A concept for the integrated process description, PLC programming and simulation using Petri nets: application in a production process

Despite the development of a variety of PLC/DCS system programming tools and analysis methods, the programming and, more generally, the automation system synthesis approach still includes a significant degree of automation expertise, in order to overcome problems resulting from process complexity, inadequate process description or final application verification. For a more systematic design of the automation application, initial concepts and guidelines are proposed, based on the concurrent operation of a number of Petri-net based modules that are structured in the form of a cooperating network. This network can include modules ranging from the highest possible level of the application ("master coordinating module") to the finest levels of the individual equipment (e.g "motor" or "valve" modules). These modules include not only the traditional "automation" or "programming" modules, but also modules for the modeling of physical behavior of the system under automation, as well as fault handling elements. These concepts are demonstrated in an industrial application. The use of a unified Petri-net structure for the integrated description of the application facilitates the overall analysis, radically reduces the design, installation and re-engineering time and increases the flexibility of the system.