Anglian water adopts IEC 61131 for telemetry & process control applications

In 1998, Anglian Water initiated a joint project with Logica to develop a new outstation, called the Micro Medina 4 (MM4), based on Rockwell Automation´s PC open controller product range. A key design and cost requirement for the MM4 was that it should operate reliably as a PLC as well as a data telemetry outstation. The MM and earlier outstations ran a proprietary text based language known as Medina Sequence 88 developed by Logica. The economic options for the MM4 were an updated object-based version of this language, or the IEC 61131-3 based ISaGRAF soft PLC target. Anglian Water chose ISaGRAF to gain the benefits of supporting an international standard for process control software development, which is becoming dominant in the open control and mainstream PLC markets. Implementation of IEC 61131-3 through use of the MM4 has brought the anticipated benefits outlined in the paper.