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X-Home has moved to the right?

Discussion in 'Troubleshooting' started by William, Apr 4, 2014.

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  1. William

    William New Member

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    Well I'm back. I jumped the connection on the Ramps board to simulate a end stop, but it did not stop the X from going left. I took off the LCD controller and reloaded applicable firmware, that was not the problem. So, I've posted a video on Youtube showing the behavior. Please take a look. Thanks, as always.
     
    #21 William, Apr 7, 2014
  2. SteveC

    SteveC Well-Known Member

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    Everything is on the wiki: http://reprap.org/wiki/RAMPS_1.4
    http://reprap.org/mediawiki/images/c/ca/Arduinomega1-4connectors.png
    http://reprap.org/mediawiki/images/f/f6/RAMPS1.4schematic.png
    http://reprap.org/mediawiki/images/4/49/Ramps_v1.4_shield_bothsides.png

    I looked at your video and yes that is really strange. I'll think about it but nothing comes to mind to explain that.

    Shot in the dark, but if you are familiar with the Arduino you could load a simple test that tests the port bit for the X-limit input. Looks like the end stop microswitch toggles between 5V and GND. So just set D2 for Xmin (or is it D1 for Xmax?) as an input and output it the the LED at D13.

    void setup() {
    pinMode(13, OUTPUT);
    pinMode(2, INPUT); //or D1/
    }
    void loop(){
    digitalWrite(13, digitalRead(2));
    }
     
    #22 SteveC, Apr 7, 2014
  3. William

    William New Member

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    Thanks Steve. I should be able to do that test, but later this evening.
     
    #23 William, Apr 7, 2014
  4. Ziggy

    Ziggy Moderator
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    It is possible to reproduce the X Axis behaviour you are seeing on a perfectly working Robo by holding the X Axis home switch closed.

    With the X Axis switch held closed, the carriage moves left/right under Repetier manual control no problem. But when you try to home the X, the carriage just moves slightly to the right.

    So I expect you could

    a) Have a faulty microswitch (ie permanently or intermittently open circuit)
    b) The X Axis switch connections are incorrectly connected.
    c) Faulty digital input port on the Arduino
    d) Wrong X Axis home switch parameter setting in the Marlin firmware

    My money is on (b) but...

    First thing I would do is remove the connections from the X Axis home switch, short them together and try homing the X carriage from the furtherest point on the right side. Note: you need to be really quick on the emergency stop button with this because the X carriage could take off hard to the left. If the carriage tries to home then it points to a faulty switch.

    Second is to short the X Axis switch connections together directly on the Ramps board (leaving the switch connections off ). Try the same X Axis home procedure - again be quick on the emergency stop button. If the carriage tries to home you have faulty wiring.

    If neither of these identify your problem there is an issue with Ramps digital input or the firmware settings. But let's prove the problem is not a or b first.
     
    #24 Ziggy, Apr 7, 2014
    2 people like this.
  5. William

    William New Member

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    Thanks Ziggy. I'll try that later when I have more time.
     
    #25 William, Apr 7, 2014
  6. Mike Kelly

    Mike Kelly Volunteer

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    Ok without a doubt in my mind your switch is bad or has an loose connection in the line.

    When the printer homes it actually checks home twice. Once to stop, backs off 5mm, then touches home again.

    What you're seeing is the printer sends a home command, immediately sees it "hit home" because the switch is failed open. It then does it's recheck by moving right 5mm, then tries to home again immediately seeing "home" state because again the faulty switch.

    This is your problem I guarantee it. Find the loose cable and resolder it or ask team robo to send you a new one. Check on the solder points on the switch itself. Give them a good hard tug, if they pull off they're faulty and you need to resolder. I've had to do this a number of times.
     
    #26 Mike Kelly, Apr 7, 2014
  7. William

    William New Member

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    I pulled gently on the red wire coming out of the switch and it pulled right out of the white insulation going into the switch. I had test the other end; I guess the switch side looked really solid and just thought it was OK. That should do it. Thanks!!
     
    #27 William, Apr 7, 2014
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