Specification of industrial digital controllers with object-oriented Petri nets

The main purpose of this paper is to present an object-oriented PN model (shobi-PN) to specify industrial digital controllers. The shobi-PN model (synchronous, hierarchical, object-oriented and interpreted Petri net), was developed to support the use of hierarchy to model both the control unit and the plant of the systems. A CAD environment, SOFHIA, was developed to model digital controllers, to validate their properties and to simulate their behaviour. SOFHIA has an open architecture, which eases the integration of multiple code generator blocks to allow the implementation of the system in a wide range of technologies (hardwired, microprogrammed, programmed). Modelling of an industrial reactor control system is considered as a case study to illustrate the model's applicability and capabilities.