010-592-B2 Rev E
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2.2
Exception States
While in Normal Operation or Battery Backup, there are three exception states that may occur.
2.2.1
Replace Battery
The FMPS enters the Replace Battery state when the charge control circuit determines the battery is not holding
a charge, or is incapable of being charged. The Replace Battery alarm initiates when the battery capacity is less
than 70% of the battery capacity stated by the battery manufacturer. The battery replacement criteria are based
on the battery test results described in Section 6.10.
2.2.2
Battery Missing
The Battery Missing condition is a critical condition because the FMPS is unable to supply the expected amount
of backup power should AC power fail. A Battery Missing alarm is sent to the ONT if one or more batteries are
missing from the FMPS; i.e., there are less than eight batteries in the unit.
2.2.3
Over-current
Over-current is a serious condition that could damage the FMPS. The state becomes active if the FMPS detects
the external load current draw exceeds the FMPS capacity; e.g., this condition could be caused by an inadvertent
short across the power leads.
The FMPS automatically determines the proper operating state and resumes operation when the Battery Missing
or Over-current conditions are removed. Replacing the battery (batteries) clears the Replace Battery alarm.
2.3
Status Signals
The status connections communicate FMPS status to the ONT(s). Status signals sent to the ONT are assertive
high; i.e., when active, the signal line is disconnected from float with respect to the “Telemetry Return” pin. Status
signals are open collector (open circuit = alarm, and low impedance = no alarm).