The Most Important Basic Rules For Ensuring Emc - Siemens S5-155U System Manual

3.1.2
The Most Important Basic
Rules for Ensuring EMC
System Manual
C79000-B8576-C199-03
Principles of Installation of Systems for EMC
It is often sufficient to comply with a few elementary rules for
ensuring EMC. When installing the control system, therefore, observe
the following five basic rules.
When installing the programmable controllers, provide large-area
good quality grounding of the inactive metal parts (see Section 3.2).
• • Make a large-area low-impedance interconnection of all inactive
metal parts.
• • For screw connections on painted and anodized metal parts, either
use special contact washers or remove the insulating protective
layers.
• • If possible, do not use aluminium parts. Aluminum oxidizes easily
and is therefore less suitable for grounding.
• • Make a central connection between the chassis ground and the
ground/protective ground conductor system.
Ensure proper routing of lines when wiring (see Sections 3.3.1
and 3.3.2).
• • Arrange the cabling in line groups.
(AC power cable, power supply lines, signal lines, data lines)
• • Always install AC power cables and signal or data lines in separate
ducts or bunches.
• • Route the signal and data lines as closely as possible to grounded
surfaces such as cabinet elements, metal bars and cabinet panels.
Ensure that cable shields are properly secured (see Section 3.3.3).
• • Data lines must be shielded. The shield should be connected at
both ends.
• • Analog lines must be shielded. For the transfer of signals with low
amplitudes, it may be advisable to connect the shield at only one
end.
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