steppermotor control

chrillz

I have a bipolar stepper motor controller which I try to control with my bs2. (The schematic can be found at http://farm4.static.flickr.com/3195/2910951388_0e05a5c7cc_b.jpg)

It needs to get a high or low signal on the "Direction"-pin (depending on if it is to be driven clockwise or counter clockwise), and also needs to be pulsed at the "Step-pin" with the desired frequency.

Now my problem is that when I try to control the motor with my basic stamp it seems to overstep the motor and it gets really week. I have successfully controlled the stepper-controller via the parallelport on my laptop with a software called Turbo CNC. At a frequency of ca 200 Hz the motor is really strong and runs great!

The basic stamp code that I´ve tried is:

HIGH 1 ' Dir-pin, making the motor run clockwise
freqout 2, 10000, 200 ' Step-pin, should give the motor a pulse with the frequency of 200Hz for 10 seconds right?

This code makes the motor whissle and turn weekly.. Does anybody know what´s wrong?

Post Edited (chrillz) : 1/5/2009 11:30:14 PM GMT

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chrillz

I think Your board is looking for the STEP pattern. something like this
%1100
%0110
%0011
%1001

The rate at which You feed this pattern will control its speed.
I could be wrong. I'm not familiar with Your stepper board.
Take a look at DATA,READ,and SHIFTOUT
Experiment #27 is a good place to start. "StampWorks Manuel"Pg. 150

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PJAllen

FREQOUT doesn't send out a hard digital pulse-form.

In PBASIC Help we read, "FREQOUT generates one or two sine waves using a PWM algorithm."· Not what you're looking for.

So, I think you want to look at using PULSOUT (or PULSOUT nested in a FOR...NEXT or DO...LOOP...UNTIL.)

chrillz

The same steppercontroller can be driven by an Arduino with this code:

found on dev.www.reprap.org/bin/view/Main/Stepper_Motor_Driver_1_2

#define stepPin 4
#define dirPin 5

void setup()
{
  Serial.begin(9600);
  Serial.println("Starting stepper exerciser.");

  pinMode(stepPin, OUTPUT);
  pinMode(dirPin, OUTPUT);

  digitalWrite(dirPin, HIGH);
  digitalWrite(stepPin, LOW);
}

void loop()
{
    int i, j;
    
    for (i=1650; i>=600; i-=150)
    {
      Serial.print("Speed: ");
      Serial.println(i);
      
      for (j=0; j<2000; j++)
      {
        digitalWrite(stepPin, HIGH);
        delayMicroseconds(2);
        digitalWrite(stepPin, LOW);
        delayMicroseconds(i);
      }

      delay(500);
      Serial.println("Switching directions.");
      digitalWrite(dirPin, !digitalRead(dirPin));

      for (j=0; j<2000; j++)
      {
        digitalWrite(stepPin, HIGH);
        delayMicroseconds(2);
        digitalWrite(stepPin, LOW);
        delayMicroseconds(i);
      }

      delay(1000);
      Serial.println("Switching directions."); 
      digitalWrite(dirPin, !digitalRead(dirPin));
  }
}

"The basic way the motor exerciser works is this:
The stepper will take 2000 steps in one direction
The stepper will take 2000 steps in the opposite direction
The speed will increase or decrease."

It seems like the corresponding way to do it in Pbasic, for just running the motor 2000 steps should be like:

counter VAR word
HIGH Dir_Pin
FOR counter = 1 to 2000
HIGH Step_Pin
PAUSE 20
LOW Step_Pin
PAUSE 20
NEXT

Am I in the right direction?

PJAllen

Looks right, too.· A series of PULSOUTs, a series of HIGH/LOWs, same difference.· Give it a whirl.

Post Edit -- Just wanted to add for the others that your L297·generates the Gray Code with each Clock input, as appropriate given the state of the Dir input.

Post Edited (PJ Allen) : 1/6/2009 12:21:54 PM GMT

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chrillz

I see why You want to use the BS2, The other Stamp needs way to much code just to spin a stepper!

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