Pololu Motor driver speed controlnot working

Projects Programming
1

HI,

I'm finishing up my Fan motor controller and I have the current parameters set.

I'm using a Pololu Motor driver VNH5019
Fan unit is Brushed 12vdc max 6amps
Only running M1 as the motor output.

  1. Arduino turns on the VNH5019 shield via LDR at >400 ( ie sunny day)
  2. The Motor shield runs for 1 hour on and 1 hour off to allow fan to stand down ( I have this set at 1 min to test for now so I don't wait round for 1 hour)
  3. Speed to run fan at 50% of rated fan output.

However,

I cant get the motor to run via the PWM to less than 100% forward speed, I'm keen to run it in all cases at 50% that of full speed if makes sense.

All the code works well and functions all work except that of the md.setM1Speed(200) function.

I can see why this is not working, Have I missed some code to call md.setM1Speed(200) function??

My current code looks like this:

#include "DualVNH5019MotorShield.h"

const long oneSecond = 1000; // a second is a thousand milliseconds
const long oneMinute = oneSecond * 60;
const long oneHour = oneMinute * 60;
const long oneDay = oneHour * 24;

DualVNH5019MotorShield md;

int sensorPin = A0; // select the input pin for LDR//
int sensorValue = 0; // variable to store the value coming from the sensor
/*int analogPin = 6;
int val = 0; */

void setup()
{
Serial.begin(115200);
Serial.println("Dual VNH5019 Motor Shield");
md.init();
pinMode(6, OUTPUT); //pin connected to the VNH5019 M1EN//
}

void loop()
{
// read the value from the sensor:
sensorValue = analogRead(sensorPin);
Serial.print("LDR light reading of ");
Serial.println(sensorValue); //prints the values coming from the sensor on the screen

if(sensorValue < 400) //setting LDR threshold value//
digitalWrite(6,LOW); //turn VNH5019 off//

else digitalWrite(6,HIGH); //turn VNH5019 ON//
delay(2);

//motor startup//
Serial.println("M1 Speed 50% Forward");// 400 is 100%//
md.setM1Speed(200);
Serial.print("M1 current: ");
Serial.println(md.getM1CurrentMilliamps());

Serial.print("Delay: ");
Serial.println("delay for 1 min");
delay(oneMinute);

// read the value from the sensor:
sensorValue = analogRead(sensorPin);
Serial.print("LDR light reading of ");
Serial.println(sensorValue); //prints the values coming from the sensor on the screen

if(sensorValue < 400) //setting LDR threshold value
digitalWrite(6,LOW); //turn VNH5019 OFF//

else digitalWrite(6,HIGH); //turn VNH5019 ON//
delay(2);

//motor shutdown//
Serial.println("M1 Speed 0% stopped");
md.setM1Speed(0);
Serial.print("M1 current: ");
Serial.println(md.getM1CurrentMilliamps());

Serial.print("Delay: ");
Serial.println("delay for 1 min");
delay(oneMinute);

}

2

Do the examples with the library work as expected ?

3

NO, Ive tested with the demo code from Pololu but does nor work either.

cheers
jas

4

Ive tested with the demo code from Pololu but does nor work either.

Time to carefully check the wiring.

How is the motor powered ?

5

HI Bob,

The arduino is powered from the VNH5019 shield jumper and the Pololu shield has 12vdc input.

Currently I have the shield running positive out of M1 and Negative back into shield neg.

Image attached.

The thing I didnt try with the demo code is Positive on M1 and neg on M2 for motor 1.

I'll try this and come back to forum.

12vdc brushed fan

IMG_20170403_114439.jpg
IMG_20170403_114439.jpg1000×1333 332 KB

6

HI,

Well simple fix and thanks for you help, I didnt think to look at connections and I have the:

Positive into M1A
Negative into Ground from shield

Now have the:

Positive into M1A
Neg into M1B

Now the code fully works and speed control.

Thanks to everyone for the support.

jason