Real-time performance analysis of a fieldbus-based network

Message delay is one of the main issues in a real-time fieldbus-based distributed control system (DCS). Serious delay will degrade the performance of a control system and even invalidate it. Industry-used fieldbuses try to improve their real-time capacity using different algorithms. In this paper, we investigate the real-time performance of the fieldbus-based network. We take LonWork as our model. The media access control (MAC) algorithm, which mainly determines the performance of a network, is described. On the basis of a mathematical model, we analyze the throughput of the system. Finally, the message delay is presented.