Switch the meter display to the power (active power P, power factor λ) interface, and check whether the power display is negative or not. And whether the power factor is between 0.9-0.95, and then check whether the incoming and outgoing wires of the current signal wire are connected reversely (that is, the current The incoming wire must be the same as the incoming wire end of the instrument) and consistent with the wiring diagram on the instrument.

1. The voltage value between the communication output A and B of the measuring instrument should be between +(4.4-4.5)V; 2. Check whether the communication wiring method is correctly wired in accordance with the wiring diagram requirements (that is, the communication terminal A/B of the corresponding to communication serial port A/B);