Operating instructions

2.1.4. Earth Connection
It is important that all stations connected to the PROFIBUS network are connected to the same
earth potential. The earth connection must have a 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 frequency converter on a conductive rear plate. Particularly when there are long distances
between the stations in a PROFIBUS network, it can be necessary to use additional potential
equalizing cables, connecting the individual stations to the same earth potential.
2.1.5. Cable Routing
The PROFIBUS communication cable must be kept away from motor and brake resistor 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 rec-
ommended, especially where cables run in parallel over long distances.
If the PROFIBUS cable must cross a motor cable or brake resistor cable, the cables must cross at
an angle of 90°.
VLT
®
Profibus 2. How to Install
MG.33.C4.02 - VLT
®
is a registered Danfoss trademark 15
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