XXIX. ASR '2004 Seminar, “Instruments and Control“, Ostrava, April 30, 2004 261

Program Support of Laboratory Stands Control

SMUTNÝ, Lubomír

Prof. Dr. RNDr. Katedra ATŘ-352, VŠB-TU Ostrava, 708 33 Ostrava-Poruba lubomir.smutny@vsb.cz, http://www.vsb.cz/~smu50

Annotation: This contribution describes program and instrumentation support solved at the Department CSI 352 of the VŠB-TU of Ostrava for experimental measurement and control tasks with laboratory models (Hot Air Plant – HAP and Water Container Level Control - WCLC). They allow realizing all-important measurement and controlling tasks: - identification of static and dynamic system and sensors characteristic, - experimental verification of controller synthesis results, - synthesis of the new control algorithms. Lab stands HAP and WCLC there are program supported with simulation program tools (for instance MATLAB-Simulink or SIPRO) and mainly with own program module WinCTRL (version 2.0) for real time control of physical function models. Properties and results of control tasks obtained by this program module will be presented.

Keywords: laboratory stand, hot air plant, program support, controller, algorithm

1 Introduction Illustration of practical physical (real) models is cardinal importance for engineering

experimental exercises, for comparing of the computer simulation tasks with practical experiences and with real-time measured signals from the technological or lab plants. Experimental verification of the theoretical knowledge responds to need for accelerated acquisition and adoption of "best practice" techniques and methods and it increases the quality engineering education by Total Quality Management (TQM) principles.

Experimental stands allow easy understanding principles of the real industrial plants parts, measurement and control devices, signals character, noise, dynamic responses and easier crossing to the real technological systems. Experimental verification of theoretical knowledge responds to need for accelerated acquisition and adoption of "best practice" techniques and methods and it increases the quality engineering education. Basic demands for design and experimental stands education application for laboratory exercises we can described with these points [SMUTNÝ, 2003B], [OBEYSEKARE, U. & GRINSTEIN, F. 1997]:

Similarity of physical laboratory model with real industrial devices (plants). Good dynamical responses of output signals (quick reaction, short time constants). Miniaturization of dimensions, power input, etc. Unified input and output electrical signals (U = 0-10 [V], I = 4-20 [mA]). Good possibility of connection with any computers or alternative digital units (PLC,

Industrial PC - IPC, Industrial microcomputer - IMC). Availability of model function parts and their reasonable price. Easy production in condition of department Mechanical and electronic workshop.

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2 Laboratory stand HAP On the Department of Control Systems and Instrumentation of VSB-TU Ostrava were

designed and produced a few of laboratory experimental stands, models and education aids for measurement and control tasks [SMUTNY, 2003B].

On the Figure 1 we can see the block schema of experimental laboratory model HAP (Hot-Air Plant) as a physical model of air-conditioning. This is actual model version HAP2003 with two ventilators (left side of model) for better realization of air flow disturbances (main fan - ventilator and secondary disturbance ventilator).

Photoresistor

Microcomputer unit (CTRL)

Inputs

Outputs

RS 232

Computer PC

Electronic unit of HAP

Covering tube Bulb

Thermistors

Vane apparatus -flow meter

Voltage source

Thermoanemometr

Secondary disturbance ventilator

Main ventilator

Ucc = 240 V

Figure 1 Block schema of HAP (Hot-Air Plant) with computer PC and measurement unit CTRL

The Lab stand HAP presents function module of air conditioning and it is used on the experimental laboratory education for all study forms, not only on the Faculty of Mechanical Engineering VŠB-TU of Ostrava, but also on other seven technical faculties at Czech Republic. Stand HAP allows to realize all directions of real laboratory education with all-important tasks connected with:

∗ Identification of static and dynamic system and sensors properties, ∗ Intuitive even experimental verification of controller synthesis results, ∗ Verification of the new control algorithms (fuzzy, neuron, genetic, ...). Laboratory stand HAP is also used for demonstration of function multilevel control

systems in environment of the program support SCADA/MMI on the Web environment [YOUNG 1997]. Air condition plant HAP allows to connect the approach with simulation program tools (for instance own department tool – SIPRO or MATALB-Simulink) with physical function model, which is much more similar to real industrial plant with all its function defects (noise, nonlinear properties of sensors and actuators, disturbances, etc.). Very important is also program support with module WinCTRL 2.0, which allows easy using of all plant function modes and control algorithms.

On the Figure 2 we can see new model of HAP (model 2003) in uncovered configuration, with two parallel big fans at detailed figure. This configuration enables testing measurement of flow by the anemometer and bulb temperature with noncontact sensor IR 300. On this configuration there were testing the provisional (calibrated) third flow air sensor (miniature

XXIX. ASR '2004 Seminar, “Instruments and Control“, Ostrava, April 30, 2004 263

axial vane apparatus with calibration procedure) – anemometer YK 200PAL Micronix. It allows the precision measuring of air flow on HAP plant tunnel and their comparison in particular configurations.

Figure 2 New model of HAP (model 2003) – uncovered configuration, with 2 parallel

big fans (ventilators) – detailed figure. This configuration enables testing measurement of flow by the anemometer and bulb temperature with noncontact sensor

Figure 3 Hot-air plant (HAP) laboratory model with microelectronic unit CTRL, electronic unit of HAP stand and PC

On the Figure 3 we can see the whole instrumentation of Hot-air plant (HAP) with microelectronic unit CTRL, electronic unit of HAP stand and PC computer.

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3 Laboratory stand Water container level control - WCLC On the Department of Control Systems and Instrumentation of VŠB-TU Ostrava there

were designed and produced other type of interesting lab stand - Water Container Level Control (WCLC) with industrial controller KS 98+ (Philips) and PC supervising system [BALŠÁNEK, 2004]. The block schema of typical control system with digital controller we can see on the next Figure 4.

Controller Controlledplant

w(t) e(t) u(t)

v2(t)

y(t)

-

A/D D/Ae(kT) u(kT)

v1(t) v3(t)

Figure 4 Block schema of control system with digital controller

Principle of realization the lab plant WCLC we can see on other Figure 5. This stand contains the main tank (container No.1) and it fills with pumping device from the waste tank No.2. The main tank has controlled electro-mechanical vessel V for disturbance adjustment.

Tank No.1 for control task

Ultrasonic level sensor

pumping device

Controlled vessel V

ControlWebWinGap-CTRL

RS - 232

RS

-232

ControllerKS 98+

Powertransmiteer

0-10

V0-

10V

0-10V

Unit CTRL

0-10V

Waste tank N2

Figure 5 Level control on the water tank with output disturbance by controlled vessel V with controller KS 98+

On the Figure 6 we can see a photo of Water container level control (WCLC) – laboratory model with industrial controller KS 98+ (Philips) and PC with CTRL unit supervising [BALŠÁNEK, 2004].

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Figure 6 Water container level control (WCLC) – laboratory model with

industrial controller and PC with CTRL unit supervising

Program support of PC measurement and control tasks there is program module WinCTRL [KOPECKÝ, 2003]. It is a new version with possibility to connect to PC two types of A/D/A converters, not only CTRL – RS232 serial external measurement unit (12 inputs, 4 outputs, 0 – 10 V), but also internal A/D/A converter, for instance AD 512 (Humusoft Prague).

Module WinCTRL has at his portfolio other types of control algorithms (On-Off with penalization, Fuzzy algorithm), it has a new possibility for output data presentation (output chart *. bmp format), it provides the change of set point value in the control task running.

On the next figures we can see some control charts – on Figure 7 is level control with supervising of program module WinCTRL (a controller KS 98+ has the parameters KP1=KP2=18, TI=36s). Blue line is controlled value (water level), red line is disturbance of output flow by vessel V (see Figure 5), and green line is action value of pump.

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Figure 7 Water container level control (WCLC) – program module WinCTRL

supervising (controller KS 98+ parameters KP1=KP2=18, TI=36s)

On the next two figures (Figure 8 and Figure 9) we can see examples of synchronous control of temperature and air flow with two type of disturbances (sine course and Gaussian normal noise course).

Fig. 8 Example of PI algorithms for synchronous control of temperature (red line)

and flow (green line) by WinCTRL 2.0 with sine voltage on secondary ventilator (grey-green line) (Temperature – thermistor T3, PI Controller: KR=10, TI=20, Flow – vane apparatus P7, PI Controller: KR=1,1, TI=10).

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Fig. 9 Example of PI algorithms for synchronous control of temperature (red line) and flow (blue line) by WinCTRL 2.0. (Temperature – thermistor T3, PI Controller: KR=10, TI=20, Flow – vane apparatus P7, PI Controller: KR=1,1, TI=10). Red line – controlled value TemperatureT3, blue – controlled Flow P7, pointed line – grey – noise voltage on secondary ventilator). Changes of desired values: Flow – in time 70 s change P7 from 5 to 6, in time 180 s change P7 from 6 to 7. Temperature – in time 140 s change T3 from 5 to 4.

4 Conclusions Experimental lab stands allow easy understanding to principles of industrial plant parts,

measurement and control devices, signals character, noise, dynamic responses and easier crossing to the real technological systems. Verification of theoretical findings is important part of education process. Although increasingly significant methods are computer simulations, now typical with simulation programs aid (for instance MATLAB-SIMULINK) and control program modules (WinCTRL), experiments with real physical models are not interchangeable.

The courses from area of automatic control provide students with a comprehensive understanding of the automation industry and knowledge of industry automation hardware and software, so they can progress to automation careers within the local manufacturing industries.

Program support with Department CIM modules WinCTRL and SIPPRO is important help for easy solution of measurement and control task, mainly with own lab stands HAP a WCLC.

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Acknowledgement The presented results have been obtained with the financial support of the Czech Ministry

of Education, Youth and Sports, during completing of research project MSM 272300012.

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Models Control by digital Controllers). Ostrava: VŠB-TUO, Dep. CSI 352, 2004. Diploma Thesis, Supervisor Smutný, L. pp. 81.

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[3] KOPECKÝ, M. 2003. Programová podpora měřicích a řídicích úloh s PC. (Program Support of Measurement and Control Tasks with PC). Ostrava: VŠB-TUO, Dep. CSI 352, 2003. Diploma Thesis, Supervisor Smutný, L. pp. 48 + supplements.

[4] OBEYSEKARE, U. & GRINSTEIN, F. 1997. The Visual Interactive Desktop Laboratory. IEEE Computational Science and Engineering, pp. 63-71, Jan-March 1997.

[5] SMUTNÝ, L. 2003A. Inteligentní měřicí a řídicí systémy – přehled trhu (Intelligent measurement and control systems - market review). AUTOMATIZACE, vol. 46, No. 2, 2003. pp. 110 – 116. ISSN 0005-125X

[6] SMUTNÝ, L. 2003B. Measurement and Control of Experimental and Virtual Lab Stands for Improvement of Quality Education. In Proceedings of XXVIII Seminary ASR 2003 „Instruments and Control“. Ostrava : VŠB-TU Ostrava, 6. 5. 2003, pp. 321-328. ISBN 80-248-0326-7.

[7] YOUNG, P. M. 1997. An Integrated Engineering Systems and Controls Laboratory. Fort Coollins (USA): Dep. of Electrical Engineering, Colorado State University, 1997. URL http://fie.engrng.pitt.edu/fie97/papers/1286.pdf