Limit switch source UK

I think my Z axis limit switch has died. I was mid-way through a job, went to set up a second side op. but the machine won’t home. Tried restarting etc. but no good. On initialising, the Z axis drops a bit then stops and throws some errors (‘pull failed’ or something and homing failed). I took the cover off the controller and the Z LED is permanently on. The others light only when I press the limit switches.

Not sure if I should fit like-for-like (found links for the ones used by C3D) or if I should go straight to contactless as reading up seems to indicate they’re better. Is fitting the contactless type fairly easy? If anyone has links to a source in the UK that would be appreciated.

Carbide3D uses a normally open (NO) limit switch design (a little odd), but anyway, if the wire gets pinched somewhere along its travel, it will react in the way you are stating. It’s rare for the switch to get stuck in the ON position.

Do yo know what Version GRBL board you have? I had a Ver2.4 (no letter) and found out that the new proximity switches were not compatible. (Plus I think you need the new Z-plus to for the Z switch (although I could be wrong, maybe they have an adapter).


If you email into support we can get you up and running again.

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Board has v2.4e printed on it. I’ll take the multimeter and check continuity on the Z switch cable.

I’ve ordered 3x Omron ones from Digikey (£12 postage! They better be here tomorrow!) so hopefully I’ll be up and running again soon.

Will do.

Tested continuity: seems fine. Just noticed the plunger on the switch seems really wobbly though. Wonder if it’s snapped?

Sounds very similar to a failure I had on my HDZ, after upsetting it by losing steps on the way down it went into the Z limit switch hard enough to jam it on (closed circuit) permantly, this seems to be a common failure mode for these Omron switches, I’ve lost two that way and now keep a small stash of spare units. The Z homing failure on power up also sounds familiar.

I found RS components has the Omron equivalent for much cheaper than the DigiKey, but now RS lists all of the D2QW microswitches as discontinues.

You can use the D2QW-C003D or the D2QW-C003H only difference is this unit has pins for PCB through hole rather than solder tabs but checking the Omron docs this is the only difference.

Farnell has also dropped the C003D which suggests RS just ran out of old stock before the others did. They still have the C003H pin variety which I have used.

Mouser still has the D (but for how long?) and Digikey also has them.

When you get the replacement and solder it on use the Settings screen in Carbide Create to check that you’ve got it working, use a finger to operate the switch and check the Z comes up to show it’s active.


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