5 enabling / disabling the backup battery, Enabling / disabling the backup battery -8, Enabling / disabling the backup battery – Emerson Process Management Bristol ControlWave ExpressPAC User Manual
Page 76
ControlWave ExpressPAC Instruction Manual (CI-ControlWave EPAC)
Note:
If the real-time clock loses its battery backup, the ControlWave
system variable _QUEST_DATE turns ON. You can monitor
this to generate an alarm. See the System Variables section of the
ControlWave Designer Programmer's Handbook (D5125) for
more information.
Caution
You lose SRAM contents when you remove the backup battery.
If you replace a backup battery, wait at least one minute before re-
powering the system. This enables the SRAM to completely discharge.
After you install the new battery, ensure that you have placed jumper
W3 on pins 1-2 (to enable the battery).
Removing /
Replacing the
Battery
1.
If the ControlWave ExpressPAC is running, place any critical
control processes under manual control.
2.
Remove power from the ControlWave ExpressPAC.
3.
Remove the CPU/System Controller board assembly from the
housing.
4.
To remove the lithium battery, gently pry up the tab holding the
battery in the coin cell socket and remove the battery with a pair of
tweezers or needle-nosed pliers. Install the replacement battery.
5.
Replace the CPU/System Controller board assembly in the housing.
6.
Re-connect power to the ControlWave ExpressPAC.
7.
Once the battery has been replaced, the unit executes its Flash-
based application (“boot project”) at power-up, but all of the
current process data is lost. At power-up, the ControlWave
ExpressPAC acts as though it had just been booted and reverts back
to the initial values specified in its application.
5.2.5 Enabling / Disabling the Backup Battery
For maximum shelf life, the CPU/System Controller board ships
from the factory with the installed lithium backup battery disabled.
You must enable it when you install the CPU/System Controller
board.
Enabling
To enable the battery, install jumper W3 on pins 1-2.
Disabling
For maximum shelf life, you can isolate the battery from the circuit by
placing jumper W3 on pins 2-3.
5-8
Service & Troubleshooting
Revised Mar-2011