Grounding the shield on limit/homing switches

[Chris Tichy]

I did a little looking, but could not find anything. I'm looking at hooking up limit switches and I know about how NC switches are preferred, and I think I remember reading that shielded wire should be used. I know that I only ground at the controller end, but do I ground to earth ground or to the TinyG ground terminal? Earth ground and TinyG ground may not be at the same potential. My guess is to not earth ground the TinyG board, simply because if it works, don't mess with it. I would also guess that I should earth ground the shields, but more informed minds might know better, so I post this here

Thanks,
Chris

[Mike Estee]

use the tinyG board ground, there should be one near the limit switch pad.

grounding upstream can create current loops and voltage differentials which can fry the board.

Sent from my iPhone

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[Dave Hylands]

I think what Mike is really trying to say here is don't use the shielding wire as your ground.

The shielding wires should all be connected together at the TinyG end and left unconnected at the other end.

If you have a metal case, I'd connect the shield wires to the case and connect the case to the ground wire coming in from your AC plug.

--

Dave Hylands
Shuswap, BC, Canada
http://www.davehylands.com

[Chris Tichy]

The shielding wires should all be connected together at the TinyG end and left unconnected at the other end.
If you have a metal case, I'd connect the shield wires to the case and connect the case to the ground wire coming in from your AC plug.

That's what I think that I'll do. The wires will connect to the appropriate input and ground terminals and the shield wires will be terminated to earth ground all at the controller end an isolated at the other end.

Thanks.

[Mike Estee]

thanks Dave, that's a clearer explanation!

Sent from my iPhone