Removing/Replacing The Backup Battery - Emerson ControlWave EFM 3808 Instruction Manual

ControlWave Express Instruction Manual (CI-ControlWave Express)

5.2.3 Removing/Replacing the Backup Battery

5-6
Shut down the ControlWave Express by disconnecting the
2.
power at the CPU/System Controller assembly terminal TB1
(and if applicable, TB2).
Loosen the two thumb screws and remove the removable card
3.
edge cover. Also loosen the captive fastener that secures the
CPU/System Controller and Process I/O board assembly in the
housing. See Figure 2-1 to locate these components.
Disconnect all removable card edge connectors from the
4.
CPU/System Controller board and the Process I/O board. Label
or otherwise identify them so you can easily re-connect them
later.
If present, disconnect the display/keypad from connector J2 on
5.
the CPU/System Controller board.
Carefully slide the board assembly out of the mounting
6.
chassis/enclosure.
If you need to replace either the CPU/System Controller board
7.
or Process I/O board, you need to separate the two boards. Use a
pair of needle-nosed pliers to squeeze the pair of tabs associated
with each of the six nylon mounting posts, while gently pulling
the CPU/System Controller board away from the Process I/O
board. Carefully unplug the boards from their interface
connectors. Align the replacement boards with each other and
press them together so that the interface connectors and
mounting posts properly mate; then squeeze together so that the
mounting post tabs capture the CPU/System Controller board.
To install the replacement boards, power must be off. Align the
8.
boards (assembly) with the mounting chassis/enclosure so that
the Process I/O board is adjacent to the bottom of the unit and
then slide the assembly into the unit.
Replace all cables removed in steps 2 through 5.
9.
Replace the removable card edge cover and tighten the two
10.
thumb screws. Apply power and test the unit.
: The CPU/System Controller board draws power from the battery
Note
only if the board loses power. The system SRAM has a standby
current draw of 20 μA maximum for each part plus 2 μA for the
real time clock. For a ControlWave Express containing 2MB of
SRAM, a worst-case current draw of 42 μA allows a battery life
of approximately 9,000 hours. This means you should not need
to replace a battery until the ControlWave Express has been in
service for an extended period (normally many years).
Service & Troubleshooting Revised Mar-2011