Communication system among Petri net controllers

We propose a programmable controller based on Petri net which describes the status of a whole system, the controller and the controlled object. Since the Petri net controller can be made up on one chip VLSI package, it is difficult to deal with a large Petri net. To solve the problem we propose here a method to divide a large Petri net into several smaller nets and communication systems among these controllers to perform a whole Petri net cooperatively. The communication uses bus connection for the simplicity of hardware and partly one-to-one connection for faster speed.