Petri net arc types

Scenario

Petri nets become much more expressive once arc types carry semantics. This example shows a start transition that requires permission, is inhibited by a fault, consumes two buffer tokens, and can be reset from a fault state.

Annotation key

• -- is a read arc: test without consuming.
• -o is an inhibitor arc: enabled only when the place is empty.
• => is a reset arc: clear the source place when the transition fires.