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Limit switch wiring
« on: December 31, 2015, 05:22:58 PM »
Hope this is not a sore subject, I've been reading alot here about limit switches and that long post with Mike, I actually learned quit a bit from everyone's responses. This is not a question about Mach 3 yet as I will set that up after I change this wiring I suspect it was part of my problem before.

I am rewiring my switches from the control box with shielded cable, I have the cable shielding grounded in the control panel and the wires from the pins coming out to a terminal bar. As I start the run to the first limit switch the cable will be grounded these switches will be wired in series switches NC. My question is this, on shielded cable how do I maintain the shielding ground between switches at there different locations, do I splice into the cable to make my switch connection or have a jumper to maintain my ground. I hope I am explaining this right. I am using one pin for my XYZ limits
Thanks Bill
Re: Limit switch wiring
« Reply #1 on: December 31, 2015, 06:37:12 PM »
Hi Bill.
  I couldn't find an illustration so I'll try to explain.
I used 2 wire with a braided shield. I peeled an inch or so of the insulation off at the switch then pulled one wire up through the shield and only cut the one wire and connected one end to the com and the other to the NC term on the switch, never cutting the shield or the other wire.
The other wire only gets connected to the last switch in the series.
This worked well for the lathe and the x and y on the mill, the z was separate.
Hope this might help,
still looking for a pic ...
Re: Limit switch wiring
« Reply #2 on: December 31, 2015, 07:59:23 PM »
sorta like this ....


Offline Davek0974

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Re: Limit switch wiring
« Reply #3 on: January 01, 2016, 03:59:17 AM »
If I were doing it, I would run a separate wire to each switch, ground each shield in my cabinet and make the series connection in the cabinet.

Slightly more wire but easier to fault find i think?

I have a row of DIN connectors with the series connections made on the panel side, all my inputs and outputs just go to their own connector terminals which are all numbered and shown on a sketch.
« Last Edit: January 01, 2016, 04:01:07 AM by Davek0974 »
Re: Limit switch wiring
« Reply #4 on: January 02, 2016, 02:41:53 PM »
Where do you find braided shield 2 wire 18 ga?
I purchased 2 wire 18 ga with a drain wire and foil sheeting. Will this work?
Also, I'm trying to upgrade an old zenbot 24x16 that I bought in 2006, and I'm having lots of problems.
my computer died, so all the settings that worked before don't seem to be correct any more.
my x axis is moving toward the home switch, but the z DRO is moving.
None of my limit switches are lighting up in the diagnostics screen.
Any suggestions where to start trying to diagnose these problems?
Thank you,
Chris May
Re: Limit switch wiring
« Reply #5 on: January 02, 2016, 04:26:01 PM »
 I'm using 4 wire 18ga with the foil sheath, wish I could get the 2 wire but can't get here and I had the four. I am soldering together the aluminum strand that is running along the foil.