Screening The Bus Cable And Emc Precautions - Siemens SINAMICS CU240S DP-F Operating Instructions Manual

Installing/Mounting
4.4 Connecting a CU240S DP or CU240S DP-F via PROFIBUS DP
Figure 4-5 Removing a bus connector
4.4.2

Screening the bus cable and EMC precautions

Description
The following EMC-related precautions must be taken to ensure interference-free
PROFIBUS DP operation.
Screening
The screen of the PROFIBUS DP cable must be connected in the bus connector. Additional
screening is provided using a screen clamp on the bus cable screen which must make 360°
contact with the protective earth. The solid copper core must not be scored when the
insulation is removed from the core ends. You must also ensure that the screen of each bus
cable is connected to protective earth at both the cabinet entry point and in the inverter
housing.
Note
The bus cables must be internally twisted and screened, and installed separately from power
cables with a minimum distance 20 cm (7.8 inches). The braided screen and underlying
laminated foil screen (if applicable) must be connected in a 360°, positive connection at both
ends, that is, the screen on the bus cable between two inverters must be connected to the
inverter housing at both ends. The same applies to the screen of the bus cable between the
PROFIBUS DP master and inverter.
Crossovers between bus and power cables must be laid at an angle of 90°.
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Operating Instructions, 07/2008 - FW 3.2, A5E00766042B AD
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Control Units CU240S