GRAFCET and Petri Nets Outline Introduction GRAFCET - EPFL

GRAFCET
GRAFCET - definition
Definition
Evolution rules
Defining actions
Taking time into account
Defining transition conditions
Execution algorithm
Macrostep and macroactions
Directed graph derived from PN
Quadruple C = {S, TR, A, M 0 }
N steps s i ∈ S; each step s i may be
active (X i = true) or not (X i =false).
M 0 denotes the set of steps active at startup
L transitions tr i ∈ TR; to each transition is
associated a boolean condition (receptivity)
Steps and transitions are linked by arcs a i ∈ A
+ EVOLUTION CONDITIONS
1 L=1
b1
2 L=0
/b1
Real-Time Programming GRAFCET and Petri nets 5
© J.-D. Decotignie, 2007
Real-Time Programming GRAFCET and Petri nets 6
© J.-D. Decotignie, 2007
Exercise - syntax
Exercise - syntax (2)
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Real-Time Programming GRAFCET and Petri nets 7
© J.-D. Decotignie, 2007
Real-Time Programming GRAFCET and Petri nets 8
© J.-D. Decotignie, 2007