Ethernet Connection For The Device; To Achieve Better Emc Protection - Beijer Electronics BoX2 pro Installation Manual

6.2. Ethernet Connection for the Device

4
Shielded
1-1
2-2
3-3
8-8
5
0.1 F
250 V
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 Ethernet shield of the device is directly connected to the chassis, see 2 in drawing above.
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 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.
The shield can be grounded via an external 0.1 μF / 250 V film capacitor, see 5 in drawing above.
This connects the HF transients to ground.

6.3. To Achieve Better EMC Protection

• Initially, use the original cabling from Beijer Electronics primarily.
• Place the 24 V DC and communications cabling in one cable trunk/cable duct and 230/380 V AC in
another. If the cables need to be crossed, cross them at 90° only. Avoid combining the cabling for
stronger 24 V DC outputs with the communication cabling.
Beijer Electronics, MAEN275
Industrial Ethernet
RJ45
RJ45
RJ45
RJ45
BoX2 device
RJ45
2
BoX2 device
3
RJ45
Short and
BoX2 device
unshielded
RJ45
BoX2 device
RJ45
17
Additional Installation Tips
1
2023-09