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9410 series - User manual
t
PF
Kt
Round up the result of the calculation to the nearest integer number of pulses.
Calculation for number of required pulses
This example calculates the number of pulses required for an inductive load 3-phase test point
with a test duration of 60s; the source is configured to use V = 120V, I = 5A, PF = -0.5; the pulse
constant of the meter under test is Kt = 1.8 Wh/pulse.
Round the number up to the nearest integer: Number of pulses = 9
Percentage error calculation for accuracy verification testing
Accuracy verification testing requires you to calculate the percentage error between the meter
being tested and the reference/standard.
Calculate the percentage error for every test point using the following formula:
Energy error = (EM - ES) / ES x 100%
Where:
• EM = energy measured by the meter under test
• ES = energy measured by the reference device or energy standard.
NOTE: If accuracy verification reveals inaccuracies in your meter, they may be caused by typical
sources of test errors. If there are no sources of test errors present, please contact your local
Siemens representative.
Typical sources of test errors
If you see excessive errors during accuracy testing, examine your test setup and test procedures
to eliminate typical sources of measurement errors.
Typical sources of accuracy verification testing errors include:
• Loose connections of voltage or current circuits, often caused by worn-out contacts or
terminals. Inspect terminals of test equipment, cables, test harness and the meter under test.
• Meter ambient temperature is significantly different than 23 °C (73 °F).
• Floating (ungrounded) neutral voltage terminal in any configuration with unbalanced phase
voltages.
7EN05-0336-09
Test duration in seconds (s) which must
be longer than 30 seconds
Power factor
Pulse constant programmed in the meter
under test in Wh/pulse
Verifying accuracy
267
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