Keba KeTop T100, User Manual, Page: 145 / 163

14.3.1.5 Coupling paths
The transfer of interference signals from an interference source to an interfer-
ence sink can take place via various coupling paths.
Coupling paths very often consist of two or more parallel lines running closely
together. The coupling is a field coupling that takes place at low frequencies
either via the electrical field (capacitive coupling) or via the magnetic field (in-
ductive coupling).
At high frequencies and with corresponding expansion of the parallel running
lines one speaks about an electromagnetic coupling due to close linking of both
field types.
Direct coupling can occur when electrical circuits from the interference source
and electrical circuits from the interference sink have common line compo-
nents.
If there is a large distance between an interference source and an interference
sink then one speaks of a radiation coupling.
14.3.2 EMC measures
In principle, all devices should be designed in such a way as to function reliably
in the planned environment and in doing so should not interfere with other
systems. All products of the Kemro product range (K2 control systems and
KeTop) meet these requirements and it is not necessary to use any of the EMC
measures described below when the specified additional units, cables and
wiring are used.
However, additional EMC measures may be necessary for various reasons.
The following text is designed to help the user to correctly implement any ad-
ditional EMC measures.
14.3.2.1 Shielding
Electromagnetic emission problems and immunity problems often occur in
products at the same time. Likewise, EMC measures are mostly effective in
the case of both emission problems and immunity problems.
Shielding fulfils two main tasks. On the one hand, the penetration of electro-
magnetic fields into sensitive electronic parts is prevented and, on the other
hand, the radiation of electromagnetic fields is also prevented.
A complete EMC shield consists of a shielded housing, which protects the
sensitive electronics and prevents them from transmitting interference, and
cable shields that shield the sensitive interface signals and prevent the device
from transmitting interference via its interfaces.
The cable shield basically connects two shielded housings together and must
therefore be connected directly to the shielded housings of the sensitive elec-
tronics (connection points).
Particular attention should be paid to the connection between the cable shield
and the shielded housings of the device. In order that the shield effect is main-
tained even at higher frequencies, care must be taken to ensure that the cable
shield connects to the largest possible surface area and thereby acts as a
CE Conformity, Directives and Standards
© KEBA 2009
User's Manual V1.50 145