ER9 series three-phase multi-function power recording instrument instruction manual. This instrument measures the true effective value of voltage, current, frequency, active power, reactive power, power factor, active power value and reactive power value of three-phase alternating current circuit; At the same time, it records the voltage, current, active power, reactive power, power factor, active power value and reactive power value. It can generate various reports; and it can transfer the recorded parameter curve and historical data and power value report to the PC for data analysis through U disk or SD card, and provide RS485 communication interface and support MODBUS-RTU protocol. It can be widely used in medium and low voltage distribution cabinets, industrial automation, intelligent switch cabinets, building automation, energy management systems, etc.