beta.c File Reference

Resistive divider used for measuring temperature. More...

#include "beta.h"
#include "foxmath.h"
#include <math.h>
#include <stdbool.h>
#include <stdint.h>

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Go to the source code of this file.

Macros
#define	BETA_KELVIN   (273.15f)
#define	BETA_ADC_VOLTAGE_V_MAX_V
#define	BETA_ADC_VOLTAGE_V_MIN_V

Functions
int16_t	BETA_GetTemperatureFromBeta (uint16_t adcVoltage_mV)
	returns temperature based on measured ADC voltage More...
int16_t	BETA_TemperatureFromResistance (float_t resistance_Ohm)
	returns temperature corresponding to NTC resistance More...
float_t	BETA_ResistanceFromTemperature (int16_t temperature_ddegC)
	returns NTC resistance corresponding to temperature, used to compute Vmin and Vmax of the divider More...

Detailed Description

Resistive divider used for measuring temperature.

Copyright

© 2010 - 2023, Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V. All rights reserved.

SPDX-License-Identifier: BSD-3-Clause

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

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3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

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Author

foxBMS Team

Date

2020-01-17 (date of creation)

Updated

2023-02-03 (date of last update)

Version

v1.5.0

Prefix

BETA

Definition in file beta.c.

Macro Definition Documentation

BETA_ADC_VOLTAGE_V_MAX_V

#define BETA_ADC_VOLTAGE_V_MAX_V

Value:

    (float_t)(                                                                            \
        (BETA_RESISTOR_DIVIDER_SUPPLY_VOLTAGE_V * BETA_ResistanceFromTemperature(1400)) / \
        (BETA_ResistanceFromTemperature(1400) + BETA_RESISTOR_DIVIDER_RESISTANCE_R_1_R_2_Ohm))

Defines for calculating the ADC voltage on the ends of the operating range. The ADC voltage is calculated with the following formula:

V_adc = ( ( V_supply * R_ntc ) / ( R + R_ntc ) )

Depending on the position of the NTC in the voltage resistor (R_1/R_2), different R_ntc values are used for the calculation.

Definition at line 82 of file beta.c.

BETA_ADC_VOLTAGE_V_MIN_V

#define BETA_ADC_VOLTAGE_V_MIN_V

Value:

    (float_t)(                                                                            \
        (BETA_RESISTOR_DIVIDER_SUPPLY_VOLTAGE_V * BETA_ResistanceFromTemperature(-400)) / \
        (BETA_ResistanceFromTemperature(-400) + BETA_RESISTOR_DIVIDER_RESISTANCE_R_1_R_2_Ohm))

Defines for calculating the ADC voltage on the ends of the operating range. The ADC voltage is calculated with the following formula:

V_adc = ( ( V_supply * R_ntc ) / ( R + R_ntc ) )

Depending on the position of the NTC in the voltage resistor (R_1/R_2), different R_ntc values are used for the calculation.

Definition at line 86 of file beta.c.

BETA_KELVIN

#define BETA_KELVIN   (273.15f)

inverse temperature coefficient for ideal gas

Definition at line 67 of file beta.c.

Function Documentation

BETA_GetTemperatureFromBeta()

int16_t BETA_GetTemperatureFromBeta

(

uint16_t

adcVoltage_mV

)

returns temperature based on measured ADC voltage

Parameters

adcVoltage_mV

voltage in mV

Returns

corresponding temperature in deci °C or FLT_MAX/FLT_MIN if NTC is shorted or got disconnected. The caller of this functions needs to check for these return values to prevent invalid data.

Definition at line 104 of file beta.c.

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BETA_ResistanceFromTemperature()

float_t BETA_ResistanceFromTemperature

(

int16_t

temperature_ddegC

)

returns NTC resistance corresponding to temperature, used to compute Vmin and Vmax of the divider

Parameters

temperature_ddegC

in deci °C

Returns

corresponding resistance in Ohm

Definition at line 149 of file beta.c.

BETA_TemperatureFromResistance()

int16_t BETA_TemperatureFromResistance

(

float_t

resistance_Ohm

)

returns temperature corresponding to NTC resistance

Parameters

resistance_Ohm

resistance in Ohm

Returns

corresponding temperature in deci °C

Definition at line 135 of file beta.c.