How to ground shielded cables?
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I have a question regarding stepper motor wiring:
People suggest to use shielded cable and that it should go to ground on one side.
But where and how shall i ground the cable shields on the duet wifi?Using shielded cable without ground doesn't bring any advantage or?
I assume the magnetic field caused by the stepper motor current will induce voltage into the cable shield. But there is no way current can flow. -
See http://reprappro.com/documentation/ormerod-2/wiring/#Fitting_the_cover_and_wire_routing for how RepRapPro did it.
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I still have my RepRapPro Mendel with it's shielded stepper wiring. The cables are about 700mm long. I also have my coreXY with unshielded steppers and cables that are about 2 metres long for the Z motor and up to 1.4 metres for the XY motors. Never had a problem or seen any spikes. The only thing I did was to twist the wires together and route them so that there are no long parallel runs with other sensor wiring. It may not be best practice but it works for me.
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The reason that RepRapPro used shielded cables on their later kits was so that they could claim CE compliance in respect of electromagnetic emissions for the printer when assembled.
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See http://reprappro.com/documentation/ormerod-2/wiring/#Fitting_the_cover_and_wire_routing for how RepRapPro did it.
This is nice as you see what it could look like.
The interesting image from that page:
https://reprappro.com/wp-content/uploads/2014/05/ORM2-wiring-34.jpgAnd its description:
"All the wiring looms use shielded cable, to reduce the effects of Electro-Magnetic Interference (EMI). It is important that the shielding makes contact with ground, by earthing them through the metal case. Each wire has a slot in the case; bend each cable so it sits in the slot. Make sure that there is not sideways pressure on the housings, where they are plugged onto the pins of the Duet; they can loose their contact with the pin, and make a faulty connection."
