Emc Measures For Flexi Link And Flexi Line - Mitsubishi MELSEC-WS0-CPU0 User Manual

Figure 21:
Connection of the cable
Note
Connecting devices
4.9

EMC measures for Flexi Link and Flexi Line

Flexi Link or Flexi Line cables are used to transmit communication signals.
Electromagnetic influences may disturb the signal transfer and interrupt the
communication. In order to minimize electromagnetical interference, the following
measures are required:
 Connect all inactive metallic parts (control cabinet doors and housing, DIN
mounting rails etc.) to the same reference potential.
 Connect the reference potential to the protective earth conductor.
 Connect the protective earth conductor to the external earth potential.
 Connect both ends of the shield of the shielded cables to the reference potential
directly at the entrance to the system (control cabinet, frame, DIN mounting rail).
 Connect the cable shield again to the reference potential as close as possible to
the CPU module (e.g. on the mounting rail) using suitable cable clamps. The cable
clamps must completely enclose the cable shield.
 Keep the stripped cable ends as short as possible.
 Isolate the screening braiding end e.g. with a suitable shrink tube.
 All connections must be made electrically well conducting with low impedance.
 Stub lines or star-shaped EFI wiring are not permitted.
 Load cables (e.g. for frequency changers, electronic speed controllers, contactors,
brakes etc.) and small-signal cables (e.g. measuring lines, analog sensors, field
bus lines etc.) must be laid separately and with low inductive coupling.
Chapter 4
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