The use of OPC in simulation systems - experiences and future prospects

The aim and motivation of the OPC (OLE for Process Control) family of specifications is to enable open connectivity between of the software components in the enterprise e.g. PLC (Programmable Logic Controller), DCS (Distributed Control System) and SCADA (Supervisory Control And Data Acquisition) systems, databases and business management software. The OPC specifications have been welcomed by the industry and most industrial automation products support at least a part of the specifications, which have thus become an industrial standard. The role of simulation in industrial applications is emerging in engineering projects as well as in operation and maintenance of industrial plants. In engineering, simulation is used on one hand for evaluating process and automation designs before the system is implemented, and on the other hand for providing a realistic process response for testing the automation software. In operation and maintenance, it is becoming popular to use simulation models embedded in automation systems for e.g. predicting plant behaviour or validating measurement data. Furthermore, the use of simulation for operator training has long traditions. In all applications, open connectivity to other industrial automation and enterprise software is a key issue for the efficient use of simulation. The wide acceptance of the OPC standard and the large number of existing and available software products make OPC an attractive choice as the means of communication in simulation systems. However, the background of the standard causes some problems. Essential interfaces needed for controlling the course of simulation are not included in the standard, and the available OPC implementations do not scale up to high enough communication frequencies in large scale and demanding simulation applications. VTT has prototyped the use of OPC in simulation systems by implementing relevant server functionality in Apros - the Advanced Process Simulation software. The product has been connected to other software using both OPC Data Access (DA) and other means of communication. This paper will give a review on the experiences and enlighten future prospects of using OPC in the field of dynamic process simulation, e.g. OPC DeXchange (DX) and OPC XML Data Access (XML DA)