1.1 INTRODUCTION

• Ideal for parallel control problems

• Basic logic functions are shown below,

• We can model various logic functions with Petri nets,

• Reachability allows us to determine if a state (set of places) is possible given an initial condition.

• Boundedness determines whether the number of states will be controlled, or grow/shrink.

• Deadlock and liveliness - will the controller find itself unable to continue.

• The procedure for producing ladder logic and other programs from the Petri Nets, is identical to producing Ladder Logic for SFC diagrams.

• Petri nets have been used for the modeling, control and validation of the control model [Teng and Black, 1988]