Siemens SIMATIC S7-1500 System Manual page 75

Wiring
6.8 Front connector for the I/O modules
4. Bring the front connector into the pre-wiring position. To do this, hook the front connector
into the bottom of the I/O module and swivel the front connector upward until the front
connector latches (Figure 3).
Result: In this position, the front connector still protrudes from the I/O module (Figure 4).
However, front connector and I/O module are not yet electrically connected. By means of
the pre-wiring position, you can easily wire the front connector.
Figure 6-6
5. Begin to completely wire the front connector.
6. Put the strain relief around the cable harness, and pull the strain relief for the cable
harness tight.
74
Wiring front connectors for I/O modules without shield contact element
S7-1500 Automation System
System Manual, 02/2014, A5E03461182-AB