Home sends print head to rear right

Discussion in 'Calibration, Help, and Troubleshooting' started by Hphock, Feb 16, 2018.

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  1. Hphock

    Hphock Member

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    I finally got around to building my printer and when I click home, the print head moves to the rear right of the big box. I have a dual (non hybrid) with the OctoPrint upgrade.
     
  2. Old_Tafr

    Old_Tafr Well-Known Member

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    When it should be near left it is far right? Near left being the "Home" = 0,0 as printed on the bed.

    Dual as originally supplied sounds very much like mine, including Octoprint.

    Did you follow the build WiKi .........to the letter? such things like setting up the micro switches that sense the position at "home" and stop the X-Carriage at 0,0 .

    As the micro switches sense the "home" position and stop the X-Carriage in the right place what is stopping the carriage at the far right instead of the near left?

    I have a very dim recollection of having to reverse the direction of one movement using Octoprint, could be X or Y direction, unlikely but maybe Z, but the puzzling aspect is what moves the carriage to a certain position (which is?) and then stops it? Without the limit micro switches I assume it would just crash as there is nothing to sense where the X-Carriage is.

    It would seem odd, but not totally impossible that both X and Y motors were working in the opposite direction to that intended. Does the bed move up and trigger the optical sensor correctly?
     
  3. Hphock

    Hphock Member

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    I followed the wiki to a T I think.

    With the printhead in the center of the machine, the bed is still about 3/4 of the way up.

    I turn the unit on, goto the Prepare-Home selection, press the button. The printhead moves to the right rear and crashes into the corner and continues to try to go there. Even if I manually press both micro switches, nothing happens.
     
  4. Ephemeris

    Ephemeris Well-Known Member

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    Let's double check polarity:

    Turn the BigBox off
    Manually drag the carriage to the middle of print range
    Power up

    Use the front panel controls to move +X 10 mm
    Did it move 10 mm to the right as seen from the front? (that's what it should do)

    Use the front panel controls to move -X 10 mm
    Did it move 10 mm to the left as seen from the front? (that's what it should do)

    Use the front panel controls to move +Y 10 mm
    Did it move 10 mm away from you as seen from the front? (that's what it should do)

    Use the front panel controls to move -Y 10 mm
    Did it move 10 mm towards you as seen from the front? (that's what it should do)

    Report back!

    We can definitely solve this :)
     
  5. Old_Tafr

    Old_Tafr Well-Known Member

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    This is the bit I was after; your original post implied that the on requesting it "home" it homed back right , not crashed and tried to break free :)

    As @Ephemeris suggests it sounds like both X & Y motor controls are reversed. BUT...... You say nothing happens (like movement stops) when you manually hit the micro-switches?

    A lot of people including me have the mains switch or even a kill switch (there is mod somewhere to add a kill switch to the front panel) close at hand to cope with situations like this.

    Out of interest what happens when you manually move the bed? i.e. Z As both Z motors are on the same Rumba board controller the bed may go in the wrong direction. If one was reversed and one not, then it would rip the bed apart in a quite spectacular way bending rods etc.

    PS. With the original firmware on the Rumba board there is a problem with moving the bed from the front panel, turn the control knob slowly and not too many turns at a time otherwise you may find the bed keeps on going, usually in the down direction ! Another need for the kill switch being close at hand!

    A similar head crash into the dump bucket occurs with the original firmware, when you stop a print and start another without resetting everything.
     
  6. Hphock

    Hphock Member

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    I manually moved the carriage to the middle of print range
    Power up

    Use the front panel controls to move +X 10 mm and selected 10mm

    The controls only let me select increments of +40mm at a time and only in the positive direction (per the controls)

    The carriage moved 40mm to the left...

    I could rotate the control back to 000.0 but not -10, so the carriage would not go past the start point.

    Using the front panel controls to move +Y 10 mm

    Again, the controls only let me select increments of +40mm at a time and only in the positive direction (per the controls)

    The carriage moved 40mm to the rear...

    Use the front panel controls to move -Y 10 mm
    I could rotate the control back to 000.0 but not -10, so the carriage would not go past the start point.

    When the carriage was 80 to the left and 80 to the rear, I moved X from +80mm to +40 so the carriage would move to the right. When it was moving to the right, I triggered the microswitch and it stopped immediately, so the switch works.

    I verified the Y my having the carriage move forward and triggered the microswitch and it stopped immediately.

    So some how it would appear that I need to reverse the X and Y steppers. (flip wires? Octoprint setting? Other setting?)

    Thanks!

     
  7. Ephemeris

    Ephemeris Well-Known Member

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    That's great news because it's easy to fix! Turn power off. When a stepper is running backwards, all you need to to do is find the connector for the backwards running stepper where it plugs into the Rumba, and flip it 180 degrees, then plug it back into the board. Manually reposition the carriage to the middle of the print area, power up, and run your test again.
     
  8. Hphock

    Hphock Member

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    I cannot find where to move the Z axis on the control panel. I am only given X and Y options under the prepare menu.


     
  9. Ephemeris

    Ephemeris Well-Known Member

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    Marlin's organization is a bit whacky to me. I switched to a DuetWiFi board a while back and never looked back. Take a look at THIS.
     
  10. Old_Tafr

    Old_Tafr Well-Known Member

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    Hmmmmmmmmm it's there, i use it all the time, e.g. when a print fails or is finished. I will have a look later today.
     
  11. Hphock

    Hphock Member

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    Latest attempt:
    I manually moved the carriage to the middle of print range
    Power up

    Use the front panel controls to move +X 10 mm and selected 10mm

    The controls only let me select increments of +40mm at a time and only in the positive direction (per the controls)

    The carriage moved 40mm to the right

    I could rotate the control back to 000.0 but not -10, so the carriage would not go past the start point.

    Using the front panel controls to move +Y 10 mm

    Again, the controls only let me select increments of +40mm at a time and only in the positive direction (per the controls)

    The carriage moved 40mm to the front

    All seemed to be great so I tried Prepare-Home and the printhead crashed to the right rear.
     
  12. Ephemeris

    Ephemeris Well-Known Member

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    Are you saying it moved in the correct direction but four times as far?
     
  13. Hphock

    Hphock Member

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  14. Ephemeris

    Ephemeris Well-Known Member

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    This is either a firmware issue or a jumper issue on the stepper drivers.

    You bought the BigBox with the stock Rumba controller with the A4988 stepper driver boards already installed?

    If so it it may be that the jumpers that control the stepper driver are in wrong.

    Read this

    http://www.reprap.org/wiki/RUMBA#with_A4988

    My guess is you have it set to moving using full steps instead of 1/4 steps.

    Quick update/warning:
    Do not remove or reinstall the A4988 drivers except when everything is POWERED OFF!
    When reinstalling an A4988, make sure you insert it in the correct/original orientation!!!
     
    #14 Ephemeris, Feb 20, 2018
    Last edited: Feb 20, 2018
  15. Hphock

    Hphock Member

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    I looked at the jumpers but not sure is all 3 under the stepper board need to be there or not. I did not modify the board and the stepper drivers were installed. I might not be clear when I said it was moving 40mm. I go to prepare: Move Axis: 10mm: X axis and then I turn the dial on the LCD, the values shown on the LCD are +40,+80,+120 etc.
     
  16. A Dragon In A Pie Costume

    A Dragon In A Pie Costume Well-Known Member

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    check if your X and Y cables are reversed, or if you are an owner of the 1.0 bb check if the cable polarities are correct?
     
  17. Hphock

    Hphock Member

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    Beem under the weather the last 24+ hours so I'll get back to this when I am up and about. Cheers
     

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