Maintenance   
9.6 Module installation / removal 
  S7-300, CPU 31xC and CPU 31x: Installation 
9-10  Operating Instructions, Edition 08/2004, A5E00105492-05 
Putting a new module into service 
Proceed as follows to put the new module into service: 
1.  Open the front panel. 
2.  Reinstall the front connector. 
3.  Close the front panel. 
4.  Switch the load voltage back on. 
5.  Reset the CPU to RUN mode. 
CPU
PS
1
2
 
 
The figure illustrates the described steps: 
(1)  Move the front connector into operating position 
(2)  Close front panel. 
 
Reaction of the S7-300 after module replacement 
After a module replacement, the CPU switches to run mode, provided no error has occurred. 
If the CPU stays in STOP, you can view the cause of error in STEP 7 (see the 
STEP 7 
 User 
manual).