The utility model provides a communication protocol converter, provide power supply circuit, CAN communications protocol circuit, serial port protocol interface circuit and data storage circuit including MCU microprocessor with for the signal processing process, CAN communication circuit includes CAN bus isolation transceiver and CAN communication power isolation circuit, the receipt data pin of CAN bus isolation transceiver with send data pin and connect MCU microprocessor through a CAN communication power isolation circuit respectively, serial port protocol interface circuit includes data transmission driver and data receipt driver with MCU microprocessor signal connection. The utility model discloses accomplished CAN bus and RS 422, RS 485 protocol conversion work between the serial ports, because to be the communication power be independent isolation, admittedly still have functions such as data storage, breakpoint retransmission and trouble storage inquiry the reliable and stable work of the system that guarantees the time.