(SKU:SEN0214) 20A电流传感器

20A电流传感器

简介

这款20A电流传感器模块采用ACS712霍尔电流感应芯片，具有量程大、简单易用、体积小巧、精度较高、无需焊接等特点，可用于直流电流和交流电流的测量。在设计上做了高压隔离，确保使用的安全性。模块输出的电压线性对应测量电流，且接口为Gravity 3P接口，即插即用。

该模块不建议在20A及以上的大电流情况下长时间工作。在测量高压电时，请注意安全。

产品参数

供电电压：+5.0V
测量范围：0 ~ ±20A DC， 0 ~ 17A(RMS) AC
测量容忍电压：220V AC，311V DC
相对误差：±3%
尺寸：39mm * 22mm *17mm
接口：Gravity PH2.0-3P
重量：18g

引脚说明

20A电流传感器引脚对应表
标号	名称	功能描述
1	GND	GND
2	VCC	5V电压输入
3	信号线	信号输出
4	测量电流输入+	测量电流输入端
5	测量电流输出-	测量电流输出端

使用教程

本教程演示如何使用这款20A电流传感器。

准备

硬件
- Arduino UNO x1
- 20A电流传感器模块 x1
- Gravity PH2.0-3P接线 x1
- 杜邦线、导线若干
软件
- Arduino IDE 版本1.6.8 点击下载Arduino IDE

接线图

样例代码

/***********************************************************
 This sample code shows how to use 20A current sensor module.
 
 Created 2016-4-26
 By Bernie Chen <bernie.chen@dfrobot.com>
 
 GNU Lesser General Public License.
 See <http://www.gnu.org/licenses/> for details.
 All above must be included in any redistribution
 ****************************************************/

/***********Notice and Trouble shooting***************
 1.Connection and Diagram can be found here, http://wiki.dfrobot.com.cn/index.php?title=(SKU:SEN0214)_20A%E7%94%B5%E6%B5%81%E4%BC%A0%E6%84%9F%E5%99%A8#.E6.A0.B7.E4.BE.8B.E4.BB.A3.E7.A0.81
 2.This code is tested on Arduino Uno.
 ****************************************************/

const int currentSensorPin = A0; //define sensor pin
const int mVperAmp = 100; // use 185 for 5A Module, and 66 for 30A Module
float Vref  = 0; //read your Vcc voltage,typical voltage should be 5000mV(5.0V)

void setup()
{
    Serial.begin(115200);
    Vref = readVref(); //read the reference votage(default:VCC)
}

void loop()
{
    /*If you are reading DC current, use this function to read DC current. Then uncomment the AC function.*/
    float CurrentValue =  readDCCurrent(currentSensorPin); 	
    /*If you are reading AC current, use this function to read AC current,it returns the RMS. Then uncomment the DC function.*/
    //float CurrentValue =  readACCurrent(currentSensorPin); 
    Serial.println(CurrentValue);
    delay(500);
}

/*read DC Current Value*/
float readDCCurrent(int Pin)
{
    int analogValueArray[31];
    for(int index=0;index<31;index++)
    {
      analogValueArray[index]=analogRead(Pin);
    }
    int i,j,tempValue;
    for (j = 0; j < 31 - 1; j ++)
    {
        for (i = 0; i < 31 - 1 - j; i ++)
        {
            if (analogValueArray[i] > analogValueArray[i + 1])
            {
                tempValue = analogValueArray[i];
                analogValueArray[i] = analogValueArray[i + 1];
                analogValueArray[i + 1] = tempValue;
            }
        }
    }
    float medianValue = analogValueArray[(31 - 1) / 2];
    float DCCurrentValue = (medianValue / 1024.0 * Vref - Vref / 2.0) / mVperAmp;  //Sensitivity:100mV/A, 0A @ Vcc/2
    return DCCurrentValue;
}

/*read AC Current Value and return the RMS*/
float readACCurrent(int Pin)
{ 
   int analogValue;             //analog value read from the sensor output pin
   int maxValue = 0;            // store max value
   int minValue = 1024;         // store min value 
   unsigned long start_time = millis();
   while((millis()-start_time) < 200) //sample for 0.2s
   {
       analogValue = analogRead(Pin);
       if (analogValue > maxValue) 
       {
           maxValue = analogValue;
       }
       if (analogValue < minValue) 
       {
           minValue = analogValue;
       }
   }
   float Vpp = (maxValue - minValue) * Vref / 1024.0;
   float Vrms = Vpp / 2.0 * 0.707 / mVperAmp; //Vpp -> Vrms
   return Vrms;
}

/*read reference voltage*/
long readVref()
{
    long result;
#if defined(__AVR_ATmega168__) || defined(__AVR_ATmega328__) || defined (__AVR_ATmega328P__)
    ADMUX = _BV(REFS0) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1);
#elif defined(__AVR_ATmega32U4__) || defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__) || defined(__AVR_AT90USB1286__)
    ADMUX = _BV(REFS0) | _BV(MUX4) | _BV(MUX3) | _BV(MUX2) | _BV(MUX1);
    ADCSRB &= ~_BV(MUX5);   // Without this the function always returns -1 on the ATmega2560 http://openenergymonitor.org/emon/node/2253#comment-11432
#elif defined (__AVR_ATtiny24__) || defined(__AVR_ATtiny44__) || defined(__AVR_ATtiny84__)
    ADMUX = _BV(MUX5) | _BV(MUX0);
#elif defined (__AVR_ATtiny25__) || defined(__AVR_ATtiny45__) || defined(__AVR_ATtiny85__)
    ADMUX = _BV(MUX3) | _BV(MUX2);
#endif
#if defined(__AVR__)
    delay(2);                                        // Wait for Vref to settle
    ADCSRA |= _BV(ADSC);                             // Convert
    while (bit_is_set(ADCSRA, ADSC));
    result = ADCL;
    result |= ADCH << 8;
    result = 1126400L / result;  //1100mV*1024 ADC steps http://openenergymonitor.org/emon/node/1186
    return result;
#elif defined(__arm__)
    return (3300);                                  //Arduino Due
#else
    return (3300);                                  //Guess that other un-supported architectures will be running a 3.3V!
#endif
}

函数功能说明： float readDCCurrent(int Pin) ,该函数用来测量直流电流。 float readACCurrent(int Pin) ,该函数用来测量交流电流，测得的是交流电流的有效值。根据被测电流，选择相应的函数调用即可，不能两个函数同时调用。

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