ModelicaAdditions.PetriNets.Examples

ModelicaAdditions.PetriNets.Examples.Parallel

Information

This is an example to demonstrate in which way parallel activities can be modelled by a Petri net. When transition "Par1" fires (after 1 second), two branches are executed in parallel. After 6 seconds the two branches are synchronized in order to arrive at place "P6".

Before simulating the model, try to figure out whether branch P2-P3-P5 or branch P2-P4-P5 is executed.

Simulate for 7 seconds and plot the following variables:

  S1state, P1state, P2state, ..., P6state

Modelica definition

model Parallel 
  "Example to demonstrate parallel activities described by a petri net  "
   
  extends Modelica.Icons.Example;
  output Boolean S1state;
  output Boolean P1state;
  output Boolean P2state;
  output Boolean P3state;
  output Boolean P4state;
  output Boolean P5state;
  output Boolean P6state;
  PetriNets.Place01 S1(initialState=true);
  PetriNets.Place11 P1;
  PetriNets.Parallel Par1(condLabel="time>1");
  PetriNets.Place12 P2;
  PetriNets.Transition T1(condLabel="time>2");
  PetriNets.Transition T2(condLabel="time>3");
  PetriNets.Place11 P3;
  PetriNets.Transition T3(condLabel="time>4");
  PetriNets.Place11 P4;
  PetriNets.Transition T4(condLabel="time>5");
  PetriNets.Place21 P5;
  PetriNets.Synchronize Sync1(condLabel="time>6");
  PetriNets.Place10 P6;
equation 
  connect(Par1.outTransition1, P1.inTransition);
  connect(T1.outTransition, P3.inTransition);
  connect(P3.outTransition, T3.inTransition);
  connect(P1.outTransition, Sync1.inTransition1);
  connect(Sync1.outTransition, P6.inTransition);
  connect(T2.outTransition, P4.inTransition);
  connect(P4.outTransition, T4.inTransition);
  connect(S1.outTransition, Par1.inTransition);
  connect(T3.outTransition, P5.inTransition1);
  connect(T4.outTransition, P5.inTransition2);
  connect(P2.outTransition2, T2.inTransition);
  connect(Par1.outTransition2, P2.inTransition);
  connect(P5.outTransition, Sync1.inTransition2);
  connect(P2.outTransition1, T1.inTransition);
  Par1.condition = time > 1;
  T1.condition = time > 2;
  T2.condition = time > 3;
  T3.condition = time > 4;
  T4.condition = time > 5;
  Sync1.condition = time > 6;
  
  /*output variables*/
  S1state = S1.state;
  P1state = P1.state;
  P2state = P2.state;
  P3state = P3.state;
  P4state = P4.state;
  P5state = P5.state;
  P6state = P6.state;
end Parallel;