Bed leveling using dual z motors

  • As the bed was losing its position on power off due to the weight causing it to run down the leadscrews I have re-confured the z axis to use independent z motors.
    I am using the E1 output for the second motor.
    The problem is that the motors are not moving the same distance as each other.
    Thankfully I removed the bed before testing.
    I think it must be due to settings of the E1 output but have been unable to figure out what
    Firmware is v2.01
    Can anyone advise where I am going wrong?

    ; General preferences
    M111 S0 ; Debugging off
    G21 ; Work in millimetres
    G90 ; Send absolute coordinates...
    M83 ; ...but relative extruder moves

    M555 P1 ; Set firmware compatibility to look like RepRapFirmare
    M564 H0 ; Limit axis
    M572 D0 S0.18 ; Set extruder pressure advance.
    M667 S1 ; Select CoreXY mode

    ; Network

    ; Drives
    M584 X0 Y1 Z2:4 ; 2 Z motors connected to driver outputs 2 & 4
    M671 X-80:480 Y200:200 ; Z lead screws are at (-80,200) (480,200)

    M569 P0 S0 ; Drive 0 goes forwards
    M569 P1 S0 ; Drive 1 goes forwards
    M569 P2 S0 ; Drive 2 goes backwards
    M569 P3 S0 ; Drive 3 goes backwards
    M569 P4 S0 ; Drive 4 goes backwards
    M350 X128 Y128 Z128 E16 I0 ; Configure microstepping without interpolation
    M92 X800 Y800 Z3200 E95 ; Set steps per mm
    M566 X900 Y900 Z12 E120 ; Set maximum instantaneous speed changes (mm/min)
    M203 X12000 Y12000 Z1200 E3000 ; Set maximum speeds (mm/min)
    M201 X1000 Y1000 Z1000 E5000 ; Set accelerations (mm/s^2)
    M906 X855 Y855 Z1200 E800 I30 ; Set motor currents (mA) and motor idle factor in per cent
    M84 S30 ; Set idle timeout

    ; Axis Limits
    M208 X0 Y0 Z0 S1 ; Set axis minima
    M208 X400 Y400 Z450 S0 ; Set axis maxima

    ; Endstops
    M574 X1 Y1 S0 ; Set active low endstops

  • Hi FlyingScot, can you try adjusting your M584 to include your extruder as well:
    M584 X0 Y1 Z2:4 E3; 2 Z motors connected to driver outputs 2 & 4

  • Thaks for your quick reply Mike that has sorted it.
    I knew it would be something simple but just could not see it.



  • So you can use both of you're Leadscrews (z-Motors) to level you're Bed?
    Cause i've got the same issue that my Bed goes down a little bit over time.

    Could you explain how the Meshbedleveling and other Stuff work with that?

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