To test for metrology accuracy, a source generator is used to provide the voltage (J2) and current (J14 and J1) to the system. Additionally, a nominal voltage of 120V, calibration current of 10A with phase calibration at 60° and nominal frequency of 60Hz are used. During all of the tests, the board is powered directly using the 3V3 power supply from bench.

When the voltage and current are applied to the system, the system outputs the active energy pulses and reactive energy pulses at a rate of 6400 pulses/kWh. The pulse output is fed into a reference meter (in the test equipment for this reference design, this pulse output is integrated in the same equipment used for the source generator) that determines the energy % error based on the actual energy provided to the system and the measured energy as determined by the active and reactive energy output pulse of the system. In this reference design, active energy error testing and reactive energy error testing are performed after running energy gain calibration, phase calibration, and energy offset calibration.

All active and reactive energy testing is performed using two 200μΩ shunts and the current is varied from 100mA to 100A while voltage is held at 120V.