Instruction list verification using a Petri net semantics

In order to adapt a Petri net based verification framework to programmable logic controllers, a Petri net semantics is introduced formally for a subset of the standardized instruction list language [IEC 1131-3]. For that purpose, the subset's syntax as well as static and operational semantics are specified strictly. Having that, the operational reference semantics is substituted by an equivalent Petri net semantics. Due to this prudent practice, the equivalence proof of the substitution step is obvious.