Installation OZD Profi 12M ...
Release
01
07/2017
49
Properties of cable type A:
– Characteristic impedance: 135 - 165 Ohm
– Capacity coating: ≤ 30 pF/m
– Loop resistance: ≤ 110 Ohm/km
– Wire diameter: > 0.64 mm
– Wire cross section: > 0.34 mm
2
4.7 Connecting the function ground and the
shield of the bus cable
WARNING
There is no contact separation between the bus lines and the
connection for the function ground.
Observe the following safety instructions:
Do not use bus lines to connect repeaters to device parts which have a
different earth potential. The different voltages could destroy the
repeaters.
Avoid electrical bus lines, which are partly or entirely laid outside
buildings. If lightening strikes close by, this could destroy the repeaters.
Use F/O cables for bus connections outside buildings.
The shield of the bus cable, together with the function ground connection,
must be connected to an equipotential rail in the switch cabinet. The
equipotential rails of the switch cabinets, which are connected to one
another by means of an electrical RS 485 bus cable, must have a low-
impedence connection to one another.
The function ground of the repeater is effected by means of the
connection of the screw terminal block on front of the device.
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