User`s manual

Battery life and replacement procedure Maintenance and inspection
MELSEC System Q, Hardware 10 – 20
10.3.3 SRAM card CPU module battery replacement procedure
Replacement procedure of SRAM card battery Q2MEM-1MBS and Q2MEM-2MBS
 Open the front cover while the programmable controller power supply is on.
 With a flat-blade screwdriver, etc., remove the battery holder locking switch from the LOCK
position (also refer to section 5.2.3).
 Remove the battery holder from the SRAM card.
 Remove the old battery from its holder.
 Insert a new battery into the holder in the correct direction.
 Insert the battery holder to the memory card and check that the battery holder fixing switch
is set to the LOCK position.
 Monitor SM52 to verify on/off. If the special relay is still set, indicating with SD52 a low CPU
battery voltage, retry the replacement.
The following figure shows some of the steps for replacing the battery.
NOTES Before replacing battery b ack up the SRAM card data using a programming device.
The battery replacement at the CPU must be done with power supply ON. Observe all safety
precaution when working with power supply switched on:
When replacing the battery with the programmable controller power supply off, proceed as
follows:
- Back up the SRAM card data using a programming device.
- Remove the memory card and replace the battery.
- Insert the memory card into the CPU.
- Write the backed up data from the programming device to the memory card.
When dismounting or mounting the battery holder on the SRAM card, take care so that the
battery does not come out of the battery holder.
Fig. 10-6: Replacing SRAM card batteries Q2MEM-1MBS and Q2MEM-2MBS
Release battery holder
locking switch
Remove battery holder
Remove battery
Insert new battery
+ (positive)
Insert battery holder
Release
direction