An industrial case study covering the use of IEC 1131-3 in connection with the engineering and operation requirements of the water industry

Bechtel have utilised or drawn upon many areas of the IEC 1131-3 standard during the design of their library of standard software modules (SSMs) starting with function block diagrams and sequential function blocks through to structured text and ladder diagram. The resulting library of SSMs that have been developed, sit together so successfully in a truly modular form that it is possible to replace an updated SSM within a configured and operational system without affecting any other section of the system. The software engineering techniques promoted in IEC 1131-3 have enabled Bechtel to implement the SSM approach across new projects and will now help to get away from the past where bespoke code was developed time and time again resulting in a different approach to the same problem of control, site by site. Bechtel´s engineers and their contractors are now implementing this philosophy on a large number of key contracts with several water utilities to assess the success of the project