Auto calibration probe points unreachable



  • Im trying to use autocalibration on a delta using a bltouch but I'im getting an unsual behavior : the nozzle goes down, then without moving probes the amount of points I had set and finishes by throwing "G32
    Error: Auto calibration failed because probe point P0 was unreachable using the current delta parameters. Try a smaller probing radius."

    I have tried down to a 50mm probing radius even tough my bed has a 125mm radius and double checked all the delta parameters but I still get no movement and the error. Looking at the coordinates of the probing points they should easily be reachable for the probe, the only thing Ive noticed is that if I put the nozzle at Z0 and go to Y25 for example the nozzle touches the bed (because its irregular/convex) but I dont see what that would have to do with the probing radius.

    Thanks for helping



  • Did you follow the delta autocalibration wiki page? Could you share your bed.g file?



  • @oliof yes I followed it, the only thing I didn't do was mesure different trigger heights since the guide says that it is not necessary for first-time calibration and to return to it later.

    here is latest bed.g that I tried (90mm probing radius) :0_1565405346043_bed.g

    UPDATE: I tried entering the different trigger heights of the points in bed.g and it doesn't help, exact same behavior.
    The problem is that the G30 commands like G30 X0 Y84.9 S-1 are not moving the nozzle.



  • First, replace your M98Pdeployprobe.g and M98retractprobe.g with M401 and M402 respectively (and I am almost sure neither is needed with a properly configured BLTouch).

    Second, this comment makes me wonder if you have setup your probe correctly:

    ; 10 points, 6 factors, probing radius: 90, probe offset (1.5, -398)

    If your probe offset is at -398 for Y that's most likely the culprit as the head would try to move another 398mm to get the probe above the bed, resulting in an unreachable position.

    So, please share your config.g -- especially your G31 (and M558 to verify your BLTouch setup) is of interest. If you have a config-override.g please include that as well.



  • @oliof you were right I forgot the dot: it's 39.8 and not 398 wich would be an insane offset. I can't beleive I copied this multiple times without noticing. When the error was talking about delta parameters it threw me off but I guess the probe offset is one of them.
    Thanks a lot !


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