SATEC EM920 Operation Manual - Manual (Page 19)

Chapter 2 Operating the EM920
Monitoring the Meter Battery
EM920 Power Quality and Revenue Meter 19
Monitoring the Meter Battery
A backup lithium battery keeps the meter clock running when
the power is removed from the meter.
You can monitor the status of the battery from the front
display on the Device Info pages (see
Device Info Display in
Chapter 3) and via the device diagnostics.
When the lithium battery voltage drops below the minimum
allowed level, it is indicated by the blinking “Battery Low”
icon on the display and via the device diagnostics. In this
event, the battery should be checked and replaced if
required.
NOTE
Always clear the battery operation time counters after
replacing a battery. See
Reset of Accumulators and Log Files
in Chapter 6 for information on how to clear the operation
counters in your meter.
Billing and Energy Metering
The EM920 provides true four-quadrant energy
measurements with Class 0.2 ANSI C12.20 accuracy. The
following energy quantities are available for instrumentation
and billing:
• kWh delivered (Q1+Q4)
• kWh received (Q2+Q3)
• kWh net (Q1+Q4)-(Q2+Q3) - instrumentation
• kvarh delivered (Q1+Q2)
• kvarh received (Q3+Q4)
• kvarh net (Q1+Q2)-(Q3+Q4) - instrumentation
• kvarh Q1, Q2, Q3, Q4 quadrants
• kVAh delivered (Q1+Q4)
• kVAh received (Q2+Q3)
• kVAh total (Q1+Q2+Q3+Q4)
Energy Measurement Channels
The EM920 uses two independent current channels for high-
accuracy energy measurements and for conventional high-
range instrumentation. They provide different gain and
measurement ranges as necessary for billing accuracy energy
metering and for power quality and fault monitoring.
1-second currents and powers provided by the meter and the
corresponding engineering display readings are taken from
the energy measurement channel. They begin measurements
from 5 mA starting currents and up to 20 A RMS with 5 A
secondaries, while instrumentation currents provide
measurements up to 50 A RMS.