Using PLC, PMU integrated control scheme, the control system is based on the bus mode, through the serial bus (RS485), the field scattered equipment including inverters, sensors, field instruments, etc. are organically combined, and the field signals are collected to the PLC through the serial bus. After arithmetic processing, it is transmitted from the bus to the execution equipment (frequency converter, solenoid valve) to perform corresponding actions, so as to meet the needs of the entire process.