Chapter 2 Operating the EM720
Meter Security
16
EM720 Power Quality and Revenue Meter
in Chapter 3 for information on diagnostics
indicators. See
how to inspect the meter diagnostics messages from the
display.
The device diagnostics status is stored in a non-volatile
register, which may be inspected and cleared from the meter
display, via the supplemental PAS software, or from a user
application. See
Viewing and Clearing Device Diagnostics
Chapter 6 on how to clear the device diagnostics status in
your meter.
All diagnostic events with time stamps are also recorded in
the meter Event log and can be inspected via PAS (see
In the event of a device fault, check the fault reason and
clear the device diagnostics. See
Appendix G for the list of diagnostic messages and their
meanings. In the event of a time fault, update the device
clock. In the event of a configuration reset, check the setup
affected by the fault via the device Event log, and then verify
the setup data.
Hardware failures are normally non-critical recoverable faults
that do not cause a system failure but may cause data loss.
Hardware failures are often caused by excessive electrical
noise in the region of the device. If the device continuously
resets itself, contact your local distributor.
Device Fault Alarm
The EM720 provides a global "DEVICE FAULT" event flag that
is asserted all the time while one of the diagnostic events
exists. It can be monitored via a setpoint (see
in Chapter 5) to give a fault indication through a
relay output. If the alarm relay is programmed for failsafe
mode
using inverting polarity, then its normally closed
contacts will be open if either the meter looses power or a
device fault occurs.
Meter Security
The EM720 provides 3-level password security for protecting
meter setups and accumulated data from unauthorized
changes. Meter readings are not software protected.
Access to particular setup and control items is granted
depending on the security level of the password you entered.
The passwords can be 1 to 8 digits long.
The following table shows the meter security levels and user
access rights.
Password Security
Level
Access
Rights
Password 1
Low
Reset of billing and engineering maximum
demands, and device diagnostics.
Meter clock update.
Display setup.
