Representation and implementation of function blocks by the event delegation model

Abstract

Function blocks (FBs) defined in IEC-PAS 61499-1 will provide us a method to construct industrial process measurement and control systems (IPMCSs) based on object oriented design (OOD). The system model specified in IEC-PAS 61499-1 consists of some devices and each device has some resources. This is represented by regarding virtual machines as resources. In the application model, FBs call each other through the event flow and data held in FBs are exchanged by data flow. Design patterns such as observer can be applied to representing the event flows of FBs. We can regard the data flow as a particular kind of event flow, and this design pattern is also applied to the data flow. Since we can use easily the event delegation model based on the observer in JavaBeans/spl trade/, which is suitable for describing FBs. We propose a representation of FBs using the event delegation model of JavaBeans/spl trade/. The interfaces of FBs are specified in a common way, the interface declaration of FBs can be separated from its implementation and is represented by the abstract classes or interfaces in OOD. We also propose an implementation of FBs using Java/spl trade/ in this paper. We have developed a software tool prototype for engineering and running of FB system.