A toolset for model checking of PLC software

Abstract

Model checking is a powerful formal verification method that can also be used to evaluate PLC software. A lot of manual work and some expertise are still needed. Proposed methods for automating the process rely on standardised specification languages, but PLC software is often vendor-specific, and the source code for function blocks may not even be available. We propose a toolset for model checking of function block based software. After manually modelling the elementary function block library, the model of any block diagram can be specified with easy-to-use graphical tools. The counterexamples output by the model checker can also be visualised using a “living” function block diagram. Our toolset is based on integrating the popular model checker NuSMV with the open source modelling platform Simantics.