Analog Devices / tempsensors

Library to support temperature sensor conversions and lookups

ntc_10k_44031.cpp@4:d8246c20aed2, 2021-07-01 (annotated)

Committer:
mahphalke
Date:
Thu Jul 01 13:41:18 2021 +0530
Revision:
4:d8246c20aed2
Parent:
2:bcfa5a2f21c9 
Adding equation to calculate 10K 44031 NTC temperature using Beta value

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mahphalke 1:f65f6fadda5d 1 /*!
mahphalke 1:f65f6fadda5d 2 *****************************************************************************
mahphalke 1:f65f6fadda5d 3 @file: ntc_10k_44031.cpp
mahphalke 1:f65f6fadda5d 4
mahphalke 1:f65f6fadda5d 5 @brief: This file contains functionality for 10K NTC 44021 model
mahphalke 1:f65f6fadda5d 6
mahphalke 1:f65f6fadda5d 7 @details:
mahphalke 1:f65f6fadda5d 8 -----------------------------------------------------------------------------
mahphalke 1:f65f6fadda5d 9 Copyright (c) 2021 Analog Devices, Inc. All rights reserved.
mahphalke 1:f65f6fadda5d 10
mahphalke 1:f65f6fadda5d 11 This software is proprietary to Analog Devices, Inc. and its licensors.
mahphalke 1:f65f6fadda5d 12 By using this software you agree to the terms of the associated
mahphalke 1:f65f6fadda5d 13 Analog Devices Software License Agreement.
mahphalke 1:f65f6fadda5d 14
mahphalke 1:f65f6fadda5d 15 *****************************************************************************/
mahphalke 1:f65f6fadda5d 16
mahphalke 1:f65f6fadda5d 17 #include <math.h>
mahphalke 1:f65f6fadda5d 18 #include "thermistor.h"
mahphalke 1:f65f6fadda5d 19 #include "ntc_10k_44031.h"
mahphalke 1:f65f6fadda5d 20
mahphalke 4:d8246c20aed2 21 /* Convert the temperature using Beta factor specified for 44031 10K NTC */
mahphalke 4:d8246c20aed2 22 //#define NTC_10K_44031_CONVERT_USING_BETA_VALUE
mahphalke 4:d8246c20aed2 23
mahphalke 4:d8246c20aed2 24 #if defined(NTC_10K_44031_CONVERT_USING_BETA_VALUE)
mahphalke 4:d8246c20aed2 25 #define NTC_10K_44031_RESISTANCE_AT_25C 10000 // 10K
mahphalke 4:d8246c20aed2 26 #define NTC_10K_44031_ROOM_TEMP_IN_KELVIN 298.15
mahphalke 4:d8246c20aed2 27 #define NTC_10K_44031_BETA_VALUE 3694
mahphalke 4:d8246c20aed2 28 #endif
mahphalke 4:d8246c20aed2 29
mahphalke 1:f65f6fadda5d 30 #ifdef DEFINE_LOOKUP_TABLES
mahphalke 1:f65f6fadda5d 31 /* 10K NTC look-up table. Values are resistance in ohm for temperature
mahphalke 1:f65f6fadda5d 32 * range from -10 to 80C with +/-1C tolerance.
mahphalke 1:f65f6fadda5d 33 * @note This function uses Steinhart-Hart equation for deriving look-up table.
mahphalke 1:f65f6fadda5d 34 **/
mahphalke 1:f65f6fadda5d 35 const uint32_t ntc_10k_44031rc::lut[] = {
mahphalke 1:f65f6fadda5d 36 47561, 45285, 43131, 41091, 39158, 37327, 35591, 33946, 32385,
mahphalke 1:f65f6fadda5d 37 30905, 29500, 28166, 26900, 25697, 24555, 23470, 22438, 21457,
mahphalke 1:f65f6fadda5d 38 20524, 19637, 18792, 17989, 17224, 16495, 15801, 15140, 14510,
mahphalke 1:f65f6fadda5d 39 13910, 13337, 12791, 12271, 11774, 11299, 10847, 10414, 10002,
mahphalke 1:f65f6fadda5d 40 9607, 9231, 8870, 8526, 8197, 7882, 7581, 7293, 7018,
mahphalke 1:f65f6fadda5d 41 6754, 6501, 6259, 6028, 5806, 5593, 5389, 5194, 5006,
mahphalke 1:f65f6fadda5d 42 4827, 4654, 4489, 4331, 4178, 4032, 3892, 3757, 3628,
mahphalke 1:f65f6fadda5d 43 3503, 3384, 3269, 3159, 3053, 2951, 2852, 2758, 2667,
mahphalke 1:f65f6fadda5d 44 2580, 2496, 2415, 2337, 2262, 2189, 2120, 2053, 1988,
mahphalke 1:f65f6fadda5d 45 1926, 1866, 1808, 1752, 1698, 1646, 1596, 1548, 1501,
mahphalke 1:f65f6fadda5d 46 1456
mahphalke 1:f65f6fadda5d 47 };
mahphalke 1:f65f6fadda5d 48 #endif
mahphalke 1:f65f6fadda5d 49
mahphalke 1:f65f6fadda5d 50
mahphalke 1:f65f6fadda5d 51 /*!
mahphalke 1:f65f6fadda5d 52 * @brief This is a constructor for ntc_10k_44031rc class
mahphalke 1:f65f6fadda5d 53 * @return none
mahphalke 1:f65f6fadda5d 54 */
mahphalke 1:f65f6fadda5d 55 ntc_10k_44031rc::ntc_10k_44031rc()
mahphalke 1:f65f6fadda5d 56 {
mahphalke 1:f65f6fadda5d 57 /* Coefficients of Steinhart-Hart equation for 10K NTC to convert
mahphalke 1:f65f6fadda5d 58 * NTC resistance into equivalent temperature */
mahphalke 1:f65f6fadda5d 59 ntc_10k_44031rc::coeff_A = 1.032*pow(10, -3);
mahphalke 1:f65f6fadda5d 60 ntc_10k_44031rc::coeff_B = 2.387*pow(10, -4);
mahphalke 1:f65f6fadda5d 61 ntc_10k_44031rc::coeff_C = 1.580*pow(10, -7);
mahphalke 1:f65f6fadda5d 62
mahphalke 1:f65f6fadda5d 63 #ifdef DEFINE_LOOKUP_TABLES
mahphalke 1:f65f6fadda5d 64 ntc_10k_44031rc::lut_offset = -10; /* Min temperature obtained through LUT */
mahphalke 1:f65f6fadda5d 65 ntc_10k_44031rc::lut_size = 90; /* Temperature range defined in LUT
mahphalke 1:f65f6fadda5d 66 [lut_offset : lut_size - lut_offset] */
mahphalke 1:f65f6fadda5d 67 #endif
mahphalke 1:f65f6fadda5d 68 }
mahphalke 1:f65f6fadda5d 69
mahphalke 1:f65f6fadda5d 70
mahphalke 1:f65f6fadda5d 71 /*!
mahphalke 1:f65f6fadda5d 72 * @brief Convert the thermistor resistance into equivalent temperature using
mahphalke 4:d8246c20aed2 73 * Steinhart-Hart equation Or Beta value for 10K 44031 NTC
mahphalke 1:f65f6fadda5d 74 * @param resistance[in] - thermistor resistance
mahphalke 4:d8246c20aed2 75 * @return Thermistor temperature value in Celcius
mahphalke 1:f65f6fadda5d 76 */
mahphalke 1:f65f6fadda5d 77 float ntc_10k_44031rc::convert(const float resistance)
mahphalke 1:f65f6fadda5d 78 {
mahphalke 4:d8246c20aed2 79 #if defined(NTC_10K_44031_CONVERT_USING_BETA_VALUE)
mahphalke 4:d8246c20aed2 80 float temperature;
mahphalke 4:d8246c20aed2 81 temperature = (1 / ((log(resistance / NTC_10K_44031_RESISTANCE_AT_25C) /
mahphalke 4:d8246c20aed2 82 NTC_10K_44031_BETA_VALUE) + (1 / NTC_10K_44031_ROOM_TEMP_IN_KELVIN))) - 273.15;
mahphalke 4:d8246c20aed2 83 return temperature;
mahphalke 4:d8246c20aed2 84 #else
mahphalke 1:f65f6fadda5d 85 return thermistor::convert(resistance, coeff_A, coeff_B, coeff_C);
mahphalke 4:d8246c20aed2 86 #endif
mahphalke 1:f65f6fadda5d 87 }
mahphalke 1:f65f6fadda5d 88
mahphalke 1:f65f6fadda5d 89
mahphalke 1:f65f6fadda5d 90 #ifdef DEFINE_LOOKUP_TABLES
mahphalke 1:f65f6fadda5d 91 /*!
mahphalke 1:f65f6fadda5d 92 * @brief Convert the thermistor resistance into equivalent temperature using
mahphalke 1:f65f6fadda5d 93 * lookup table for 10K 44031 NTC
mahphalke 1:f65f6fadda5d 94 * @param resistance[in] - thermistor resistance
mahphalke 1:f65f6fadda5d 95 * @return Thermistor temperature value
mahphalke 1:f65f6fadda5d 96 */
mahphalke 1:f65f6fadda5d 97 float ntc_10k_44031rc::lookup(const float resistance)
mahphalke 1:f65f6fadda5d 98 {
mahphalke 1:f65f6fadda5d 99 return thermistor::lookup(lut, resistance, lut_size, lut_offset);
mahphalke 1:f65f6fadda5d 100 }
mahphalke 1:f65f6fadda5d 101 #endif