Abstract

The supervisory control theory of Discrete-Event Systems (DES) can be used to construct a supervisor for any event-driven system in which the state space is discrete. To implement supervisors we propose to use Programmable Logic Controllers (PLC), which are widely used in industrial applications. In our work, we develop a new conversion algorithm which directly transforms a supervisor represented by a finite automaton to a Ladder Logic Diagram (LLD). To demonstrate the correctness of our proposed approach and discuss the issues that may arise in modeling and development of DES supervisors, we design supervisors for a boiler control system using supervisory control theory of Ramadge and Wonham, convert DES supervisors to PLC controllers using our conversion technique, and verify by setting a virtual plant setup using a PLC simulation software that the converted LLD can be executed by the PLC and that the original behavior of the DES supervisors under PLC implementation can be achieved.