Installation guide

Memory Module and Battery Backup Unit
775013 A-3
Removing the DMM1100
The DMM1100 only needs to be removed if the NiCd battery no longer
accepts a charge properly (NiCd battery life expectancy is approximately 5
years), or if the DMM1100 is being salvaged from a controller that has
failed.
, WARNING
Replace the battery only with the same or
equivalent type of battery recommended by the
battery manufacturer. Dispose of used batteries as
described under “Recycling the Battery” on page
A-5.
DMM1100 Functional Description
Whenever the system is running, the DMM1100’s battery backup circuitry is
standing by, monitoring the voltage level of VCC. In the event of a power
failure, the VCC voltage level will begin to drop. When the battery backup
circuitry detects this voltage drop, it checks the status of the disk cache. If
the cache is empty, the battery backup circuitry does nothing.
If the cache contains data during a power failure, the DMM1100’s battery
backup circuitry will maintain cache data integrity until the power is
restored. When power is restored and the system finishes the bootstrap
process, the cache contents will be written to the disk array. The cache
contents will then be flushed from the cache.
Status Indication
The status of the battery can be checked with the gas gauge feature that can
be accessed in GAM (version 2.1x or greater is needed). The gas gauge
appears on the screen as two meters— a battery power meter and a charge
level meter— each calibrated from 0 to 100.
The battery power meter indicates the battery capacity in hours. It will
indicate a charge duration of up to 100 hours. The firmware will detect the
memory and assign a value based upon the charge level of the battery and the
power consumption rate of the memory.
The charge level meter displays the charge state of the battery expressed in
percent (100% indicates a fully charged battery).