Setting up Bed level with 3 motors



  • Bit of trouble.... Any help would be appreciated.
    I have the config setup, but I know something isn't correct.
    Any time the bed is supposed to move (Z goes down 5mm to home X or Y) the motors have a high pitch wine. They do slightly move each time, but its more like a short jump. All 3 motors have power and hold the screws in place after the printer power up. But when they are supposed to move and wine, they are very easy to spin.

    Bed
    G28 ; home
    ;M401 ; deploy Z probe (omit if using bltouch)
    G30 P0 X10 Y80 Z-99999 ; probe near a leadscrew
    G30 P1 X127 Y290 Z-99999 ; probe near a leadscrew
    G30 P2 X270 Y80 Z-99999 S3 ; probe near a leadscrew and calibrate 3 motors
    ;M402 ; retract probe (om
    it if using bltouch)

    Config
    M584 X0 Y1 Z9:7:8 ; three Z motors connected to driver outputs 9, 7 and 8
    M671 X-50:127:310 Y80:385:80 S5 ; leadscrews at front left, back middle and front right



  • Another thing or two to note.

    When I am looking at the classic web interface, it says the Z motor (acting like there only 1), is set to 1400ma. It should be 1200 per the config. I don't know where it is getting 1400ma from.

    When the bed is supposed to be moving up to the probe to home, the E6 hear LED it lit up....



  • So it looks like, whatever the Extruder (E0) is set to in power 1400ma, the Z motors are also set to.

    I updated E0 to 1200, and the Z motor also changed... I do not know where the E and Z are crossed...


  • Moderator

    Can you post your entire config? I think the axis definition isn't quite right and the order of commands matters.



  • Hi,

    Try filling out your M584 to specify what motor connections 2,3,4,5 & 6 do.

    Sometimes funny things happen when defaults are relied upon.

    Frederick


  • Moderator

    @BlueDust said in Setting up Bed level with 3 motors:

    M584 X0 Y1 Z9:7:8

    Ah yes of course, you're missing the E definitions.



  • Thank you!
    You guys are awesome!

    I just copied the config out of the Wiki and it does not have E in the example on setting up 2 or 3 motor bed leveling.

    https://duet3d.dozuki.com/Wiki/Bed_levelling_using_multiple_independent_Z_motors

    I have more tweaking to do, but it does actually work now.

    Thanks again!


  • Moderator

    Thanks for pointing that out. I'll make a note in the wiki to make sure to include your extruder definition as well.


  • Moderator

    @BlueDust said in Setting up Bed level with 3 motors:

    https://duet3d.dozuki.com/Wiki/Bed_levelling_using_multiple_independent_Z_motors

    Updated to include the gcode wiki note for M584:

    https://duet3d.dozuki.com/Wiki/Gcode#Section_M584_Set_drive_mapping
    VERY IMPORTANT! Assigning a drive using M584 does not remove its old assignment. Therefore, if you assign a drive that defaults to being an extruder drive, you should also assign the extruder drives explicitly as in the above example. Failure to do so may result in unexpected behaviour.



  • 2 more comments.
    My Extruder drive never changed from Drive 3. It just was not called out when I had to explicitly call out the 3 Z motors (per what the wiki was, but now you updated with E). All I did was move the Z from drive 2, to 7, 8, and 9.

    Can the heat map be updated to show the original and/or the new level after G32 is run?
    Just to see the difference. Also, if the bed needs to level more than it is allowed to correct itself in the GCODE, this may be good to see. I think I saw 1mm max correction unless it is called out.

    Thanks again!



  • @BlueDust said in Setting up Bed level with 3 motors:

    My Extruder drive never changed from Drive 3. It just was not called out when I had to explicitly call out the 3 Z motors (per what the wiki was, but now you updated with E). All I did was move the Z from drive 2, to 7, 8, and 9.

    but 7,8,9 remained extruders and additionally became z motors at the same time.



  • I didn't realize everything was considered an Extruder if not declared. (Except for X, Y, Z labeled drivers). That explains my biggest question when setting up my Duet2 last year as I wasn't aware of M584 until now. Now that I need it to setup this bed leveling feature.

    Thanks!


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