IEC65A control languages-a practical view

Control of a manufacturing process requires the co-operation of many diverse pieces of software and hardware, from motor drives and temperature controllers through to SCADA (supervisory control and data acquisition) packages and MIS (management information services) systems. System integrators implementing a CIM (computer integrated manufacturing) system are faced with configuring and connecting a diverse range of products from many different vendors; they need to understand firstly how to configure each element in the control system and secondly how to interconnect them. If, however, the control systems were to be configured in the same distributed control language running on a standard communication network, then the configuration task would be greatly simplified. If the language was also capable of being used for both SCADA and production control (as well as process control), and the system could be interfaced relatively easily to traditional MIS systems then CIM becomes a real possibility. IEC65A is a draft standard which describes such distributed control languages. The authors describe the standard, outline its problems and present extensions to the standard which resolve some of the problems