Dual X endstops and homing

I need some help understanding configuration settings for dual X setup.

In my initial configuration I tried to replicate my Velleman Vertex K8400 printer that has Tool 0 at the right and Tool 1 at the left.  
My settings were

Right motor was connected to the default X driver and left (X2) motor was connected to 3rd (unused) extruder's driver.

All endstops were tested with M119 and worked correctly.
Both print heads moved correctly, however, during homing, X2 motor would not stop when MIN_HARDWARE_ENDSTOP_X2 was triggered.

Then I decided to swap the motors, made left motor X and right motor X2.
I changes settings to 
The behavior was the same - MAX_HARDWARE_ENDSTOP_X2 would trigger but not stop X2 motor during homing.

Since nether MIN, nor MAX X2 endstops worked, I decided to switch to the default endstops

Surprisingly, this configuration worked just fine, but I left wondering, are these settings correct and if they are, under which conditions MIN and MAX ENSTOP_X2 should be used.

I am attaching my configuration.h file in case somebody wants to have a look at it. 

If you are running Repetier firmware on dual X printer, I'd really appreciate if you share your configuration.h file with me.

P.S. My mainboard is Ultratronics PRO v1.0


  • Looks like zipped attached file got stripped. Here is the link to my Configuration.h on Dropbox https://www.dropbox.com/s/pearvktl8a1d362/Configuration.h?dl=0
  • There is definitely an issue with my configuration, because if Tool 0 is out of home position and I switch to Tool 1 (motor X2), Tool 0 returns to home (X_MIN) and then Tool 1 while already at X_MAX starts pushing further right ignoring X_MAX endstop.

    I tried to enable MAX_HARDWARE_ENDSTOP_X2 and assigned X2_MAX_PIN the ORIG_X_MAX_PIN, while keeping MAX_HARDWARE_ENDSTOP_X enabled, but this did not change anything.

    Need to resolve this a.s.a.p. Any help/advise would be very much appreciated.

  • Forget X2, x min endstop is for tool 0 left and x max endstop for tool 1 right.
  • edited August 2019
    @Repetier THANKS!! 

    I am making progress (just successfully finished the very 1st print with single print-head), but there are still too many unknowns. 

    The issue with X2 trying to to move beyond X2 endstop was resolved by correcting STEPPER_HIGH_DELAY value from 0 to 2. I also changed DOUBLE_STEP_DELAY from 1 to 0. Before making these changes I had inconsistent moving distances along all axes. Now movement is precise and motors became extremely quiet even with regular 8825 steppers. The brand of NEMA17 steppers that I am using is HANPOSE.

    My next question is - can I have Z-probe on X2, or it MUST be on X (i.e. on left print-head) ?

  • Dual-X has no z probe at all. The bed must be physically flat. You can move both extruders same time over bed so they must have same distance to bed all the time.

    If you have a z probe one on left extruder is enough as you would only use it for testing bed leveling is physically ok. If you use it to level software wise firmware will do it I think but right extruder might hit bed then in ditto print mode. Not sure what is when switching extruders - meaning do not know when it adjusts to new height.
  • Sorry, what do you mean by "Dual-X has no z probe at all." ?

    Dual-X printers usually have bigger beds (mine is 40x40cm), which need bed leveling and distortion correction. I understand that nozzles have to be very well leveled, but could you confirm that G32 and G33 will work if I have DUAL_X_AXIS enabled ? I was thinking to have Z-prove attached to one of 2 print-heads and use it the same way I currently do on my other printer with single print head.

  • At least ditto printing requires flat bed. You can not adjust height to 2 or more extruders at the same time.

    I have no dual x at the moment and never had one with z probe so can not say for sure. But I think G32/G33 will work if attached to left extruder (0). The unsure part is what happens if you switch heads that are at different places. Lets say one left requiring -0,5 correction and then you switch to the right requiring 0.5 correction. When will it adjust z for that.
  • My plan is to have left nozzle and z-probe at fixed height and level the bed relative to it. The right nozzle will be adjustable along Z, which should allow me to align it with the left nozzle vertically.

  • You set z offset for right nozzle if it has an offset. On extruder switch the difference will be added on z position. So one z probe is enough. A physical correction should not be needed unless you want ditto printing but then again the bad should be planar or one will be off.
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