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]