User's Manual

ANSI Electric Meter v3.1 User’s Guide 61
Clock Settings
The meter clock can be configured to synchronize itself internally at all times, or to
synchronize itself with the utility line’s frequency. If the utility line’s frequency is
selected and there is a power outage, the meter will synchronize the clock internally
until power is restored, at which point it will re-synchronize itself with the utility
line’s frequency.
Note: You can change this clock setting with the NES Provisioning Tool. However,
the meter must be power cycled after the change for it to take effect.
If the meter is powered up and starts without a valid clock setting, the following
actions will be performed as soon as the clock is set:
 Any Self-read or One-time-read scheduled to occur during the power-off
duration, or after the power-up and before the clock was set.
 The duration and date/time that the power outage occurred will be recorded
in the meter event log.
Load Profile Back-fill Upon Power-up
When the meter is powered-up, the load profile is either fully or partially filled with
records that would have been recorded, but were missed during the power outage
time-period. The data that is stored in those records is dependent on the values
selected for logging. Accumulators such as energy values, power-off minutes, and
power-off counts are stored as the values that are present in the meter at power-up.
Instantaneous values such as voltage, current, and power factor are stored as zero.
The following describes the load profile back-fill scenarios that could occur:
 If the power to the meter is lost and is restored on the same day, the missing
entries are completely back-filled upon power-up.
 If the power is lost on one day and power-up occurs on the next day, the
missing entries are completely back-filled upon power-up.
 If the power outage occurs on one day and power-up occurs on a day other
than the same or the next day, data is only partially back-filled. The missing
records are created for the remainder of the day on which the power was lost
and for the start of the day on which power was restored. Data for any full
calendar days of power outage between the day the power went off and the
day it came back on is not included in the load profile. A full calendar day is
considered to be the 24-hour period from midnight to midnight.
Start-up Time
Metering energy measurements are started in less than 1 second after the meter is
powered-up at normal operating voltage. Full operation of all meter functions and
communication systems occurs a little over 2 seconds after the meter is powered-up.
Energy Measurements and Calculations
The electrical values that are provided by the meter include meter energy
(summation of phases; totals, or per individual tariff), instantaneous values such as
voltage and current. All values are updated once per second for usage such as
viewing, data logging, or communications.