In: Computers and Chemical Engineering, Special Issue, Vol. 22, pages 969-972. 1998.
Abstract: Place- and transition-invariants of structured operating procedures described by low level Petri nets containing a plant-level and embedded operating unit-level procedures are analyzed in this paper. Place-invariants form a set of system states with, conservation property while transition-invariant correspond to cyclical behavior of the system. It is shown how the place and transition-invariants of the complete operating procedure can be determined from the invariants of the plant- and unit-level procedures. The results are illustrated on a simple example.
Keywords: Petri net invariants, chemical engineering, structured operating procedures.