A High Performance Field Network Based on a Tree Topology

Even though fieldbuses are largely used in the industrial automation and process control environments, their performances are, in general, noticeably lower than fast Ethernet networks. This is particularly true for the CAN protocol, which suffers from serious limitations on the bus extension when bit rates above 500 kbit/s are considered. Such drawbacks cannot be overcome by means of improvements in the technology of transceivers, as they depend on the finite propagation speed of signals on the bus. In this paper, a combined solution is presented and discussed that is based on a tree topology and adopts overclocking mechanisms, so as to provide a network whose behaviour is almost the same as traditional CAN and whose performance resembles fast Ethernet.