Research And Design Of CAN Bridge Used In Distributed Measure And Control System

Distributed real-time control systems require a powerful communication link between remote subsystems. The Controller Area Network (CAN) was developed to support such applications. The CAN is a desirable, cheap solution for networks in industrial environments, but it also has problems that there is limit on the maximum length of a single CAN when it is used in industrial environments. A solution is to divide the CAN network into segments and connect them by using internetworking devices. Bridges are high performance internetworking devices that are used to interconnect LANs.This study gets investigate of the design and application of the dual-port CAN/CAN bridge used in distributed real time control system. First, it depicts the characteristics and hierarchical structure of the CAN Bus, the function , standardization, arithmetic. Then, it has a brief introduction about the hardware design technique, software networking protocol and storage-transmit mechanism of the CAN/CAN bridge. At last, it gives the detailed design way of the CAN/CAN dual-port bridge used in the storage batteries distributed detect and control system.The aim of this study is not only to discuss the applicability of the CAN/CAN bridge and to validate its usefulness for real time control applications, but also to investigate the characteristics of the interconnected CAN systems, by using bridges, in distributed environments.It can be validated that there are several advantages by using a CAN/CAN multiple ports bridge in the system to divide the CAN network into segments. The principle to partition the segments is that every node in each segment has the same function or transmits data frequently. The advantages are as below. First, it extends the transmit distance of the network. Second, it insures the nodes' drive capability in every segment. Third, it lets every segment have different transmit speed which is the best appropriate. Last, it isolates different kind of messages to lighten the Bus load, improves the network bandwidth and guarantees the real-time messages transmitting and receiving.