... accuracy. 3. Good operation functions. Model: YD4E-9S4Function1). Measurement: U, I, P, Q, PF, F, EP all power parameter.2). Class: active ... RS485 communication interface, support Modbus-RTU protocol.Technical ParameterAccuracyU,I 0.2 class, P,Q 0.5 class, Active electric energy 0 ...