Difference between M561 and G29 S2 SOLVED

  • Is not clear to me what is the difference between M561 (Disable Bed Compensation) and G29 S2 (Disable Mesh Grid Compensation)
    They are both in the auto Delta Calibration menu in the DWC

  • I think G29 S2 only wipes the height map but leaves the Delta calibration,
    M561 clears both.

  • @jmjcoke
    G29 S2 wipes the height map completely or only until reboot

  • I have not checked, but I would say the the map would still be in you folder just not applied until reboot or you run a G29 S1.

  • @jmjcoke
    Ok but what happens if I have my delta geometry described (M665 and M666) in config.g as I don't like to use config override.
    Do you mean M561 and G29S2 will overwrite my config.g values?
    I dont think so

  • A successful G29 probe sequence stores the resulting heightmap in a file in the system folder, called "heightmap.csv". It does not touch config_override at all.

    G29 S1 loads the heightmap from that file into memory and "activates" it, that is the printer will make moves to compensate Z, according to the map.

    G29 S1 "Deactivates/Unloads" the map from memory, meaning the printer will no longer adjust Z via the map. It does not touch the file. You could load it later, view it, etc.

    Unless YOU delete it, move it, etc, OR you perform another G29 that over-writes it, the file will not change.


    Delta Calibration, from G32, does not auto-save. The adjustments to M665 (which may be one or several depending on the last G30 in bed.g) become active in memory after a successful G32 probe sequence. An M500 will save the M665 with adjusted parameters (and several other things) to config_override.g. A reboot or power cycle will clear the in-memory settings (really, back to config.g settings), and an M501 would be required to reload the config_override.g file again, to put those adjustments (as vs. what is in config.g) back into force.

    If you perform things in a certain sequence, it would be possible to see an "M665" entered with no parameters at the console return one set of values, see a second set in config.g's M665, and a third set in config_override.g's M665.

    Following a different sequence, they could all three be exactly the same.

    It is really up to you, and when you issue the various commands.


    I, personally, have never used M561 and can't comment on what it does.

  • administrators

    M561 and G92 S2 do exactly the same thing. M561 was implemented a long time ago. When I implemented mesh bed compensation, I added G92 S2 to keep the relevent commands in one place and make them easier to remember.

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