Integrating CNet and IEC 61499 function blocks

Abstract

CNet and IEC 61499 function blocks both have been defined for designing modular, concurrent and distributed control systems. CNet components as well as IEC 61499 function blocks allow modularization and hierarchization. Both concepts describe system behavior in an event-discrete manner. CNet does so by means of a special class of colored Petri nets called PNet, while function blocks use separate event paths and so-called execution control charts that trigger algorithms in basic function blocks. CNet interfaces consist of special Petri net elements, while function blocks have typed data and event inputs and outputs. This paper will show (a) that function block interface definitions consisting of data and event ports with appropriate data-event associations have semantically equivalent counterparts in CNet and vice versa, and (b) that exploiting these equivalences allows the definition of adapters that transform CNet components into function blocks and vice versa, and finally (c) that this enables CNet/PNet models to implement the behavior of function blocks as an alternative to execution control charts and algorithms.