Homing problem 377.08 (edge)

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  • June 21, 2013 at 10:39 am #4211
    mcgyvr
    Member

    Installed 377.08 (edge) firmware and just got my homing/limit switches setup.

    When I do a G28.2 for some reason the machine moves the opposite way of the homing switch for what seems like 2 motion cycles (approx .5″ then another .5″ or so) then switches direction going towards the proper homing switch. Hits the switch..backs off (latch backoff).. then goes the zero backoff distance as it should.

    But WHY the 2 movements in the opposite direction before it goes towards the homing switches??

    June 21, 2013 at 4:04 pm #4215
    mcgyvr
    Member

    Nevermind.. Got it sorted out (so far)

    In TinyG what do you consider an NC switch

    Shows that the wrong setting can cause all sorts of goofy stuff..
    I would expect the wrong switch setting to “instantly” shut the machine down but it seems it can cripple along for a while with the wrong setting till something else happens. weird..

    June 21, 2013 at 4:28 pm #4217
    mcgyvr
    Member

    err..umm not fixed.. First time it homed perfectly..
    Then I ran a small test gcode file and that seemed fine.
    Then I decided to home (G28.2) again and it always does fine with the X axis but then I was having 2 problems.. Seemed like 50% of the time the Y axis would move one direction for about an inch then the other direction for about an inch then just stop and think it was homed (no Y axis switches where ever actuated)

    Then the other times both X and Y would home perfectly but as soon as it was done tiny G would just reset I guess (spindle light on and spindle direction light flashing quickly).. A quick reset and it would be back up for a few minutes then the homing would take it down again.

    ????
    I’m at my wits end now.. This thing was working totally fine before I had the home/limit switches set up.. Now its just “goofy”

    I am using the TinyG APP with a tablet to control do all this.. maybe its the problem as it has been crashing a LOT also.. Might have to drag a laptop back there and see if the problems go away when I’m not using the app

    June 21, 2013 at 9:13 pm #4218
    alden
    Member

    It’s a fact that homing needs to be set up exactly for it to work. And the switches need to be firing exactly and not picking up spurious noise. All I can recommend is that you start from the beginning and enable on thing at a time.

    Disable all axes min and max switches and make sure $st is set NC or NO for your switch config.

    Then enable Xmin (or max, if you are set up that way) for homing only. Not homing + limit. See if you can home X. (g28.2 x0). Remember that if homing does not back all the way off the switch with the zero offset you will have problems.

    Do the same for Y, and then Z. See if you can home them individually, and in combination.

    Only once all homing works go back and enable limits. Or not. See if things still work. Then record your configuration.

    June 24, 2013 at 1:28 pm #4230
    mcgyvr
    Member

    well I rewired all homing/limit switches with shielded 1 pair cables and grounded the shield at one end and now it seems to be working perfectly.
    I’m really surprised that noise effected NC switches but it did.. Half the time it would “think” it was homed and stop before it even got to the switches, the other half of the time it would work just fine.. But now with the shielded cables its working perfectly all the time (so far.. homed it 25 times so far).

    Oh and it sure would be REALLY..REALLY nice going forward if you either switch those pin headers to screw down terminals or at least included a proper mating connector and a handful of crimp contacts with each board. (even just a few 2 position connectors with a 6″ pigtail of wire on each would be fine) It was a pain to scrounge my junk draw till I found some mating connectors that would fit then splice into them.

    June 24, 2013 at 9:04 pm #4231
    alden
    Member

    Glad you got it working, and I appreciate the thoughts. The version 8 board has the homing connections brought out on screw terminals. We do try to advance the board – I guess this is little comfort as you have a v7, but your suggestions are welcome.

    I also did a re-write of the homing pages to make it easier to walk through. See:
    https://github.com/synthetos/TinyG/wiki/Homing-and-Limits-Description-and-Operation
    https://github.com/synthetos/TinyG/wiki/Homing-and-Limits-Setup-and-Troubleshooting

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