NORD Drivesystems BU0020 - Manual (Page 45)

4 Bus Configuration
BU 0020 GB-2612 45
4.3 Cable layout and shielding (EMC measures)
If EMC measures are not in place, high-frequency interference which is mainly caused by switching
processes or lightning often causes electronic components in the bus subscribers to be faulty and
error-free operation can no longer be ensured.
Appropriate shielding of the bus cable reduces electrical interference which can arise in an industrial
environment.
The best shielding qualities can be achieved with the following measures:
• Do not make cable connections shorter than 1m between bus participants
• Avoid long connections between bus participants
• Shield the bus cable at both ends with large-area connection to the plug housing
• Avoid spur lines (above 1.5MBaud spur lines are no longer permissible)
• Avoid extensions to bus cables via plug connectors
Bus lines should be laid with a minimum spacing of 20cm to other lines which carry a voltage higher
than 60V. This applies to lines laid inside and outside of control cabinets.
Special attention should be paid to bending radii:
Fixed cable Freely laid cable Bending radius of cable
Minimum radius
5 x cable diameter
Minimum radius
10 x cable diameter
Correct Incorrect
Fig. 4: Installation and cable laying information
ATTENTION
If earthing potential values are different, transient current may flow through shielding which
is connected on both sides. This may be a danger to electronic components. Differences
in potential must be reduced by means of adequate potential equalisation.
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