Redesign distributed IEC 61131-3 PLC system in IEC 61499 function blocks

In this paper we discuss the problem of migration from the PLC control to the event-driven and component based architecture of IEC 61499 function blocks. We are using a conveyor system to illustrate three different migration methods: object-oriented in basic function block, object-oriented in composite function block and class-oriented in basic function block. The advantages and limitations are summarized and guideline for migration is provided.