Research On Long-distance Communication Of CAN Bus And Analysis Of TTCAN

CAN bus is one of the serial communication networks, which supports distributed control and real-time control. CAN bus network has the advantages of higher reliability, Better real-time, low price, and easy to implement. It's widely used in industry control field. Its communications baud rate can reach 1Mbps and the longest transmission distance could be more than 10km, however, the transmission distance of CAN bus usually can not reach the theoretical value.In This thesis, I analyze the composition network and protocol of the CAN bus, testify the factors that impacts on CAN bus network transmission distance. Basing on CAN bus control system for coal mine specific projects, I research on long-distance communication of CAN bus by constructing the experiment system. The major tasks are listed as follows:First, through comparison of several common field bus technologies. I analyze the reasons that CAN bus has the priority to be choosed for industry automation control field;Second, I analyze the characters, specification, frame structure and data exchange principle of CAN bus. The factors that impacts on CAN bus network transmission distance are discussed.Third, I produce a simulation of the characteristic impedance of 120Ωwires in accordance to national safety standards for coal mines, use ZLG USBCAN-I and Jiyang photoelectric USB-CAN Adapter as two nodes of the communication experiment. The experiments are done with different transmission distances and various terminal resistances. the experimental results are analyzed in details, I summarized the CAN bus network long-distance communication pattern.Fourth, Through constructing Coal Mine Control system based on CAN bus,I described several issues which should be paid attention to during constructing the CAN network in the future.Finally, I elaborate the time system considering that time-triggered real-time TTCAN protocol has good performance in the last chapter.It's meaningful to construct the practical CAN bus network system since the analysis and the experiments on CAN-bus transmission distance and TTCAN protocol are based on practical environments.