Formal Modeling of Function Block Applications Running in IEC 61499 Execution Runtime

The execution model in a new standard for distributed control systems, IEC 61499, is analyzed. It is shown how the same standard compliant application running in two different standard compliant runtime environments may result in completely different behaviors. Thus, to achieve true portability of applications between multiple standard compliant runtime environments a more detailed execution model is necessary. In this paper a new runtime environment, Fuber, is presented along with a formal execution model. In this case the execution model is given as a set of interacting state machines which makes it straightforward to analyze the behavior of the application and runtime together using existing tools for formal verification.