Petri net tools for the specification and analysis of discrete controllers

An approach is presented for the specification, modeling, and analysis of discrete-state systems and controllers. The approach features a rule-based state-variable-specification formalism that is translated into Petri net models composed of interconnected state machines. The concept of reduced reachability graphs is introduced as a means of reducing the computational effort required to isolate and analyze subcomponent behavior within the system. The target application is discrete manufacturing systems where the costs involved in writing, debugging, and maintaining of code for online process control can be significantly reduced through the use of automated modeling and analysis techniques. The approach is illustrated by an example of a simple discrete-state system