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PowerLogic™ PM5500 series user manual Chapter 15—Verifying accuracy
HRB1684301-01 133
Using the values from the above example, the maximum pulse constant for the digital
output is:
6. Set the pulse constant (K) to a value below Kmax (for example, 300 pulses/kWh),
then calculate the new maximum output pulse frequency at Pmax:
7. Check the new maximum pulse frequency against the limits for the LED and digital
outputs:
As expected, changing K to a value below Kmax allows you to use the digital output
for energy pulsing.
8. Follow the procedure in “Energy pulsing” on page 80 to set the pulse constant (K) in
the meter.
Typical sources of test errors
If excessive errors are observed during accuracy testing, examine your test setup and
test procedures to eliminate typical sources of measurement errors:
• 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.
• Inadequate meter control power, resulting in the meter resetting during the test
procedure.
• Ambient light interference or sensitivity issues with the optical sensor.
• Unstable power source causing energy pulsing fluctuations.
• Incorrect test setup: not all phases connected to the reference device or the energy
standard. All phases connected to the meter under test should also be connected to
the reference meter/standard.
• Moisture (condensing humidity), debris or pollution present in the meter under test.
Kmax
3600 (digital output maximum pulse frequency)
Pmax
------------------------------------------------------------------------------------------------------------------------
3600 25
285.6
------------------------==
Kmax 315.13 pulses per kWh=
New maximum pulse frequency
K Pmax
3600
------------------------
300 pulses/kWh 285.6 kW
3600 seconds/hour
---------------------------------------------------------------------==
New maximum pulse frequency 23.8 pulses/second 23.8 Hz==
23.8 Hz
·
LED maximum pulse frequency (2.5 kHz)
23.8 Hz
·
digital output maximum frequency (25 Hz)