LMD298 doesnt drive till analogpin has no voltage

Projects Programming
1

Hi,

i have following code:

#include <Arduino.h>

#define DIRA 6
#define DIRB 5

uint8_t tst = 0;
int EcuMdMinusPIN = A1;
int ECUMDMinus; //Signal-close

void setup()
{
  Serial.begin(9600);

  pinMode(DIRA, OUTPUT);
  pinMode(DIRB, OUTPUT);

  digitalWrite(DIRA, LOW);
  digitalWrite(DIRB, LOW);

  digitalWrite(DIRA, HIGH);
  digitalWrite(DIRB, LOW);

  delay(1000);
  digitalWrite(DIRA, LOW);
  digitalWrite(DIRB, HIGH);
  delay(1000);

  digitalWrite(DIRA, LOW);
  digitalWrite(DIRB, LOW);
}

void loop()
{
  ECUMDMinus = analogRead(EcuMdMinusPIN);
  if (ECUMDMinus > 100)
  {
    if (!tst)
    {
      tst = true;
      Serial.println("Motor soll fahren");
      digitalWrite(DIRA, HIGH);
      digitalWrite(DIRB, LOW);
    }
  }
}

In the setup i use a LMD298 to drive a electric motor first to the left, than to the right. In the loop function i wait till i have voltage on ECUMDMinus. If i have voltage on it i set the LMD and the electric motor drives to the right.

Now to the behavior i didn´t unterstand:

If i have voltage on ECUMDMinus i print on Serial "Motor soll fahren" but the electric motor doens´t turn to a direction. If I release the Voltage on ECUMDMinus the electric motor starts to turn.

Why is that so? In my understanding the motor should start in that moment i have voltage on ECUMDMinus ?!

2

To get help you should:

Read the forum guidelines.
Post your code.
Use the IDE autoformat tool (ctrl-t or Tools, Auto format) before posting code in code tags.

Post a schematic of the project.
Post data sheets for all major components.

3

Try printing the value of ECUMDMinus to serial monitor after it is read. Maybe you will be surprised by the values.

4

Difficult to say without a schematic, but understand that there is always a voltage on ECUMDMinus, there is always a voltage on everything, that's basic physics. Whether the voltage is what you think it is is a different question. With that in mind what do you really mean by there being and not being a voltage on ECUMDMinus?

5

Solved.

6

Thanks.

Sorry, don't know the answer to your question, but having a schematic will most likely help someone else to help you.

7

I found out that i have a hardware problem here.

I will check this

8

This topic was automatically closed 120 days after the last reply. New replies are no longer allowed.