Getting motors to turn.

Home › Forums › gShield › grblShield Support › Getting motors to turn.

Tagged: , , ,

Viewing 8 posts - 1 through 8 (of 8 total)
  • Author
    Posts
  • August 6, 2011 at 10:26 am #1797
    rymanvw
    Member

    Hey guys I just got my Grbl Shield and I am having trouble getting my motor to turn I am able to communicate with my arduino and send commands but it seems like they dont do anything. I am wondering if maybe my power supply is to small I am using a 12v 750mamp power supply for now until i get my bigger one just for testing i have run my stepper before with it and it worked just fine. The blue light on the grbl shield comes on, it doesnt matter which way the stepper pins go in as long as they are in the right order correct? I also did not alter the grbl code at all I just flashed it to my arduino. Is there anything that I have to change? I got it from github. I am running a Arduino Uno. If my serial terminal program is responding and everything that means it is definitely working? Please Help. Thanks

    August 6, 2011 at 4:51 pm #1798
    HadleyRille
    Member

    That should be enough. I tested mine with a similar supply. If the blue light is coming on and you’re able to send commands that get acknowledged with an “ok”, then the problem is in the motors or how they’re connected.

    Are you sure you have the motor connected properly? With a two phase bipolar motor, you should connect one phase to the first two pins and the other to the next two. If you have one phase reversed, the motor might run rough or not turn at all, but you’ll definitely hear it trying.

    It’s also possible the current adjustment pots are turned all the way down. If that were the case, you wouldn’t get any movement either. Issue a long movement command like “G0 X1000” and try turning up the current until the motor starts turning.

    Finding the sweet spot for the current pots for my motors was the trickiest thing for my setup. I don’t have any good way to measure how much current was being delivered, and had to do it by trial and error.

    August 6, 2011 at 7:36 pm #1799
    rymanvw
    Member

    The blue light is coming on and after I send a command it is saying okay. I am as sure as someone can be that my motor is hooked up properly. The LED next to each axis flashes when I manually turn the motor shaft. It does not flash when I send my commands which have been “G0X1000” or “G0X05Y05Z05” or many other combinations with out the “”, all have an ok after them. I have run the motor before and it worked fine. The pots I have adjusted clockwise full open and counter clockwise full closed. Maybe I should reflash my arduino? I really dont know what could be wrong. I dont get a peep out of the motor. I am using the cheap $15 Sparkfun motor and I found this video http://vimeo.com/23756500 and hooked them up the same way and I looked at the datasheet.

    August 7, 2011 at 11:42 am #1800
    rymanvw
    Member

    Okay so here is a new development. First of all the led next to the steppers that is coming on is red not blue like most of the videos i have seen. also after I send a gcode like g0x100 then when I press the reset button the motor nudges a little bit. sometimes it moves one step and sometimes it looks like it tries to move one step. Anyways thats all I’ve come up with so far.

    August 7, 2011 at 11:07 pm #1801
    HadleyRille
    Member

    The led not lighting up during movement sounds like a good indication that the pots aren’t set right. If I set the current pot all the way down it doesn’t light up at all. The board uses PWM to modulate current, and I think you’ve got the duty cycle set all the way down to zero. Back driving the motor causes the led to light up on my board, so that makes me think it’s hooked up right. Try setting the current pot in the middle of the range.

    Don’t worry about the red color of the LED, that’s the color that they’re making them now. The LED lights up when one of the phases of the motor is energized I think. I see mine flash at a rate proportional to the step rate.

    If you’re sure the motor is hooked up correctly and the current pot is not at zero, then I don’t know what the problem could be.

    August 8, 2011 at 11:28 am #1802
    Riley
    Keymaster

    @rymanvw,

    Depending on your motor I would assume that you need a bigger power supply. A good test is just to get a PC power supply and use the 12v (yellow normally) to power the board. This will give MUCH more current then 700mah. Try turning the pot all the way to the left then issue a g0x10000 or something similar and turn the pot up until it moves. Let me know if this works out for ya.

    Riley

    August 8, 2011 at 12:42 pm #1803
    rymanvw
    Member

    Okay I have figured out the problem. After spending the last 4 days messing around with this thing trying every possible thing to get it to work. I went to the home page and started from the beginning. Suddenly I realized that there is a grbl shield patch for the grbl code… I was using the generic grbl code from github. I loaded it up and BAM it worked no problems. Thanks alot for all your guys help. I’m an idiot.

    -Ryman

    August 12, 2011 at 8:13 am #1804
    Riley
    Keymaster

    haha ! OK that works too. Still think your power supply is on the low side. Read alden’s follow up post here:

    http://www.synthetos.com/forums/topic.php?id=231

    Riley

  • Author
    Posts
Viewing 8 posts - 1 through 8 (of 8 total)
  • You must be logged in to reply to this topic.