Abstract: According to the requirements of a cigarette factory , the change of distribution system parameters is monitored in real time, so that the problems in parameters can be timely warned. A power distribu-tion parameter monitoring system based on ModBus RTU protocol is proposed in the paper. The systemrealizes the serial communication between MCU and PLC. The MCU receives the data of power parameters and carries on the analysis and processing, then displays the monitored parameters through the multidigit tube to realize the real-time monitoring of the parameter state. The practical application proves thatthe system can monitor all kinds of distribution parameters with stable operation, good real-time performance , simple software.

Key words: ModBus RTU agreement, microcontrollers, serial communication, power distribution parameters