7.2
Identifying Modes of Operation
In order to fully understand the power supply functions, it is important to recognize the
modes of operation indicated by the LEDs in the front panel SYSTEM STATUS,
CHARGER STATUS, and optional APM blocks.
7.2.1
System Status Block
The SYSTEM STATUS block indicates the utility and battery input status, plus verifies
the output of the power supply. The green AC OUTPUT LED should remain ON at all
times.
7.2.1.1 AC LINE Operation
Indicates Line operation with the power module operating on utility power. Power is
available from the utility and acceptable voltage is present at the output.
7.2.1.2 STANDBY Operation
Indicates Inverter operation using the batteries and inverter. Standby power is avail-
able from the batteries and acceptable voltage is present at the output.
7.2.1.3 TRANSFER or SELF-TEST Mode
On standard XM units:
When all three LEDs are ON at the same time, the power module is in its transfer mode, preparing to
transfer back to AC LINE power. The complete re-transfer takes approximately 10 to 50 seconds to ensure
that incoming voltage and frequency has stabilized, and to allow the module to synchronize wave forms with
the utility. When the transfer is complete, the red "STANDBY POWER" LED will go out.
Units equipped with APM or USM logic upgrades:
When all three LEDs are ON at the same time, the unit is in either its self-test or transfer mode. Check
the yellow LED marked "TEST IN PROGRESS" in the APM block. If the LED is ON, the power module is in
its self-test mode; if the LED is OFF, the power module is preparing to transfer back to AC LINE operation.
38
7. OPERATION
AC OUTPUT
LED (green) ON
AC OUTPUT
LED (green) ON
AC OUTPUT
LED (green) ON
LINE POWER
LED (green) ON
STANDBY POWER
LED (red) ON
LINE POWER
LED (green) LED ON
STANDBY POWER
LED (red) ON
