ETcontroller_ST/TEnergyMonitor/TEnergyMonitor.cpp

/*
 * TEnergyMonitor.cpp
 *
 *  Created on: 07 apr 2018
 *      Author: Emanuele
 */

#include "TEnergyMonitor.h"

TEnergyMonitor::TEnergyMonitor(Serial* _pc){
	pc=_pc;
}


//--------------------------------------------------------------------------------------
// Sets the pins to be used for voltage and current sensors
//--------------------------------------------------------------------------------------
void TEnergyMonitor::voltage(PinName _inPinV, double _VCAL, double _PHASECAL)
{
   inPinV = _inPinV;
   VCAL = _VCAL;
   PHASECAL = _PHASECAL;
   offsetV = ADC_COUNTS>>1;
   adcV = new AnalogIn(inPinV);
}

void TEnergyMonitor::current(PinName _inPinI, double _ICAL)
{
   inPinI = _inPinI;
   ICAL = _ICAL;
   offsetI = ADC_COUNTS>>1;
   adcI = new AnalogIn(inPinI);
}

//--------------------------------------------------------------------------------------
// Sets the pins to be used for voltage and current sensors based on emontx pin map
//--------------------------------------------------------------------------------------
//void TEnergyMonitor::voltageTX(double _VCAL, double _PHASECAL)
//{
//   inPinV = 2;
//   VCAL = _VCAL;
//   PHASECAL = _PHASECAL;
//   offsetV = ADC_COUNTS>>1;
//}
//
//void TEnergyMonitor::currentTX(unsigned int _channel, double _ICAL)
//{
//   if (_channel == 1) inPinI = 3;
//   if (_channel == 2) inPinI = 0;
//   if (_channel == 3) inPinI = 1;
//   ICAL = _ICAL;
//   offsetI = ADC_COUNTS>>1;
//}

//--------------------------------------------------------------------------------------
// emon_calc procedure
// Calculates realPower,apparentPower,powerFactor,Vrms,Irms,kWh increment
// From a sample window of the mains AC voltage and current.
// The Sample window length is defined by the number of half wavelengths or crossings we choose to measure.
//--------------------------------------------------------------------------------------
void TEnergyMonitor::calcVI(unsigned int crossings, unsigned int timeout)
{
   #if defined emonTxV3
	int SupplyVoltage=3300;
   #else
	int SupplyVoltage = readVcc();
   #endif

  unsigned int crossCount = 0;                             //Used to measure number of times threshold is crossed.
  unsigned int numberOfSamples = 0;                        //This is now incremented

  //-------------------------------------------------------------------------------------------------------------------------
  // 1) Waits for the waveform to be close to 'zero' (mid-scale adc) part in sin curve.
  //-------------------------------------------------------------------------------------------------------------------------
  bool st=false;                                  //an indicator to exit the while loop

  unsigned long start = millis();    //millis()-start makes sure it doesnt get stuck in the loop if there is an error.

  while(st==false)                                   //the while loop...
  {
     startV = adcV->read_u16();                    //using the voltage waveform
     if ((startV < (ADC_COUNTS*0.55)) && (startV > (ADC_COUNTS*0.45))) st=true;  //check its within range
     if ((millis()-start)>timeout) st = true;
  }

  //-------------------------------------------------------------------------------------------------------------------------
  // 2) Main measurement loop
  //-------------------------------------------------------------------------------------------------------------------------
  start = millis();

  while ((crossCount < crossings) && ((millis()-start)<timeout))
  {
    numberOfSamples++;                       //Count number of times looped.
    lastFilteredV = filteredV;               //Used for delay/phase compensation

    //-----------------------------------------------------------------------------
    // A) Read in raw voltage and current samples
    //-----------------------------------------------------------------------------
    sampleV = adcV->read_u16();                 //Read in raw voltage signal
    sampleI = adcI->read_u16();                 //Read in raw current signal

    //-----------------------------------------------------------------------------
    // B) Apply digital low pass filters to extract the 2.5 V or 1.65 V dc offset,
    //     then subtract this - signal is now centred on 0 counts.
    //-----------------------------------------------------------------------------
    offsetV = offsetV + ((sampleV-offsetV)/1024);
	filteredV = sampleV - offsetV;
    offsetI = offsetI + ((sampleI-offsetI)/1024);
	filteredI = sampleI - offsetI;

    //-----------------------------------------------------------------------------
    // C) Root-mean-square method voltage
    //-----------------------------------------------------------------------------
    sqV= filteredV * filteredV;                 //1) square voltage values
    sumV += sqV;                                //2) sum

    //-----------------------------------------------------------------------------
    // D) Root-mean-square method current
    //-----------------------------------------------------------------------------
    sqI = filteredI * filteredI;                //1) square current values
    sumI += sqI;                                //2) sum

    //-----------------------------------------------------------------------------
    // E) Phase calibration
    //-----------------------------------------------------------------------------
    phaseShiftedV = lastFilteredV + PHASECAL * (filteredV - lastFilteredV);

    //-----------------------------------------------------------------------------
    // F) Instantaneous power calc
    //-----------------------------------------------------------------------------
    instP = phaseShiftedV * filteredI;          //Instantaneous Power
    sumP +=instP;                               //Sum

    //-----------------------------------------------------------------------------
    // G) Find the number of times the voltage has crossed the initial voltage
    //    - every 2 crosses we will have sampled 1 wavelength
    //    - so this method allows us to sample an integer number of half wavelengths which increases accuracy
    //-----------------------------------------------------------------------------
    lastVCross = checkVCross;
    if (sampleV > startV) checkVCross = true;
                     else checkVCross = false;
    if (numberOfSamples==1) lastVCross = checkVCross;

    if (lastVCross != checkVCross) crossCount++;
  }

  //-------------------------------------------------------------------------------------------------------------------------
  // 3) Post loop calculations
  //-------------------------------------------------------------------------------------------------------------------------
  //Calculation of the root of the mean of the voltage and current squared (rms)
  //Calibration coefficients applied.

  double V_RATIO = VCAL *((SupplyVoltage/1000.0) / (ADC_COUNTS));
  Vrms = V_RATIO * sqrt(sumV / numberOfSamples);

  double I_RATIO = ICAL *((SupplyVoltage/1000.0) / (ADC_COUNTS));
  Irms = I_RATIO * sqrt(sumI / numberOfSamples);

  //Calculation power values
  realPower = V_RATIO * I_RATIO * sumP / numberOfSamples;
  apparentPower = Vrms * Irms;
  powerFactor=realPower / apparentPower;

  //Reset accumulators
  sumV = 0;
  sumI = 0;
  sumP = 0;
//--------------------------------------------------------------------------------------
}

//--------------------------------------------------------------------------------------
double TEnergyMonitor::calcIrms(unsigned int timeout)
{

   #if defined emonTxV3
	int SupplyVoltage=3300;
   #else
	int SupplyVoltage = readVcc();
   #endif

	//Reset accumulators
	sumI = 0;
	unsigned long NumberOfSamples=0;
	unsigned long start=millis();

  while ((millis()-start)<timeout*1000)
  {
    sampleI = adcI->read_u16();

    // Digital low pass filter extracts the 2.5 V or 1.65 V dc offset,
	//  then subtract this - signal is now centered on 0 counts.
    offsetI = (offsetI + (sampleI-offsetI)/1024);
	filteredI = sampleI - offsetI;

    // Root-mean-square method current
    // 1) square current values
    sqI = filteredI * filteredI;
    // 2) sum
    sumI += sqI;
    NumberOfSamples++;
  }

  double I_RATIO = ICAL *((SupplyVoltage/1000.0) / (ADC_COUNTS));
  Irms = I_RATIO * sqrt(sumI / NumberOfSamples);
  return Irms;
}

long TEnergyMonitor::readVcc(){
	return 3340;
}