Procedures For Replacing Battery - Mitsubishi FX3UC SERIES User Manual

FX Series Programmable Controllers
3UC
User's Manual - Hardware Edition

12.4.3 Procedures for replacing battery

When the battery voltage drops while the PLC power is on, the "BAT" LED on the panel is lit in red, and
M8005 and M8006 (latch) are turned on.
The memory can be retained for about one month after the lamps turn on. However, the operators may not
immediately find the lamps to be on. Prepare a new battery promptly, and replace the battery with the new
one.
Before replacing the battery
Step 4 of the replacement procedure (below), must be performed within 20 seconds after step 3, or
the memory content could be lost.
1
Turn the power OFF.
2
Remove the main unit
Disconnect all connected cables including the power cable, I/O cable, communication cable and
extension cable.
Remove the main unit from the DIN rail.
3
Remove the battery cover.
Attach a screwdriver to the battery cover on the underside of the PLC as
shown in the right figure ( ).
Slightly move the ( ) side of the battery cover.
Grasp the cover ( ) between your fingers and remove it.
(The right figure is FX
4
Remove the old battery.
Extract the old battery from the battery holder, and disconnect the battery
connector.
5
Install the new battery.
Connect the battery connector to the new battery, and insert the battery into
the battery holder.
6
Attach the battery cover.
Cation
1) Battery replacement requires users to verify data integrity such as the PLC program (when a memory
cassette is not attached), latched (battery backed) device values and RTC values. Before switching the
PLC to RUN, ensure the safety of the operation.
2) If the battery backed data becomes unstable, clear the latched (battery backed) devices, and transfer the
data again. Set the RTC and default values again if necessary.
12 Test Operation, Adjustment, Maintenance and Troubleshooting
→ For details on the specifications and functions of the battery,
-32MT/D.)
3UC
→ For the clear method of keeping devices, refer to the programming manual.
refer to Section 11.5 "FX
3U
12.4 Maintenance
11
12
-32BL (Battery)"
A
B
C
D
E
F
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