Analog Devices / tempsensors

Library to support temperature sensor conversions and lookups

ptc_ky81_110.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: ptc_ky81_110.cpp
mahphalke 1:f65f6fadda5d 4
mahphalke 1:f65f6fadda5d 5 @brief: This file contains functionality for PTC KY81/110 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 "thermistor.h"
mahphalke 1:f65f6fadda5d 18 #include "ptc_ky81_110.h"
mahphalke 1:f65f6fadda5d 19
mahphalke 1:f65f6fadda5d 20 #ifdef DEFINE_LOOKUP_TABLES
mahphalke 1:f65f6fadda5d 21 /* PTC look-up table. Values are resistance in ohm for temperature
mahphalke 1:f65f6fadda5d 22 * range from -10 to 80C with +/-1C tolerance.
mahphalke 1:f65f6fadda5d 23 * @note This table is derived based on the look-up table specified
mahphalke 1:f65f6fadda5d 24 * in the datasheet of KY81/110 part. The linear interpolation
mahphalke 1:f65f6fadda5d 25 * has been used to obtain 1C step size.
mahphalke 1:f65f6fadda5d 26 **/
mahphalke 1:f65f6fadda5d 27 const uint32_t ptc_ky81_110::lut[] = {
mahphalke 1:f65f6fadda5d 28 747, 753, 760, 767, 774, 781, 787, 794, 801, 808, 815, 822, 829, 836,
mahphalke 1:f65f6fadda5d 29 843, 850, 857, 864, 871, 878, 886, 893, 901, 908, 916, 923, 931, 938,
mahphalke 1:f65f6fadda5d 30 946, 953, 961, 968, 976, 984, 992, 1000, 1008, 1016, 1024, 1032, 1040,
mahphalke 1:f65f6fadda5d 31 1048, 1056, 1064, 1072, 1081, 1089, 1097, 1105, 1113, 1122, 1130, 1139,
mahphalke 1:f65f6fadda5d 32 1148, 1156, 1165, 1174, 1182, 1191, 1200, 1209, 1218, 1227, 1236, 1245,
mahphalke 1:f65f6fadda5d 33 1254, 1263, 1272, 1281, 1290, 1299, 1308, 1317, 1326, 1336, 1345, 1354,
mahphalke 1:f65f6fadda5d 34 1364, 1373, 1382, 1392, 1401, 1411, 1421, 1431, 1441, 1450, 1460, 1470,
mahphalke 1:f65f6fadda5d 35 1480, 1490
mahphalke 1:f65f6fadda5d 36 };
mahphalke 1:f65f6fadda5d 37 #endif
mahphalke 1:f65f6fadda5d 38
mahphalke 1:f65f6fadda5d 39
mahphalke 1:f65f6fadda5d 40 /*!
mahphalke 1:f65f6fadda5d 41 * @brief This is a constructor for ptc_ky81_110 class
mahphalke 1:f65f6fadda5d 42 * @return none
mahphalke 1:f65f6fadda5d 43 */
mahphalke 1:f65f6fadda5d 44 ptc_ky81_110::ptc_ky81_110()
mahphalke 1:f65f6fadda5d 45 {
mahphalke 1:f65f6fadda5d 46 temperature_coeff = 0.79; /* Temperature coefficient for KY81/110 */
mahphalke 1:f65f6fadda5d 47
mahphalke 1:f65f6fadda5d 48 #ifdef DEFINE_LOOKUP_TABLES
mahphalke 1:f65f6fadda5d 49 ptc_ky81_110::lut_offset = -10; /* Min temperature obtained through LUT */
mahphalke 1:f65f6fadda5d 50 ptc_ky81_110::lut_size = 90; /* Temperature range defined in LUT
mahphalke 1:f65f6fadda5d 51 [lut_offset : lut_size - lut_offset] */
mahphalke 1:f65f6fadda5d 52 #endif
mahphalke 1:f65f6fadda5d 53 }
mahphalke 1:f65f6fadda5d 54
mahphalke 1:f65f6fadda5d 55
mahphalke 1:f65f6fadda5d 56 /*!
mahphalke 1:f65f6fadda5d 57 * @brief Convert the thermistor resistance into equivalent temperature
mahphalke 1:f65f6fadda5d 58 * @param resistance[in] - thermistor resistance
mahphalke 1:f65f6fadda5d 59 * @return Thermistor temperature value
mahphalke 1:f65f6fadda5d 60 * @note Resistance at room temperature is 1000 ohms (1K)
mahphalke 1:f65f6fadda5d 61 */
mahphalke 1:f65f6fadda5d 62 float ptc_ky81_110::convert(const float resistance)
mahphalke 1:f65f6fadda5d 63 {
mahphalke 1:f65f6fadda5d 64 return (((resistance - 1000) / 1000) * (100.0 / temperature_coeff)) + 25.0;
mahphalke 1:f65f6fadda5d 65 }
mahphalke 1:f65f6fadda5d 66
mahphalke 1:f65f6fadda5d 67
mahphalke 1:f65f6fadda5d 68 #ifdef DEFINE_LOOKUP_TABLES
mahphalke 1:f65f6fadda5d 69 /*!
mahphalke 1:f65f6fadda5d 70 * @brief Convert the thermistor resistance into equivalent temperature using
mahphalke 1:f65f6fadda5d 71 * lookup table for KY81/110 NTC
mahphalke 1:f65f6fadda5d 72 * @param resistance[in] - thermistor resistance
mahphalke 1:f65f6fadda5d 73 * @return Thermistor temperature value
mahphalke 1:f65f6fadda5d 74 */
mahphalke 1:f65f6fadda5d 75 float ptc_ky81_110::lookup(const float resistance)
mahphalke 1:f65f6fadda5d 76 {
mahphalke 1:f65f6fadda5d 77 return thermistor::lookup(lut, resistance, lut_size, lut_offset);
mahphalke 1:f65f6fadda5d 78 }
mahphalke 1:f65f6fadda5d 79 #endif