Z=0 datum was not determined probing.

  • How do I fix this error? It just started showing up after a firmware update: Duet Maestro M3D Promega

    Warning: the height map was loaded when the current Z=0 datum was not determined probing. This may result in a height offset.

  • administrators

    It means that you have both a Z endstop switch and a Z probe, and you used the endstop switch to home Z. The problem with this arrangement is that the endstop switch and the Z probe need to agree on where Z=0 is. If they don't, then your height map will show a significant offset, corresponding to the different in Z=0 levels. The difference between these two Z=0 levels is likely to be affected by temperature.

    Ways round this include:

    • Ignore it, if you are satisfied that it doesn't cause any problems. The main issue is likely to be that a height map that you produce by probing one day may not work when you load it from the SD card another day, because the difference in Z=0 as seen by the endstop switch and as seen by the Z probe has changed.
    • Instead of using the endstop switch to home Z, use the Z probe. See https://duet3d.dozuki.com/Wiki/ConfiguringRepRapFirmwareCartesianPrinter#Section_Homing_Z_using_a_Z_probe.
    • After homing Z using the endstop switch, and before either probing (G29 or G29 S0) or loading a height map (G29 S1), do a single G30 probe at/near the centre of the bed.

  • Thank you !

    This happened after I updated the firmware. It was never an issue before and I'm not sure how or why it's reading the IR probe all of the sudden. I've always used the Z-Probe ( limit switch ) and it worked just fine. How do I disable the IR probing function and should I do that?

  • administrators

    That message is new in the 2.03RC firmware, that's why you didn't have it before.

    I suspect that you have set up your homez.g file and the Z homing section of homeall.g incorrectly. See https://duet3d.dozuki.com/Wiki/ConfiguringRepRapFirmwareCartesianPrinter#Section_Homing_Z_using_a_Z_probe. Z homing using a Z probe should be done using a G30 command, not a G1 S1 or G1 H1 command.

  • Hi thanks, for the info but as I havent meshed the bed yet I cant ignore it and using G30 without the switch, the head crashes in to the bed, I have no desire currently to use IR probe. How can I disable it or have the firmware ignore it?
    As above recently updated and now having issues.

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