GE Industrial Solutions AF-600 FP BACnet - Manual (Page 14)

3.1.4 Cable Routing
The BACnet communication cable must be kept away from motor cables to avoid coupling of high frequency noise from one cable to the other. Normally a distance
of 200 mm is sufficient, but maintaining the greatest possible distance between cables is generally recommended, especially where cables run in parallel over
long distances.
When crossing is unavoidable, the BACnet cable must cross motor at an angle of 90 degrees.
3.2 System Specifications
3.2.1 EMC Precautions
The following EMC precautions are recommended to achieve interference-free operation of the BACnet network. Additional EMC information is available in the
AF-600 FP Drive Design Guide. Please also consult the BACnet master manual for further installation guidelines.
NB!
Ensure compliance with relevant national and local regulations, for example in protective earth connection.
3.2.2 Connection of the Cable Screen
It is recommended to connect the screen to ground in both end of the Bus Cable. This ensures the optimum resistance towards EMC noise. screen of the BACnet
cable must always be connected to ground at both ends, meaning the screen must be connected to ground in all stations connected to the BACnet network. It
is very important to have a low impedance ground connection of the screen, also at high frequencies. This can be obtained by connecting the surface of the
screen to ground, for example by means of a cable clamp or a conductive cable gland. The AF-600 FP Series has various clamps and brackets to enable a proper
ground connection of the BACnet cable screen.
3.2.3 Earth Connection
It is important that all stations connected to the BACnet network are connected to the same earth potential. The earth connection must have low HF (high frequency)
impedance. This can be achieved by connecting a large surface area of the cabinet to earth, for example by mounting the AF-600 FP series on a conductive rear
plate. Particularly when there are long distances between the stations in a BACnet network, it can be necessary to use additional potential equalizing cables,
connecting the individual stations to the same earth potential. The use of Repeaters with galvanic isolation or Fibre optic can improve the EMC performance and
reduce Ground loop Current.
AF-600FP BACnet
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