Frey, G.; Minas, M.:
Internet-based development of logic controllers using Signal Interpreted Petri Nets and IEC 61131
Proceedings of the SCI 2001, Volume 3, pp. 297-302, Orlando (FL) USA, July 22-25, 2001 (ISBN 980-07-7543-9).

    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 the languages designed to program them. From this overview we conclude that in this application area a language is missing that is capable of the simple graphical description of sequential and concurrent behavior. SIPN are such a language. We present the SIPN approach and some corresponding analysis methods. Since programming a controller without tool-support is nearly impossible we present a tool for graphical editing, animation, 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 was also considered. The tool was implemented using DiaGen, an innovative workbench for generating graphics editors. Due to the fact that a new method is best promoted if it is freely available and furthermore not very demanding in resources and administrative efforts, the tool was realized as a Java-Applet that can be executed from a standard web browser on virtually any PC.