Auto bed leveling



  • I'm building a corxy system it uses 4 worm gear stepper motor driven by belts to left the Z axis can I install 4 mechanical endstop on the max side and a Zprob on the min side. So where when I request to home all I want the bed to go all the way to the max so it can adjust the 4 corners acording to the position of the limit switches and then to travel to min extruder side and do 4 corners probing.



  • @moe-adams9093 said in Auto bed leveling:

    I'm building a corxy system it uses 4 worm gear stepper motor driven by belts to left the Z axis can I install 4 mechanical endstop on the max side and a Zprob on the min side. So where when I request to home all I want the bed to go all the way to the max so it can adjust the 4 corners acording to the position of the limit switches and then to travel to min extruder side and do 4 corners probing.

    Yes you can do that if all four Z motors have their own drivers.

    Homing script would be pretty standard, you would just have to ensure it's configured to home to max, probably M574 Z2 ...

    For the 4-point leveling, you would have to set the coordinates of the bed pivots in config.g using M671

    Then you would have to probe all four corners, using G30 commands with coordinates specified.


  • Moderator

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

    It's a lot easier to do in RRF3. Assign all z axis drivers and then specify the endstop switches for the z axis in a single M574 line for Z. Then home as normal using G1 H1 Z.

    You can also use the probe itself to do the leveling and save yourself some endstops. This is also described in that link.



  • Thanks for the support



  • Quick question i have duet ethernet and duex 5 i need to add 2 closed loop external driver is it possible to add 2 extra external driver using conn-LCD with the duex 5 connected. thank you


  • Moderator



  • So the expansion port pins are going to the duex5 only left is Coon-lcd and Coon-SD the form is only taking about Coon LCD so is that said only one external can be added or can I use coon lcd and coon SD for 2 motors. Please correct me if I'm wrong I just don't want to order them before I'm 100% sure Thank you.


  • Moderator

    @moe-adams9093

    From DC42:
    "yes, 2 on CONN_LCD
    if some of the DueX5 motor outputs are not being used, you could also connect an EBOB to the Duet expansion connector in parallel with the DueX5, then you could use the step/dir outputs for those motor outputs on the EBOB, but not the enable outputs"



  • Thanks for the response I have few questions to set some clarification before I do so. I have 2 avaliable drives on the duex5 if I disable the jumper on the underside for both and take step and dir and Ena will that provide +5v? Also my second question what about the ground lead for -step and -dir, -ena where they will be placed. Third question what will be the number for the drivers in the configuration file. Last question endstops will be connected to the drivers that are associated with the one I disabled. Thank you in advance


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    @moe-adams9093 said in Auto bed leveling:

    Thanks for the response I have few questions to set some clarification before I do so. I have 2 avaliable drives on the duex5 if I disable the jumper on the underside for both and take step and dir and Ena will that provide +5v? Also my second question what about the ground lead for -step and -dir, -ena where they will be placed. Third question what will be the number for the drivers in the configuration file. Last question endstops will be connected to the drivers that are associated with the one I disabled. Thank you in advance

    Two issues here:

    1. The signal levels on the expansion bus are 3.3V with low current. The EBOB converts them to 5V single-ended.

    2. RepRapFirmware expects to find two TMC2660 drivers on a DueX2, or five on a DueX5. If you want to cut the Enable traces to use different numbers and use external drivers in the corresponding slots, you would need to recompile the firmware. We may implement auto-detection of TmC2660 drivers in the future, but that isn't in RRF yet.

    Drivers that need single ended drive are best connected between STEP- and +5V on the EBOB for the step input, and similarly for DIR and ENA.



  • Ok I see it looks like its a bit complicated going from EBOB terminal and I thought about one thing is I don't want to lose the additional drives maybe in the future might use those for additional extruder i would say it will better for me to install a shift registrar and convert 3.2 to 5 volt on the COON-LCD connection.
    Question can I use boost converter from 3.3 v to 5v or it has to be a logic shift register. Thank you


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