Siemens Siwarex U, Device Manual

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3BHARDWARE CONFIGURATION AND INSTALLATION
- Interference that acts via the process wiring (e.g. measuring lines).
- Interference that enters the system via the power supply and/or protective earth.
The interference can impair the perfect functioning of SIWAREX U.
4.2.4 Coupling mechanisms
Depending on the propagation medium (conducted or non-conducted) and the
distance between the source of interference and the device, interference gets into
the automation system via four coupling mechanisms:
Conductive coupling
Capacitive coupling
Inductive coupling
Radiation coupling
4.2.5 Five basic rules for ensuring EMC
If you observe the five basic rules, you can ensure EMC in most cases.
Rule 1: Extensive grounding
When installing the automation devices, ensure the inactive metal parts are
grounded well and extensively (see following sections).
Connect all inactive metal parts extensively and with low impedance with ground
(large cross-sections).
Perform bolt connections on lacquered or anodized metal parts either with special
contact disks or remove the insulating protective layers at the contact points.
Do not use aluminum components for ground connections if at all possible.
Aluminum oxidizes a little and is therefore less suitable for grounding.
Make a central connection between the grounding and the ground/protective
conductor system.
Rule 2: Proper wiring
Divide the wiring up into wire groups (high-voltage lines, power supply lines, signal
lines, measuring lines, data lines).
Always lay the high-voltage lines and measuring/data lines in separate channels or
bundles.
Lead the measuring lines as close as possible to ground planes (e.g. support
beams, metal rails, cabinet panels).
Rule 3: Attaching the cable shields
Ensure the cable shields are attached properly.
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SIWAREX U