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Author Topic: Rewiring limit switches w/ shielded wire  (Read 3474 times)

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Rewiring limit switches w/ shielded wire
« on: January 27, 2010, 05:12:08 PM »
All-
I'm trying to solve some erratic behavior with my router table by replacing the limit switch wiring. Limits are currently wired with 18 ga speaker wire. Good news is I'm coachable but bad news is I'm not an electronics wiring genius. I've attached two images that might help. Feel free to mark them up as needed and repost.
I have 22 ga two conductor shielded wire, and I can trace the existing wiring to connect them to the BOB correctly. What I don't know is where to connect the ground wire at both the switch end and the enclosure/BOB end. Do I attach the limit grounds to the BOB, or a common ground inside the enclosure? I can see what looks like a common grounding point inside the enclosure(marked on photo), but it's too far away from the actual BOB to use it as a grounding point for the switch grounds. Seems like a simple enough thing to do I just have no idea how to do it. Thanks to all who might be able to help.
I've also determined one of the switches on the y axis to be flaky; since our work never comes close to the limits on the y is there a way I can eliminate this switch from the wiring circuit until we can get a replacement?
« Last Edit: January 27, 2010, 05:22:23 PM by bergdoerfer »

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Re: Rewiring limit switches w/ shielded wire
« Reply #1 on: January 27, 2010, 05:24:18 PM »
Only connect the screen at the cabinet end and  put it to the Gnd terminal in yellow circle. Either solder extensions on or use some form of screw terminals to extend them, soldering is best though.
Hood
Re: Rewiring limit switches w/ shielded wire
« Reply #2 on: January 27, 2010, 05:44:08 PM »
Apologies- the screen? Are you referring to the ground wire? So I'm not supposed to attach the ground wire to the switch at all?
Also - the flaky switch. Can I omit it from the circuit until a new one can be sourced? It's so flaky that vibration from the machine
causes it to be intermittent thereby resulting in random stoppage. Thanks Hood

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Re: Rewiring limit switches w/ shielded wire
« Reply #3 on: January 27, 2010, 05:55:08 PM »
I am not sure LOL, depends what you are calling Gnd wire. The Screen is what you want to connect to the Gnd terminal you have circled in Yellow.
Yes you can remove the switch as long as you keep the circuit intact, that will depend on how they are presently wired. Normal practice is to have your switches wired in series and use the Normally Closed contacts on the switch, so in the pic above you would feed the wire from you BOB to the C on the first switch then from NC on first to the C on the next switch, then NC to C on next switch etc then back to your input on the BOB. You can do this with all switches and just use one input or you can if you wish have separate circuits for each axis and use 3 inputs.
 If that is the way you have them wired you can remove the faulty switch and just join its wires together to keep the circuit intact.
Hood
Re: Rewiring limit switches w/ shielded wire
« Reply #4 on: January 27, 2010, 06:06:58 PM »
The wire I'm using has 2 insulated conductors and 1 uninsulated twisted wire conductor(I'm calling this the ground wire), with everything surrounded by foil running the length of the wire. Thanks Hood

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Re: Rewiring limit switches w/ shielded wire
« Reply #5 on: January 27, 2010, 06:11:22 PM »
Is the unisulated wire in contact with the foil? If so that is what they call a drain wire and that is used to connect the screen (foil) to the Gnd terminal.
Hood
Re: Rewiring limit switches w/ shielded wire
« Reply #6 on: January 27, 2010, 07:37:05 PM »
yup drain wire that's it- thanks again