Migration of a PLC Controller to an IEC 61499 Compliant Distributed Control System: Hands-on Experiences

IEC 61499 ushers in a new trend of software development in the area of Industrial Process Measurement and Control System (IPMCS). This new standard simplifies the development of distributed IPMCS applications through inclusion of re-usability, encapsulation and modularity. IEC 61499, due to its close resemblance with Object-Oriented (OO) paradigm also paves the way to integrate modeling techniques like UML into the development process of the distributed IPMCS applications. Yet a remarkable challenge is there to integrate or re-design the systems, elements or components designed using a monolithic language like the ones on Programmable Logic Controllers (PLCs). In this work it is attempted to share the experiences faced while attempting to migrate a PLC controlled centralized laboratory application into an IEC 61499 compliant distributed control application. The targeted distributed control system consists of network-enabled controllers where the IEC 61499 compliant control sub-applications should run. It needs to be mentioned that the development process did not start from analysis of the specification of the instrument to be controlled but rather from a formal specification of it written in Signal Interpreted Petri Nets (SIPN).