User's Manual

Table Of Contents
Chapter 5: Configuration
Power Management Properties
Psion Teklogix 7545 Hand-Held Computer User Manual 119
5.6.7.3 Suspend Threshold And Estimated Battery Backup
The Suspend Threshold adjustment tells the system when to shut down when the battery
drains. If you choose Maximum Operating Time, the unit will run until the battery is com-
pletely empty; the RAM is only backed up for a short period of time. If you choose
Maximum Backup Time, the hand-held shuts off with more energy left in the battery so
RAM can be backed up for a longer period of time.
The Estimated Battery Backup is the amount of battery power that has been reserved or set
aside to protect data until a charged battery can be installed in the 7545. When the battery
capacity is depleted up to the Estimated Battery Backup reserve specified in the Suspend
Threshold menu, the 7545 shuts off automatically and uses the reserve power to preserve the
Important: Selecting Maximum backup time will reserve approximately 20% of the
battery capacity for memory backup. Once the battery is drained, the system
RAM memory is lost and the unit must cold boot.
In most real-time transaction environments this is not a problem (it only
takes a few seconds to cold boot). Batch transaction environments, where
data is not saved to a non-volatile memory (such as an SD FLASH card),
may need to pay particular attention to this parameter. Psion Teklogix does
not recommend the storage of any valuable data in system RAM.
The 7545 Windows CE 5.0 environment does not store any critical data in
RAM (such as the registry or file system).
If your application does not save data to RAM, Psion Teklogix recommends
keeping the Suspend Threshold setting as low as possible to maximize
battery run time.
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