Design of CAN central control modular based on USB

Abstract. The central control modular of liquid level data acquisition and transmission system based on CAN bus was introduced. The modular was controlled by PC for transmitting and receiving data to CAN units through the USB port by the USB2.0-CAN High Speed adapter card designed by CP2102 and SJAl000, and the CAN bus controller SJA1000 and CP2102 was controlled by single chip computer (SCC) AT89C51. The hardware interface circuits was introduced, and the software flowchart and PC application program was also designed. The result shows that the system has the advantages of strong real-time, high speed, high reliability, easily extending communication devices, Plug and Play supporting, and automatic configuration. Its communications quality is better than the traditional ones, such as RS232, RS485 et al., and it can be used as real-time monitor in industrial multiple devices. Intorduction CAN bus has been widely used in varies industrial field [1,2], and every network nodes take the Non-destructive arbitration technique to process the data so as to enhance the efficiency of network and checkout function, and realize Automatic Repeat Request (ARQ) when error. The communication medium can use the twisted-pairs cable, and the communication speed is 1M bp