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dual extruder robo r 1+

Discussion in 'Projects' started by allen33, Mar 1, 2017.

  1. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    No, just be consistent with it between the two extruders to avoid any ground loop (remotely possible, but avoid it anyway).
    As far as the heaters are concerned there is no polarity.
     
  2. allen33

    allen33 Member

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    Thanks
     
  3. allen33

    allen33 Member

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    does anyone know why I would have this problem with the temperature?
     

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  4. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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  5. allen33

    allen33 Member

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    I dont mean to sound like an idiot but what is MIN?
     
  6. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    0 degrees C

    Looks like yours is reading MAX (somewhere near 500c) so probably an open circuit to the thermistor
     
  7. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    However we use NTC (negative temperature coefficient) thermistors -- so I can never remember which is MAX and which is MIN for certain, but ... if the temperature reading is locked at zero or near 500 c then either shorted or open-circuit on the thermistor is the problem. Easy to do.. they are fragile.
     
  8. allen33

    allen33 Member

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    how do you fix an open circuit for a thermistor? is it really as easy as making sure everything is plugged in?
     
  9. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Yes, open circuit means that one of the wires to the thermistor is not connected or broken. A short circuit means that the wires are crossed somewhere. One gives you a minimum temperature reading and the other a maximum reading. Either way you need to trace the wiring from the RAMPS to the thermistor and find the problem.
     
  10. allen33

    allen33 Member

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    Ok. I will try that. thanks for your help again.
     
  11. allen33

    allen33 Member

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  12. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Well, I am not familiar with that link, but other than the dual-extruder specific stuff there is nothing specific to the thermistor reading bogus that requires a firmware change. You (obviously) have to define the the thermistor type in the firmware, but that being wrong would not make the reading wildly incorrect, just not accurate.
     
  13. allen33

    allen33 Member

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    from one firmware change to the thermistor it seems like everything is normal again
     
  14. allen33

    allen33 Member

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    In matter control when I go to access EEPROM to calibrate the extruders I could only find the steps per mm for one extruder how to I get access to the other one?
     
  15. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    They are both on the same line... (this is from the marlin github example)

    #define DEFAULT_AXIS_STEPS_PER_UNIT {80,80,3200,625,625,625,625} // X, Y, Z, E0, E1, E2, E3
     
  16. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    All of the ones after E0 are ... optional.
    And I don't know MC very well, but unless you have it set in the firmware (via CONFIGURATION.H) is it not accessible via the MC firmware editor... at least as far as I KNOW (which isn't much on matter control). For all I know it may not be accessible in MC regardless.
     
  17. allen33

    allen33 Member

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    So I have ran into another problem... while calibrating the extruders I seem to be +or- 5mm every time I can't quite get it perfect any suggestions?
     
  18. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    You need to be a lot more clear about what (exactly) you are doing "calibrating the extruders"
    Not sure what you mean by that, when I built a dual extruder machine the only tricky part was making sure that the Z offset for both extruders was identical. That accomplished by using identical extruders. Same brand same model.

    If you mean that they are not exactly extruding (for example) 100mm when told to extrude 100mm that is adjusted in the firmware as discussed and you should be able to get that really close. If it is off 5mm from a 100 though ... I would not be extremely concerned.
     
    #38 mark tomlinson, May 8, 2017
    Last edited: May 8, 2017
  19. allen33

    allen33 Member

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    so basically I'm trying to calibrate steps per mm of both extruders
     
  20. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    eSteps? I guess that is what you mean, well you know how to do that I assume :)
    If you get it within 5mm (over a range of 100) I wouldn't worry about it. But if you really want to get it perfect you may need to tune the stepper drivers that are running the extruder steppers.
     

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