Propagation Of Electromagnetic Interference - Siemens SIMATIC Ident System Manual

Planning the RF300 system
4.5 Guidelines for electromagnetic compatibility (EMC)
● Route the signal cables as close as possible to chassis surfaces.
● Twist the feed and return conductors of separately installed cables.
● Routing HF cables:
avoid parallel routing of HF cables.
● Do not route cables through the antenna field.
Shielding for the cables
● Shield the data cables and connect the shield at both ends.
● Shield the analog cables and connect the shield at one end, e.g. on the drive unit.
● Always apply large-area connections between the cable shields and the shielding bus at
the cabinet inlet and make the contact with clamps.
● Feed the connected shield through to the module without interruption.
● Use braided shields, not foil shields.
Line and signal filter
● Use only line filters with metal housings
● Connect the filter housing to the cabinet chassis using a large-area low-HF-impedance
connection.
● Never fix the filter housing to a painted surface.
● Fix the filter at the control cabinet inlet or in the direction of the source.
4.5.4

Propagation of electromagnetic interference

Three components have to be present for interference to occur in a system:
● Interference source
● Coupling path
● Interference sink
Figure 4-11
If one of the components is missing, e.g. the coupling path between the interference source
and the interference sink, the interference sink is unaffected, even if the interference source
is transmitting a high level of noise.
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Propagation of interference
System Manual, 07/2016, C79000-G8976-C345-0x
SIMATIC RF300