To test for metrology accuracy of the design, a source generator is used to provide the 1 voltage and 3 currents to the system. Each of the three currents use the same voltage signal for the corresponding calculation of power. In this design, a nominal voltage of 230 V, calibration currents of 1 A, and nominal frequency of 50 Hz are used. Under these voltage and current conditions, each voltage-current mapping has RMS gain calibration, power gain calibration, and power phase correction performed on them. Once the system has been calibrated, the metrology testing is then performed.

After calibrating the design, different voltage and current condtions are applied to the design. When the voltage and currents are applied to the system, the design outputs active energy pulses for a selected voltage-current mapping at a rate of 6400 pulses/kWh. This pulse output is fed into a reference meter (in the test equipment for this design, this pulse output is integrated in the same equipment used for the source generator) that determines the energy % error for that voltage-current mapping based on the actual energy provided to the system and the measured energy as determined by the active energy output pulse of the design. In addition to the energy error tests, the RMS voltage % error, RMS current % error, and active power % error tests are performed as well. Since the time between pulses at low currents is relatively large, the averaging interval at lower currents would be much larger for the active energy reading compared to the averaging time at lower currents for the active power readings. The longer averaging time of the active energy readings leads to averaging out more noise, which results in better results for the active energy % error readings than the active power % error readings.

For the active energy error, current is varied from 50 mA to 20 A . A phase shift of 0° (unity power factor), 60° (0.5 power factor, inductive), and –60° (0.5 power factor, capacitive) is applied between the voltage and current waveforms fed to the reference design. Based on the error from the active energy output pulse, a plot of active energy % error versus current is created at 0°, 60°, and –60° phase shifts for each voltage-current mapping. When testing the accuracy of a voltage-current mapping, the same currents and phase shift are applied simulatenously for all voltage-current mappings.

To test RMS accuracy, the RMS readings were used from the GUI since the pulse output that was used for the energy accuracy tests cannot be used for RMS voltage and current. For the voltage testing, 1-A current is applied for each phase and the voltage is varied from 9–270 V on each phase simultaneously. After applying each voltage, the resulting RMS voltage reading from the GUI is logged for each phase after the readings stabilize. Once the measured RMS voltage readings are obtained from the GUI, the actual RMS voltage readings are obtained from the reference meter, which is necessary because the source generator may not accurately generate the requested values for voltage, especially at small voltages. With the reference meter measured RMS voltage and the RMS voltage value of the GUI, the RMS voltage % error is calculated. A similar process is used to calculate the RMS current % error and active power % error by using 230 V for each phase and varying current from 100 mA to 20 A.