Design and Analysis of Packet Switched Networks for Control Systems

This paper contains a methodology for analyzing and designing a computer network for application to complex control systems. The focus is on the analysis and design of a local area network (LAN) for realizing the high-level control network that interconnects input-output controllers with devices for monitoring and analysis and with high-level controllers such as supervisory PLCs. Part of the development given in this paper can also be applied to the device-level network (fieldbus) that interconnects input-output controllers with sensors, actuators, and other devices in the system being controlled. The high-level network and the device-level network form a two-layer architecture that is typical in control applications. A procedure is given for generating a network design with a hierarchical hub topology having full redundancy. Then in terms of a graph model of the network, procedures are given for studying network availability and analyzing the information flow rates through the links and internal nodes of the network