Reengineering of IEC 61131 into IEC 61499 Function Blocks

Abstract

In order for industrial automation manufacturers to remain competitive, they must utilise modern design approaches. Existing approaches using IEC 61131 languages are not object oriented and are difficult to reconfigure for other applications. IEC 61499 is an open standard aimed at replacing IEC 61131, adding modern design features and hardware abstraction. Therefore there is a need to migrate existing code bases using IEC 61131 technologies into the newer IEC 61499 language for future development. IEC 61499 is appealing to developers because of the simplified specification approach and benefits related to the language's abstraction. The basic design unit or function block provides a graphical method for control flow design, and uses algorithms written in any programming language. This object oriented approach enables easy block reuse and simple reconfigurability. This paper presents a semi-automated process for the reengineering of Ladder Logic routines, from Rockwell, into a function block system. The process automatically translates all data types, variable declarations and ladder logic routines into their C equivalents. The function block architecture for the desired system components must be developed, but into which the generated code is encapsulated and used. The approach enables manufacturers using IEC 61131 to migrate their code base into a modern framework, with no loss of previous design efforts and minimal once-off overhead. IEC 61499 then allows for a more stream lined development process with reusable components.