ntc_conversion.hpp

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#pragma once
#include <cmath>
#include <cstdint>
 
//--------------------------------------
//  Conversion Constants
//--------------------------------------
 
namespace NTC::Constants {
constexpr float ABSOLUTE_ZERO_CELSIUS_ = -273.15F; 
constexpr float KELVIN_OFFSET_ =
    273.15F; 
constexpr float REFERENCE_TEMPERATURE_C_ =
    25.0F; 
// Default Steinhart-Hart coefficients: the TDK NTCG163JF103FT1S, fitted
// exactly to the nominal resistances of its spec sheet's Table 3 at -40 C
// (188.5 kOhm), 25 C (10.00 kOhm) and 125 C (0.534 kOhm). Within 0.2 C of
// Table 3 from -40 C to +125 C and 0.41 C at +150 C.
constexpr float STEINHART_HART_A_ =
    8.767633e-4F; 
constexpr float STEINHART_HART_B_ =
    2.527899e-4F; 
constexpr float STEINHART_HART_C_ =
    1.906681e-7F; 
 
// Validation limits
constexpr float MIN_RESISTANCE_OHMS_ =
    0.1F; 
constexpr float MAX_RESISTANCE_OHMS_ =
    1000000.0F; 
constexpr float MIN_TEMPERATURE_CELSIUS_ =
    -273.15F; 
constexpr float MAX_TEMPERATURE_CELSIUS_ =
    1000.0F;                               
constexpr float MIN_BETA_VALUE_ = 1000.0F; 
constexpr float MAX_BETA_VALUE_ = 5000.0F; 
 
// Numerical precision constants
constexpr float EPSILON_FLOAT_ = 1e-6F;   
constexpr float EPSILON_DOUBLE_ = 1e-12F; 
constexpr float ONE_FLOAT_ = 1.0F;        
constexpr float ZERO_FLOAT_ = 0.0F;       
 
// Time conversion constants
constexpr uint32_t MILLISECONDS_PER_SECOND_ =
    1000U; 
 
// Temperature conversion constants
constexpr float CELSIUS_TO_FAHRENHEIT_MULTIPLIER_ =
    9.0F / 5.0F; 
constexpr float FAHRENHEIT_OFFSET_ = 32.0F; 
constexpr float FAHRENHEIT_TO_CELSIUS_MULTIPLIER_ =
    5.0F / 9.0F; 
} // namespace NTC::Constants
 
//--------------------------------------
//  Conversion Methods
//--------------------------------------
 
namespace NTC {
 
bool ConvertResistanceToTemperatureBeta(float resistance_ohms,
                                        float resistance_at_25c,
                                        float beta_value,
                                        float *temperature_celsius) noexcept;
 
bool ConvertTemperatureToResistanceBeta(float temperature_celsius,
                                        float resistance_at_25c,
                                        float beta_value,
                                        float *resistance_ohms) noexcept;
 
bool ConvertResistanceToTemperatureSteinhartHart(
    float resistance_ohms, float coeff_a, float coeff_b, float coeff_c,
    float *temperature_celsius) noexcept;
 
bool ConvertTemperatureToResistanceSteinhartHart(
    float temperature_celsius, float coeff_a, float coeff_b, float coeff_c,
    float *resistance_ohms) noexcept;
 
bool ConvertResistanceToTemperatureDefault(float resistance_ohms,
                                           float *temperature_celsius) noexcept;
 
bool ConvertTemperatureToResistanceDefault(float temperature_celsius,
                                           float *resistance_ohms) noexcept;
 
//--------------------------------------
//  Voltage Divider Calculations
//--------------------------------------
 
bool CalculateThermistorResistance(float voltage_thermistor,
                                   float reference_voltage,
                                   float series_resistance,
                                   float *resistance_ohms) noexcept;
 
bool CalculateThermistorVoltage(float resistance_ohms, float reference_voltage,
                                float series_resistance,
                                float *voltage_thermistor) noexcept;
 
bool CalculateVoltageDividerRatio(float resistance_ohms,
                                  float series_resistance,
                                  float *ratio) noexcept;
 
//--------------------------------------
//  Validation Functions
//--------------------------------------
 
bool ValidateResistance(float resistance_ohms, float min_resistance,
                        float max_resistance) noexcept;
 
bool ValidateTemperature(float temperature_celsius, float min_temperature,
                         float max_temperature) noexcept;
 
bool ValidateVoltage(float voltage_volts, float min_voltage,
                     float max_voltage) noexcept;
 
bool ValidateBetaValue(float beta_value) noexcept;
 
bool ValidateSteinhartHartCoefficients(float coeff_a, float coeff_b,
                                       float coeff_c) noexcept;
 
//--------------------------------------
//  Utility Functions
//--------------------------------------
 
bool CalculateBetaValue(float temp1_celsius, float resistance1_ohms,
                        float temp2_celsius, float resistance2_ohms,
                        float *beta_value) noexcept;
 
bool CalculateSteinhartHartCoefficients(
    float temp1_celsius, float resistance1_ohms, float temp2_celsius,
    float resistance2_ohms, float temp3_celsius, float resistance3_ohms,
    float *coeff_a, float *coeff_b, float *coeff_c) noexcept;
 
bool CalculateTemperatureAccuracy(float resistance_ohms,
                                  float resistance_at_25c, float beta_value,
                                  float resistance_tolerance,
                                  float beta_tolerance,
                                  float *accuracy_celsius) noexcept;
 
[[deprecated("pass R25 and B: CalculateTemperatureAccuracy(R, r25, beta, "
             "tol_r, tol_b, &acc)")]]
bool CalculateTemperatureAccuracy(float resistance_ohms,
                                  float resistance_tolerance,
                                  float beta_tolerance,
                                  float *accuracy_celsius) noexcept;
 
bool CalculateOptimalSeriesResistance(float thermistor_resistance_at_25c,
                                      float beta_value, float min_temperature,
                                      float max_temperature,
                                      float *optimal_resistance) noexcept;
 
[[deprecated("pass B: CalculateOptimalSeriesResistance(r25, beta, t_min, "
             "t_max, &r)")]]
bool CalculateOptimalSeriesResistance(float thermistor_resistance_at_25c,
                                      float min_temperature,
                                      float max_temperature,
                                      float *optimal_resistance) noexcept;
 
} // namespace NTC::Constants
 
//--------------------------------------
//  Conversion Methods
//--------------------------------------
 
namespace NTC {
 
bool ConvertResistanceToTemperatureBeta(float resistance_ohms,
                                        float resistance_at_25c,
                                        float beta_value,
                                        float *temperature_celsius) noexcept;
 
bool ConvertTemperatureToResistanceBeta(float temperature_celsius,
                                        float resistance_at_25c,
                                        float beta_value,
                                        float *resistance_ohms) noexcept;
 
bool ConvertResistanceToTemperatureSteinhartHart(
    float resistance_ohms, float coeff_a, float coeff_b, float coeff_c,
    float *temperature_celsius) noexcept;
 
bool ConvertTemperatureToResistanceSteinhartHart(
    float temperature_celsius, float coeff_a, float coeff_b, float coeff_c,
    float *resistance_ohms) noexcept;
 
bool ConvertResistanceToTemperatureDefault(float resistance_ohms,
                                           float *temperature_celsius) noexcept;
 
bool ConvertTemperatureToResistanceDefault(float temperature_celsius,
                                           float *resistance_ohms) noexcept;
 
//--------------------------------------
//  Voltage Divider Calculations
//--------------------------------------
 
bool CalculateThermistorResistance(float voltage_thermistor,
                                   float reference_voltage,
                                   float series_resistance,
                                   float *resistance_ohms) noexcept;
 
bool CalculateThermistorVoltage(float resistance_ohms, float reference_voltage,
                                float series_resistance,
                                float *voltage_thermistor) noexcept;
 
bool CalculateVoltageDividerRatio(float resistance_ohms,
                                  float series_resistance,
                                  float *ratio) noexcept;
 
//--------------------------------------
//  Validation Functions
//--------------------------------------
 
bool ValidateResistance(float resistance_ohms, float min_resistance,
                        float max_resistance) noexcept;
 
bool ValidateTemperature(float temperature_celsius, float min_temperature,
                         float max_temperature) noexcept;
 
bool ValidateVoltage(float voltage_volts, float min_voltage,
                     float max_voltage) noexcept;
 
bool ValidateBetaValue(float beta_value) noexcept;
 
bool ValidateSteinhartHartCoefficients(float coeff_a, float coeff_b,
                                       float coeff_c) noexcept;
 
//--------------------------------------
//  Utility Functions
//--------------------------------------
 
bool CalculateBetaValue(float temp1_celsius, float resistance1_ohms,
                        float temp2_celsius, float resistance2_ohms,
                        float *beta_value) noexcept;
 
bool CalculateSteinhartHartCoefficients(
    float temp1_celsius, float resistance1_ohms, float temp2_celsius,
    float resistance2_ohms, float temp3_celsius, float resistance3_ohms,
    float *coeff_a, float *coeff_b, float *coeff_c) noexcept;
 
bool CalculateTemperatureAccuracy(float resistance_ohms,
                                  float resistance_tolerance,
                                  float beta_tolerance,
                                  float *accuracy_celsius) noexcept;
 
bool CalculateOptimalSeriesResistance(float thermistor_resistance_at_25c,
                                      float min_temperature,
                                      float max_temperature,
                                      float *optimal_resistance) noexcept;
 
} // namespace NTC