AWWA IMTECH51421

Programmable Logic Controllers (PLCs) are the primary computer tool through which plant operating data is gathered and water treatment processes are controlled. Due to increasing needs for process control, automation, and safety, the numberof PLCs being installed in water treatment plants has grown rapidly over the past few years. This creates increased loads on overall control systems including supervisory control and data acquisition (SCADA) systems. Growth may also lead to inconsistencies in standards and a lack of vision for future plant control systems. At the same time, trends in the industry are pointing towards more open systems with improved integration with SCADA and business systems as opposed to proprietary equipment. These trends create new challenges to ensure that systems are consistent, reliable, optimized, and remain abreast of technology. The skills required to support these systems are also changing. EPCOR, which owns and operates two water treatment plants in Edmonton, Alberta, Canada, uses PLC-PCbased control systems and SCADA software at EPCOR's water treatment plants. This paper presents EPCOR's experience in developing a PLC master plan to deal with these challenges. The master plan was intended to provide overall direction as to PLC purchasing, technology selection, documentation, equipment optimization, and future growth. The paper discusses the steps involved in the master planning study, areas identified in the study as needing improvement, the challenges involved in implementing the recommendations, and the benefits realized. Includes table.