User's Manual

48 Meter Operation
Main Cover Removal
Removal of the meter main cover will initiate a tamper event. A cover removal
tamper event is recorded whether power is on or off to the meter. Once power is
restored, a report of the tamper condition is sent to NES System Software, if the
meter is communicating with a Data Concentrator.
When the meter is installed, or the main cover is removed for servicing, a tamper
diagnostic event is set in the meter.
Note: When the main cover tamper event flag is set, additional activations of the
tamper switch are not recorded. In this state, unauthorized removal and
replacement of the cover could occur without detection. All tamper signals
should be recorded and cleared regularly by NES System Software to reset the
tamper event flag into a state to enable detection.
Display Indicator for Cover Tamper Switch
This display indicator, , is illuminated when the main cover tamper switch is
open. This indicates that the main cover is not installed or not installed properly.
Meter installation or service personnel should make sure this indicator is off after
they have replaced the cover, to be sure the cover is installed properly and that the
tamper switch is closed.
Reverse Energy
Reverse energy flow occurs when the meter has been installed upside down, or if the
premise being metered generates power. The meter can detect reverse current flow
on individual phases. If reverse current is detected for 10 consecutive seconds this
tamper event is signaled.
Phase Inversion
Phase inversion is detected by the Data Concentrator only for single-phase
applications and indicates that the neutral and the phase have been swapped. The
Data Concentrator can be programmed to alert NES System Software to this
condition.
The meter stores the last reported phase inversion status from the Data
Concentrator. If a meter is connected to a Data Concentrator and a phase inversion
is measured and reported to the meter, the alarm condition will persist, even if the
meter is later powered up without a Data Concentrator and there is no longer a
phase inversion present (unless this status was cleared by the system). A Data
Concentrator must be connected to the meter and must measure and report the
corrected phase status to the meter for the meter to stop logging this alarm.
Current Flow with No Voltage
When current flow greater than 2 amps is detected on a phase for which there is low
or no voltage, the meter can report the event as a tamper condition. For this tamper
detection to operate, at least one meter-phase must be powered (voltage present).
If a polyphase meter is configured for single-phase or two-phase operation, this
tamper detection is not reported on unused phases.