Performance evaluation of control networks for manufacturing systems

There are many different networks which have been promoted for use in manufacturing control systems. In this paper, we discuss the features of three candidates: Ethernet (CSMA/CD), ControlNet (Token Bus) and DeviceNet (CAN Bus). We consider how each of these control networks could be used as a communication backbone for a networked control system. A detailed discussion of the medium access control protocol for each network is provided. The medium access control protocol is responsible for providing both the satisfaction of the time-critical/real-time response requirement over the network and the quality and reliability of the communication between devices on the network. For each protocol, we derive the key parameters of the corresponding network when used in a control situation, including bandwidth, magnitude of the expected time delay, and variation in time delays. Simulation results axe presented for several different scenarios, and the advantages and disadvantages of each network are summarized. © 1999 American Society of Mechanical Engineers (ASME). All rights reserved.