Download Steam Net Simulation with Real Control System

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Conclusions and suggestions for further investigations
In this master thesis it is shown that it is possible to use a real control system, writte n
in Siemens Simatic PCS 7 and with the sampling period one second, to control a
simulated process, written in Dymola. The control system and the process run on the
same PC, under Windows NT. The simulated steam net and the control system has
both been built to be used in the investigations in this master thesis, but they are
based on data from a real control system.
If the solutions presented should be used in a real project some improvements have
to be made. At first some work has to be spent on making a better model of the
process and to validate and compare with the real process. Solvina has done this in
previous projects so it shouldn’t be a problem, although it takes some time.
In a real system much more signals than in this demo system are sent between the
process and the control system, for instance start signals to the motors,
acknowledgement signals and signals to lock the valves. Such signals have not been
included in the demo system presented here but they will probably not cause too
much problem. The J++ program could perhaps be extended to handle such signals
or the control system could be extended, using sequential function charts, to handle
acknowledgements of different signals.
S7-PLCSIM can only simulate the behaviour of a single PLC. Since the paper
process industry sometimes uses two or more PLC:s to control their process it is
desirable to investigate how to handle that situation. Is it possible to divide the
system into two, investigating once at a time? Another possibility is to try to
communicate with real PLC:s instead using OPC, which is a standardized set of
interfaces, properties and methods to be used in applications for process control and
automated production [9][15]. This has to be investigated further if it is to be used in
such an application.
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