●
It is not necessary to lay the KeTop cable separately.
14.3.3.1
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. It is therefore
urgently recommended to use a suitable KEBA connection box.
All connection cables available from KEBA (KeTop TTxxx, KeTop ICxxx, Ke-
Top XD040 and KeTop CD040) 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 con-
nected to as large a surface area of the connector housing as possible.
Fig.14-11:
Correct shield connection for DSUB and RJ-45 connectors
1
... Metallised or metallic housing
2
... Connect the shield to a large surface area
●
The use of pig tails for contacting the cable shield via plug pins is unsuitable.
The inductivity of such pig tails represents high impedance resistance for
higher frequency interference; this means an apparent break in the cable
shield. Interference is then no longer diverted and works directly on the
inner lines.
CE Conformity, Directives and Standards
KeTop T50VGA
© KEBA 2009
User's Manual V1.50
150
Summary of Contents for KeTop T100
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