Siemens SIMATIC NET PROFIBUS, Owner'S Manual, Page: 269 / 490

Installing LAN Cables
C-7
PROFIBUS Networks SIMATIC NET
6GK1970-5CA20-0AA1 Release 2 05/2000
C.4 Electromagnetic Compatibility of LAN Cables
Electromagnetic Compatibility (EMC)
Electromagnetic compatibility (EMC) includes all questions of electrical, magnetic
and electromagnetic immunity and emission.
To avoid external interference affecting electrical systems, these effects must be
reduced to a certain level. The measures involved include the design, structure
and correct connection of the LAN cable. The components and LAN cables for
SIMATIC NET PROFIBUS meet the requirements of the European standards for
devices used in an industrial environment. This is documented by the CE marking.
Note
The limit values specified can only be guaranteed if the matched components for
SIMATIC NET PROFIBUS are used consistently! The installation instructions in
this manual and in the manuals of the networked programmable logic controllers
must also be adhered to exactly!
C.4.1 Measures to Counter Interference Voltages
Overview
Measures are often taken to suppress interference voltages when the control
system is already in operation and problems occur receiving signals. You can often
reduce the investment necessary for such measures (for example special
contactors) by remembering the following points when installing your automation
system.
These include the following:
S
Connecting all inactive metal parts to chassis ground
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Shielding devices and cables
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Suitable positioning of devices and cable routing
S
Special noise suppression measures