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6.3 Display Panel Message Interpretation
The message displayed on the 7400-M can be categorized into two types: (a) ALARM messages- These are
messages which need urgent attention and warn of a UPS shut down or imminent shut down – the load would
normally transfer to the bypass supply if it is available. All alarm messages are accompanied by an audible warning.
(b) WARNING messages – these are messages generated to warn or confirm to the operator of actions taken (i.e. if
the rectifier AC input supply power switch was opened, the Warning message would read – RECTIF-SWITCH
OPEN). The following table lists the various messages displayed on the operator panel together with a description
of their interpretation.
Item
No.
DISPLAY ALARM MESSAGES Interpretation – Action
1. CUT-OFF EMERGENCY This alarm indicates that the UPS was by local or remote (if fitted) Emergency Power Off
button (EPO), which is normally due to operator action – investigate why the emergency
power off pushbutton was pressed. If EPO push button was not pressed then check the
continuity of the circuit to the remote switch. Customer connections; auxiliary terminal
block, X3; pins 10 & 11 normal closed.
2. INV. SOFTWARE BLOCK The INV. SOFTWARE BLOCK alarm is active whenever the inverter is not producing its
correct output voltage; either because it has been switched off; or due to an internal fault, it
normally be accompanied by one or more other inverter fault conditions.
3. INV. OVER-VOLTAGE
INV. UNDER-VOLTAGE
OUTPUT: NO VOLTAGE
OUTPUT: WAVEFORM ERR
Most of the Inverter fault messages are self-explanatory, however the WAVEFORM ERR
informs the operator that the output voltage peak has flattened caused by an internal
inverter problem and therefore will be out of limits.
4. INV. OVERTEMPER Over temperature is sensed by a normally close thermostat (90
0
C operating) fitted to each
inverter heat sink. If an over temperature condition arises, the audible alarm will
accompany this message; the inverter stops and load transfers to bypass after 3 minutes.
5. CUT-OFF OVERTEMPER This message informs the operator that the inverter has been switched off and that the load
has been transferred to bypass due to inverter over temperature.
6. OVER LOAD PRESENT The Inverter overload had an inverse load/time characteristic; i.e. it will accept 125%
overload for 10 minutes And 150% for 60 seconds. If this characteristic is exceeded then
the load transfers to the bypass supply, the inverter stops and the overload alarm
annunciates. The [OVERLOAD PRESENT] alarm will annunciate as soon as the load
exists 100%of the UPS rating, and the load will transfer to bypass some time later –
depending on the degree of overload present.
7. CUT OFF OVERLOAD This message informs the operator that the load has transferred to bypass due to an
inverter load.
8. OUTPUT SWITCH OPEN This is a status alarm. The output switch must be selected ‘CLOSED’ at all times except
when operating the maintenance bypass supply.
9. BYPASS SWITCH OPEN This is a status alarm. The bypass input switch must be closed all times.
10. BATTERY SWITCH OPEN This is a status indication only. Note that if the UPS is operating with the battery circuit
breaker open and the mains power, then the UPS output will also fail, together with load
power, since the inverter has no battery back-up.
11. BATTERY FUSE FAIL This problem should be rectified as soon as possible. If the mains power fails, then the
UPS output will also fail, together with load power, since the inverter has no battery back-
up.
12. BATTERY TEST FAILED The system has carried out a test of the battery. If this alarm is not accompanied by a
[BATTERY SWITCH OPEN] or [BATTERY FUSE FAIL] message then a full check of the
battery bank is required.
13. DC BUS: UNDERVOLTAGE When the inverter is operating on the battery, this message is displayed when the battery
voltage has fallen below a preset value. If the input AC power cannot be restored you
should shut down your loads.
14. BATTERY E.O.D. Battery discharge has continued beyond a preset value. The inverter will have to be shut
down, the system will attempt a transfer to bypass, if there is no bypass supply available,
any load still connected will be without power.
15. RECT: SOFTWARE BLOCK THE RECT. SOFTWARE BLOCK alarm is active whenever the battery charger (rectifier) is
not producing its correct output voltage; this can be caused by, an operator selection to off;
an input supply failure; an open rectifier AC input power switch or an internal fault which
may be accompanied by one of the fault conditions.
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