New Petri net controller for distributed Petri net

When a large Petri net system is implemented, several LSI Petri net controllers are used and connected in order to build a whole system. For this purpose, the authors propose a new Petri net controller, which can hold much more places than the one proposed before. It also has the new control of tokens for kill-arc and shared-places among sub Petri nets are also proposed. Four accessible registers of tokens makes it possible to access four tokens at the same time, so one can use place-numbers instead of bit-patterns of places as used by the previous controller. This reduces the memory to log n/n of the previous. The new control of tokens makes it easy to keep consistency of tokens among a group of sub Petri net controllers. One can implement LSI Petri net controllers for several time larger Petri nets than previous ones and it is as fast as previous controllers.