Interference-Free Installation Of Centralized And Distributed Interface Circuits; Interference-Free Installation Of Centralized Interface Circuits; Interference-Free Installation Of Distributed Interface Circuits - Siemens S5-155U System Manual

Interference-Free Installation of Centralized and Distributed Interface Circuits

3.5 Interference-Free Installation of Centralized and Distributed
Interface Circuits
3.5.1
Interference-Free
Installation of Centralized
Interface Circuits
3.5.2
Interference-Free
Installation of Distributed
Interface Circuits
3 - 30
Subjects described in the following sections are the shielding and
grounding concept with centralized and distributed interface circuits.
Information on component selection, the mechanical arrangement and
wiring can be found in the appropriate reference manuals for the
interface modules.
Note
If you use components which are not approved for the installation
of a centralized or distributed interface circuit, interference
rejection may be impaired.
When you connect the CC and EU centrally via suitable interface
modules, no particular shielding and grounding measures are required.
Ensure, however, that
• • all subracks are interconnected at a low resistance;
• • the subracks in a grounded arrangement have star-configuration
grounding;
• • the contact springs of the modules are clean and not bent, which
could affect the path to ground for interference currents.
If you interconnect the CC and EU in a distributed arrangement using
suitable interface modules, no particular shielding and grounding
measures are usually required. Only in industrial environments with
an extremely high level of interference is there a need for special
shielding and grounding.
In these cases, please observe the following points:
• • Cable shields should be connected to the shield bar in the cabinet,
immediately after the cable inlet;
- insulation is fully stripped from the cable for the purpose;
- braided shields are secured to the shield bar with as large an area
as possible (e.g. with metal ties which enclose the shield over a
large area).
• • Shield bars should be connected to the frame or cabinet panel over
a large area.
• • Cable shields should be connected to the cabinet conductor.
System Manual
C79000-B8576-C199-03