Generative programming for programmable logic controllers

Many attempts have been made to implement supervisors derived by synthesis procedures peculiar to the supervisory control theory (SCT), most adopting the event-based supervisory control paradigm. However, when considering code generation schemata for programmable logic controllers (PLCs), hardware resources are limited and event tracking is hard to realize satisfactorily. Moreover, previous work has highlighted differences between the abstract model adopted by SCT and realistic process control situations. Inappropriate solutions to these issues may result in code generation schemata that produce unreliable PLC code. A generative programming approach for PLCs based on a dual paradigm, the state-based supervisory control paradigm, is investigated in this paper. Such an approach exhibits interesting properties. For instance, the maximum depth of the PLC stack as well as PLC cycle timing evaluations become possible. Furthermore, well-known code optimization techniques can be used to obtain more efficient code.