Development of a low cost digital energy meter

Abstract

This paper presents a versatile low cost equipment that allows simultaneous display of usually required measurements in electric circuits, like true RMS (Root Mean Square) values of mains voltage and current, line frequency, power factor, active, reactive and apparent power, and energy. The equipment is based on a microcontroller that interfaces current and voltage transducers through 16 bits sigma-delta ADCs (Analog to Digital Converters). The microcontroller controls the periodic acquisition of the measured signal waveforms, makes the respective calculations and presents the results on an alphanumeric display. The equipment also provides a serial port that enables the communication with other devices allowing the interface through a SCADA (Supervisory Control and Data Acquisition) system.