SATEC EM920 Operation Manual - Manual (Page 21)

Chapter 2 Operating the EM920
Instrumentation Metering
EM920 Power Quality and Revenue Meter 21
The present tariff rate is indicated on the EM920 display. If
required, tariff-switching pulses with a programmable
duration can be output via the meter relays.
End of Billing
The meter can be configured to trigger a reset of billing
maximum demands and an end of billing period automatically
on a monthly schedule, manually via the sealable DEMAND
RESET button, and remotely via communications. It can also
be done via control setpoints using any programmable
internal or external trigger, like a specific time schedule or an
external pulse.
You can select the reset sources via the Device Options setup
(see
Device Options and Mode Control in Chapter 5).
The EM920 uses a one-day protection lockout time to avoid
multiple consecutive resets of the billing maximum demands.
Billing Data Recording and Load Profiling
The EM920 provides automatic recording of the billing data to
flash files:
• Monthly billing period data for the last 24 billing
periods
• Daily energy and maximum demand profile for the last
120 days
• 15-min energy load profile for 120 days or 30-min
profile for 240 days.
Maximum demand profiling for monthly and daily billing data
profiles can be individually configured for every register.
See Factory Preset Data Log Files in Chapter 5 and Billing and
Load Profile Log Files in Appendix D for more information on
the file layout and contents.
Billing Data Display
The EM920 display indicates billing energy, maximum
demand and cumulative maximum demand registers for the
present billing period and for three previous billing periods.
The display is automatically configured for your set of billing
registers and your tariff schedule. See
Billing Period Data
Displays in Chapter 3 for the display layout.
Instrumentation Metering
Instrumentation metering provides real-time measurements
and time-integration for local and remote power monitoring
and control, and a source for power quality evaluation and
triggering the logical controller and Fault recorder.
See Parameters for Monitoring and Logging in Appendix A for
a full list of the electricity and status measurements provided
by the EM920.
All RMS quantities are based on 1/2-cycle true RMS
measurements as per IEC 61000-4-30.