beta.h File Reference

Resistive divider used for measuring temperature. More...

#include "general.h"

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Macros
#define	BETA_POSITION_IN_RESISTOR_DIVIDER_IS_R_1   (false)
#define	BETA_RESISTOR_DIVIDER_SUPPLY_VOLTAGE_V   (4.096f)
#define	BETA_RESISTOR_DIVIDER_RESISTANCE_R_1_R_2_Ohm   (10000.0f)
#define	BETA_T_REF_C   (25.0f)
#define	BETA_R_REF_Ohm   (10000.0f)
#define	BETA_BETACOEFFICIENT   (3984.0f)

Functions
int16_t	BETA_GetTemperatureFromBeta (uint16_t adcVoltage_mV)
	returns temperature based on measured ADC voltage More...
int16_t	BETA_TemperatureFromResistance (float resistance_Ohm)
	returns temperature corresponding to NTC resistance More...
float	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 - 2021, Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V. All rights reserved.

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1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
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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

2021-02-24 (date of last update)

Prefix

BETA

     V_supply
       --.--
         |
       +-.-+
       |   |
       |   |  R_1
       |   |
       +-.-+
         |
         .--- V_adc
         |
       +-.-+
       |   |
       |   |  R_2
       |   |
       +-.-+
         |
       --.--
        GND

Definition in file beta.h.

Macro Definition Documentation

BETA_BETACOEFFICIENT

#define BETA_BETACOEFFICIENT   (3984.0f)

BEta coefficient of the NTC

Definition at line 107 of file beta.h.

BETA_POSITION_IN_RESISTOR_DIVIDER_IS_R_1

#define BETA_POSITION_IN_RESISTOR_DIVIDER_IS_R_1   (false)

Position of the NTC in the voltage resistor true: NTC is positioned above the voltage tap for the ADC voltage. This equals resistor R_1 in the above circuit diagram

false: NTC is positioned below the voltage tap for the ADC voltage. This equals resistor R2 in the above circuit diagram

Definition at line 89 of file beta.h.

BETA_R_REF_Ohm

#define BETA_R_REF_Ohm   (10000.0f)

NTC resistance at reference temperature

Definition at line 104 of file beta.h.

BETA_RESISTOR_DIVIDER_RESISTANCE_R_1_R_2_Ohm

#define BETA_RESISTOR_DIVIDER_RESISTANCE_R_1_R_2_Ohm   (10000.0f)

Resistance value of the other resistor (not the NTC) in the resistor divider in kOhm.

Definition at line 98 of file beta.h.

BETA_RESISTOR_DIVIDER_SUPPLY_VOLTAGE_V

#define BETA_RESISTOR_DIVIDER_SUPPLY_VOLTAGE_V   (4.096f)

Resistor divider supply voltage in volt

Definition at line 92 of file beta.h.

BETA_T_REF_C

#define BETA_T_REF_C   (25.0f)

Reference temperature

Definition at line 101 of file beta.h.

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 95 of file beta.c.

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BETA_ResistanceFromTemperature()

float 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 140 of file beta.c.

BETA_TemperatureFromResistance()

int16_t BETA_TemperatureFromResistance

(

float

resistance_Ohm

)

returns temperature corresponding to NTC resistance

Parameters

resistance_Ohm

resistance in Ohm

Returns

corresponding temperature in deci °C

Definition at line 126 of file beta.c.