Siemens S7-400 installation manual Key for example, Example 2 EMC--compliant Wall Mounting

Assembling and Installing Systems

Key for example 1

The numbers in the following list refer to the numbers in Figure A-2.

Table A-1		Key for Example 1
No.		Key	Meaning
1	Grounding strips		If there are no large-area metal-to-metal
			connections, you must interconnectinactive metal
			parts such as cabinet doors or support plates via
			grounding strips or to ground. Use short grounding
			strips with a large surface.
2	Supporting bars		Connect the supporting bars and the cabinet
			housing over a large area (metal-to-metal
			connection).
3	Secure the rack		There must be a large-area metal-to-metal
			connection between supporting barand rack.
4	Signal lines		Use cable clamps on the protective ground bar or an
			additional shield bus forlarge-area connection of the
			shield of signal lines.
5	Cable clamp		The cable clamp must surround the braided shield
			over a large area and ensuregood quality contact.
6	Shielding bus		Provide a large-area connection between the shield
			bus and supporting bars (metal-to-metal
			connection). The cable shields are connected to the
			shield bus.
7	Protective ground		Provide a large-area connection between the protec-
	bar		tive ground bar and supporting bars (metal-to-metal
			connection). Connect the protective ground bar to
			the protective conductor system via a separate con-
			ductor (minimum cross-section 10 mm2).
8	Conductor to the		Provide a large-area connection between the
	protective conductor		conductor and the protective conductor system
	system (grounding		(grounding point).
	point)

Example 2: EMC--compliant Wall Mounting

If you operate your S7-400 in a low-interference environment in which the permissible ambient conditions are complied with (see the Module Data reference manual, Chapter 1), you can mount your S7-400 in frames or on the wall.

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

Provide a shield bus for connecting the cable shields if you install shielded cables. The shield bus can simultaneously serve as the protective ground bar.

Automation System S7-400	Hardware and Installation	A-11
A5E00850741-01