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Arduino – Stroommeter DC 20A (ACS712)

Hardware

ACS712 stroommeter module op basis van de ACS712ELC-20A chip. Met deze sensor kun je zowel wissel- als gelijkstroom meten tot maximaal 20A. Geschikt voor het meten van 230V netspanning.

De sensormodule kan 20A positief en negatief meten. De output is 100mV per gemeten Ampere.

ACS712 chip:

Pinout

Pin:	Functie:
+5v	+5V
OUT	DATA
GND	GND

Aansluiten op de Arduino

Sluit de stroommeter module aan volgens onderstaand overzicht:

Arduino Pin:	ACS712 Pin:
+5v	+5V
A0	DATA
GND	GND

Script #1

Sluit de stroommeter module aan zoals hierboven aangegeven.

void setup() {
  Serial.begin(9600); //Start Serial Monitor to display current read value on Serial monitor
}

void loop() {
unsigned int x=0;
float AcsValue=0.0,Samples=0.0,AvgAcs=0.0,AcsValueF=0.0;

  for (int x = 0; x < 150; x++){ //Get 150 samples
  AcsValue = analogRead(A0);     //Read current sensor values   
  Samples = Samples + AcsValue;  //Add samples together
  delay (3); // let ADC settle before next sample 3ms
}
AvgAcs=Samples/150;//Taking Average of Samples

//((AvgAcs * (5.0 / 1024.0)) is converitng the read voltage in 0-5 volts
//2.5 is offset(I assumed that arduino is working on 5v so the viout at no current comes
//out to be 2.5 which is out offset. If your arduino is working on different voltage than 
//you must change the offset according to the input voltage)
//0.100v(100mV) is rise in output voltage when 1A current flows at input
AcsValueF = ((AvgAcs * (5.0 / 1024.0)) - 2.5 )/0.100;

Serial.println(AcsValueF);//Print the read current on Serial monitor
delay(50);
}

void setup() {

Serial.begin(9600); //Start Serial Monitor to display current read value on Serial monitor

}

void loop() {

unsigned int x=0;

float AcsValue=0.0,Samples=0.0,AvgAcs=0.0,AcsValueF=0.0;

for (int x = 0; x < 150; x++){ //Get 150 samples

AcsValue = analogRead(A0); //Read current sensor values

Samples = Samples + AcsValue; //Add samples together

delay (3); // let ADC settle before next sample 3ms

}

AvgAcs=Samples/150;//Taking Average of Samples

//((AvgAcs * (5.0 / 1024.0)) is converitng the read voltage in 0-5 volts

//2.5 is offset(I assumed that arduino is working on 5v so the viout at no current comes

//out to be 2.5 which is out offset. If your arduino is working on different voltage than

//you must change the offset according to the input voltage)

//0.100v(100mV) is rise in output voltage when 1A current flows at input

AcsValueF = ((AvgAcs * (5.0 / 1024.0)) - 2.5 )/0.100;

Serial.println(AcsValueF);//Print the read current on Serial monitor

delay(50);

}

Resultaat seriële monitor:

-0.00
0.00
-0.00
0.35
1.07
2.33
1.85
1.29
-0.00
0.00
1.84
3.64
7.81
0.00

-0.00

0.00

-0.00

0.35

1.07

2.33

1.85

1.29

-0.00

0.00

1.84

3.64

7.81

0.00

Script #2

Dit script maakt geen gemiddelde waarden en komt wat zenuwachtiger over…

Sluit de stroommeter module aan zoals hierboven aangegeven.

int sensorValue;
long current;


void setup() {
  // Start de seriele poort.
  Serial.begin(9600);
}

void loop() {
  // Lees de waarde van de analoge ingang.
  sensorValue = analogRead( 0 );
  // Print de analoge waarde naar de console.
  Serial.print(sensorValue, DEC);
  Serial.print( " = " );
  // Pas het maximale bereik aan.
  if( sensorValue < 103 ) sensorValue = 102;
  else if( sensorValue > 921 ) sensorValue = 922;
  sensorValue -= 102;
  // Calculeer de stroom.
  current = ( ( sensorValue * 49951 ) >> 10 ) - 20000;
  // Print de waarde naar de console.
  Serial.print( (int)current, DEC );
  Serial.println( " mA" );
  // Wacht 100 milliseconden
  delay(100);
}

int sensorValue;

long current;

void setup() {

// Start de seriele poort.

Serial.begin(9600);

}

void loop() {

// Lees de waarde van de analoge ingang.

sensorValue = analogRead( 0 );

// Print de analoge waarde naar de console.

Serial.print(sensorValue, DEC);

Serial.print( " = " );

// Pas het maximale bereik aan.

if( sensorValue < 103 ) sensorValue = 102;

else if( sensorValue > 921 ) sensorValue = 922;

sensorValue -= 102;

// Calculeer de stroom.

current = ( ( sensorValue * 49951 ) >> 10 ) - 20000;

// Print de waarde naar de console.

Serial.print( (int)current, DEC );

Serial.println( " mA" );

// Wacht 100 milliseconden

delay(100);

}

Het resultaat

Bronnen:
microcontroller-project.com