Algorithm to convert programmable logic controller Ladder Logic Diagram models to Petri Net models

Petri Nets (PN) modeling has been proposed as an alternative to Ladder Logic Diagram (LLD) modeling to program complex programmable logic controllers (PLCs) due to its high level of abstraction and functionalities. Due to design legacy, existing LLD models are converted to PN models. This paper proposes a new algorithm to efficiently convert existing LLD models to their PN models equivalences. The algorithm can also be used even if there is no existing LLD model to be analyzed. Several actual LLD models have been tested to show the efficiency of the new algorithm compared to existing conversion algorithms. The generated PN models show that the new algorithm is 13.3% to 74.3% more efficient compared to existing LLD-to-PN conversion techniques.