calibration.h

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#ifndef CALIBRATION_H
#define CALIBRATION_H
 
#include "config.h"
 
//
// Calibration values
//-------------------
// Three calibration values are used in this sketch: f_powerCal, f_phaseCal and f_voltageCal.
// With most hardware, the default values are likely to work fine without
// need for change. A compact explanation of each of these values now follows:
 
// When calculating real power, which is what this code does, the individual
// conversion rates for voltage and current are not of importance. It is
// only the conversion rate for POWER which is important. This is the
// product of the individual conversion rates for voltage and current. It
// therefore has the units of ADC-steps squared per Watt. Most systems will
// have a power conversion rate of around 20 (ADC-steps squared per Watt).
//
// powerCal is the RECIPROCAL of the power conversion rate. A good value
// to start with is therefore 1/20 = 0.05 (Watts per ADC-step squared)
//
inline constexpr float f_powerCal[NO_OF_PHASES]{ 0.05000F, 0.05000F, 0.05000F };
//
// f_phaseCal is used to alter the phase of the voltage waveform relative to the current waveform.
// The algorithm interpolates between the most recent pair of voltage samples according to the value of f_phaseCal.
//
//    With f_phaseCal = 1, the most recent sample is used.
//    With f_phaseCal = 0, the previous sample is used
//    With f_phaseCal = 0.5, the mid-point (average) value in used
//
// NB. Any tool which determines the optimal value of f_phaseCal must have a similar
// scheme for taking sample values as does this sketch.
//
inline constexpr float f_phaseCal{ 1 }; 
//
// For datalogging purposes, f_voltageCal has been added too. Because the range of ADC values is
// similar to the actual range of volts, the optimal value for this cal factor is likely to be
// close to unity.
inline constexpr float f_voltageCal[NO_OF_PHASES]{ 0.8151F, 0.8184F, 0.8195F }; 
 
inline constexpr float lpf_gain{ 0 }; 
inline constexpr float alpha{ 0.002 };
//--------------------------------------------------------------------------------------------------
 
#endif  // CALIBRATION_H