Industrial Networks: Connecting Controllers via OPC

In order to modernize their infrastructure and keep up with the state of the art, ABB Power Systems decided to replace the older controller AC450 with a new generation of controllers called AC800M. Just like its predecessor, its main task is to work as a sequencer in an otherwise mostly unchanging topology. Although the new controller AC800M provides modern communication features and a sophisticated application development system, it lacks of a communication interface compatible with the residing controllers AC160. A hardware approach addressing this problem is in development, but not available at this point of time. Thus the decision was made to realize the connection using OPC, a widely spread and open software communication interface standard with a high potential of reusability. In addition, it was aimed at gaining additional knowledge about the OPC interface, which is commonly used in industry. In this thesis, we evaluate adequate hardware and software to realize this connection and we have programmed the controllers with applications to evaluate its performance and integrity. In addition, we are making considerations about redundancy that is vital in automation business in order to increase reliability and availability. We have shown that it is possible to interconnect controllers using OPC with satisfactory average performance results. Due to high maximum round trip times and high complexity when realizing redundancy, it is recommended to use such a system for testing purposes or non-critical operational applications, but not for critical systems. In this thesis we also identify and judge several alternative ways of connection.