Layer inconsitency after PID Autotuning



  • I have a custom built Omerod 2 that is currently running a Duet 0.8.5:

    Firmware Name: RepRapFirmware for Duet
    Firmware Electronics: Duet 0.85
    Firmware Version: 1.22 (2018-07-26b2)
    Web Interface Version: 1.21.2-dc42

    I am using an authentic E3D V6 with a silicon sock and titan direct extruder for a hot end.

    I recently had gone thru and rebuilt the machine. I lengthened the X and Z axis and replaced the Y and X belts with GT2 gears and pulleys. Everything was running as it should, printing very nice (better then before). I then upgraded from 1.14 to 1.22 and ran the PID autotune (something I never did before). And now I have weird layering occuring. The layers expand and shrink in a very repeatable pattern and I do not know why. I do not use any auto leveling so the Z axis only moves when the layer changes.

    From what I read it has something to do with the PID that is run, and I have done the auto tune a few times and still the problem exists.

    Here is what the print looks like:

    0_1535421827621_problems.jpg
    here is the original config file:
    0_1535421896639_config.g

    and here is the new config file
    0_1535421962964_config.g

    and the PID file
    0_1535421990399_config-override.g



  • You are currently running bang-bang mode, which is why your print looks like this. You can verify your setting by sending an M307 H1. There are two ways to correct this. You could add a M501 command to the end of your config.g (which is missing and belongs there) and this will allow your stored settings in config-overide.g to be read and PID would then work. Or you could remove the comments on the M307 commands in your config.g and this would also restore PID. I am a belts and suspenders guy so I use both.



  • I will adjust those. However, I ran the autotune just before printing (and did the M500 command, which wrote the config.override.g file.

    The number I have remmed out I did after the autotune (I put that number there based off the 1st autotune) which did not help.

    However, as an update I have now noticed my e steps are not correct anymore. I am recalibrating them now. I do not know why they have changed (extruding 110mm exactly, vs 100mm).



  • Stored parameters cannot be read without including a M501 command in your config.g:
    https://duet3d.dozuki.com/Wiki/Gcode#Section_M501_Read_stored_parameters


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