Wasp WDT2200 User Reference Manual - Chapter 2 Power System
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© 2003 Wasp Technologies, Inc.
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Chapter 2 Power System
2.1 Power System
Main Power
The terminal is operated by a rechargeable 3.7V 880mAH rated Li-Ion battery pack. The main battery should be
sufficient to for daily operation up to 12 hours. Actual duration may vary with usage.
Backup Power
An onboard 3V 190mAH Lithium button cell battery (CR2032) is used as the secondary power source to back up the
data in RTC (real time clock chip) and RAM memory to provide users a data-loss free environment.
Normally the WDT2200 gets power from main power source to back-up RTC and RAM and puts the Lithium battery in
standby state. When the main power source is removed or the voltage falls below the minimum level necessary to back-
up the RAM and RTC properly, the power circuit of the WDT2200 automatically switches to the Lithium battery for
back up. It is recommended that the main battery always be placed inside the unit with enough capacity for back-up
purposes, in which case the Lithium battery can supply power for up to
3 years
with the unit turned off before
consuming its capacity.
It is important to know that once the power in the backup battery is consumned, all data within the terminal
will be lost. So it is very important to backup all data when replacing the backup battery.
2.2 Power Low Indication
Main Battery
When the main power source reaches the battery low condition, a warning message, as
shown to the right, will be shown on the LCD when WDT2200 is powered on or a
battery
low icon sign
will emerge on the right sidebar of LCD.
When the main battery low power condition occurs, the main battery can continue to supply
power for about 20 ~ 40 minutes with each scan reduding this figure by only about 5 seconds, however the unit may
reach the system power cutoff point and automatically turn itself off. Meanwhile, the unit continues to back-up the data
contents in RTC and RAM, but it cannot be powered up until the batteries have been recharged or replaced.
Backup Battery
When the Lithium backup battery doesn't have enough capacity to back up the system, the
message at right will be shown on LCD when the unit is powered on. In this situation you
should upload your data from the terminal immediately and install a new Lithium battery.
! WARNING !
MAIN BATTERY
VOLTAGE LOW
! WARNING !
Backup BATTERY
LOW