3.2b2 Duet3/RPi with Toolboard - G30 issue with BLTouch

  • This was reported in the 3.2b2 announcement thread, but I need to make sure it isn't buried..

    There is an issue with G30 when connected to a toolboard using 3.2b2. After initial problems, I was able to clone a 3.2b1 SD card, test everything was working, upgrade to 3.2b2 again and recreate the issue.

    The relevant lines in my homez.g are as follows

    G30 Z-99999			; sets z-height relative to print bed
    M561				; clear any bed transforms
    G30 P0 X20 Y150 Z-99999		; probe midway between front and rear belt on left side
    G30 P1 X280 Y150 Z-99999 S2	; probe midway between front and rear belt on right side

    These work fine on 3.2b1 and 3.1.1, but have erratic results on 3.2b2. Sometimes G30 will only touch down once and move on. Sometimes it will won't deploy the probe and crash into the bed. Once or twice, it sort of completed, only to go to X0 Y0 and probe there, which isn't even in the code.

  • Moderator

    BLtouch version?

  • @Phaedrux 3.1 genuine

  • If it would help, I can take some video of it failing in different ways.. like I just rebooted, then honed three times in a row. Once, it didn’t even try to probe at the start point and immediately moved to the left side of the bed. Another time it only probed the center point once, then moved on. The third time, it probed the center point correctly once, moved way too high for the second pass, and failed by it not touching due to the dive height.. weird stuff.

    I’m rolling back to 3.2b1, but am willing to roll forward to 3.2b2 if there is anything specific I can help with.

  • Here is a quick video before I roll back to 3.2b1 on the test machine on my workbench. It shows the G30 Z-99999 being skipped (no probe in center), the tool moves to X20, probes twice (correctly), probe retracts, and then it probes again without the probe extended before moving on to X280..



    Edit- rolled back to 3.2b1 again and it was successful the first try. No changes to any configs..

  • Moderator

    Thanks. What is your M558 and G31 being used at the time?

  • @Phaedrux - here you go..

    M558 K0 P9 C"20.io0.in" H6 F200 T12000 A5 R0.1 S0.01
    G31 X20 Y20 Z2.60 P25

  • And if the P25 in my G31 is questioned, here is the homez.g routine working again on 3.2b1. It's done this way as Z is belt driven and it first lifts the gantry to max-Z to remove any skew between left and right. When it comes down, it will always be between 10-15mm above the bed depending on the build plate used.

    Oh, and please forgive anything 'off' in the videos - this is a very early prototype that has been torn down more times than I can count..


  • I suspect the problem you are seeing is related to the issue reported here: https://forum.duet3d.com/topic/19074/bed-levelling-traming-odd-message-3-2-beta-2

    I think it is a general beta2 issue and not specifically toolboard related (though having a toolboard may impact the timing and cause it to happen more often).

    If you get the chance you may want to re-run the test with gcode and SBC debug enabled (using m111 p3 s1 and m111 p16 s1). This may provide a little more information as to what is going on.

  • I still can't get 3.2b2 to probe, which is pretty much a deal breaker. Has the cause been identified?

    I'm stuck in a bad place where I can't view the height map on 3.2b1 (DWC issue resolved in 3.2b2) but can't probe in 3.2b2..

  • @oozeBot dc42 got a bltouch 3.1 in the post today so will be looking at the issues with the toolboard.
    In the meantime, you could build the SBC version of DWC from the github wiki. Its fairly easy to build. It can then just be uploaded through the systems tab.
    If you can't get it to build, drop me a pm

  • @jay_s_uk Thanks! I'll see if I can carve out some time this afternoon to do this.. in the meantime, I've pulled a new Duet3 and RPi out of the box to setup 3.2b2 without a printer attached. I can then upload the height map to view from our 3.2b1 machines.. it ain't pretty, but I just rebuilt one of our machines and have to get it re-leveled somehow.

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