Keba Kemro KeTop T10, Руководство по проектированию устройства

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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.
18.2 EMC measures on KeTop
The KeTop is designed for industrial applications. Considerable electromag-
netic and electrostatic interference can occur in this environment. For this
reason special emphasis was placed on interference immunity and data se-
curity in the design of the device. The EMC design implemented and described
below considers all the above named sources of interference and the possible
coupling paths.
●
All shielding and filter measures (filtered power supply) in the KeTop are
carried out directly on the printed circuit board.
●
The special design of the KeTop cable guarantees interference immunity
even for greater connection lengths, i.e. the data lines (communication
signals) are shielded and so they are separated from the control lines
(power supply, enabling control device, emergency off, key-operated
switch etc.) inside the KeTop cable.
●
Power supply lines in the control cabinet are usually unshielded. They are
therefore laid outside the KeTop cable shield in order to prevent a coupling
with the sensitive data lines.
●
The unshielded control and power supply lines are either filtered on entry
into the shielded housing of the KeTop or separated from the electronics
in such a way that any interference signals carried by these lines cannot
affect the internal electronics of the KeTop.
●
It is not necessary to lay the KeTop cable separately.
Shield connections
The cable shield of the KeTop cable can be considered to be an extension of
the KeTop shielded housing (=printed circuit board) to the shielded housing of
the communication partner (e.g.: PLC). From this it can be deduced that the
shielded connections from the cable shield to the device shields make a fun-
damental contribution to the interference immunity of the KeTop. It is not
necessary to wire shielded connections to earth. The shielding connection in
the KeTop is made via the RJ-45 connector in the connection slot.
Connecting the KeTop via the connection box (e.g. CB211) guarantees safe
shielding protection right through to the communication partner. All connection
cables available from KEBA guarantee correct shielding connection.
For self-made cables the following conditions must be met for shielding data
lines:
●
On every connector design (DSUB or RJ-45) the cable shield must be
connected to as large a surface area of the connector housing as possible.
KeTop T10 Appendix: Electromagnetic Compatibility
© KEBA 2014
Project engineering manual V1.02 75