Siemens S5-135U/155U appendix Example of Rack and Wall Mounting for EMC

Installation Guidelines

3.2.3Example of Rack and Wall Mounting for EMC

To operate your control system in a low-interference environment whilst observing the permissible ambient conditions (see ªTechnical Specificationsº), you can mount the programmable controllers on racks or directly on walls.

Picked-up interference should be given a path to large metal surfaces. You should therefore secure standard sectional rails, shield and protective conductor bars to metal structural elements. For wall mounting in particular, installation on reference potential surfaces made of sheet steel has proved advantageous.

When installing shielded cables, provide a shield bar for connecting the cable shields. The shield bar can also be the protective conductor bar.

Ensure the following for rack and wall mounting:

SSuitable contacting aids should be used on painted and anodized metal parts. Use special contact washers or remove the insulating protective layers.

SProvide large-area, low-impedance metal-to-metal connections when securing the shield/protective conductor bar.

SAC conductors must be covered.

Reference Potential

Surface

ShieldedSignal

Line

Cable Clamp for

Shield Contact

Shield/Protective

Conductor Bar

Connection to

P. Ground: 10 mm@

Figure 3-3 Wall Mounting of an S5-135/155U PLC

System Manual	3-11
C79000-G8576-C199-06