The modelling and analyzing of sequential control systems using invariant properties of Petri net

In this paper, the authors use Petri nets to model sequential control systems, and explain this way of modelling and analyzing them by using the invariant properties of Petri nets. A sequential control system consists of many components which have a few state values. The authors have proposed a method to model such sequential control systems by using Petri nets with place invariance to restrict and to be suitable for the state values, as well as a method of dividing a large Petri net into some small sub nets using the same place invariance. A typical sequential control system, an automated measuring tank system, is discussed here to show the effectiveness of the modelling and analysis methods. Finally, the authors take advantage of transition invariant properties in order to analyze such divided sub-nets.