Multi-Tap additional parameter



  • It's probably just greed on my part but I found myself asking "Is two taps really enough?".

    In all probability two is fine but a third would significantly reduce the chances of a glitched match.

    Unfortunately it would also slow down the probing procedure so what I am proposing is an additional M558 parameter that specifies the number of sequential matches required.

    This could actually be a double parameter in the form M558 L3:5 which would specify that three out of the last five results need to be within tolerance.

    The double parameter would allow the current behaviour to be simulated for a quicker probe or more rigorous probing to be performed for a noisy environment.

    Anybody got any views on the matter (positive or negative)?



  • I couldn't test the multi touch Feature and don't know what actually happens with the probed Values in the Background,
    but what you're saying makes sense.



  • DC will probably clarify this but, as I understand it:

    The firmware probes repeatedly until either two consecutive results are within tolerance (i.e. their difference is less than or equal to the value in the S parameter of M558) or the number of attempts specified in the A parameter have been made.

    In the latter case the average of the probe attempts is used. (I'm not sure if any additional processing is performed to discard outliers such as using the two closest readings or using a geometric mean)



  • I've set mine to 5 taps, but if the first and second agree it moves on, and so far they always have using Piezo20 probe units (I'm using 0.03mm tolerance on that particular machine as it is not very precise, I am using 0.01mm tolerance on my delta with smart effector and sometimes it needs to probe 3 times to get agreement, but that's 10 microns, so I think its pretty good). Yes its slower than 1 tap probing, but this feature reduces the risk of a bad calibration/levelling, which does not stop or pause the print resulting in a bad print or a head crash, and this risk is greater the more automated and less attended your printer is.


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