Accelstepper without motor or driver.

[ss_a...@yahoo.co.uk]

I'm trying to debug my arduino sketch with just the arduino since I can't move my steppermotor and driver to my computer easily. Is it possible to do so?

What does "stepper.currentPosition()" if no motor or motor driver is connected?

[Sandy Noble]

Yep you don't need anything connected to run the software - accelstepper does not get any feedback from the driver circuit or the motor.  CurrentPosition() will just be 0.0 (at startup), or whatever you last moved it to otherwise.

sn

On 24 April 2013 23:27, <ss_a...@yahoo.co.uk> wrote:

I'm trying to debug my arduino sketch with just the arduino since I can't move my steppermotor and driver to my computer easily. Is it possible to do so?

What does "stepper.currentPosition()" if no motor or motor driver is connected?

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Sandy Noble

[ss_a...@yahoo.co.uk]

Thanks, that's good to know. This leads me to another question, the code below has some unexpected behaviour. The code prints the current position when "CPos" is received over serial and sets a position to move to with "CPos x" where x is a number. The unexpected behaviour is that currentPosition() does not match the requested position, but only on odd tries. i.e sending "CPos 1", will not work ("CPos" will still report 0), then sending "CPos 2" will work, then sending "CPos 3" will not work, then sending "CPos 1" will work (it has nothing to do with the actual number requested). Asking for a negative number (CPos -1) will result in currentPosition() reporting an ever increasing number. Any ideas why this is happening?

#include <AccelStepper.h> //library for stepper motor

#include <SerialCommand.h> //library for serial commands

#define EDDIR 19      // PIN Easydriver Direction

#define EDSTEP 18     // PIN Easydriver Step

int SMode =8;

int SPosition=0;

int SPitch=5000;

int SDistance=5000;

int SPercent=0;

// Define a stepper and the pins it will use

AccelStepper stepper(AccelStepper::DRIVER, EDSTEP, EDDIR);  //pin 2=step, pin 3=dir

SerialCommand SerialStepper;     // SerialCommand object

void setup() {  

  //Set Pins and baud rate

  Serial.begin(9600);     // open the serial connection usually at 19200bps

  pinMode(EDDIR, OUTPUT); // set pin 12 to output

  pinMode(EDSTEP, OUTPUT); // set pin 12 to output

  

   //Set Serial callback functions

  SerialStepper.addCommand("CPos", StepperPosition);    // Reports or moves motor to position

 }

 

//Stepper Position Callback function used over serial communication, moves to position

void StepperPosition() {

  char *arg;

  arg = SerialStepper.next();     // Get the next argument from the SerialCommand object buffer

  String Cmd=arg;

  if (Cmd != NULL) {               // if a command option was given move to position

     SPercent=Cmd.toInt();

     SPosition= SPercent;//map(SPercent,0,100.0,0,SPitch);

     Serial.print("req:");

     Serial.println(SPosition);

     stepper.moveTo(SPosition);}

   else {

         Serial.print("got:");

         Serial.println(stepper.currentPosition());

   }

}

void loop()

{ 

  SerialStepper.readSerial();

  stepper.run();

} 

 

[Sandy Noble]

Good example - not sure why it's behaving quite that way (perhaps that is a sign of a genuine bug), but I can make it work properly (I think) by explicitly setting a speed in the setup()

  stepper.setMaxSpeed(500);

  stepper.setAcceleration(500);

Maybe that does the trick?  I guess it is stuck on speed 0 otherwise.  But that doesn't explain to me why it does the backwards thing, or the alternate working thing.

sn

} 

 

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Sandy Noble