Appendix C EMC Standards
5
C1.3 Cables
Grounding a shielded cable
Cables drawn from the control box carry high-frequency noise. When they are outside of the control box, they
are like antennas emitting noise. The cables connected to digital input/output modules, analog input/output
modules, temperature measurement modules, network modules, and motion control modules should all be
shielded cables to prevent the emission of noise. Using shielded cables also increases the resistance to
external noise. You improve the resistance to noise if the signal cables that are connected to the digital
input/output modules, analog input/output modules, temperature measurement modules, network modules,
and motion control modules are all shielded cables that are grounded properly. If you do not use shielded
cables or ground the shielded cables correctly, noise resistance will not improve. Make sure the shield of any
connected cable contacts the control box. You must scrape any paint off of the control box at the contact point.
All fastening must be metal, and the shield must contact the surface of the control box. Use washers to correct
any unevenness or use an abrasive to level the surface.
Ground the shield of a shielded cable as close to a module as possible. Ensure that there is no electromagnetic
induction between grounded cables.
To Next Page
Loading...
Need help?
General
