User's Manual
Table Of Contents
- Introduction
- Product Description
- Operating Instructions
- Outputs
- Testing
- Installation and Removal
- Glossary
- Display
- Nameplate Information
- Wiring Diagrams
- Technical Specifications
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Contact Elster Electricity for information
REX Meter
5 Testing Technical Manual
5-10 30 November 2006
Installation Site
Te st i ng
Since no adjustments are required for the REX meter, the main reason to test a
meter is to make sure it is operating within factory specifications. Typically, all
that needs to be done is to check the meter calibration.
Accuracy Tests
Accuracy tests confirm that the kWh readings meet calibration standards. The
method of manually counting pulses requires a stopwatch.
To count pulses manually, the following procedure should be used:
1. Place a known load on the meter.
2. Start the stopwatch when the LCD K
h
pulse indicator turns off and start
counting the number of pulses made by the indicator. Be sure to count
each time the K
h
pulse indicator (square indicator) turns off.
3. After a sufficient time to account for various response times, stop the
stopwatch when the LCD K
h
pulse indicator turns off. Record both the
time on the stopwatch and the number of pulses counted.
4. Remove the load from the meter.
5. Calculate the expected number of pulses using the following formula:
Note: Time is measured in minutes.
6. Verify that the calculated pulse value matches the observed pulse
count. This indicates that the meter is performing accurately.
7. Calculate the kWh using this formula:
The calculated kWh may not be exactly equal to the observed kWh. The time
the meter was energized with the load applied and the time between starting
and stopping the stopwatch can vary the calculations. This is normal and does
not necessarily reflect inaccurate measurements.
8. Verify that the calculated kWh is equal to the change in kWh reported
on the REX LCD. This indicates that the meter is calculating kWh
accurately.
60
1000
K
tkW
value pulse calculated
h
×
×
=
1000
value pulse calculatedK
kWh calculated
h
×
=