Five Basic Rules For Securing Emc - Siemens SIMATIC ET 200SP Operating Instructions Manual

Installing
3.3 EMC-compliant installation
3.3.4

Five basic rules for securing EMC

Observe these five basic rules to secure EMC.
Rule 1: Large area grounding contact
● When installing the devices, make sure that the surfaces of inactive metal parts are properly
bonded to chassis ground (see following sections).
● Bond all inactive metal parts to chassis ground, ensuring large area and low-impedance
contact (large cross-sections).
● When using screw connections on varnished or anodized metal parts, support contact with
special contact washers or remove the protective insulating finish on the points of contact.
● Wherever possible, avoid the use of aluminum parts for ground bonding. Aluminum oxidizes
very easily and is therefore less suitable for ground bonding.
● Provide a central connection between chassis ground and the ground/protective conductor
system.
Rule 2: Proper cable routing
● Organize your wiring system into cable groups (high-voltage/power supply/signal/
measurement/data cables).
● Always route high-voltage and data cables in separate ducts or in separate bundles.
● Install the measurement cables as close as possible to grounded surfaces (e.g. supporting
beans, metal rails, steel cabinet walls).
Rule 3: Fixing the cable shielding
● Ensure proper fixation of the cable shielding.
● Always use shielded data cables. Always connect both ends of the data cable shielding to
ground on a large area.
● Keep unshielded cable ends as short as possible.
● Always use metal/metalized connector housings only for shielded data cables.
Rule 4: Special EMC measures
● All inductors that are to be controlled should be connected with suppressors.
● For cabinet or enclosure lighting in the immediate range of your controller, use incandescent
lamps or interference suppressed fluorescent lamps.
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Technology module TM SIWAREX WP351 HF
Operating Instructions, 01/2020, A5E47521010-AA