Siemens Simatic S7-300 CPU 31xC Series Installation And Operating Instructions Manual page 171

Initial situation
The module you want to replace is still mounted and wired. You want to install the same type
of module.
Warning
Disturbances can corrupt data if you insert or remove S7-300 modules while data are being
transferred via the integrated interface of your CPU. You should never replace any modules
of the S7-300 while data traffic is active at an integrated interface. If you are not certain
whether or not data transfer is active on the interface, unplug the connector at the interface
before you replace the module.
Removing the module (SM/FM/CP)
To remove the module:
Step
1.
2.
3.
4.
5.
6.
7.
S7-300, CPU 31xC and CPU 31x: Installation
Operating Instructions, Edition 08/2004, A5E00105492-05
20-pin front connector
Switch the CPU to STOP.
Switch off the load voltage to the module.
Remove the labeling strip from the module.
Open the front panel.
Unlock the front connector and remove it.
To do so, press down the unlocking
mechanism with one hand and pull out
the front connector at the grips using
the other hand.
Undo the module fixing screw(s).
Swing the module out.
9.6 Module installation / removal
40-pin front connector
Remove the fixing screw from the middle of the
front connector. Pull the front connector out,
holding it at the grips.
Maintenance
9-7