Touch Sensor setup failing

I went to try by touch block last night and it just kept failing. First because I wasn’t close enough (ok, that one is on me, although the way the error fades in and out quickly in UGS caused me to miss it the first few times).

However, even when I made contact, it failed. It marred the surface and pounded the bit in to it.

I took it off, grabbed a multi meter and did a buzz test for conductivity on the cable. Cable is fine. I did a buzz test with the block in the circuit and it was also fine. But when I put it on the machine and the bit comes in to contact, it does NOT trigger. So I backed up and tried to trigger it with and without the block, closing the circuit by hand. It also did not get picked up by the controller.

I tried to follow the video, and got as far as running the “measure” test, which is when I discovered it wasn’t triggering the contact sensor. Also, I noticed there appears to be an error in the video. Assuming the XYZ page is correct, when the narrator switches to the XY page he appears to swap the two sets of dimensions. If I understand correctly, they should match the same items on the XYZ page, but they got swapped on the screen. That confused me for a while too. @chrismakesstuff am I seeing that correctly, is that an error? Check between 2m 40s and 2m 55s in the video. Looks like distance and offset for swapped on the XY tab? Also, the screens in the video do not match the screens in the recommended August 2019 build of UGS. Do you know which version was used in the video?

Any idea on why my touch sensor isn’t triggering or how I can troubleshoot it from here?


Jeff: Just a quick observation. You aren’t holding onto the block when you run the probe module, are you?

Also, make sure that the positive and negative are connected to the green plug correctly.

Finally, make sure that the screw holding the wire into the plastic cover is tight.

That’s all I’ve got.

Thanks, Grant.

Nope, not holding the block during the test. I have double checked the terminal connections at the controller but will undo and re-do those. The connectivity test does work via the clamp down screws on the terminal block.

It didn’t pass my logic test last night so in frustration I set it aside. Will give it another go today. Logically it should work, unless the pins on the controller aren’t sensing contact for some reason inside my controller…

More questions, Jeff. Does it fail in all three axes?

It fails right at the start, it doesn’t register the first contact so it errors out. After plunging the bit in to the block, of course.

Double-check where you’ve plugged it into the controller. I had the same thing happen after I reorganized the wiring to my controller, only to discover I’d plugged the probe connector into the wrong block on the controller…

@jwoody18 you’re correct, I didn’t notice this before. Thanks for letting me know, maybe @andy can jump into the YT editor and get this fixed up.

As an FYI, there’s also another source of info on our Touch Plate page here:

This has the same info as the video does and some other further clarifications which can certainly help in getting your probe up and running. Maybe you’ll find your solution there

Thanks @chrismakesstuff I’m going to give it another go today and will report back with the results.


I gave it another go and still had issues but I took out the multimeter and again confirmed that everything was fine on the lead and connector. I was about to try a direct jumper of the pins on the Longboard to confirm the pins were good when I decided to try and reseat it yet again. This time I was a bit more insistent and I noticed that it seated a bit deeper than it had before and deeper than the surrounding “spare” connectors on the other inputs that shipped with it. When I did a manual test of just a Z probe (ready to interrupt instead of causing more damage), it worked!

I would recommend people always confirm the circuit is being detected before using a probe each day. It is easy enough for a loose connector or poor connection to catch you out and break a bit and damage your probe block and or the workpiece. I’ve had that happen on a Shopbot as well, so I’m going to add a continuity check to my process before I trust it with bits.

Happy to have it working now that I need to run that 1/16th bit…


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