Siemens SIMATIC S7-1500 System Manual page 154

Flexible automation concepts
9.2 Configuration control (option handling)
Station option 1 with m odule that is not present
The module that is located in slot 3 in the station master is not present in the station option 1.
Slot 3 must be designated in the control data record accordingly with 255 (= not present).
①
Figure 9-6
154
Module is not present in the station option 1.
Example: Hardware configuration of station option 1 with the associated control data
record in STEP 7
Automation system
System Manual, 09/2016, A5E03461182-AD