Siemens S5-135U/155U System Manual page 228

CPUs, Memory Cards, Memory Submodules, Interface Submodules
Proceed as follows to replace the submodule battery:
Step
Using the RAM
Submodule with
Battery Backup
Caution
!
EPROM-battery-backed RAM submodules must not be programmed via the
EPROM interface of the PG, otherwise they can be destroyed.
Before inserting or removing the RAM submodule into or out of the CPU,
switch the PLC power supply off: this is to ensure that data of the RAM
submodule are not corrupted.
Inserting
Initial situation:
Unprogrammed
Memory
Submodules
Step
5-88
Action
1 Open the upper side of the cover by releasing the snap-on catch.
2 Slacken the screws on the left and right of the battery.
3 Replace the submodule battery and secure the new battery with
screws, observing the polarity.
4 Close the cover again.
The CPU is in the programmable controller.
The power supply of the PLC is switched off.
The mode switch of the CPU is at STOP.
Action
1 First insert the battery in the RAM submodule.
2 Insert the RAM submodule in the CPU.
3 Switch the power supply of the programmable controller on.
4 Carry out an overall reset.
5 Connect your programmer (PG) to the CPU.
6 When the user program has been loaded into the RAM
submodule, reset the CPU.
System Manual
C79000-G8576-C199-06