Homing with Stall Detection on 3HC

  • I have just added a 3HC board to provide capacity for an extra axis and am testing with RepRapFirmware 3.2beta4.1. I have configured sensorless homing on this new axis but seem unable to detect a stall, regardless of the settings for the axis. Homing fails with a "G28 U Error: Homing failed" message.

    During my investigations, I found a comment that suggested that sensorless homing was not supported on the 3HC expansion board. Please could you confirm if this is actually the case?

    Duet 3 6HC
    Duet 3 Expansion 3HC (ID 1)
    RepRapFirmware 3.2beta4.1

    Axis U configured as follows:
    M584 X2 Y1 Z0 C5 U1.0
    M208 X-185:178.5 Y-149:49 Z0:300 C0:500 U0:110
    M92 X100 Y100 Z1600 C200 E834:834:409:409 U400
    M350 X16 Y16 Z16 U16 I1
    M566 X400 Y400 Z8 C2 U400 E1000:1000:1000:1000
    M203 X35000 Y35000 Z1200 C10000 U10000 E5000:5000:5000:5000
    M201 X6000 Y6000 Z400 C500 U6000 E2500:2500:2500:2500
    M906 X2000 Y2000 Z1330 C500 U1500 E1400:1400:1000:1000 I30
    M574 U1 S3
    M915 U S1 F1 H200 R1

    homeu.g is as follows:

    G91 ; use relative positioning

    G1 H2 U0.5 F10000 ; energise motors to ensure they are not stalled

    M400 ; make sure everything has stopped before we change the motor currents
    M913 U70 ; drop motor currents to 70%

    G1 H1 U-120 F10000 ; move up 150mm, stopping at the endstop
    G1 H1 U2 F2000 ; move away from end
    G1 H1 U-120 F10000 ; repeat the homing move because it doesn't always work first time
    G1 H1 U30 F4000 ; move away from end
    G90 ; back to absolute positioning

    M400 ; make sure everything has stopped before we reset the motor currents
    M913 U100 ; motor currents back to 100%

    I have tried a range of parameters for the stall detection, current settings and speeds. No stalls are recorded in the logs.

  • Moderator

  • Thanks. Interestingly, that page doesn't come up in search results for 'stall' and 'home'.

  • Moderator

    The search is rather pedantic. It should show up now though. And hopefully it won't be much longer before it's irrelevant.

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