Emerson Liebert NXL series Operation And Maintenance Manual page 77

Liebert NXL UPS
Event Message Event Definition
Controls
The Controls Communication Failure
Comm Fail event indicates a loss of communications
between the Controls and Human
Machine Interface (HMI).
The Controls Communication Failure
event is displayed when the HMI
detects a loss of communication with
Controls on the Controller Area
Network (CAN).
An infrequent occurrence that resets
immediately is probably not serious.
Controls Reset
This alarm means one or more critical
Required settings have been changed by user
during UPS operation.
The change(s) will not take effect until
after a UPS Controls reset. This
operation should only be performed by
an authorized service personnel.
This alarm is cleared after UPS
Controls reset.
DC Link
The positive (or negative) DC Bus has a
Gnd Fault +
ground fault.
The UPS controls monitor the DC Bus
positive (or negative) half for a voltage
imbalance caused by current flow to
DC Link
ground. This fault means excessive
Gnd Fault -
ground current is detected.
In normal operation, with the batteries
connected, the most likely cause of a
current path to ground is a leaking
battery.
If your system includes an optional
Battery Ground Fault Monitor, check if
the Battery Ground Fault message is
present also.
EMO Shutdown
An Emergency Module Off (EMO)
command has been detected.
A Remote EMO would display the
"REMO Shutdown" alarm.
In response to an EMO, the UPS
transfers to Bypass and shuts off.
Liebert NXL alarm and status messages (continued)
Page 77
Operation and Maintenance Manual 250-300-400-800kVA
Recommended Action
If the alarm does not clear, or if the alarm
condition returns, contact your factory-
authorized service provider.
Press "SILENCE" to silence the audible
alarm.
Press "SILENCE" to silence the audible
alarm.
Press "RESET" to clear the fault.
Perform a visual inspection of the
batteries. Look for signs of leaking
battery acid or excessively corroded
battery terminals.
If there are no visible signs of defective
batteries, open one Battery Breaker.
Press "RESET" and see if the condition
clears. If the condition clears, you have
isolated the problem to that battery
string.
If the condition will not clear, repeat the
test with each connected battery string.
Once the location is identified, or if the
battery string tests are inconclusive,
contact your factory-authorized service
provider.
Press "SILENCE" to silence the audible
alarm.
Resolve the issue that precipitated the
EMO.
For safety, the UPS latches an EPO
event. To clear the latch, press the EMO
Reset pushbutton on the External
Interface Board (EIB).
Verify the EMO is cleared by pressing
"RESET" and observing that the EPO
alarm in the Active Event Window is
gone.
Restart the UPS by pressing "Startup,"
"Manual Start," and follow the prompts.