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IndustryArena Forum > CNC Electronics > Stepper Motors / Drives > Strange problem, not been able to work it out.
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  1. #1
    Join Date
    Oct 2009

    Strange problem, not been able to work it out.

    This one has me puzzled, maybe someone can help?

    I am setting up a new laser engraver, using GRBL, Arduino UNO and CNC shield. The shield has a double Y using cloned A driver.

    I had all the setting done correctly I thought, I could move the machine in all the correct directions and then I came to doing the homing.
    I pressed the homing button and all moved in the right directions, Z was OK, Y gave a problem (not worked that one out yet) and X didn't complete due to Y having the problem. I will check out all the wiring and connections tomorrow when I have more time as it is late here now.
    The strange problem is that after trying to home, the X and Y axis will now only move in a positive direction, no matter which direction I try to move in. The Z will work OK in both directions.
    I reset the program (LaserGRBL) and I even closed the program and restated it again, shut the computer and the machine down and restated them again, but still the problem persists.
    I am at a loss to work out what has happened. I guess I wont get much sleep tonight thinking about it.

  2. #2
    Join Date
    Mar 2015

    Re: Strange problem, not been able to work it out.

    The Arduino Uno has only 1 enable pin. If you connect it to 4 drivers, you could overload this pin (20mA max) . This is however not your problem because than the steppers wouldn't move at all.

    If steppers move in only one direction, I would first check the voltage level on the direction pin at the stepper side. Typically It should be high (4V or more) when moving in one direction and low (1 V or less) when moving in the other direction. If you measure the voltage at the working driver (direction and enable) you have something to compare.
    If this is the problem, there maybe is a lose connection.

    You could swap the not working driver and the working driver. This way you can check if the driver is not the problem.

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