Stepper won't move faster than 25rpm

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junglemap
 
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Joined: Tue Oct 04, 2011 3:03 pm

Stepper won't move faster than 25rpm

Post by junglemap »

Hi, I have an Atmega 328 with MotorShield. I have a 12v 1.8˚ bipolar stepper that works but will not go any faster than 25 rpm. If I try any setSpeed value between 30 and 300 it just goes slower and seems to have a hard time at that.
Any suggestions? is my code missing anything?

Thanks!


#include <AFMotor.h>


AF_Stepper motor(200, 2);


void setup() {
Serial.begin(9600);
Serial.println("Stepper test");

motor.setSpeed(25);

motor.step(10, FORWARD, SINGLE);
motor.release();

}

void loop() {

motor.step(10, FORWARD, SINGLE);



}

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adafruit_support_bill
 
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Re: Stepper won't move faster than 25rpm

Post by adafruit_support_bill »

What are you using for a power supply? How do you have it connected?

junglemap
 
Posts: 8
Joined: Tue Oct 04, 2011 3:03 pm

Re: Stepper won't move faster than 25rpm

Post by junglemap »

Just the USB from the Arduino.. Not enough power? motor is 400 milliamp.

I just tried running it at 40 rpm with the 5v Arduino ext power adapter and it still wont do it. Or does the MotorShield need the power directly?

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adafruit_support_bill
 
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Re: Stepper won't move faster than 25rpm

Post by adafruit_support_bill »

Just the USB from the Arduino
That is 5v@500mA max - not enough voltage or current for your motor. You motor will want to see 12v@400mA on each energized coil. Since generally there will be 2 energized coils at a time while stepping, you will need 12v @800 mA for the motor. It is generally better to use a separate power supply for the motor. Remove the Power Jumper and wire the external supply to the external power terminals on the shield.

junglemap
 
Posts: 8
Joined: Tue Oct 04, 2011 3:03 pm

Re: Stepper won't move faster than 25rpm

Post by junglemap »

Thank You.. It performs much better now with 12v external power, but it still will not go faster than 100 rpm. Is this the limit for this stepper maybe?

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adafruit_support_bill
 
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Re: Stepper won't move faster than 25rpm

Post by adafruit_support_bill »

1.8 degree steppers are designed more for precision than speed.

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