Additional Installation Tips
7.2 Ethernet Connection in the Panel
PC
1
2
3
4
5
1-1
2-2
3-3
8-8
RJ45
RJ45
RJ45
RJ45
RJ45
RJ45
RJ45
RJ45
Industrial Ethernet
Panel PC
Panel PC
Panel PC
Panel PC
Shielded
Short and
unshielded
0.1 uF
250 V
5351
In some industrial units for Ethernet, the RJ45 contact’s shield is connected to the
chassis via a capacitor, see 1 in drawing above.
The Panel PC’s Ethernet shield is directly connected to the chassis, see 2 in
drawing above.
1. Check whether the other Ethernet unit has its shield directly grounded or
grounded via a capacitor.
Note:
In many cases, connecting the shielded Ethernet cabling to the chassis at both ends is
inappropriate. Hum or grounding loops can occur. Unshielded cabling may even result
in fewer communication errors.
A good solution may be to use a shielded Ethernet cable, but to connect the shield
at one end only.
One option is to break the shield, see 3 in drawing above.
A more elegant method is to expand the shielded Ethernet cabling with a piece of
unshielded Ethernet cable, see 4 in drawing above.
You can ground the shield via an external 0.1 uF/250 V plastic capacitor, see 5 in
drawing above. This will connect the HF transients to the ground.
Beijer Electronics, MAEN043
26
