Examples Of An Emc Compatible Installation - Siemens SIMATIC S7-300 Hardware And Installation Manual

Appendix
construction or machine) must be bonded to the protective conductor system in a
star circuit.
Observe for ground connection:
• In the same way as with active elements, exercise meticulous care to
interconnect inactive metal elements.
• Always make sure that you have a low-impedance interconnection between
metal elements (e.g. large and highly conductive contact surface).
• The protective insulating finish on varnished or anodized metal elements must
be pierced or removed. Use special contact washers or completely remove the
finish on the point of contact.
• Protect your connecting elements against corrosion (e.g. with a suitable grease)
• Interconnect moving chassis ground elements (e.g. cabinet doors) with flexible
ground straps. Always use short ground straps with a large surface (the surface
is decisive for the diversion of high-frequency currents).
11.2.4

Examples of an EMC compatible installation

Introduction
Below you can find two examples of an EMC compatible PLC installation.
Sample 1: EMC compatible cabinet installation
The figure below shows a cabinet installation with the measures described above
(bonding of inactive metal parts to chassis ground and connecting the cable
shielding to ground). This sample applies only to grounded operation. Note the
points in the figure when you install your system.
11-8
S7-300 Programmable Controller Hardware and Installation
A5E00105492-01