... AC three phase active energy measuring(three phase three ... mechanical counter, unit is kWh, record accumulated total active energy.Display range: 5+1, ... 6+1Accuracy active energy measuring, no need degugging ... standardAccording to IEC62053-21 standardFUNCTIONS:Total energy= positive active+negative active Indicate ... direct connectionImpulse constant:3200imp/kWh,400imp/kWhStandard level:1.0class,2 ...