Installing 
  5.4 Labeling the modules 
S7-300, CPU 31xC and CPU 31x: Installation 
Operating Instructions, Edition 08/2004, A5E00105492-05 
5-9 
5.4  Labeling the modules 
Slot numbers Assignment 
You should assign a slot number to each one of the mounted modules, thus making it easier 
to assign the modules in the configuration table in STEP 7. The table below shows the slot 
number assignment. 
Table 5-4  Slot numbers for S7 modules 
Slot number  Module  Comment 
1  Power supply (PS)  – 
2  CPU  – 
3  Interface module (IM)  to the right of the CPU 
4  1. Signal module (SM)  to the right of the CPU or IM 
5  2. Signal module (SM)  – 
6  3. Signal module (SM)  – 
7  4. Signal module (SM)  – 
8  5. Signal module (SM)  – 
9  6. Signal module (SM)  – 
10  7. Signal module (SM)  – 
11  8. Signal module (SM)  –