Z Probe only shows "No Contact"

I am upgrading an original X-Carve (like, very original) with the X-Carve upgrade kit. While testing the X-Controller, I found a problem with the Z probe. With Easel’s machine setup I was able to configure the axis and home the machine. Using UGS, I can control the machine as expected. Except for auto-probe.

In the setup, when it is time to hook up the Z-Probe, the UI always says “No Contact.” I tried connecting the banana tip directly to the ground clip, but no change. I issued $$ to grbl, but it always returns $10=115 whether the probe wires are connected or not.

I have tested the probe on both sides with a DMM. When the clip and banana plug are in contact, the wires are shorted with less than 500mΩ. So there is not an issue with the physical probe.

Before I take the cover off the X-Controller, is there some other flag that needs to be set in grbl to enable the Z-probe?

Try this thread to see if you can determine what the problem is.

I issued $$ to grbl, but it always returns $10=115 whether the probe wires are connected or not.

$$ is the command to display the the grbl parameters.

The question mark (?) command returns status information where you can verify the state of the probe input.

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This is probably an issue with the internal ribbon cable either being not fully engaged or being backwards. Someone recently had an issue with the board itself.

The question mark (?) command returns status information where you can verify the state of the probe input.

Thank you for the clarification. Which field is the probe? When I issue ? everything is 0. I can see the 3 fields for the limit switches because activating them changes those. Connecting or disconnecting the probe does not change any other fields.

the internal ribbon cable either being not fully engaged or being backward.

I reseated both ends of the ribbon cable. The key is in the correct position.

I measured the “Probe” pin and the “GND” pin independently, with reference to another ground pin. With the z-probe and ground clip separated, the “Probe” pin measures 5 volts. With the z-probe and clip touching each other (directly), “Probe” pin measures 0 volts. I expect the Probe pin is an INPUT pin configured with a pull-up resistor; this is the behavior I would expect.

I verified again that Easel claims there is “No contact.” This occurs in Safari and Chrome on OSX. I checked in Windows 7 with chrome on the same computer with a virtual machine.

In the general case, this is correct. Hardware is working.

Easel does funky things.

What is the state of the hardware when you get the “No Contact” from Easel?

Is the wire plugged into the socket on the X carriage, or are you bypassing that step during your testing?

What version of grbl do you have loaded?

It is only in Easel. The probe works fine in UGS. Which is fine with me.

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Is it GRBL v1.0c? How old is the Xcontroller?

2 years ago they had a firmware issue where the probe wouldn’t work in Easel but it would work in UGS/others.

You may want to try either re-flashing v1.0c or updating to v1.1f

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Is it GRBL v1.0c? How old is the Xcontroller?

Good suggestion. It was 1.0. I ordered in April '18 and I received it sometime in June. I guess the units built before April 2018 didn’t get the benefit of firmware released almost a year before. (Wonder why it took 2 months to ship it then?)

But updating to 1.1f doesn’t fix any issues with Easel communication. Before updating the X-Controller’s firmware, I updated my “easel driver.” With grbl 1.0, Easel would stop at the homing step with my older “driver” version. (I don’t know what that I had before…)

Easel now says “Starting Homing”, the x-carve homes X and Z fine. However, Y would stop after hitting the limit switch. (There is no fine Y-axis adjustment.) The in-browser dialog never changed from “Starting Homing.”

Regardless, UGS is working as expected.

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