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implemente a new sqrt() function, due to some bugs in the math libra… #17

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implemente a new sqrt() function, due to some bugs in the math libra… #17

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24 changes: 20 additions & 4 deletions EmonLib.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -154,10 +154,14 @@ void EnergyMonitor::calcVI(unsigned int crossings, unsigned int timeout)
//Calibration coefficients applied.

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


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


//Calculation power values
realPower = V_RATIO * I_RATIO * sumP / numberOfSamples;
Expand All @@ -178,7 +182,7 @@ double EnergyMonitor::calcIrms(unsigned int Number_of_Samples)
#if defined emonTxV3
int SupplyVoltage=3300;
#else
int SupplyVoltage = readVcc();
double SupplyVoltage = readVcc();
#endif


Expand All @@ -199,7 +203,8 @@ double EnergyMonitor::calcIrms(unsigned int Number_of_Samples)
}

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

//Reset accumulators
sumI = 0;
Expand Down Expand Up @@ -258,4 +263,15 @@ long EnergyMonitor::readVcc() {
return (3300); //Guess that other un-supported architectures will be running a 3.3V!
#endif
}
double EnergyMonitor::squareRoot(double fg)
{
double n = fg / 2.0;
double lstX = 0.0;
while (n != lstX)
{
lstX = n;
n = (n + fg / n) / 2.0;
}
return n;
}

1 change: 1 addition & 0 deletions EmonLib.h
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Expand Up @@ -58,6 +58,7 @@ class EnergyMonitor

long readVcc();
//Useful value variables
double squareRoot(double fg);
double realPower,
apparentPower,
powerFactor,
Expand Down