Modular implementation of discrete event systems as sequential function charts applied to an assembly cell

Modular implementation of discrete event models in programmable logic controllers (PLCs) using sequential function charts (SFCs) is investigated. Synchronisation of such models, typically finite state automata of Petri nets, is not well defined in the synchronous PLC-world. We develop an algorithm that computes event monitors for synchronising concurrently executing SFCs. The methodology is applied to an assembly cell.