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9 QS872A Distribution Monitoring Module
Overview
This section describes the Distribution Monitoring Module features, functions, and alarms. Figure 9-1
shows the QS872A Distribution Monitoring Module board. This board is installed on the left wall of the
Distribution Module (if equipped). This board may also be used in external distribution panels.
LED: This is a tri-color LED and will illuminate accordingly for the conditions shown below.
LEDs: *= On
Green
*
Communication Failure
If the LVD board loses communication with the system controller, it will blink its LED in red color. Note
that during a battery on discharge event, the system controller signals the LVD board to disconnect the
batteries from the system once the battery strings have discharged to the threshold voltage set by the
user. This command is not possible during a communication failure. If communication is lost during
this event, the LVD boards will disconnect at the backup disconnect voltage of 35V +/- 1V.
Similarly, when the utility supply source returns, the rectifiers will power up and the output bus voltage
will rise to the Float Set Point set by the user. Once the output voltage crosses the reconnect threshold
also set by the user, the system controller commands the LVD contactor to close and connect the
batteries to the bus voltage. During communication loss with the controller, this command will not be
possible. In this case, the LVD contactor will reconnect at the backup reconnect voltage of 48V +/- 1V.
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Distribution Module With Front Door Open
Figure 9-1:Distribution Monitoring Module
Amber
Red
*
*
Flashing
Distribution Mounting Module
Communication Loss with System Controller
Condition
Normal
Minor Alarm
Major Alarm
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