Siemens 9410DC, Руководство пользователя, Страница: 157 / 172

Verifying accuracy 9410 series
4. Connect the control equipment used for counting the standard output pulses using
one of these methods:
Option Description
Energy pulsing LED Align the red light sensor on the standard test bench armature over the
energy pulsing LED.
Digital output Connect the meter’s digital output to the standard test bench pulse
counting connections.
NOTE: When selecting which method to use, be aware that energy pulsing LEDs
and digital outputs have different pulse rate limits.
5. Before performing the verification test, let the test equipment power up the meter
and apply voltage for at least 30 seconds. This helps stabilize the internal circuitry
of the meter.
6. Configure the meter’s parameters for verifying accuracy testing.
7. Depending on the method selected for counting the energy pulses, configure the
meter’s energy pulsing LED or one of the digital outputs to perform energy pulsing.
Set the meter’s energy pulse constant so it is in sync with the reference test
equipment.
8. Perform accuracy verification on the test points. Run each test point for at least 30
seconds to allow the test bench equipment to read an adequate number of pulses.
Allow 10 seconds of dwell time between test points.
Calculate the number of required pulses
The reference test equipment typically requires you to specify the number of pulses
required for a test duration of “t” seconds.
Normally, the number of pulses required is at least 25 pulses, and the test duration is
greater than 30 seconds.
Use the following formula to calculate the required number of pulses:
Ne Number of metering elements used
V Test point voltage in line-to-neutral volts (V) per phase
I Test point current in amps (A) per phase
t Test duration in seconds (s) which must be longer than 30 seconds
PF Power factor
Kt Pulse constant programmed in the meter under test in Wh/pulse
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.
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