Hirschmann OZD Genius G12-1300, User Manual

Page: 33 / 72

Installation OZD Profi 12M ...
Release 01 07/2017
33
3.3 Arrangement of devices and cables
3.3.1 Reducing interference by providing adequate space:
A simple yet effective way of reducing interference is to separate devices and
cables causing interference from those affected by interference. Inductive
and capacitive interference injection decreases by the square of the distance
between the elements concerned. This means that doubling the distance
reduces the interference by a factor of 4. If the arrangement of the various
elements in a building or in the switch cabinet is taken into consideration at
the planning stage, the cost of the necessary interference suppression
measures is generally very low.
Note: Between an OZD Profi 12M ... and a power switching element (e.g.
contactor, relay, temperature regulator, switch, etc.) a minimum separation
of 5.9 in (15 cm) is to be maintained. This minimum separation is to be
measured between the outer edges of the components and in all directions
around OZD Profi 12M ... . The power supply wires (24 V DC and 0 V) for the
OZD Profi 12M ... must not be laid in the same cable duct as cables for load
circuits. The wires (24V DC and 0 V) should be twisted together.
3.3.2 Standard recommendations for the arrangement of
devices and cables
EN 50174–2 contains recommendations for arranging devices and cables
which are aimed at reducing mutual interference to a minimum.
3.3.3 Using bus line shields
It is important to observe the following when shielding bus lines:

Use only fully shielded PROFIBUS lines. The shields of these lines must
be of sufficient thickness to satisfy the legal requirements for interference
radiated and interference received.

Always attach the shields at both ends of the bus lines. The legal
requirements vis-à-vis interference radiated and interference received for
your system will only be satisfied if shields are connected at both ends
(CE symbol).

Attach the shield for the bus line at the connector plug housing or at the
cable clamps provided.

In the case of steady-state operation, it is advisable to strip the shielded
line entirely and connect it with the shielding bus/protective conductor rail.