Twisted pair cable
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Electromagnetic compatibility, EMC
Electromagnetic compatibility (EMC) encompasses both the emission of interference to
the environment as well as immunity against any such interference from the immediate
Information on EMC included in the data sheets for RXB / RXL devices. Information
on immunity defines the operational environment for the product, where it can
operate without a problem.
Disturbances that are too high in a given environment (greater than the stated
immunity) can impact trouble-free operation. Such disturbance exists, for example, in
the vicinity of radio stations or variable speed drives and their cabling, but also at
switched loads. They can accept very high levels.
High frequency of the disturbance
Steep slopes (upper wave)
Long parallel run
The most effective protection against coupling of disturbances is separate cabling
(separate chambers in a cable duct) for signal and control lines from lines that
Twisted pair or screened cable must be planned if this separation is not sufficient or
Individual wires (not twisted pair) are not permitted in principle in DESIGO and
Synco building automation and control systems. Normally, however, cabling without
When using twisted pair cabling in the same cable duct with strongly disturbing
lines, the two cable types must be at least 150 mm from another.
KNX bus cable: See Section 4.1
When using screened cable together with power lines in the same duct, no minimum
distance to the wiring causing disturbance required.
To achieve optimum screening of the cable screen used, the cable screens must be
connected on both sides and touching on all sides with the structure. (Structure = Metal
housing, mounting plates, panel frames, etc., which are connected to the building).
Which is why we refer to it as grounding (versus earthing, which is intended to protect
people and not EMC).
Cable screens must always be throughout and have solid coverage. Any break in
the screening significantly reduces the effect of screening.
Installation guide RXB, RXL
Periphery wiring (without bus)
28 Feb 2009