Minas, M.; Frey, G.:
Visual PLC-Programming using Signal Interpreted Petri Nets.
Proceedings of the American Control Conference 2002 (ACC2002), Anchorage, Alaska, Vol. 6, pp. 5019-5024, May 2002.

    In this contribution we present a graphical programming approach for Programmable Logic Controllers (PLCs) based on a special type of Petri net, the Signal Interpreted Petri Net (SIPN). We give an introduction to PLCs and an overview on the languages used to program them. From this overview we conclude, that for PLCs a language is missing that is capable of the simple graphical description of sequential and concurrent behavior.
    SIPN is such a language. We present the SIPN approach and some corresponding analysis methods. Furthermore we report on some experiments done in a university course, that show that the method is indeed useful in solving control problems.
    Since programming a controller without tool-support is nearly impossible we present a tool for graphical editing and compilation of SIPN. In the development of the tool, not only the implementation of the SIPN as it is defined in theory played a role, but the projected application area and user interest were also considered.