Danfoss 5000 Flux Manual page 7

Connection of the cable screening
The shielding of the PROFIBUS cable always needs
to be of a large-area, low-impedance type on both
sides. As a matter of principle, the screen should be
put up with a large area and low impedance at all
PROFIBUS stations. It is very important to have an
earth connection with low impedance even at high
frequencies. This can be achieved by connecting
the shield surface to earth, for example with the
help of a cable bow or a conductive cable
connector.
The VLT is equipped with various terminals and
supports in order to provide a flawless shielding of
the PROFIBUS cable. The shield connection is
shown in the following diagram.
Diagram, bus connection
MG.90.D1.02 – VLT is a registered Danfoss trademark
VLT ® 5000/5000 Flux/6000 HVAC/8000 AQUA PROFIBUS
Earthing
It is important to connect all stations linked to the
PROFIBUS network to the same earth potential.
The earthing must have a low high-frequency im-
pedance. This can be achieved by connecting a
protective housing surface which is as large as
possible to earth, for example by mounting the
to a conductive rear wall.
Especially in the case of large distances between
the stations of a PROFIBUS network, the additio-
nal use of potential equalization cables to connect
the individual stations to the same earth potential
may be necessary.
Bus connection
VLT
7