Siemens SIMATIC S5 Manual page 54

IP 266
The following applies as regards cable shielding:
• The cable shields must be placed on a shield bus near the cable inlet in the
cabinet.
• Braided shields must be secured to the shield bus over as large an area as
possible (e. g. using metal-plated cable clamps which span the shield).
• When using cables with foil shields, the sheath wire must be connected over
the shortest possible path (less than 3 cm) with the shield bus.
• The shielding must be routed from the shield bus to the module.
• The shield bus must be conductively connected to the supporting bar, the
housing cabinet and the central earthing point in the cabinet.
Switching cubicle
Shield bus
Figure 3-2. Shielding Cables to the IP 266 in a Cabinet
• To ensure interference-free operation, it is absolutely necessary that all cables
be grounded on both ends, i. e. the shield must be brought into contact with
both the shield bus on the PLC and the I/O connector.
EWA 4NEB 812 6057-02
1 3 5
2 4 6
Sheath wire
Cable with foil shield
and sheath wire
Installation Guidelines
7 9 1 3 5 7 9
8 10 2 4 6 8 10
To the module
Cable with
braided shield
3-3