Developments in industrial control languages - where next?

This paper reviews the influence of standards on the development of software languages for industrial control systems. It considers the progress that has come from standardisation and issues still remain to be addressed. The features of various languages that have been used for programming industrial control systems over the past twenty years such as Modula 2, Ada, C, C++ are considered against benefits from using the IEC languages from the programmable logic controller (PLC) standard IEC 61131. The paper also considers the wider issues regarding tools and languages to deal with the complete life cycle of industrial control systems - from user requirements through coding, to final test and delivery. Finally, it considers the benefits of having re-usable code in the form of function blocks as proposed by the emerging standard IEC 61499.