ABB PP885, Hardware And Installation Manual

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Section 7 Additional Installation Tips
To Achieve Better EMC Protection
To Achieve Better EMC Protection
• Use shielded cables for RS232 communication.
• Use twisted pair and shielded cabling for RS422 and RS485.
• Use the cabling intended for the bus type; Ethernet, Profibus, CC-Link, CAN,
Device Net etc.
• Install and connect according to applicable specifications for the relevant bus
standard.
• Use shielded cabling for Ethernet, preferably with foil and a braided shield.
• D-sub covers should be shielded, and the shield should be connected to the
cover 360° where the cable enters.
• Connect the shield at both ends.
Shielded cable
Not same potential
Ground plane 1 Ground plane 2
Ground plate Ground plate in another building
0.1 μ F/250 V
With longer distances, there is a risk that the ground potential may be different. In
that case, the shield should only be connected at one end. A good alternative is to
connect the other end of the shield to the ground via a 0.1 µF/250 V plastic capacitor.
Both ends are then connected to the ground in terms of HF, but only connected to the
ground at one end in terms of LF, thus avoiding the 50/60 Hz grounding loops.
Metal cabinet Metal cabinet
Terminal or connector Terminal or connector
EMC cable gland
Plastic cable gland
Shielded cable
Short distance
Cable clamp
in steel
Shielded cable
3BSE069463-600 Rev D 37