DSSD566/DTSD566 three phase Electronic Multifunction Programmable watt-hour meter is a hi-tech intelligent energy-measuring instrument composed of analog-to-digital converter A/D, calendar clock, special microprocessor CPU, liquid crystal display LCD and switching power supply and so on. This meter can measure import/export active/reactive energy, maximum demand, power, voltage, current, and perform data processing with reference to relative tariff. It conforms to all technical requirements to multi-function meter specified in IEC61036, IEC61268, IEC60687, IEC1107, DL/T614 and DL/T645.