... -260V AC/DC or 18-30V AC/DC(24V DC)Measure ParametersRMS measurement, 1/3 phase volt,amp,power,power factor,frequency,KWH ... freelyFrequency0-2.5KHzAccuracyVolt: ±0.2% F.S±2 digitAmp: ±0.2% F.S±2 digitPower: ±0.2% F.S±2 digitPower factor: ±0 ... .3% F.S±2 digitFrequency: ±0.3% F.S±2 digit Alarm OutputRelay ...