Interfacing KL23H251 motor using NJM2670D2-ND

Forum 2005-2010 (read only) Hardware Interfacing
1

Hi Everyone,

This is my very first electronics project and so please bare with me for this naïve question.

I have attached an arduino to a H-Bridge using the Bipolar Stepper Motor circuit configuration (Data sheet: (http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=NJM2670D2-ND). I tested the circuit by attaching LEDs to the output pins using the following arduino program:

void loop() {
digitalWrite(enablePin, HIGH); // sets the Enable ON
digitalWrite(intA1B1Pin, HIGH); // Send HIGH to A1 & B1 pins
digitalWrite(intA2B2Pin, LOW); // Send LOW to A2 & B2 pins
delay(2000);
digitalWrite(enablePin, HIGH);
digitalWrite(intA1B1Pin, LOW);
digitalWrite(intA2B2Pin, LOW);
delay(2000); // waits for a two seconds
}

The LEDs connected to OUTA1 & OUTB1 glow once every two seconds. As far as I understand my circuit matches the data sheet and behaves exactly as it is supposed to.

Now, I connect the KL23H251-24-8B stepper motor to the output pins.
Series connection:

Green goes to OUTA1
Yellow/Red are tied together
Blue goes to OUTA2

White goes to OUTB1
Orange/Black are tied together
Brown goes to OUTB2

I am using an external DC power supply (HY3005) that provides an adjustable voltage (set to 9V initially).

I then change my arduino program to the following and start the execution:
void loop() {
digitalWrite(enablePin, HIGH); // sets the Enable ON
digitalWrite(intA1B1Pin, HIGH); // Send HIGH to A1 & B1 pins
digitalWrite(intA2B2Pin, LOW); // Send LOW to A2 & B2 pins
delay(10);
digitalWrite(enablePin, HIGH);
digitalWrite(intA1B1Pin, LOW);
digitalWrite(intA2B2Pin, LOW);
delay(2000); // waits for a two seconds
}

I hear a faint buzz inside the motor. The motor won't start. I tried with different connections and voltages. I noticed that the motor buzzes loudly for different settings. The H-Bridge is getting heated up if I increase the delay when the intA1B1is HIGH.

I checked all the voltages across the Vcc & ground and looks like everything is just fine... Its just that the motor doesn't work...??? It a brand new one....

Whats wrong with my setup Any suggestions?? Thanks.

2

I had a similar "buzzing" experience with a unipolar stepper and in my case it was because i hooked up the wires from the stepper in the wrong sequence. But i guess you doublechecked that already.

Are you sure you have the right voltage for the motor ?

Can your powersupply deliver the required current ?

Sometimes the ground from the motor powersupply has to be connected to the Arduino ground.

3

Sometimes the ground from the motor powersupply has to be connected to the Arduino ground.

That would be always. :wink:
Its a good habit to do even in isolated circuits.

4

I checked the circuits carefully. I somehow can't upload the circuit diagram. Please look at the first figure on pg5: I checked the circuits carefully. I somehow can't upload the circuit diagram. Please look at the first figure on pg5. (http://www.keyen.com.tw/product/NJRC/NJM2670.pdf)

Are you sure you have the right voltage for the motor ?
Can your powersupply deliver the required current ?
Yes, I connected the Vmm ground to the common ground. My external power supply is this: http://www.elexp.com/tst_3003.htm . I set the voltage to 9V? and increased it to even 30V. When I executed the test, I can see about 1.5AMPs on the voltage supply's current output. Unfortunately, all this current is being used to heat up the H-Bridge instead of turning the motor. The power supply is brand new (I got it at Amazon).

I wanted to try this circuit on a bread board, but I hesitated to do so because the motor can end up drawing more than 1Amp, which is more than what a typical bread board can handle. So, I checked my circuit with LEDs on a breadboard. The LEDs connected to OUTA1 & OUTB1 glowed once every 2 secs. I alternated the test with OUTA2 & OUTB2 and everything seemed fine.

I thought that this is good enough to go to the next step. I then soldered a prototype board and rechecked the circuit again with LEDs. Looked like everything just worked fine. Now I connected the motor only to realize that everything fell apart.

When I checked the voltage across the Chip pins, I see 5V on Vcc, and 9V on OUT1A & OUT1B? (off course whenever the intA1B1Pin is set to HIGH).

The problem is that the chip is getting heated up if I set intA1B1 HIGH for a long time. So, I tried with intA1B1 HIGH for 10ms with a LOW for another 2sec. This takes care of the heating problem, but the motor doesn't turn.

This makes me sure that my arduino – Hbridge circuit is fine but my motor connections are wrong? but I tried all permutations and combinations of the motors? it just doesn't work! Weird...

5

I guess I got it working. :slight_smile:

Use the following sketch if anyone wants to interface with NJM2670

int enablePin  = 4;    // select the input pin for the potentiometer
int intA1 = 3;
int intA2 = 4;
int enA  = 5;
int intB1 = 6;
int intB2 = 7;
int enB  = 8;
int delayTime=20;
int slow = 0;

void setup() {
  pinMode(enA, OUTPUT);  // declare the ledPin as an OUTPUT
  pinMode(intA1, OUTPUT);  // declare the ledPin as an OUTPUT
  pinMode(intA2, OUTPUT);  // declare the ledPin as an OUTPUT
  pinMode(enB, OUTPUT);  // declare the ledPin as an OUTPUT
  pinMode(intB1, OUTPUT);  // declare the ledPin as an OUTPUT
  pinMode(intB2, OUTPUT);  // declare the ledPin as an OUTPUT
  shutdown();
}
void shutdown()
{
  digitalWrite(intA1, LOW);    // sets the LED off
  digitalWrite(intA2, LOW);    // sets the LED off
  digitalWrite(intB1, LOW);    // sets the LED off
  digitalWrite(intB2, LOW);    // sets the LED off
  digitalWrite(enA, LOW);    // sets the LED off
  digitalWrite(enB, LOW);    // sets the LED off

}

void loop() {
   //Step 1 Coil A +
  digitalWrite(intA1, LOW);    // sets the LED off
  digitalWrite(intA2, HIGH);    // sets the LED off
  digitalWrite(intB1, LOW);    // sets the LED off
  digitalWrite(intB2, LOW);    // sets the LED off
  digitalWrite(enA, HIGH);    // sets the LED off
  digitalWrite(enB, LOW);    // sets the LED off
  delay(delayTime);
  shutdown();
   delay(slow);
   
  //Step 2 Coil B +
  digitalWrite(intA1, LOW);    // sets the LED off
  digitalWrite(intA2, LOW);    // sets the LED off
  digitalWrite(intB1, LOW);    // sets the LED off
  digitalWrite(intB2, HIGH);    // sets the LED off
  digitalWrite(enA, LOW);    // sets the LED off
  digitalWrite(enB, HIGH);    // sets the LED off
  delay(delayTime);
  shutdown();
   delay(slow); 
  //Step 3 Coil A -
  digitalWrite(intA1, HIGH);    // sets the LED off
  digitalWrite(intA2, LOW);    // sets the LED off
  digitalWrite(intB1, LOW);    // sets the LED off
  digitalWrite(intB2, LOW);    // sets the LED off
  digitalWrite(enA, HIGH);    // sets the LED off
  digitalWrite(enB, LOW);    // sets the LED off
  delay(delayTime);
   shutdown();
   delay(slow);
   
  //Step 4 Coil B -
  digitalWrite(intA1, LOW);    // sets the LED off
  digitalWrite(intA2, LOW);    // sets the LED off
  digitalWrite(intB1, HIGH);    // sets the LED off
  digitalWrite(intB2, LOW);    // sets the LED off
  digitalWrite(enA, LOW);    // sets the LED off
  digitalWrite(enB, HIGH);    // sets the LED off
  delay(delayTime);
  shutdown();
   delay(slow);
}