limit switches

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berrows@comcast.net
Posts: 38
Joined: Thu May 31, 2018 1:12 am
Model of CNC Machine: probotix fireball 90

limit switches

Post by berrows@comcast.net »

Hi all, the problem is, Mach3 continues to tell me to reset (limit switch is triggered). I have checked all the switches and they test good. My Z switch to me seems a bit suspect. When I manually trigger the switch you can barely hear the click, but when I release it you get a good loud click. My Y limit travel switch never gets used. Can I switch the two to see if the Z switch could be going bad or will mach3 continue to tell me to reset no matter what I switch. I contacted Mach3 and they said to check for EMI. There is nothing else on this line. At a stand still ! Thanks for any and all help...Doug

Jimcad
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Posts: 54
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Model of CNC Machine: Alpha CNC 6090 with 4th Axis

Re: limit switches

Post by Jimcad »

You could bypass the switch as a temporary test.
If it's a "Break" circuit you could connect the two leads together so it can't break the connection.
If it's a "Make" circuit just disconnect the leads so it can't make the connection.
I'm not a "sparky" so I hope I've used the correct terminology but I hope it made sense.

Jim

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Tex_Lawrence
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Model of CNC Machine: Shapeoko3XXL; JTech7W; V-CarvePro 11.016
Location: Dayton, Texas (Don't Mess With My Texas!)

Re: limit switches

Post by Tex_Lawrence »

berrows@comcast.net wrote:
Thu Sep 22, 2022 1:01 am
... When I manually trigger the switch you can barely hear the click, but when I release it you get a good loud click.
You can't completely check a switch by the sound of the spring mechanism inside. You need to check it electrically by passing a current through the contacts. That could be as simple as an multimeter/ohmmeter checking that it is truly OPEN (no current passes) or CLOSED (some current passes.)

You could fool around and wire something like a battery and an LED to it for testing.

You could also swap it between other limit switches as long as they look physically the same (they most probably are.) That's a purty common troubleshooting technique. It could potentially move the problem over to the swapped switch function, so you would have to be ready to detect that the problem has moved.
Crooked Wood Products - Custom Wood
Truth lies dormant in our future history ― Tex LXX

berrows@comcast.net
Posts: 38
Joined: Thu May 31, 2018 1:12 am
Model of CNC Machine: probotix fireball 90

Re: limit switches

Post by berrows@comcast.net »

Thanks Jimcad and Tex for getting back to me. I really don't know anything about Break or Make but I may try switching switches. Thanks again...Doug

NewAtThis
Posts: 46
Joined: Sat May 21, 2022 11:39 am
Model of CNC Machine: KillerBee 1075, Duet3 MB6HC controller

Re: limit switches

Post by NewAtThis »

"Break" or "Make" refers to the operation of the switch, specifically (and respectively) NC (normally closed, and which opens when the switch is "pressed" and NO (normally open, and which closes when the switch is 'pressed').
Be wary of taking the advice of someone who thinks he knows what he's doing, and don't listen to me!

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