16-bit multifunction board for data capture and storage. The software
suite has been upgraded to include the algorithms required for the digital communication to
the multifunction board via the PC’s internal PCI bus. Modifications to the user interface
(GUI) include the display of the acquired data in a virtual instrument format, and a signal
selectable graphical presentation of an approximately two hour process history for individual
sensors. The programming code has been developed using C++ and compiled for execution
on a Windows 2000TM operating system.
iv
Significance
The test apparatus developed as part of this project will provide a platform for the evaluation
of various inline sensor technologies. Incorporation of inline monitoring of oil quality in
marine platforms will provide engineering officers and life cycle managers with a real-time
assessment of the various degradation mechanisms occurring within the engine. With real
time data, a proactive, as opposed to a reactive, approach may be adopted with respect to
equipment health monitoring. While the focus of the current project was on detecting the
ingress of water into hydraulic systems, the degradation/contamination mechanisms
characterized by the apparatus are generally applicable to other systems, such as gearboxes for
propulsion systems, operation of critical equipment (radar systems, armament), as well as
main machinery engine lubricants.
Future Plans
The upgrade and expansion of the laboratory test rig and wireless data transfer capability will
allow DRDC to evaluate new sensor technology to monitor shipboard equipment as it
becomes available.
It is planned to carry out a shipboard trial of selected sensors, in the near future, in an
operational setting. This trial will take place over a six month period and will include ease of
operation, survivability and the determination of the preferred data output format.
KarisAllen, K.J., 2007. Modification of the Laboratory Oil Condition Test Rig and Wireless
Data Acquisition System to Accommodate a Schroeder TWS-C Water Sensor. DRDC
Atlantic CR 2007-112, Defence R&D Canada – Atlantic.
v
Sommaire
Introduction
Habituellement, seule une analyse hors site permet d'estimer la dégradation et la
contamination des fluides hydrauliques sur les plates-formes maritimes. Pour ce faire, l'on
prélève une petite quantité d'huile du circuit de lubrification et on l'expédie en laboratoire.
Cette méthode présente les désavantages suivants : (1) retard entre l'échantillonnage et
l'évaluation, (2) non-représentativité possible de l'échantillon par rapport au volume total
d’huile et (3) introduction possible d'erreurs dans l'analyse causée par la technique
d'échantillonnage. Récemment, plusieurs entreprises commerciales ont été créées en vue du
développement de capteurs en ligne contrôlés par un circuit électronique qui permettent
d'évaluer les propriétés rhéologiques des huiles. Ces systèmes sont capables de produire une
évaluation en temps réel du volume total d’huile.
Résultats
Une importante mise à niveau a été apportée à la suite matérielle/logicielle d’acquisition du
dispositif d’essai de surveillance d’état de l’huile au laboratoire de RDDC afin de tenir
compte des capteurs supplémentaires. Cette mise à niveau comprend la conception et la
fabrication d’une carte de conditionnement de signal sur mesure, capable de traiter jusqu’à
seize signaux d’entrée provenant des capteurs de surveillance d’état. Dix des seize circuits de
module sont capables de traiter les signaux de sortie des deux émetteurs à boucle de courant
de 4-20 mA à alimentation interne et externe tandis que les six autres modules traitent à la fois
les signaux de tension différentielle et de référence asymétriques. Les seize signaux de sortie
conditionnés ainsi produits sont acheminés vers une carte commerciale multifonction de
16 bits pour la saisie et le stockage des données. La suite logicielle a été mise à niveau afin
d’inclure les algorithmes nécessaires à la communication numérique avec la carte
multifonction par l’intermédiaire du bus PCI interne de l’ordinateur personnel. Les
modifications à l’interface utilisateur (GUI) comprennent l’affichage des données acquises en
format Virtual Instrument (instrument virtuel), et une présentation graphique sélectionnable
par signal, offrant un historique de traitement pour chaque capteur, couvrant environ deux
heures. Le code de programmation a été développé en C++ et compilé pour exécution sur un
système d’exploitation Windows 2000MD.
Des modifications ont également été apportées au prototype de la suite logicielle/matérielle
sans fil pour l’acquisition de données des capteurs incorporés à un appareil d’essai de
surveillance d’état de l’huile en laboratoire. Les algorithmes de la suite logicielle/matérielle
ont été configurés pour permettre l’acquisition de données de multiples stations de détection à
distance simultanément actives. Le matériel d’acquisition se compose d’une carte
multifonction polyvalente couplée à un émetteur-récepteur RF de 433 MHz. Les données
transmises par les stations de détection à distance sont reçues par une station de base RF et
acheminées par bus vers un enregistreur de données d’ordinateur personnel pour stockage et
post-traitement. Deux programmes logiciels ont été développés pour commander les fonctions
du système. Le premier comprend les algorithmes utilisés pour acquérir les données des
capteurs reliés à une station RF autonome à distance et transmettre les données à la station de
vi
base RF. Le programme de la station de détection à distance a été conçu conformément au
protocole établi par le système d’exploitation TinyOSMD à « architecture ouverte ». Le second
programme logiciel développé est axé sur un ordinateur personnel, qui offre une interface
utilisateur pour parser, analyser et stocker les messages qui entrent en paquets de données. Le
code de programmation a été développé en langage C++ et compilé pour exécution sur un
système d’exploitation Windows XPMD.
Portée
L’appareil d’essai développé dans le cadre du projet offrira une plate-forme pour l’évaluation
de diverses technologies de détection en ligne. L’incorporation de la surveillance en ligne de
la qualité de l’huile sur les plates-formes maritimes permettra aux officiers du génie et aux
gestionnaire de cycle vie d’évaluer en temps réel les divers processus de dégradation qui se
produisent dans le moteur. À l’aide de données en temps réel, une approche proactive, et non
réactive, peut être adoptée pour la surveillance du bon état de l’équipement. Bien que le
présent projet ait porté sur la détection de l’entrée d’eau dans les systèmes hydrauliques, les
processus de dégradation/contamination caractérisés par l’appareil sont généralement
applicables à d’autres systèmes, par exemple les boîtes d’engrenages des systèmes de
propulsion, l’exploitation d’équipements essentiels (systèmes radar, armement) ainsi que les
lubrifiants des moteurs des machines principales.
Recherches Future
La mise à niveau et l’expansion de l’appareil d’essai en laboratoire et de la capacité de
transfert de données sans fil permettront à RDDC d’évaluer de nouvelles techniques de
détection en vue de la surveillance d’équipements de bord à mesure qu’elles deviennent
disponibles.
Il est prévu de mener, dans un avenir prochain, un essai de capteurs sélectionnés à bord de
navire dans le contexte opérationnel. L’essai, qui aura lieu sur une période de six mois,
portera notamment sur la facilité d’utilisation, la surviabilité et la détermination du format
préféré de sortie des données.
KarisAllen, K.J., 2007. Modification of the Laboratory Oil Condition Test Rig and Wireless
Data Acquisition System to Accommodate a Schroeder TWS-C Water Sensor (modification
de l’appareil d’essai de l’état d’huile et d’un système d’acquisition de données sans fil).
Document CR 2007-112 de RDDC Atlantique, RDDC Atlantique.
vii
viii
Table of contents
Abstract........................................................................................................................................ i
Executive summary ................................................................................................................... iv
Sommaire................................................................................................................................... vi
Table of contents ....................................................................................................................... ix
List of figures ............................................................................................................................ xi
1.
INTRODUCTION......................................................................................................... 1
2.
BACKGROUND........................................................................................................... 2
2.1
Complex Permittivity Theory........................................................................... 2
3.
DEVELOPMENT OF A HARDWARE/SOFTWARE SUITE FOR THE
EVALUATION OF OIL CONDITION MONITORING SENSORS ........................................ 5
3.1
3.2
3.3
4.
General Description of the Mechanical Systems.............................................. 5
3.1.1
Description of the Oil Circulation Loop.............................................. 5
3.1.2
Description of the Sensor Configurations ........................................... 6
System Hardware Development ....................................................................... 8
3.2.1
General Description............................................................................. 8
3.2.2
Description of the Analog Signal Conditioning Interface ................... 8
System Software Development ...................................................................... 12
3.3.1
General Description........................................................................... 12
3.3.2
Oil Conditioning Software Functionality .......................................... 12
DEVELOPMENT OF A WIRELESS DATA ACQUISITION SYSTEM.................. 17
4.1
Laboratory Sensor and RF Module Hardware................................................ 17
4.1.1
General Description........................................................................... 17
4.1.2 Functional Description of Main Hardware Components for the
Laboratory RF Acquisition System ................................................................ 17
4.2
Laboratory System Software Development.................................................... 21
4.2.1 Design and Implementation of the Remote Sensor Module
Software.......................................................................................................... 22
ix
4.2.2 Design and Implementation of Laboratory PC Communication
Software.......................................................................................................... 23
5.
CONCLUSIONS AND RECOMMENDATIONS ...................................................... 29
6.
REFERENCES ............................................................................................................ 30
Appendix A – Software Output Data File Structure................................................................. 31
Appendix B – General Procedural Protocol for Activating the System Hardware and Software
Components of the Laboratory Acquisition and Control System............................................. 33
Appendix C – General Procedural Protocol for Activating the System Hardware and Software
Components of the Wireless RF System .................................................................................. 35
List of symbols/abbreviations/acronyms/initialisms ................................................................ 37
Distribution list......................................................................................................................... 39
x
List of figures
Figure 1.1. Schematic representation of the three main subcomponents associated with a
sensor based health monitoring system. .............................................................................. 1
Figure 2.1. Schematic representation of an impedance bridge circuit........................................ 4
Figure 3.1. Top view of the oil circulation loop utilized. ........................................................... 5
Figure 3.2. Photograph of the EASZ-1TM dielectric sensor. ....................................................... 6
Figure 3.3. Photograph of the Biode eCup TM viscosity sensor. ................................................. 6
Figure 3.4. Photograph of the circulation loop manifold showing the various threaded plug
sensors incorporated into the system for evaluation. .......................................................... 7
Figure 3.5. Photograph of the custom analog electronic interface. ............................................ 9
Figure 3.6. Schematic representation of the circuit utilized for the manifold temperature
sensor................................................................................................................................. 10
Figure 3.7. Schematic representation of the circuit utilized for the manifold pressure
sensor................................................................................................................................. 11
Figure 3.8. Bitmap showing the main GUI associated with the oil condition monitoring
software. ............................................................................................................................ 13
Figure 3.9. Bitmap showing the pop-up window associated with the <System/Calibrate>
command located on the main menu bar........................................................................... 14
Figure 3.10. Bitmap showing the pop-up window associated with the <System/Test
Configuration> command located on the main menu bar. ................................................ 14
Figure 3.11. Bitmap showing the pop-up window associated with the <System/Data
Acquisition> command located on the main menu bar. .................................................... 15
Figure 3.12. Bitmap showing the pop-up window associated with the <System/System
Tuning> command located on the main menu bar. ........................................................... 16
Figure 4.1. Photograph of the MDA300CA™ multifunction I/O board. ................................. 18
Figure 4.2. Photograph of the MPR410CB™ RF transceiver board. ....................................... 19
Figure 4.3. Photograph of the stacked MDA300CA™ and MPR410CB™ arrangement. ....... 19
Figure 4.4. Schematic representation of the wire connector terminal configuration for the
MDA300CA™. ................................................................................................................. 20
xi
Figure 4.5. Photograph of the injection moulded remote station transceiver and enclosure. ... 20
Figure 4.6. Schematic representation of the master/slave communication protocol between the
remote sensor station RF controller and the PC data logger. ............................................ 21
Figure 4.7. Logic flow diagram for the remote sensor station TinyOS™ software controller. 23
Figure 4.8. Logic flow diagram for the PC data logger software controller data
communication thread. ...................................................................................................... 24
Figure 4.9. Bitmap of the main GUI interface associated with the condition monitoring
software controller............................................................................................................. 26
Figure 4.10. Bitmap showing the pop-up window associated with the <System/Calibrate>
command located on the main menu bar........................................................................... 26
Figure 4.11. Bitmap showing the pop-up window associated with the <System/Test
Figure 4.12. Bitmap showing the pop-up window associated with the <System/Data
Acquisition> command located on the main menu bar. .................................................... 27
Figure 4.13. Bitmap showing the pop-up window associated with the <System/Mote
xii
1.
INTRODUCTION
Over the past several years, DRDC Atlantic has embarked on a program for the evaluation of
existing technologies, as well as the development of new technologies for application in
platform specific health monitoring systems. It has been envisioned that dedicated sensor,
hardware, and software suites may be employed to provide engineering officers with real time
monitoring with respect to the performance of critical ships’ systems. Potential ships’
systems for monitoring include main machinery components, as well as critical load bearing
members of the structural hull form. Identified general applications for dedicated monitoring
systems include detecting the ingress of water into high pressure hydraulic systems, assessing
the rheological properties of main machinery lubricants [1], conducting rotating machinery
vibration analysis, and measuring structural strain [2].
In general, a dedicated health monitoring system is comprised of three main subcomponents
(Figure 1.1). The first subcomponent is a sensor, which converts the parameter of interest to
an output signal capable of being measured. The majority of sensors are analog devices,
which are designed and manufactured to be property specific. Sensors are normally designed
to convert the property into an electrical analog output signal. The second subcomponent in
the system is an electronic hardware package, which inputs the analog output signal from the
sensor and converts the signal into a standardized digital format (A/D conversion). As is the
case for many commercial sensors, the hardware may impose amplification and filtering on
the input signal prior to the A/D conversion process. The final subcomponent in the system is
a method of storing the digital signal, which also provides the algorithms for conducting any
online post-processing required. Digital signals are normally routed to a microprocessorbased system, which stores the data on a non-volatile medium. Software or firmware
associated with the microprocessor can be configured to conduct the post-processing required
for the specific application.
Figure 1.1. Schematic representation of the three main subcomponents associated with a sensor based
health monitoring system.
The current study is focused on the evaluation of sensors capable of detecting the ingress of
water into high-pressure hydraulic systems using the DRDC oil condition monitoring test
system. Owing to the hardware capacity limitations associated with the existing system, an
upgrade to the hardware/software suite has been proposed for the integration of the additional
sensors. Specifically, a sixteen channel signal conditioning and A/D conversion hardware
suite has been developed for acquiring the signals generated by the sensors. A PC based
software suite has been developed for controlling the hardware, displaying the real- time
sensor data, and data storage. The existing wireless hardware/software suite has also been
modified to include the additional sensors for the acquisition and transmission of data from
multiple remotely located sensor sites to a single-node, personal computer (PC) base station.
1
2.
BACKGROUND
In general, methodologies for assessing the degradation/contamination sustained by hydraulic
oil or main machinery lubricants can be divided into three broad categories, namely, offsite
analysis, onsite offline analysis, and online real-time analysis [3,4]. In an offsite analysis, a
relatively small quantity of oil is removed from the system and sent to a laboratory.
Disadvantages of this methodology include the time lag between sampling and assessment,
the fluid analyzed may not be representative of the entire charge, and the potential for the
introduction of error into the analysis owing to the sampling technique. While onsite offline
methodologies reduce the time lag between sampling and analysis, this methodology still
contains the remaining drawbacks associated with offsite methodologies.
Recently, several commercial ventures have been initiated for the development of inline
sensors monitored by electronic hardware systems for the assessment of the properties of
various oils [4]. These systems have the capability of providing a real-time assessment of the
entire charge of oil to the lifecycle equipment manager, facilitating a proactive approach to
predicting and trouble shooting potential problems. Proprietary sensor systems have been
developed based on several oil properties including conductance, relative dielectric constant,
magnetic permeability, infrared transmission spectroscopy, X-Ray fluorescence spectroscopy,
and acoustic impedance. While many of these systems are still in the prototype development
stage, systems have become available for evaluation. DRDC Atlantic has procured several
inline prototype systems for evaluation which exploit changes in the complex permittivity of
the lubricant, including, a Lubrigard Oil Condition SensorTM [5], an ANALEXrs SensorTM [6],
an EASZ-1 Sensor TM [7] and a Schroeder TestMate TWS-C Sensor [8]. DRDC has also
procured a prototype Biode eCup TM sensor [9] designed to monitor the viscosity of oil using
an acoustic impedance technique.
2.1 Complex Permittivity Theory
At a fundamental level, systems which utilize changes in the dielectric constant of an oil to
determine its degradation are monitoring the changes in the relative permittivity (εf) of the
fluid as represented by:
ε f = ε r .ε o
(2.1)
where εr is the relative permittivity (dielectric constant) and εo is the permittivity of free
space. While the permittivity of free space is a wholly real value, the relative permittivity of
most oils consists of a complex relationship given as [10]:
ε r = ε real − jε imaginary
(2.2)
where the real and imaginary components represent an energy storage and energy dissipation
term, respectively. Thus, equation 2.2 may also be represented by:
2
ε r = ε (1 − j Tan δ )
(2.3)
where δ is the phase angle and is dependent on the ratio of the imaginary to real components
of the complex permittivity. While the dynamic range of the complex composite value
(dielectric constant) for typical oils over their usable life cycle is very limited (2.2-2.8), the
dynamic range of the jTan δ component can be as much as 20:1 [10]. Thus, while the
dielectric constant may be utilized as a parameter for monitoring the degradation of oil, Tan δ
(phase angle) provides increased sensitivity to changes in quality. Both the LubrigardTM and
ANALEXrsTM sensor systems monitor the change in Tan δ as an indicator of oil quality
[6,10].
Typical sensor head designs (such as the Lubrigard TM, ANALEXrs TM, EASZ-1TM and
Schroeder TestMate TWS-C systems) are comprised of coaxial electrodes where the oil
(dielectric) resides in the gap between the inner and outer electrodes. Thus, the sensor head is
configured as a capacitance which can be represented as:
C =εf .
A
d
(2.4)
where A and d represent the effective surface area of the electrodes and gap spacing between
the electrodes, respectively. Thus, for a given ratio of A/d, the complex capacitance of the
fluid is given by:
C = ε (1 − j Tan δ ).
A
d
(2.5)
C f = Co (1 − j Tan δ )
(2.6)
or, alternatively,
While the impedance of the real component of equation 2.6 is independent of the imposed
input signal frequency, the impedance of the imaginary term is a function of applied
frequency as given by:
Z=
1
jω C
(2.7)
Several electrical configurations including RC circuits, RLC oscillators, and RC bridge
configurations may be employed to monitor either the composite complex capacitance or the
Tan δ associated with the sensor head. While a simple RC circuit is relatively easy to deploy,
it normally requires some post processing of the data to generate the parameters of interest.
RLC oscillator circuits have the advantage that the capacitative component of the sensor head
can be balanced against a circuit inductance to generate a condition of phase resonance. At
conditions of phase resonance, the equivalent impedance of the circuit is real and Tan δ can
be directly related to the output signal across the resistive element. One drawback of this
circuit, however, is the relatively narrow band width of capacitance over which resonance is
3
effectively established. Bridge circuits (Figure 2.1) are utilized in numerous sensor
conditioning circuits where the relative change in the sensor output signal is small over the
dynamic range of interest. Typically, the sensor provides the impedance for one of the arms
of the circuit. In this configuration, the circuit can be constructed to balance the initial
impedance of the sensor head. Thus, the output from the bridge circuit represents only the
change in the sensor impedance against fixed elements of known impedance. Bridge circuits
are normally employed for signals which require significant amplification prior to
measurement.
Figure 2.1. Schematic representation of an impedance bridge circuit.
4
3.
DEVELOPMENT OF A HARDWARE/SOFTWARE
SUITE FOR THE EVALUATION OF OIL CONDITION
MONITORING SENSORS
3.1 General Description of the Mechanical Systems
3.1.1 Description of the Oil Circulation Loop
The primary objective for the oil circulation loop was the simulation of the temperature and
pressure characteristics of the hydraulic or lubrication system of interest. Figure 3.1 shows a
top view of the oil circulation loop utilized for this study. The system capabilities include the
simulation of temperature and pressure ranges between approximately 30oC to 130oC and 45
psig to 90 psig, respectively. A detailed description of the functionality of the oil circulation
loop has been provided in a previous study [1].
Figure 3.1. Top view of the oil circulation loop utilized.
5
3.1.2 Description of the Sensor Configurations
Figure 3.2 to Figure 3.4 show the sensors integrated into the oil circulation loop. In general,
two mechanical connection configurations were provided by the various manufacturers of the
devices. The first configuration (Figure 3.4) was a plug arrangement where the sensor was
inserted into the flow stream via a threaded penetration. Plug sensors were incorporated into
the system by constructing a stacked manifold assembly where the segments were machined
to the coupling requirements of individual sensors. The various plug devices included
LubrigardTM , ANALEXrsTM , and Schroeder TestMate TWS-C dielectric sensors, as well as
automotive temperature and pressure sensors. The second configuration (Figure 3.2 and
Figure 3.3) was a flow through arrangement where the sensor was shrouded within a
containment vessel with input and output ports. Flow through sensors were incorporated into
the system by direct coupling to the oil circulation circuit. It should be noted that while the
EASZ-1TM dielectric sensor was coupled into the pressure side of the circulation loop, the
Biode eCup TM viscosity sensor was included in the oil return line owing to the pressure
limitations associated with the sensor configuration.
Figure 3.2. Photograph of the EASZ-1TM dielectric sensor.
Figure 3.3. Photograph of the Biode eCup
6
TM
viscosity sensor.
Pressure Sensor
Schroeder Oil Condition Sensor
Temperature Sensor
ANALEX Oil Condition Sensor
Lubriguard Oil Condition Sensor
Figure 3.4. Photograph of the circulation loop manifold showing the various threaded plug sensors
incorporated into the system for evaluation.
7
3.2 System Hardware Development
3.2.1 General Description
The electronic system control and feedback hardware was comprised of two
functional components. The first component was a custom designed analog signal
conditioning interface which provided power to, and conditioned signals from, the
various sensors incorporated into the system. Owing to the requirements of the
connection of an RF acquisition and transmission device to these signals, it was
determined that the maximum magnitude of the conditioned signals should be limited
to approximately 5 Vdc. The second component was a commercially available multifunction board which provided a digital interface to decoded and executed command
signals generated by the software via the microprocessor’s internal PCI bus. The
digital interface was configured to provide control to the various devices incorporated
into the system. The following sections provide design detail for the analog signal
conditioning interface constructed.
3.2.2 Description of the Analog Signal Conditioning Interface
Figure 3.5 shows a photograph of the custom analog signal conditioning interface developed
for this project. The various components of the analog interface were customized to the
requirements of the individual sensors incorporated into the system (Figure 3.2 – Figure 3.4).
In general, two types of signals were generated by the various sensors configured into the
system namely, voltage signals and current loop signals. The printed circuit board fabricated
for this study included a total of ten (10) current loop modules and six (6) voltage input
modules. The design of the current loop modules was generalized for the integration of both
internally and externally powered current loop devices. Configuration of the modules in
accordance with the sensor specific power requirements was affected through the wiring
arrangement of the four-pin header connector associated with each module. SPST toggle
switches were included for each current loop module to provide activation control for
individual sensors. Precision 4-20 mA current loop receivers were utilized to convert the loop
signals to the voltage signals required by the A/D converter. The design of the receiver
included the insertion of a 75 ohm resistor in the loop which generated a maximum voltage
drop of approximately 1.5 V in the circuit. Internal offsets and gains within the receiver were
designed to provide a linear 0-5 Vdc output signal from the integrated circuit.
The design of the voltage input modules was generalized for the integration of both single
ended referenced and differential signals. Configuration of the modules in accordance with
the sensor specific requirements was affected through the wiring arrangement of the four-pin
terminal block connector associated with each module. Precision differential instrumentation
amplifiers were utilized to condition the sensor input voltage signals for subsequent
digitization by the A/D converter. The design of the circuit included options for adjusting the
output signal gain, as well as providing a voltage partitioning circuit for sensor technologies
based on differential resistance.
8
Ten (10) of the sixteen (16) available circuit modules were utilized for the sensors
incorporated into the current configuration of the condition monitoring oil circulation loop
(six current loop and four voltage input modules). Sensor specific analog circuit interfaces
included:
Figure 3.5. Photograph of the custom analog electronic interface.
a) Reservoir Temperature Sensor
The reservoir temperature signal was utilized for the closed loop control of the temperature of
the oil reservoir. The sensor utilized for this purpose was a type T thermocouple. While
thermocouples do not require input power, the signal generated by a type T thermocouple is
typically in the order of millivolts and, therefore, requires amplification in order to provide
acceptable sensitivity for digitizing. Thus the low-level differential signal of the
thermocouple was provided as input to a differential instrumentation amplifier with a gain of
approximately 500. A direct calculation of the temperature associated with the output signal
(from published thermocouple relationships) was facilitated through the utilization of a
separate precision temperature IC to determine a cold junction reference temperature.
b) Manifold Temperature Sensor
Since a temperature drop will occur between the temperature controlled reservoir and the
sensor evaluation manifold, a standard automotive temperature sensor was incorporated into
the manifold to monitor the temperature in the manifold cavity. The sensor utilized was a
resistive type sensor where the resistance decreases with increasing temperature. Typical
ambient temperature resistance (Rt) of the sensor employed was approximately 12,000 ohms.
The circuit utilized for this sensor is shown schematically in Figure 3.6. The input signal to
9
the circuit was a 5Vdc power supply. A current limiting resistor (Rf) was inserted at the front
end of the circuit to provide a measure of protection to the sensor. The ratio of Rf/Rt
employed for this circuit was approximately 9/1. The nodal voltage generated between Rf
and Rt provided input to the terminals of a precision instrumentation amplifier. A gain of
approximately 10 was applied to the instrumentation amplifier. Thus, the theoretical output
from the circuit will vary from approximately 5 Vdc at ambient temperature to 0 Vdc
dependent on the voltage partitioning associated with the sensor resistance.
Figure 3.6. Schematic representation of the circuit utilized for the manifold temperature sensor.
c) Manifold Pressure Sensor
A standard 0-551 kPa (0-80 psig) automotive pressure sensor was incorporated into the
manifold to monitor the pressure in the manifold cavity. A resistive type sensor was utilized
where the sensor resistance increased with increased internal pressure. Full scale resistance
(Rp) of the sensor employed was approximately 180 ohms. The circuit utilized for this sensor
is shown schematically in Figure 3.7. The input signal to the circuit was a 5Vdc power
supply. A current limiting resistor (Rf) was inserted at the front end of the circuit to provide a
measure of protection to the sensor. The ratio of Rf/Rp employed for this circuit was
approximately 9/1. The nodal voltage generated between RL and RS provided input to the
terminals of a precision instrumentation amplifier. A gain of approximately 10 was applied to
the instrumentation amplifier. Thus, the theoretical output from the circuit will vary from
approximately 0 Vdc (at 0 kPa) to 5 Vdc (at 551 kPa) dependent on the voltage partitioning
associated with the sensor resistance.
d) LubrigardTM Oil Condition Monitoring Sensor
The LubrigardTM oil condition monitoring sensor was configured as a self contained
electronics package requiring a 24 Vdc power supply. The electronics did not contain either
analog or digital interfaces which could be exploited for automated data acquisition. Thus
while the system sensor was incorporated into the manifold, data collection for evaluation
purposes must be conducted manually from the sensor’s dedicated digital display.
10
Figure 3.7. Schematic representation of the circuit utilized for the manifold pressure sensor.
e) ANALEXrsTM Oil Condition Monitoring Sensor
The ANALEXrsTM oil condition monitoring sensor was configured as a self contained
electronics package requiring a 24 Vdc power supply. The electronics contain both an analog
and a digital (RS232) interface. The digital interface was configured and ported to a separate
microprocessor for data acquisition using a HyperTerminalTM software interface. The analog
output interface consisted of a 4-20 mA current loop. A precision current loop receiver was
integrated into the 4-20 mA loop to provide the conversion to a voltage signal required as
input to the multi-function board analog to digital converter. The output from the current loop
receiver varies from approximately 0.0 Vdc to 5.0 Vdc dependent on the Tan δ associated
with the complex permittivity of the oil being measured.
f) EASZ-1TM Oil Water Sensor
The EASZ-1TM oil water sensor was configured as a self contained electronics package. The
system was powered from an integral 4-20 mA current loop. The electronics contain both an
analog and a digital (RS232) interface. The digital interface was configured and ported to a
separate microprocessor for data acquisition using a HyperTerminalTM software interface.
The analog output interface consisted of a 4-20 mA current loop. A precision current loop
receiver was integrated into the 4-20 mA loop to provide the conversion to a voltage signal
required as input to the multi-function board analog to digital converter. The output from the
current loop receiver varies from approximately 0.0 Vdc to 5.0 Vdc dependent on the water
content of the oil being measured.
g) Schroeder TestMate TWS-C Oil Water Sensor
The Schroeder TestMate TWS-C oil water sensor was configured as a self contained
electronics package requiring a 24 Vdc power supply. The electronics contained two 4-20
mA current loop output signals representing percent water saturation of the oil and
temperature. Precision current loop receivers were integrated into the 4-20 mA loop to
provide the conversion to a voltage signal required as input to the multi-function board analog
11
to digital converter. The output from the current loop receivers varies from approximately 0.0
Vdc to 5.0 Vdc dependent on the water content and the temperature of the oil being measured.
h) Biode eCup TM viscosity sensor
The Biode eCup TM viscosity sensor was configured as a self contained electronics package
powered through a 110 VAC AC/DC converter. The electronics contain both a dedicated
digital display and two 4-20 mA current loop output signals representing viscosity and
temperature. Precision current loop receivers were integrated into the 4-20 mA loop to
provide the conversion to a voltage signal required as input to the multi-function board analog
to digital converter. The output from the current loop receivers varies from approximately 0.0
Vdc to 5.0 Vdc dependent on either the viscosity or the temperature of the oil being measured.
3.3 System Software Development
The DRDC oil conditioning monitoring software is an R&D oriented software package
designed for bi-directional communications between a PC and the interface electronics. It also
functions as a general-purpose logger for the acquired sensor data. Once the system has been
configured, data base generation and maintenance is self-supervising. Using this system
requires no previous experience with computers. The system has a single control display
which allows the operator complete access to the program functions. To initiate the program
and generate the control display, choose the Cond07 icon from the Windows™ desktop.
The software package consists of a single executable (Cond07.exe) and a dynamic link library
(daqx.dll), which combine to generate a custom designed virtual instrument executing the data
acquisition and control sequences. The programming language used to program the system
was C++ using a Borland 32 bit compiler to assemble the C++ code into machine code. The
system was designed for Windows 2000TM, a 32 bit environment and will not execute
properly in 16 bit environments such as DOS or Windows 3.1.
3.3.2 Oil Conditioning Software Functionality
Figure 3.8 shows a bitmap of the main screen GUI associated with the software suite. The
functionality of the GUI is divided into four general components. The main menu bar
(located at the top of the GUI) is used to access several pop-down window commands. The
pop-down windows associated with the <System> command are used to initialize the data
storage file identification parameter, the data acquisition display, system calibration
parameters, data storage configuration, and system PID control tuning parameters. The
<System\Save As> command is used to initialize the data storage file identification. The
format of the resulting output file is provided in Appendix A. The file identification
parameter should be initialized prior to activating the software control algorithms, as well as
the AC line power to the custom hardware interface boards. The general procedural protocol
for activating the laboratory acquisition control system is provided in Appendix B.
12
Figure 3.8. Bitmap showing the main GUI associated with the oil condition monitoring software.
Figure 3.9 shows a bitmap of the pop-up window activated by the <System/Calibrate> option.
This window consists of a series of edit boxes which facilitate user input of the calibration
constants associated with a particular sensor signal. The calibration equation is in the form of
a second order polynomial which allows the calibration of nonlinear relationships between the
acquired output sensor voltage and the respective engineering units. The second order
constant is entered in the left side box, first order constants in the left-center box, and the zero
order term in the right-center box for each sensor, respectively. The right side box contains
the engineering units of the corresponding calibration relationships.
Figure 3.10 shows a bitmap of the pop-up window activated by the <System/Test
Configuration> option. This window consists of a series of edit boxes which facilitate user
input of the sensor set point values (left side boxes). The window also provides a series of
edit boxes for the user specified input with respect to the maximum band width about the set
point. The band width is used to determine the upper control limits (UCL) and the lower
control limits (LCL) in the main display window. The band width values are used in the
calculation of both warning (yellow) and outside of range (red) limits. Fine adjustment of
individual UCL and LCL values may be affected through the track-bars provided by each
virtual instrument in the main window display.
13
Figure 3.9. Bitmap showing the pop-up window associated with the <System/Calibrate> command
located on the main menu bar.
Figure 3.10. Bitmap showing the pop-up window associated with the <System/Test Configuration>
command located on the main menu bar.
14
Figure 3.11 shows the pop-up window activated by the <System/Data Acquisition> option.
The window is used to configure the structure of the data file saved to the root directory
during test execution. It is comprised of a single scrollbar box and a series of On/Off radio
buttons. The scrollbar box is used to adjust the time (in minutes) between successive data
save operations. The On/Off radio buttons corresponding to sensors activate data save
operations for respective sensor values during the save operation. Activating the Off radio
button results in a zero entry for that particular sensor (note the overall structure of the file
remains constant).
Figure 3.11. Bitmap showing the pop-up window associated with the <System/Data Acquisition>
Figure 3.12 shows a bitmap of the pop-up window activated by the <System/System Tuning>
option. This window is used to adjust the gain constants associated with the proportional,
integral and derivative gains which are used to calculate the command duty cycle of the pulse
width modulated control signal of the heater element submerged in the reservoir oil bath. The
feedback control signal used to calculate the error associated with the closed loop control is
the temperature recorded from the type T thermocouple submerged in the oil bath. Tuning
systems with unidirectional (heating only) forcing functions are normally affected by first
adjusting the proportional gain (integral and derivative gains are initially set to zero) until the
observed temperature of the system plateau is below the desired set point temperature.
Excessive proportional gain will normally result in non-acceptable over-shoot fluctuations of
the temperature. The integral gain is subsequently increased until the set point temperature is
maintained within an acceptable control band width. For the relatively long frequency
response time constants (τ) normally associated with closed loop temperature control, the
influence of derivative gain is typically minimal, and thus, the derivative gain constant is
normally set close to zero.
15
Figure 3.12. Bitmap showing the pop-up window associated with the <System/System Tuning>
The main body of the GUI is divided into three general sections. The upper section of the
GUI contains ten virtual dial indicator instrument displays for presenting the sensor data
received from the signal conditioning hardware. Each virtual instrument displays data
including the identification of sensor signal, the magnitude of real-time process variable and
the corresponding units, the set-point variable, the magnitude of the alarm variable, and the
magnitude of the zero degree dial position variable. Virtual dial indicator instruments can be
individually configured (using the trackbars at the bottom of each dial indicator) for adjusting
the range and the sensitivity as required for the sensor being monitored. For the instruments
configured into the current system the magnitude of the warning signal (yellow) has been set
to ninety percent of the full scale range of the indicator.
The lower left-hand section of the display provides a graphical representation of the data
associated with an approximately two hour process history for an individual sensor. Process
histories for any of the signals (virtual instruments) configured into the system can be
accessed by utilizing the vertical scrollbar provided.
The lower right-hand section of the GUI provides the interface to the control section of the
program. Once the system is configured, the automated acquisition and control algorithms
may be activated by clicking the <Start> radio button provided. Deactivation of the system is
achieved by clicking the <Stop> radio button provided.
16
4.
DEVELOPMENT OF A WIRELESS DATA
ACQUISITION SYSTEM
For remote sites, radio frequency (RF) wireless acquisition and communication of sensor data
is rapidly gaining popularity. This increased popularity arises, in part, from the reduced hard
wiring requirements between the sensor locations and a central data acquisition/storage base
station. While various forms of wireless communication have been available for a
considerable time, recent advances in bandwidth and associated hardware protocols have
made it feasible to transmit large blocks of data wirelessly in a secure and expeditious
manner. Also, the power requirements of newer generation IC digital devices have
continually decreased, creating the feasibility of conducting long-term monitoring without
continual replacement of the power source.
In general, two broad categories of wireless communications devices are commercially
available. The first category encompasses dedicated hardware devices for performing a
predefined specific task. Digital logic and the communication protocols for these devices are
“hardwired” into the electronic circuitry. One of the benefits of this type of design is the
increased data transmission rate which can be achieved. However, these systems tend to be
inflexible with respect to changes in functionality.
The second category consists of devices where the designed hardware functionality is general
and is not dedicated to a specific task. In these devices, the end use functionality is controlled
via an onboard microprocessor and is generated through either downloading software
algorithms into volatile memory at runtime or by burning the software into non-volatile
memory firmware (such as an EPROM) prior to bootstrapping the device. While this
category of devices tends to require more up front development (software algorithms), its
main benefit is increased flexibility for a variety of end use functionalities.
4.1 Laboratory Sensor and RF Module Hardware
The main objective of this study was the integration of a hardware/software suite which was
capable of supporting multiple remote stations for acquiring data from several oil condition
monitoring sensors. As a secondary objective, the hardware platform should provide the
foundation for the evaluation of other types of sensor technologies.
4.1.2 Functional Description of Main Hardware Components for
the Laboratory RF Acquisition System
The laboratory RF system was configured to acquire signals from six of the ten available oil
condition hardware sensor signals (Figure 3.2 - Figure 3.4). These sensor signals included:
the oil quality signal from the ANALEXrsTM dielectric sensor, the percent water signal from
the EASZ-1TM dielectric sensor, the percent saturation and oil temperature signals from the
Schroeder TestMate TWS-C dielectric sensor, and the oil viscosity and temperature signals
17
from the Biode eCup TM acoustic impedance sensor. Detailed descriptions of the primary
signal conditioning circuits associated with each of the sensors have been provided in Section
3.2.2. In order to meet voltage range requirements of the RF multifunction board integrated
into the hardware, voltage partitioning circuits were integrated into each primary 0-5 Vdc
signal output circuit to provide a secondary 0-2.5 Vdc output range. Two eight-pin terminal
block connectors were provided on the signal conditioning board for routing the secondary
signals to the RF multifunction board via a DB9 enclosure chassis connector. The DB9
connector was also utilized to route an isolated 3.3 Vdc power source to the RF assembly.
The requirements for the acquisition and communication of the sensor data to a base station
were achieved by coupling a commercially available multi-function data acquisition board to
a 433 MHz wireless transmitter. Figure 4.1 and Figure 4.2 show photographs of the
multifunction board (MDA300CA™ [11]) and the wireless transceiver (MPR410CB™ [12]),
respectively. The two devices couple in a stacked arrangement (Figure 4.3) via a 51 pin on
board connector. In this configuration, the multifunction board is a slave device to the
transceiver board. The ATMEGA 128™ microprocessor contained on the transceiver
communicates with and controls the multi-function board synchronously via an IC2 bus
protocol. The ATMEGA 128™ also controls the transmission and receipt of data between the
remote sensor station and the system base station. The transmission and receipt is a full
duplex asynchronous protocol at a data transmission rate of 56 KB/sec. The base station is
comprised of a transceiver board (MPR410CB™) stacked on a converter board
(MIB510CA™ [12]), which is connected to the PC data logger via a RS-232 asynchronous
communications port.
The port IO on the multi-function board is provided in Figure 4.4. A more complete electrical
specification for the multi-function board is provided in reference [11]. Sensor voltages were
monitored using six of the 12-bit single end referenced A/D ports (A0-A5) on the MDA
300CA™. The differential voltage resolution of the A/D converter was approximately 0.6
mV. The remote station hardware assembly was housed in an injection molded plastic
enclosure Figure 4.5).
Figure 4.1. Photograph of the MDA300CA™ multifunction I/O board.
18
Figure 4.2. Photograph of the MPR410CB™ RF transceiver board.
Figure 4.3. Photograph of the stacked MDA300CA™ and MPR410CB™ arrangement.
19
Figure 4.4. Schematic representation of the wire connector terminal configuration for the MDA300CA™.
Figure 4.5. Photograph of the injection moulded remote station transceiver and enclosure.
20
4.2 Laboratory System Software Development
Three separate software programs were required to facilitate the acquisition, transmission and
storage of the lubricant conditioning data from the remote sensor station to the system PC.
The first program included a series of algorithms to acquire the data from the oil sensors
attached to an autonomous, remotely located RF station. The program also contains the
algorithms to wirelessly receive and transmit data to and from the base station, respectively.
The second program required is the base station software algorithm capable of receiving
messages from several remote stations and bussing the messages to a PC. This software
algorithm must also be capable of receiving a message from the PC and generating a RF
broadcast message to the appropriate, remotely located sensor station. The final software
program required is a PC based program, which provides a user interface to parse, analyse,
and store the incoming data packet messages. This program must also be capable of
generating and bussing messages to the base station to provide a means of controlling the
online functionality of the remotely located sensor station.
The overall communications protocol between the three software programs is shown
schematically in Figure 4.6. The master software controller in this system is the program
being executed in the remotely located condition monitoring sensor RF module. The initiation
of the inter-device communications sequence is keyed on the transmission of a data packet
message from the remote oil sensor controller. The transmitted data packet is received by the
base station software, where it is identified as a data packet with the appropriate destination
address (the system allows for multiple base stations to operate concurrently). For a properly
addressed data packet, the base station software converts the incoming RF protocol into a
compatible RS-232 signal for output to a PC. In this fashion, the base station acts as a
primary filter and a gateway from the remote station CPU to the PC CPU. The software
executing within the PC continuously polls the status of the RS-232 port for incoming
messages. Upon identification of an incoming message, the software imports the message and
exports an acknowledgement message back to the base station, which executes a transmission
broadcast back to the originating remote RF station. Thus, the PC software is slaved to the
remotely located sensor software controllers.
Figure 4.6. Schematic representation of the master/slave communication protocol between the remote
sensor station RF controller and the PC data logger.
For this study, the generic base station algorithms used were provided as part of the RF
hardware acquisition. The following sections detail the two customized software programs
developed to 1) acquire and transmit data from the remote sensor station and 2) receive and
21
transmit data to and from the PC base station, as well as provide the user interface to control
the online functionality of several concurrently active remote sensor stations.
4.2.1 Design and Implementation of the Remote Sensor Module
Software
The software suite developed for the remote sensor station was designed in accordance with
the protocol established by the “open architecture” TinyOS™ [13] operating system.
TinyOS™ provides a user defined, component-based operating system specifically developed
for embedded microprocessor hardware controllers. The system is based on a pre-emptive
structure of nested components comprised of hardware event handlers and tasks. At runtime,
the operating system creates two threads of execution to handle events and tasks separately.
Under the TinyOS™ model, hardware event handlers may pre-empt a currently executing task
but a task cannot pre-empt an event handler. Therefore, a concurrency model has been
included into the TinyOS™ system structure to minimize the potential of “data races”.
Programs are developed using the protocols established by the NesC compiler. The compiler
is comprised of a reduced set of “C” programming instructions, which support the
concurrency model required by the TinyOS™ operating system. NesC programs are
comprised of two types of components, namely, “modules” and “configurations”. Modules
contain the application code required to execute a specific function by the microprocessor.
Configurations provide the information required to assemble or “interface” several differing
functional modules together into a single runtime executable. The “interface” provides the
point of access information required to execute a section of component code. The
combination of configuration components and interfaces facilitates deep “nesting” within the
programming structure of the application.
The software developed for the remote RF sensor station required two main functional
algorithms. The function of the first algorithm is to control the functionality of the MDA
300CA multifunction board. The algorithm acquires the voltage data associated with the
various oil condition sensors. Figure 4.7 schematically represents the simplified logic flow of
the code implemented to control the I/O functionality of the MDA300CA™ hardware.
During the “boot strap” of the program code, the initialization/start section of the program sets
the A/D converter event timer to an initial data acquisition channel scan interval of
approximately 1 second. Upon the hardware interrupt associated with the A/D event timer,
the event handler initiates the A/D conversion of the voltages associated with the conditioned
sensor signals (port A0-A5). Subsequent to conversion, the program checks for a request to
change the data acquisition scan interval which is associated with the most recently received
message from the RF base station. If positive, the A/D event timer is reset to the new interval
and control is passed to the code section responsible for the transmission of the sensor data to
the RF base station. The transmission algorithm constructs the appropriate array structure
containing message identification filters (Group Base Station ID and Remote Station ID).
Following the identification filters, a 29-byte data block (containing the A/D values) is
configured into the message. The final two bytes of the data message represent a 16-bit CRC
value to ensure data integrity at the receiver. A broadcast message is executed which
22
transmits the entire data message to the base station. An acknowledge message event timer,
which will wait for 5 seconds, is set upon message transmission. If the acknowledge message
is received within the timeout interval, the code identifies it as a message relevant to this
particular remote station and subsequently parses out any received processor commands (such
as reset the data acquisition scan interval) which are embedded in the message. If the
acknowledge message is not received in the timeout period, the software resends the
transmission message and resets the acknowledge timer.
Once the software code was developed, it was compiled into machine code and downloaded
into the remote sensor station firmware (burned into an EPROM). This was achieved by
stacking the MPR410CB™ RF transceiver section of the remote station hardware (containing
the ATMEGA 128 microprocessor and EPROM) onto the base station MIB510CA™
communications interface board using the 51 pin onboard connector provided. The machine
code was downloaded into the MPR410CB™ hardware by using the functions contained
within the “cygwin” shell program provided.
Figure 4.7. Logic flow diagram for the remote sensor station TinyOS™ software controller.
4.2.2 Design and Implementation of Laboratory PC
Communication Software
The DRDC laboratory oil condition monitoring software is an R&D oriented software
package designed for bi-directional communications between a PC and the RF base station. It
also functions as a general-purpose logger for the acquired sensor data. Once the system has
been configured, data base generation and maintenance is self-supervising. Using this system
requires no previous experience with computers. The system has a single control display
which allows the operator complete access to the program functions. To initiate the program
23
and generate the control display, choose the RF06_02 shortcut icon from the Windows™
desktop.
The software package consists of a single executable (RF06_02.exe) and two dynamic link
libraries (CW3215.dll and TvicPort.dll), which combine to generate a series of custom
designed virtual instruments executing the data acquisition and control sequences. The
programming language used to program the system was C++ using a Borland 32 bit compiler
to assemble the C++ code into machine code. The system was designed for Windows XPTM, a
32 bit environment and will not execute properly in 16 bit environments such as DOS or
Windows 3.1. A third party dynamic link library was used to facilitate the direct port access
required for the computer to base station asynchronous communication.
Bi-directional communication between the RF base station and the PC software is conducted
over a RS-232 asynchronous bus at a data transmission rate of 56.7 KB/sec. Within the
program, the functionality of the protocol is handled within a dedicated program thread,
which is executed upon activation of the “Start” status in the main user interface display.
Figure 4.8 represents schematically a simplified version of the thread program flow algorithm.
Upon activation, the thread enters into a loop which continually polls the input “data ready”
bit of the UART hardware register for the appropriate communications port (COM10x03FD). Upon receipt of a logic high status for this bit (data available for input), the
program activates a loop (controlled by a countdown timer) which initializes a buffer with the
byte data presented to the port register (0x03FE) for an approximately 0.1 second interval.
Once this loop has timed out, the algorithm checks the integrity of the incoming data packet
(i.e. packet length, 16-bit CRC value and position of the group ID byte). If the integrity of the
message packet is considered to be intact, the algorithm subjects the packet to a series of
parsing filters, which isolate the remote station ID and the sensor data associated with the
message. If the software configuration of the remote sensor station is initialized as “On”, the
algorithm saves the sensor data to the output file specified. In the final step of the algorithm,
the thread constructs a “message received” acknowledge data packet, which is transmitted
back to the base station for general broadcast. The output message contains the ID specific
data contained within the input message received (will only be acknowledged by the
originating remote RF station upon general broadcast). The acknowledge message also
contains any command messages (such as a change in the acquisition scan interval) which are
to be executed by the remote RF station.
Figure 4.8. Logic flow diagram for the PC data logger software controller data communication thread.
24
A bit map of the main graphical user interface (GUI) associated with this program is shown in
Figure 4.9. The main display is divided into three main sections. The upper section of the
GUI contains six virtual dial indicator instrument displays for presenting the sensor data
received from the remote RF acquisition station. Each of the virtual dial indicator instruments
can be individually configured (using the trackbars at the bottom of each dial indicator) for
adjusting the range and the sensitivity as required for the sensor being monitored.
Global configuration of the system is facilitated by the options accessible through the
<System> command on the main screen menu bar. The <System/Calibrate> option (Figure
4.10) consists of a series of edit boxes which facilitate user input of the calibration constants
associated with a particular sensor signal. The calibration equation is in the form of a second
order polynomial which allows the calibration of nonlinear relationships between the acquired
output sensor voltage and the respective engineering units. The second order constant is
entered in the left-side box, first order constants in the left-center box, and the zero order term
in the right-center box for each sensor, respectively. The right-side box contains the
engineering units of the calibration relationship. It should be noted that owing to the software
configuration, calibration constants should be in the form of oC for temperature and psig for
pressure (dielectric calibration units for the sensors incorporated into the system are chosen
arbitrarily by the user).
Figure 4.11 shows a bitmap of the pop-up window activated by the <System/Test
Configuration> option. This window consists of a series of edit boxes which facilitate user
input of the sensor set point values (left-side boxes). The window also provides a series of
edit boxes for the user specified input with respect to the maximum band width about the set
point. The band width is used to determine the upper control limits and the lower control
limits in the main display window. The band width values are used in the calculation of both
warning (yellow) and outside of range (red) limits. Fine adjustment of individual values may
be affected through the trackbars provided for each virtual instrument display.
Figure 4.12 shows the pop-up window activated by the <System/Data Acquisition> option.
The window is used to configure the structure of the data file saved to the root directory
during test execution. It is comprised of a single scrollbar box and a series of On/Off radio
buttons. The scrollbar box is used to adjust the time (in minutes) between successive data
save operations. The On/Off radio buttons corresponding to sensors activate data save
operations for respective sensor values during the save operation. Activating the Off radio
button results in a zero entry for that particular sensor (note the overall structure of the file
remains constant).
Figure 4.13 shows a bitmap of the pop-up window activated by the <System/Mote
Configuration> option. This window is used to adjust the remote sensor station data
transmission interval (in seconds) using the scrollbar provided. Adjusted values will initiate a
reprogramming command to the remote station during the data acquisition sequence following
the adjustment. It should be noted that the transmission interval should remain less than the
data file save interval to mitigate the storage of identical data in the output file. The format of
the output file is provided in Appendix A. The general procedural protocol for activating the
laboratory RF acquisition system is provided in Appendix C.
25
Figure 4.9. Bitmap of the main GUI interface associated with the condition monitoring software
controller.
Figure 4.10. Bitmap showing the pop-up window associated with the <System/Calibrate> command
located on the main menu bar.
26
Figure 4.11. Bitmap showing the pop-up window associated with the <System/Test Configuration>
Figure 4.12. Bitmap showing the pop-up window associated with the <System/Data Acquisition>
27
Figure 4.13. Bitmap showing the pop-up window associated with the <System/Mote Configuration>
28
5.
CONCLUSIONS AND RECOMMENDATIONS
the acquisition and control of the DRDC laboratory oil condition monitoring test apparatus.
The upgrade includes the design and fabrication of a custom signal conditioning board
capable of supporting up to sixteen input signals from the condition monitoring sensors. Ten
of the sixteen module circuits are capable of supporting the output signals from both internally
and externally powered 4-20 mA current loop transmitters while the remaining six modules
support both single-ended referenced and differential voltage signals. The resulting sixteen
conditioned output signals are routed to a commercially available 16-bit multifunction board
for data capture and storage. The software suite has been upgraded to include the algorithms
required for the digital communication to the multifunction board via the PC’s internal PCI
bus. Modifications to the user interface (GUI) include the display of the acquired data in a
virtual instrument format, and a signal selectable graphical presentation of an approximately
two hour process history for individual sensors. The programming code has been developed
using C++ and compiled for execution on a Windows 2000TM operating system.
29
6.
REFERENCES
1. KarisAllen, K.J. “Design and Fabrication of a Laboratory Test Unit to
Demonstrate the Characterization and Collection of Data from Condition
Monitoring Sensors”, DRDC Atlantic Contract Report No. CR 2005-243, 2004.
2. KarisAllen, K.J. “Development of a Sensor System Using Conductive Polymers to
Obtain Strain Data”, DRDC Atlantic Contract Report No. CR2004-036, 2004.
3. Kus, R., “American Axel & Manufacturing Discovers the Advantages of On-Site
Oil Analysis”, Practising Oil Analysis, March-April 2004, pp 6-9.
4. Schalcosky, D.C. and Byington, C.S., “Advances in Real Time Oil Analysis”,
Practising Oil Analysis, Downloaded from Practising Oil Analysis website –
practisingoilanalysis.com, Article ID 138.
5. Lubrigard Oil Condition Sensor Users Manual, Published by Lubrigard Ltd.,
Exter, United Kingdom.
6. ANALEXrs Oil Condition Sensor Users Manual (MA-K16136), Published by
Kittiwake.
7. Model EASZ-1 Installation/Operation Manual (Rev. 0.13), Published by ESSIFLO
International PTE Ltd..
8. TestMate Water Sensor (TWS-C) Installation/Operation Manual (L-2732 (09/05)),
Published by Schroeder Industries LLC.
9. Biode Inc. eCupTM Operating Manual – P/N:100296-Rev F, Published by Biode
Inc. 2006.
10. Collister, C.J. and Weismann, P., “On-Board Oil Condition Sensing”, Published
by Lubrigard Ltd., Exter, United Kingdom.
11. MTS and MDA Sensor and Data Acquisition Boards User’s Manual, Rev. A,
Document 7430-0020-02, Crossbow Technology Inc, San Jose, California,
October 2003.
12. MPR- Mote Processor Radio Board and MIB – Mote Interface/Programming
Board User’s Manual, Rev. A, Document 7430-0021-04, Crossbow Technology
Inc, San Jose, California, October 2003.
13. TinyOS Getting Started Guide, Rev A, Document 7430-022-03, Crossbow
Technology Inc, San Jose, California, October 2003.
30
Appendix A – Software Output Data File Structure
The basic format for the laboratory data logger software and the RF acquisition software are
identical to facilitate post processing of data by a single algorithm. The header segment of the
output file consists of an alphanumeric test descriptor followed by several optional sensor
descriptors.
Test ID <char><CR>
Sensor Descriptor 1 <char><CR>
.
.
.
Sensor Descriptor N <char><CR>
The structure of each of the tab delimited data entries appended to the header segment is given
as:
Elapsed Time <float><tab> Date Stamp <date structure><tab> Time Stamp <time
structure><tab> Sensor 1 <float><tab> ……..Sensor N<float><tab><CR>
Note 1: For the engineering sensor values saved, a zero entry (0.0000) indicates that the save
operation for that particular sensor was deactivated for the test.
31
32
Appendix B – General Procedural Protocol for
Activating the System Hardware and Software
Components of the Laboratory Acquisition and
Control System
The following instructions provide a chronological procedural protocol for activating the
laboratory acquisition and control system.
1) Activate the benchtop microprocessor and allow time for the loading of the operating
system.
2) Activate the custom test apparatus interface software by double clicking the “Cond07”
icon located on the desktop.
3) If input calibration of sensor coefficients is required, access the calibration pop-up box
from the main menu by clicking on <System/Calibration>. If modification of the
calibration is not required, skip to step 4.
4) Configure the system set points and maximum UCL and LCL limits by accessing the test
configuration pop-up box from the main menu by clicking on <System/Test
Configuration>. If re-configuration is not required, skip to step 5.
5) Configure the save data file by accessing the save data pop-up box from the main menu
by clicking on <System/Save Data>. If re-configuration is not required, skip to step 6.
6) Activate AC power to the custom electronic hardware suite and the heater elements. Also
activate the power to any current loop transmitters required for the test sequence. Allow
the temperature of hardware components to stabilize (approximately 20 minutes).
7) Prior to activating the test sequence, initialize the File Name descriptor by clicking on
<System/Save Data> (maximum of 8 alphanumeric characters – no spaces).
8) Initiate an automated control sequence using the ON button in the control section of the
display.
9) Upon completion of the test, deactivate control by clicking the OFF button located in the
automated control section of the display.
10) Deactivate the system by turning off AC power to the custom electronics and the heating
element (for safety, the heating elements should be unplugged from the line power).
11) Deactivate the custom software by clicking on System/Exit.
33
12) Deactivate the microprocessor using the standard procedure associated with the hardware
and operating system.
34
Appendix C – General Procedural Protocol for
Activating the System Hardware and Software
Components of the Wireless RF System
The following instructions provide a chronological procedural protocol for activating the
laboratory wireless data acquisition system.
13) Activate the remote acquisition/transceiver module using the switch located at the end of
the module.
14) Activate the remote sensor signal conditioning hardware. For the MWM wireless system,
this is achieved by activating the AC power switch on the side of the electronics
enclosure. For the laboratory system, activate the control and signal conditioning
electronics in accordance with the procedure outlined in [1].
15) Connect the base station microprocessor to the base station transceiver via the DB9
interconnection wire (connect to COM 1 on microprocessor).
16) Activate the base station microprocessor and allow time for the loading of the operating
system.
17) Activate the base station communication/data logger program. For the MWM system, this
is achieved by double clicking the RF06_03 shortcut icon on the desktop. For the
laboratory system, this is achieved by double clicking the RF06_02 shortcut icon on the
desktop.
18) If required, configure the communication and display in accordance with the options
presented in Section 3.2.2.
19) Prior to activating the “Start” button, initialize the “File” descriptor (maximum of 8
alphanumeric characters – no spaces).
20) Activate the “Start” button on the main display GUI.
21) Activate the power to the base station transceiver by plugging the adapter into an AC
power receptacle.
Note: Once the system is fully activated, periodically flashing yellow and red LEDs should
be evident through the clear window in the top of the base station transceiver. If these LEDs
are not evident, unplug the base station AC adapter and repeat step 9.
35
36
List of symbols/abbreviations/acronyms/initialisms
DRDC
Defence Research and Development Canada
A/D
Analog to Digital
RC
Resistor-Capacitor
RLC
Resistor-Inductor-Capacitor
IC
Integrated Circuit
RF
Radio Frequency
R&D
Research and Development
PC
Personal Computer
GUI
Graphical User Interface
EPROM
Electrically Programmable Read Only Memory
CRC
Cyclic Redundancy Check
37
38
Distribution list
Internal
5
1
5
DRDC Atlantic - Mr. Randall Haggett (3 CDs, 2 Hardcopies)
DRDC Atlantic / DL(P) - Dr. Terry Foster
DRDC Atlantic Library (4 CDs, 1 Hardcopy)
11
Total Internal
External
1
1
1
1
1
1
1
1
1
1
1
1
NDHQ OTTAWA / DMSS 2
NDHQ OTTAWA / DMPPD
NDHQ OTTAWA / DMPPD 3
NDHQ OTTAWA / DGE
NDHQ OTTAWA / DMEPM (SM)
NDHQ OTTAWA / DMCM HALIFAX
NDHQ OTTAWA / DMCM IROQUOIS
NDHQ OTTAWA / DMCM Aux/Minor Warships
ADM S&T / DSTM
ADM S&T / DSTM 4
National Defence Headquarters
MGen George R. Pearkes Bldg.
101 Colonel By Drive
Ottawa, ON K1A 0K2
1
1
Commanding Officer
Fleet Technical Authority
FMF Cape Scott
PO Box 99000 Stn Forces
Halifax, NS B3K 5X5
1
1
Commanding Officer
Fleet Technical Authority
FMF Cape Breton
PO Box 17000 Stn Forces
Victoria, BC V9A 7N2
1
DRDKIM
17
Total External
28
Total
39
40
DOCUMENT CONTROL DATA
(Security classification of title, body of abstract and indexing annotation must be entered when the overall document is classified)
1.
ORIGINATOR (the name and address of the organization preparing the document.
Organizations for whom the document was prepared, e.g. Centre sponsoring a contractor's
report, or tasking agency, are entered in section 8.)
FACTS Engineering
PO Box 20039 Halifax, Nova Scotia B3R 2K9
3.
2. SECURITY CLASSIFICATION
(overall security classification of the document
including special warning terms if applicable).
UNCLASSIFIED
TITLE (the complete document title as indicated on the title page. Its classification should be indicated by the appropriate abbreviation (S,C,R or U) in
parentheses after the title).
Modification of the Laboratory Oil Condition Test Rig and Wireless data Acquisition System to
Accommodate a Schroeder TWS-C Water Sensor
4.
AUTHORS (Last name, first name, middle initial. If military, show rank, e.g. Doe, Maj. John E.)
K.J. KarisAllen
5.
DATE OF PUBLICATION (month and year of publication of
document)
6a. NO. OF PAGES (total
containing information Include
Annexes, Appendices, etc).
July 2007
7.
6b. NO. OF REFS (total cited
in document)
54
13
DESCRIPTIVE NOTES (the category of the document, e.g. technical report, technical note or memorandum. If appropriate, enter the type of
report, e.g. interim, progress, summary, annual or final. Give the inclusive dates when a specific reporting period is covered).
CONTRACTOR REPORT
8.
SPONSORING ACTIVITY (the name of the department project office or laboratory sponsoring the research and development. Include address).
PO Box 1012
Dartmouth, NS, Canada B2Y 3Z7
9a. PROJECT OR GRANT NO. (if appropriate, the applicable research
and development project or grant number under which the document was
written. Please specify whether project or grant).
9b.
Project 20Cm06
10a ORIGINATOR'S DOCUMENT NUMBER (the official document
number by which the document is identified by the originating activity.
This number must be unique to this document.)
CONTRACT NO. (if appropriate, the applicable number under
which the document was written).
W7707-063261/001/HAL
10b
OTHER DOCUMENT NOs. (Any other numbers which may be
assigned this document either by the originator or by the sponsor.)
11. DOCUMENT AVAILABILITY (any limitations on further dissemination of the document, other than those imposed by security classification)
( X ) Unlimited distribution
( ) Defence departments and defence contractors; further distribution only as approved
( ) Defence departments and Canadian defence contractors; further distribution only as approved
( ) Government departments and agencies; further distribution only as approved
( ) Defence departments; further distribution only as approved
( ) Other (please specify):
12.
DOCUMENT ANNOUNCEMENT (any limitation to the bibliographic announcement of this document. This will normally correspond to the Document
Availability (11). However, where further distribution (beyond the audience specified in (11) is possible, a wider announcement audience may be
selected).
DRDC Atlantic mod. May 02
13. ABSTRACT
(a brief and factual summary of the document. It may also appear elsewhere in the body of the document itself. It
is highly desirable that the abstract of classified documents be unclassified. Each paragraph of the abstract shall begin with an
indication of the security classification of the information in the paragraph (unless the document itself is unclassified) represented
as (S), (C), (R), or (U). It is not necessary to include here abstracts in both official languages unless the text is bilingual).
Over the past several years, DRDC Atlantic has embarked on a program for the evaluation of existing
technologies, as well as the development of new technologies for application in platform specific health
monitoring systems. It has been envisioned that dedicated sensor, hardware, and software suites may
be employed to provide engineering officers with real time monitoring with respect to the performance of
critical ships’ systems. Identified general applications for dedicated monitoring systems include
detecting the ingress of water in high-pressure hydraulic systems, assessing the rheological properties
of main machinery lubricants, conducting rotating machinery vibration analysis, and measuring
structural strain. The current study is focused primarily on detecting the ingress of water in highpressure hydraulic systems. Specifically, two additional prototype sensors have been integrated into
the DRDC oil condition monitoring test apparatus, a prototype water detection sensor (TestMate TWS-C
TM
), and an oil viscosity sensor (Biode eCup TM).
A major upgrade has been conducted with respect to the hardware/software suite utilized for the
acquisition and control of the DRDC laboratory oil condition monitoring test apparatus to accommodate
the additional sensors. The upgrade includes the design and fabrication of a custom signal conditioning
board capable of supporting up to sixteen input signals from the condition monitoring sensors. Ten of
the sixteen module circuits are capable of supporting the output signals from both internally and
externally powered 4-20 mA current loop transmitters while the remaining six modules support both
single-ended referenced and differential voltage signals. The resulting sixteen conditioned output
signals are routed to a commercially available 16-bit multifunction board for data capture and storage.
The software suite has been upgraded to include the algorithms required for the digital communication
to the multifunction board via the PC’s internal PCI bus. Modifications to the user interface (GUI)
include the display of the acquired data in a virtual instrument format, and a signal selectable graphical
presentation of an approximately two hour process history for individual sensors. The programming
code has been developed using C++ and compiled for execution on a Windows 2000TM operating
system.
Modifications to the prototype wireless hardware/software suite have also been conducted for the
acquisition of data from the sensors incorporated into a laboratory oil condition monitoring test
apparatus. The hardware and software algorithms have been configured to support data acquisition
from multiple, concurrently active, remote sensor stations. The acquisition hardware is comprised of a
general-purpose multifunction board coupled to a 433 MHz RF transceiver. Transmitted data from the
remote sensor stations is received by a RF base station and bussed to a PC data logger for storage
and post processing. Two software programs have been developed to control the functionality of the
system. The first program includes the algorithms to acquire the data from the sensors attached to an
autonomous, remotely located RF station, and transmits the data to the RF base station. The remote
sensor station program has been designed in accordance with the protocol established by the “open
architecture” TinyOS™ operating system. The second software program developed is a PC based
program, which provides a user interface to parse, analyse, and store the incoming data packet
messages. The programming code has been developed using C++ and compiled for execution on a
Windows XP TM operating system.
14. KEYWORDS, DESCRIPTORS or IDENTIFIERS (technically meaningful terms or short phrases that characterize a
document and could be helpful in cataloguing the document. They should be selected so that no security classification is
required. Identifiers, such as equipment model designation, trade name, military project code name, geographic location may
also be included. If possible keywords should be selected from a published thesaurus. e.g. Thesaurus of Engineering and
Scientific Terms (TEST) and that thesaurus-identified. If it not possible to select indexing terms which are Unclassified, the
classification of each should be indicated as with the title).
Modification to lab test rig
Wireless data acquisition system
Oil condition test rig
Water sensor
DRDC Atlantic mod. May 02

enter chapter title here - Defence Research Reports

Transcription

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