... active+negative activeDisplay data function even after power off (option)Multi-tariff measuring function: Setup T1, T2, T3 and T4 four ... A Reference frequency:50Hz, 60HzStarting current: 0.004IbConnection type choice: three phase four wires, up in down out,L1,L2,L3,N ... ,L1,L2,L3,NImpulse constant:2000imp/kWhStandard level:1.0class,2.0classAccuracy of clock: 0.5s/dCommunicating protocol: Modbus-RTU, ...