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Stepper Motor Behavior

Former Member

I have an Arduino Duo interfaced to a Mercury Stepper Motor via an EasyStepper card.

 

My program is simple. It has the motor exercising from 0 steps to 4668 steps, back to 0 and then to -4668 steps. It seems to work fine, except that the motor always seems to do a 2334 step move before starting the move.

 

I am new to the site, and have the sketch for post, but wondered if anyone has any advice.

 

 

  • 0

    Hi Stephen,

     

    I'm not sure I understand the issue 100%. Also, how quickly are you stepping? Any delays in your code?

    You'd probably need to post the code.

  • 0 in reply to shabaz

    Here is the code:

     

    This is an exercise routing to basically move the device back and forth over a 270 degree movement. The stepper motor I am using needs 200 steps for a complete rotation (1.8 degrees per step). Through gear reduction, this amounts to 9336 steps per rotation of the device being stepped.

     

    My goal is to be able to start from a known point, and move the device to preselected locations with input through other arduino pins. It seems to do a +2334 step move before starting the loop. I wrote this exercise routine as a starting point, but am perplexed at this unrequested move from the start.

     

     

    #include <AccelStepper.h>

    // Define a stepper and the pins it will use

     

    AccelStepper stepper(1, 3, 2);

     

    int pos = 7002;

     

    void setup()

    {

     

        stepper.setMaxSpeed(500);

        stepper.setAcceleration(200);

        Serial.begin(9600);

        Serial.println("Ready");

         Serial.println("Currently at ");

         Serial.println(stepper.currentPosition());

     

    }

     

    void loop()

    {

      if (stepper.distanceToGo() == 0)

      

       {

         Serial.println("Currently at ");

         Serial.println(stepper.currentPosition());

         delay(500);

         pos = -pos;

         Serial.println("Moving to ");

         Serial.println(pos);

       }

     

      stepper.runToNewPosition(pos);

    }

  • 0 in reply to Former Member

    Hi Stephen,

     

    I'm afraid I can't see what could be the issue. What happens if you comment out all the content in loop()?

  • 0 in reply to shabaz

    Commenting out the loop was a good suggestion. When gone, nothing at all moved - as expected - but it caused me to rethink and simplify the sketch. I simpled it down and now everthing works as directed by the sketch. I really don't see a lot of difference in the exectuable statements, but it works now. I'll research the cause later.

     

    Thanks for the idea.

     

    Steve