Persisting Autocalibration Results

  • Is there any way with RRF to automatically persist the results of an autocalibration (on Duet WiFi) so that the results are automatically recovered in the case of a power outage? According to the wiki, M500 is supported by RRF but I'm not sure how to setup my config so that it is used and not overridden by the M665 line that is in config.g. I apologize if the answer is obvious but I'm not near my printer where I can actually test but this has been heavy on my mind lately.

    Why I want this…? After about 30 hrs into a print a week or so ago, my extruder motor stopped working due to a wiring failure. Had I not unplugged the printer when this happened or if I'd jotted down the config, I believe I could have figured out the layer to re-start from and continued the print. However, due to the calibration settings loss and no way to run a calibration (because the print was on the bed) I had to toss out the print.


  • This is not really a solution, but there are two options that work right now:

    If your printer is mechanically stable enough, you can run an autoprobe (hot) and get the values with M666 and M665. You can then put the values in your config.g. In this case the autoprobe should produce only minor corrections to the print geometry, so you could continue without re-autoprobing if you had to.

    If your web control is running on a computer that stays up, you can put M666 and M665 commands (with no parameters) into the G-code right after the autoprobing. Their output will contain the relevant numbers and will wind up in your "G-code console", though if you're not careful it could be hard to find among the output from 30 hours of printing. Don't close the browser window, though, because this data exists only in the browser memory.

    Finally, there is a plan to create a config-override.g file that will store the printer settings, like NVRAM does in Marlin. Even if you don't use this file to set anything, it could be used to record the key parameters.

    When a print is paused, currently, the position is magically saved for later resuming, as is the information about the G-code file in use, the position inside that file, and the commanded temperatures. There's no reason one couldn't create G-codes to save that information to the SD card and load it back in after power returns. Even further in what-if land, one could rig a few-second UPS that supplied only the 5V circuit and have it trigger the saving, so your printer would recover gracefully from power outages.

  • administrators

    There are two firmware features planned that will help in this kind of situation:

    1. Persisting auto calibration values in config-override.g with M500

    2. Power off and resume functionality.

  • Thanks. I'll be looking forward to that config-override.g functionality.

    So, what does M500 currently do in RRF? Does the RR wiki need to be updated to say it isn't supported?

  • administrators


    So, what does M500 currently do in RRF? Does the RR wiki need to be updated to say it isn't supported?

    It already says that.

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