Analog Devices / Mbed OS EVAL-AD7124-Temperature_measurement

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Dependencies:   tempsensors adi_console_menu platform_drivers

app/ad7124_temperature_sensor.cpp@1:c863d7e9e272, 2021-02-22 (annotated)

Committer:
mahphalke
Date:
Mon Feb 22 05:13:58 2021 +0000
Revision:
1:c863d7e9e272
Child:
3:f20f09251190
Initial commit- Added source files

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mahphalke 1:c863d7e9e272 1
mahphalke 1:c863d7e9e272 2 /***************************************************************************//*
mahphalke 1:c863d7e9e272 3 * @file ad7124_temperature_sensor.cpp
mahphalke 1:c863d7e9e272 4 * @brief AD7124 temperature sensor functionality
mahphalke 1:c863d7e9e272 5 * @details
mahphalke 1:c863d7e9e272 6 ******************************************************************************
mahphalke 1:c863d7e9e272 7 * Copyright (c) 2021 Analog Devices, Inc. All Rights Reserved.
mahphalke 1:c863d7e9e272 8 *
mahphalke 1:c863d7e9e272 9 * This software is proprietary to Analog Devices, Inc. and its licensors.
mahphalke 1:c863d7e9e272 10 * By using this software you agree to the terms of the associated
mahphalke 1:c863d7e9e272 11 * Analog Devices Software License Agreement.
mahphalke 1:c863d7e9e272 12 ******************************************************************************/
mahphalke 1:c863d7e9e272 13
mahphalke 1:c863d7e9e272 14 /******************************************************************************/
mahphalke 1:c863d7e9e272 15 /***************************** Include Files **********************************/
mahphalke 1:c863d7e9e272 16 /******************************************************************************/
mahphalke 1:c863d7e9e272 17
mahphalke 1:c863d7e9e272 18 #include <stdint.h>
mahphalke 1:c863d7e9e272 19 #include <math.h>
mahphalke 1:c863d7e9e272 20
mahphalke 1:c863d7e9e272 21 #include <thermocouple.h>
mahphalke 1:c863d7e9e272 22 #include <ptxxx.h>
mahphalke 1:c863d7e9e272 23 #include <ntc_10k_44031.h>
mahphalke 1:c863d7e9e272 24 #include <ptc_ky81_110.h>
mahphalke 1:c863d7e9e272 25
mahphalke 1:c863d7e9e272 26 #include "ad7124_temperature_sensor.h"
mahphalke 1:c863d7e9e272 27
mahphalke 1:c863d7e9e272 28 #ifdef __cplusplus
mahphalke 1:c863d7e9e272 29 extern "C"
mahphalke 1:c863d7e9e272 30 {
mahphalke 1:c863d7e9e272 31 #endif // _cplusplus
mahphalke 1:c863d7e9e272 32
mahphalke 1:c863d7e9e272 33 #include "ad7124_regs_configs.h"
mahphalke 1:c863d7e9e272 34 #include "ad7124_support.h"
mahphalke 1:c863d7e9e272 35
mahphalke 1:c863d7e9e272 36 #ifdef __cplusplus // Closing extern c
mahphalke 1:c863d7e9e272 37 }
mahphalke 1:c863d7e9e272 38 #endif // _cplusplus
mahphalke 1:c863d7e9e272 39
mahphalke 1:c863d7e9e272 40 /******************************************************************************/
mahphalke 1:c863d7e9e272 41 /********************* Macros and Constants Definitions ***********************/
mahphalke 1:c863d7e9e272 42 /******************************************************************************/
mahphalke 1:c863d7e9e272 43
mahphalke 1:c863d7e9e272 44 /* NTC thermistor Rsense value (in ohms) */
mahphalke 1:c863d7e9e272 45 #define NTC_RSENSE 10000
mahphalke 1:c863d7e9e272 46
mahphalke 1:c863d7e9e272 47 /* PTC thermistor Ref Resistance value (in ohms) */
mahphalke 1:c863d7e9e272 48 #define PTC_RREF 5110
mahphalke 1:c863d7e9e272 49
mahphalke 1:c863d7e9e272 50 /******************************************************************************/
mahphalke 1:c863d7e9e272 51 /******************** Variables and User Defined Data Types *******************/
mahphalke 1:c863d7e9e272 52 /******************************************************************************/
mahphalke 1:c863d7e9e272 53
mahphalke 1:c863d7e9e272 54 /* Calibration constant (iout ratio) for RTD resistance measurement */
mahphalke 1:c863d7e9e272 55 static float calibration_iout_ratio = 1;
mahphalke 1:c863d7e9e272 56
mahphalke 1:c863d7e9e272 57 /******************************************************************************/
mahphalke 1:c863d7e9e272 58 /************************** Functions Definitions *****************************/
mahphalke 1:c863d7e9e272 59 /******************************************************************************/
mahphalke 1:c863d7e9e272 60
mahphalke 1:c863d7e9e272 61 /*!
mahphalke 1:c863d7e9e272 62 * @brief Convert the ADC raw value into equivalent RTD resistance
mahphalke 1:c863d7e9e272 63 * @param adc_raw[in]- ADC raw sample
mahphalke 1:c863d7e9e272 64 * @return RTD resistance value
mahphalke 1:c863d7e9e272 65 * @note RTD is biased with constant excitation current. Below formula
mahphalke 1:c863d7e9e272 66 * is based on ratiometric measurement, where fixed value of RTD RREF
mahphalke 1:c863d7e9e272 67 * (reference resistor) and gain is taken into account
mahphalke 1:c863d7e9e272 68 */
mahphalke 1:c863d7e9e272 69 static float convert_adc_raw_into_rtd_resistance(int32_t adc_raw)
mahphalke 1:c863d7e9e272 70 {
mahphalke 1:c863d7e9e272 71 float rtd_res;
mahphalke 1:c863d7e9e272 72
mahphalke 1:c863d7e9e272 73 /* Below equation is for bipolar inputs as all ADC configurations for
mahphalke 1:c863d7e9e272 74 * sensor measurement are having default bipolar mode */
mahphalke 1:c863d7e9e272 75 rtd_res = (((float)adc_raw - (1 << (AD7124_ADC_N_BITS - 1))) *
mahphalke 1:c863d7e9e272 76 (calibration_iout_ratio * RTD_RREF)) / ((
mahphalke 1:c863d7e9e272 77 AD7124_PGA_GAIN(RTD_GAIN_VALUE)) * (1 << (AD7124_ADC_N_BITS - 1)));
mahphalke 1:c863d7e9e272 78
mahphalke 1:c863d7e9e272 79 return rtd_res;
mahphalke 1:c863d7e9e272 80 }
mahphalke 1:c863d7e9e272 81
mahphalke 1:c863d7e9e272 82
mahphalke 1:c863d7e9e272 83 /*!
mahphalke 1:c863d7e9e272 84 * @brief Store the RTD calibration Iout ratio for 3-wire RTD calibration
mahphalke 1:c863d7e9e272 85 * based measurement
mahphalke 1:c863d7e9e272 86 * @param iout_ratio[in]- Iout1/Iout0 ratio
mahphalke 1:c863d7e9e272 87 * @param status[in] - Calibration ratio set/reset flag
mahphalke 1:c863d7e9e272 88 * @return none
mahphalke 1:c863d7e9e272 89 */
mahphalke 1:c863d7e9e272 90 void store_rtd_calibrated_iout_ratio(float iout_ratio, bool status)
mahphalke 1:c863d7e9e272 91 {
mahphalke 1:c863d7e9e272 92 if (status) {
mahphalke 1:c863d7e9e272 93 calibration_iout_ratio = 1 + iout_ratio;
mahphalke 1:c863d7e9e272 94 } else {
mahphalke 1:c863d7e9e272 95 calibration_iout_ratio = 1;
mahphalke 1:c863d7e9e272 96 }
mahphalke 1:c863d7e9e272 97 }
mahphalke 1:c863d7e9e272 98
mahphalke 1:c863d7e9e272 99
mahphalke 1:c863d7e9e272 100 /*!
mahphalke 1:c863d7e9e272 101 * @brief Convert the ADC raw value into equivalent PTC thermistor resistance
mahphalke 1:c863d7e9e272 102 * @param adc_raw[in]- ADC raw sample
mahphalke 1:c863d7e9e272 103 * @return PTC resistance value
mahphalke 1:c863d7e9e272 104 * @note PTC is biased with constant excitation current. Below formula
mahphalke 1:c863d7e9e272 105 * is based on ratiometric measurement, where fixed value of PTC RREF
mahphalke 1:c863d7e9e272 106 * (reference resistor) and gain is taken into account
mahphalke 1:c863d7e9e272 107 */
mahphalke 1:c863d7e9e272 108 static float convert_adc_raw_into_ptc_resistance(int32_t adc_raw)
mahphalke 1:c863d7e9e272 109 {
mahphalke 1:c863d7e9e272 110 float ptc_res;
mahphalke 1:c863d7e9e272 111
mahphalke 1:c863d7e9e272 112 /* Below equation is for bipolar inputs as all ADC configurations for
mahphalke 1:c863d7e9e272 113 * sensor measurement are having default bipolar mode */
mahphalke 1:c863d7e9e272 114 ptc_res = (((float)adc_raw - (1 << (AD7124_ADC_N_BITS - 1))) * PTC_RREF) / ((
mahphalke 1:c863d7e9e272 115 AD7124_PGA_GAIN(THERMISTOR_GAIN_VALUE)) * (1 << (AD7124_ADC_N_BITS - 1)));
mahphalke 1:c863d7e9e272 116
mahphalke 1:c863d7e9e272 117 return ptc_res;
mahphalke 1:c863d7e9e272 118 }
mahphalke 1:c863d7e9e272 119
mahphalke 1:c863d7e9e272 120
mahphalke 1:c863d7e9e272 121 /*!
mahphalke 1:c863d7e9e272 122 * @brief Convert the ADC raw value into equivalent NTC thermistor voltage
mahphalke 1:c863d7e9e272 123 * @param adc_raw[in]- ADC raw sample
mahphalke 1:c863d7e9e272 124 * @return NTC Thermistor voltage value
mahphalke 1:c863d7e9e272 125 * @note The NTC is biased with constant ADC reference voltage. Below formula
mahphalke 1:c863d7e9e272 126 * is based on ratiometric measurement, where fixed value of ADC REF
mahphalke 1:c863d7e9e272 127 * and gain is taken into account
mahphalke 1:c863d7e9e272 128 */
mahphalke 1:c863d7e9e272 129 static float convert_adc_raw_into_ntc_voltage(int32_t adc_raw)
mahphalke 1:c863d7e9e272 130 {
mahphalke 1:c863d7e9e272 131 float ntc_voltage;
mahphalke 1:c863d7e9e272 132
mahphalke 1:c863d7e9e272 133 /* Below equation is for bipolar inputs as all ADC configurations for
mahphalke 1:c863d7e9e272 134 * sensor measurement are having default bipolar mode */
mahphalke 1:c863d7e9e272 135 ntc_voltage = (((float)adc_raw - (1 << (AD7124_ADC_N_BITS - 1))) *
mahphalke 1:c863d7e9e272 136 AD7124_REF_VOLTAGE) / ((
mahphalke 1:c863d7e9e272 137 AD7124_PGA_GAIN(THERMISTOR_GAIN_VALUE)) * (1 << (AD7124_ADC_N_BITS - 1)));
mahphalke 1:c863d7e9e272 138
mahphalke 1:c863d7e9e272 139 return ntc_voltage;
mahphalke 1:c863d7e9e272 140 }
mahphalke 1:c863d7e9e272 141
mahphalke 1:c863d7e9e272 142
mahphalke 1:c863d7e9e272 143 /*!
mahphalke 1:c863d7e9e272 144 * @brief Convert the NTC thermistor voltage into equivalent resistance
mahphalke 1:c863d7e9e272 145 * @param voltage[in]- NTC Thermistor voltage
mahphalke 1:c863d7e9e272 146 * @return NTC Thermistor resistance value
mahphalke 1:c863d7e9e272 147 */
mahphalke 1:c863d7e9e272 148 static float convert_ntc_voltage_into_resistance(float ntc_voltage)
mahphalke 1:c863d7e9e272 149 {
mahphalke 1:c863d7e9e272 150 float ntc_resistance = (ntc_voltage * NTC_RSENSE) / (AD7124_REF_VOLTAGE -
mahphalke 1:c863d7e9e272 151 ntc_voltage);
mahphalke 1:c863d7e9e272 152 return ntc_resistance;
mahphalke 1:c863d7e9e272 153 }
mahphalke 1:c863d7e9e272 154
mahphalke 1:c863d7e9e272 155
mahphalke 1:c863d7e9e272 156 /**
mahphalke 1:c863d7e9e272 157 * @brief Converts raw ADC code to millivolts
mahphalke 1:c863d7e9e272 158 * @param raw_adc_code[in] Raw ADC code
mahphalke 1:c863d7e9e272 159 * @return voltage in millivolts
mahphalke 1:c863d7e9e272 160 * @details This converts the raw ADC code to millivolts for thermocouple channel,
mahphalke 1:c863d7e9e272 161 * based on the AD7124 Eval board configuration
mahphalke 1:c863d7e9e272 162 */
mahphalke 1:c863d7e9e272 163 static float convert_raw_adc_into_tc_mv(uint32_t raw_adc_code)
mahphalke 1:c863d7e9e272 164 {
mahphalke 1:c863d7e9e272 165 return (((((float)raw_adc_code - (1 << (AD7124_ADC_N_BITS - 1))) /
mahphalke 1:c863d7e9e272 166 (AD7124_PGA_GAIN(THERMOCOUPLE_GAIN_VALUE) *
mahphalke 1:c863d7e9e272 167 (1 << (AD7124_ADC_N_BITS - 1)))) * AD7124_REF_VOLTAGE) * 1000);
mahphalke 1:c863d7e9e272 168 }
mahphalke 1:c863d7e9e272 169
mahphalke 1:c863d7e9e272 170
mahphalke 1:c863d7e9e272 171 /**
mahphalke 1:c863d7e9e272 172 * @brief Convert ADC raw value into TC temperature
mahphalke 1:c863d7e9e272 173 * @param tc_sample[in] Raw TC sample
mahphalke 1:c863d7e9e272 174 * @param cjc_sample[in] Raw CJC sample
mahphalke 1:c863d7e9e272 175 * @param cjc_sensor[in] CJC sensor type
mahphalke 1:c863d7e9e272 176 * @return TC temperature
mahphalke 1:c863d7e9e272 177 */
mahphalke 1:c863d7e9e272 178 float get_tc_temperature(float tc_sample, float cjc_sample,
mahphalke 1:c863d7e9e272 179 cjc_sensor_type cjc_sensor)
mahphalke 1:c863d7e9e272 180 {
mahphalke 1:c863d7e9e272 181 Thermocouple_Type_T tcSensor;
mahphalke 1:c863d7e9e272 182 float tc_mv;
mahphalke 1:c863d7e9e272 183 float tc_temperature;
mahphalke 1:c863d7e9e272 184 float cjc_temperature;
mahphalke 1:c863d7e9e272 185
mahphalke 1:c863d7e9e272 186 tc_mv = convert_raw_adc_into_tc_mv(tc_sample);
mahphalke 1:c863d7e9e272 187 tc_temperature = tcSensor.convert(tc_mv);
mahphalke 1:c863d7e9e272 188
mahphalke 1:c863d7e9e272 189 if (cjc_sensor == PT100_4WIRE_RTD) {
mahphalke 1:c863d7e9e272 190 cjc_temperature = get_rtd_temperature(cjc_sample);
mahphalke 1:c863d7e9e272 191 } else if (cjc_sensor == THERMISTOR_PTC_KY81_110) {
mahphalke 1:c863d7e9e272 192 cjc_temperature = get_ptc_thermistor_temperature(cjc_sample);
mahphalke 1:c863d7e9e272 193 } else if (cjc_sensor == PT1000_4WIRE_RTD) {
mahphalke 1:c863d7e9e272 194 PT1000 rtd_sensor;
mahphalke 1:c863d7e9e272 195 float rtd_resistance;
mahphalke 1:c863d7e9e272 196
mahphalke 1:c863d7e9e272 197 rtd_resistance = convert_adc_raw_into_rtd_resistance(cjc_sample);
mahphalke 1:c863d7e9e272 198 cjc_temperature = rtd_sensor.convertResistanceToTemperature(rtd_resistance);
mahphalke 1:c863d7e9e272 199 } else {
mahphalke 1:c863d7e9e272 200 return 0;
mahphalke 1:c863d7e9e272 201 }
mahphalke 1:c863d7e9e272 202
mahphalke 1:c863d7e9e272 203 /* NOTE The simplest approach of adding the CJC temperature to TC temperature is taken here.
mahphalke 1:c863d7e9e272 204 * A better method is to convert RTD back to thermocouple mV, and add that to TC value
mahphalke 1:c863d7e9e272 205 * then do the thermocouple to degC conversion.
mahphalke 1:c863d7e9e272 206 * */
mahphalke 1:c863d7e9e272 207 return (tc_temperature + cjc_temperature);
mahphalke 1:c863d7e9e272 208 }
mahphalke 1:c863d7e9e272 209
mahphalke 1:c863d7e9e272 210
mahphalke 1:c863d7e9e272 211 /**
mahphalke 1:c863d7e9e272 212 * @brief Convert ADC raw value into RTD temperature
mahphalke 1:c863d7e9e272 213 * @param rtd_sample[in] Raw RTD sample
mahphalke 1:c863d7e9e272 214 * @return RTD temperature
mahphalke 1:c863d7e9e272 215 * @note Fixed PT100 RTD sensor is used
mahphalke 1:c863d7e9e272 216 */
mahphalke 1:c863d7e9e272 217 float get_rtd_temperature(int32_t rtd_sample)
mahphalke 1:c863d7e9e272 218 {
mahphalke 1:c863d7e9e272 219 PT100 rtd_sensor;
mahphalke 1:c863d7e9e272 220 float rtd_resistance;
mahphalke 1:c863d7e9e272 221
mahphalke 1:c863d7e9e272 222 rtd_resistance = convert_adc_raw_into_rtd_resistance(rtd_sample);
mahphalke 1:c863d7e9e272 223
mahphalke 1:c863d7e9e272 224 return rtd_sensor.convertResistanceToTemperature(rtd_resistance);
mahphalke 1:c863d7e9e272 225 }
mahphalke 1:c863d7e9e272 226
mahphalke 1:c863d7e9e272 227
mahphalke 1:c863d7e9e272 228 /**
mahphalke 1:c863d7e9e272 229 * @brief Convert ADC raw value into NTC temperature
mahphalke 1:c863d7e9e272 230 * @param ntc_sample[in] Raw NTC sample
mahphalke 1:c863d7e9e272 231 * @return NTC temperature
mahphalke 1:c863d7e9e272 232 * @note Fixed NTC 10K 44031RC sensor is used
mahphalke 1:c863d7e9e272 233 */
mahphalke 1:c863d7e9e272 234 float get_ntc_thermistor_temperature(int32_t ntc_sample)
mahphalke 1:c863d7e9e272 235 {
mahphalke 1:c863d7e9e272 236 ntc_10k_44031rc ntc_thermistor;
mahphalke 1:c863d7e9e272 237 float ntc_voltage;
mahphalke 1:c863d7e9e272 238 float ntc_resistance;
mahphalke 1:c863d7e9e272 239
mahphalke 1:c863d7e9e272 240 ntc_voltage = convert_adc_raw_into_ntc_voltage(ntc_sample);
mahphalke 1:c863d7e9e272 241 ntc_resistance = convert_ntc_voltage_into_resistance(ntc_voltage);
mahphalke 1:c863d7e9e272 242
mahphalke 1:c863d7e9e272 243 return ntc_thermistor.convert(ntc_resistance);
mahphalke 1:c863d7e9e272 244 }
mahphalke 1:c863d7e9e272 245
mahphalke 1:c863d7e9e272 246
mahphalke 1:c863d7e9e272 247 /**
mahphalke 1:c863d7e9e272 248 * @brief Convert ADC raw value into PTC temperature
mahphalke 1:c863d7e9e272 249 * @param ptc_sample[in] Raw PTC sample
mahphalke 1:c863d7e9e272 250 * @return PTC temperature
mahphalke 1:c863d7e9e272 251 * @note Fixed PTC KY81/110 Thermistor sensor is used
mahphalke 1:c863d7e9e272 252 */
mahphalke 1:c863d7e9e272 253 float get_ptc_thermistor_temperature(int32_t ptc_sample)
mahphalke 1:c863d7e9e272 254 {
mahphalke 1:c863d7e9e272 255 ptc_ky81_110 ptc_thermistor;
mahphalke 1:c863d7e9e272 256 float ptc_resistance;
mahphalke 1:c863d7e9e272 257
mahphalke 1:c863d7e9e272 258 ptc_resistance = convert_adc_raw_into_ptc_resistance(ptc_sample);
mahphalke 1:c863d7e9e272 259
mahphalke 1:c863d7e9e272 260 return ptc_thermistor.convert(ptc_resistance);
mahphalke 1:c863d7e9e272 261 }
mahphalke 1:c863d7e9e272 262