THE IMPACT OF SCADA PROTOCOL CHOICE ON PIPELINE MONITORING AND DECISION MAKING

This paper discusses the methods and protocols used for the acquisition of field based process information to suit requirements for pipeline monitoring and control application categories. These are real-time for model based applications, contextual for decision making and analytical for diagnostics and asset management. The three distinct application categories have different requirements for the trueness and timeliness of classes of data from the field. The limitations and strengths of two main SCADA protocols DNP3 and MODBUS are discussed in relation to the provision of data and conclusions drawn in relation to which protocol features suit which application best. The particularly sensitive model based applications of pipeline leak detection and location are discussed in relation to the resultant error and frequency response created by the transformation of information through the SCADA remote terminal units, communications structures and master station scanning regimes.