Asynchronous Control Device Design by Net Model Behavior Simulation

We discuss the problem of designing asynchronous control devices for discrete event coordination specified by a Petri net model. The design is based on the compilation of standard circuit modules corresponding to PN fragments into a net modeling PN behavior and on the semantic interpretation of the modeling circuit. The impossibility of asynchronous implementation of the indivisible operation of marking change at the circuit level leads to the necessity of modeling PN with modified rules of marking change. Modifications of the known modules, a number of new module types, the rules of the module connections, and the procedures of minimization are given that considerably improve the quality of the obtained solutions in terms of both speed and area. The design “reefs” are fixed. The minimization procedures are usually associated with a change of marking change rules producing the problems of providing the equivalence of the initial and modified PNs.