Relation between auto bed level (G32/G30) and G29



  • Hi
    I thought to ask this as a reply on another question but I figured it could be a topic on its own since I see a lot of people that have offset problem etc with auto bed levelling
    Just a quick question here: Are auto bed level(G32) and and mesh(G29) independend from each other? I see that M561 clears bed level whilst G29 S2 clears mesh....So can I do a M561 followed by a G32 to bed level using my 2 z motors and after that G29 S2 and G29?
    And can these be used independently, i.e. can I clear M561 and only do G32 and keep using G29 S1 to reuse the mesh height map and vise-versa; can I use G29 S2 and measure a new mesh with G29 without clearing the G32 auto bed level for my motors

    Another question regarding this : does the bed leveling using independent motors move the motors once and leave them there or is this like mesh compensation something that adjusts z dependend on the hotend position?

    In general I think the relation between G32/G30/M561 vs G29 S1/S2 could be explaned better in the wiki. each is explained well in it self but the relation between the 2 is not very clear

    Thanks



  • @alexlin said in Relation between auto bed level (G32/G30) and G29:

    In general I think the relation between G32/G30/M561 vs G29 S1/S2 could be explaned better in the wiki. each is explained well in it self but the relation between the 2 is not very clear

    I totally agree. I read several times the documentation, and I'm still confused how things work. And I can see there are a lot of questions about bed leveling and so, which means documentation lacks something.

    What could help is a number of working examples. Could people having working configs post (here or on wiki pages) their setup (printer type, probe model, scripts...), with comments? It would help beginners to dig into the different procedures...

    Thanks!



  • I have been meaning to post this same query regarding the various bed level operations and their interactions.

    Regarding the worked examples, my preference would be more like a table or page saying how all of these relate to and interact with each other. (Very happy if there are worked examples as well!)

    I thought of this also reading the thread about pages on the wiki associated with the G-Code list to group related commands.


  • administrators

    There are two types of bed compensation supported by RepRapFirmware.

    The OLD way uses a bed.g file with 3, 4 or 5 probe points defined in it. G32 is used to run the bed.g file.

    The NEW way is to define a grid using M557 and then use G29 to probe it.

    A complicating factor is that G32 and bed.g are also used to perform autocalibration of delta printers, auto levelling (not compensation) using multiple leadscrews, and to tell you how much to adjust manual levelling screws.

    I plan to remove the facility to do 3, 4 and 5 point bed compensation using G32/bed.g some time in the future. This should reduce the confusion, because M557/G29 will be the only way of doing bed compensation. Those who were previously using 4-point G32 bed compensation can use a 4-point mesh instead. Those who were using 3-point G32 bed compensation will have to switch to a 4-point mesh, and those using 5-point can switch to a 9-point mesh.



  • Thanks for the clarification!



  • @dc42 said in Relation between auto bed level (G32/G30) and G29:

    I plan to remove the facility to do 3, 4 and 5 point bed compensation using G32/bed.g some time in the future.

    Does that mean that 'auto levelling (not compensation) using multiple leadscrews' also will be removed? If not, is that independent of mesh or not? I.e. M561 is independent from G29 S2?
    If it will be removed...what is the alternative? endstops/axis for each motor?

    And currently are M561 and G29 S2 independent?or do the both clean the bed leveling and mesh grid?


  • administrators

    Auto bed levelling using multiple leadscrews will be retained, so will the assistance for telling you how much to adjust manual bed levelling screws if you don't have multiple leadscrews.

    M561 and G92 S2 do exactly the same thing.



  • so that means it is impossible to clean the Auto bed leveling independently from the mesh. Which again means that one should always perform auto bed level together with G29..............?


  • administrators

    @alexlin said in Relation between auto bed level (G32/G30) and G29:

    so that means it is impossible to clean the Auto bed leveling independently from the mesh. Which again means that one should always perform auto bed level together with G29..............?

    The auto bed levelling using multiple leadscrews isn't cleared by M561, G29 S2, or anything else because it is an adjustment made to individual leadscrews, not compensation applied by firmware.



  • Thanks , now it is perfectly clear to me! I already thought it just adjusted the lead screws as a 1 time action


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