Verifying accuracy

All meters are tested and verified at the factory in accordance with International Electrotechnical Commission (IEC) and American National Standards Institute (ANSI) standards.

The most common method for testing meter accuracy is to apply test voltages and currents from a stable power source and compare the meter’s readings with readings from a reference device or energy standard.

Your meter‘s power system and other parameters must be configured for accuracy testing.

The following tests are guidelines for accuracy testing your meter; your meter shop may have specific testing methods.

The meter should be tested at full and light loads and at lagging (inductive) power factors to help ensure testing over the entire range of the meter.

The meter’s energy pulsing LED and pulse outputs are capable of energy pulsing within specific limits.

Total power (Ptot) is derived from the values of the voltage and current inputs at the secondary side, and takes into account the VT and CT ratios.

This example calculation shows how to calculate power, pulse constants and maximum pulse frequency, and how to determine a pulse constant that reduces the maximum pulse frequency.

If you see excessive errors during accuracy testing, examine your test setup and test procedures to eliminate typical sources of measurement errors.