二分法查NTC温度表

2023-07-10 13:23| 来源: 网络整理| 查看: 265

在使用ADC采样温度值时，我们有3种思想去设计程序 1）excel拟合个函数 2）程序线性查值 3）直接用经验公式

今天主要分享查表的方法 1.NTC温度对应的ADC值查找表

// R25=10k,B=3950,Rup=10k,ADC=12bit static const uint16_t cNTCTable[] = { 3887, 3874, 3860, 3845, 3830, 3813, 3796, 3778, 3760, 3740, // -29~-20 3720, 3698, 3676, 3653, 3629, 3604, 3578, 3551, 3524, 3495, // -19~-10 3465, 3435, 3403, 3371, 3337, 3303, 3267, 3231, 3194, 3156, // -9~0 3118, 3078, 3038, 2997, 2955, 2913, 2870, 2826, 2782, 2738, // 1~10 2693, 2648, 2602, 2556, 2510, 2464, 2417, 2371, 2324, 2278, // 11~20 2231, 2185, 2139, 2093, 2048, 2002, 1957, 1913, 1868, 1825, // 21~30 1781, 1739, 1697, 1655, 1614, 1574, 1534, 1495, 1456, 1419, // 31~40 1382, 1346, 1310, 1275, 1241, 1208, 1175, 1143, 1112, 1081, // 41~50 1052, 1023, 994, 967, 940, 914, 888, 863, 839, 815, // 51~60 792, 770, 748, 727, 707, 687, 668, 649, 631, 613, // 61~70 596, 579, 563, 547, 532, 517, 502, 488, 475, 462, // 71~80 449, 436, 424, 413, 401, 390, 380, 369, 359, 350, // 81~90 340, 331, 322, 314, 305, 297, 289, 282, 274, 267, // 91~100 260, 253, 247, 240, 234, 228, 222, 217, 211, 206 // 101~110 };

2.宏定义

// NCT温度表数目 #define NTC_TABLE_COUNT (sizeof(cNTCTable) / sizeof(cNTCTable[0])) // NTC温度表起始温度 #define NTC_TABLE_T_FIRST (-29) 二分法查NTC温度表 static uint8_t NTC_SearchTable(uint16_t adc_val) { uint8_t s_idx, m_idx, e_idx; uint16_t m_val; // 检查数据合法性 if (adc_val > cNTCTable[0] || adc_val < cNTCTable[NTC_TABLE_COUNT - 1]) { return 0xff; } s_idx = 0; e_idx = NTC_TABLE_COUNT - 1; // 二分法查找 while (s_idx + 1 < e_idx) { m_idx = (s_idx + e_idx) >> 1; m_val = cNTCTable[m_idx]; if (adc_val < m_val) { s_idx = m_idx; } else if (adc_val > m_val) { e_idx = m_idx; } else { return m_idx; } } return s_idx; }

4./测量NTC和固定电阻分压

static uint16_t NTC_ADCConv(void) { uint16_t val; // Enable ADC1 clock CLK_PeripheralClockConfig(CLK_Peripheral_ADC1, ENABLE); ADC_DeInit(ADC1); // Initialise and configure ADC1 ADC_Init(ADC1, ADC_ConversionMode_Single, ADC_Resolution_12Bit, ADC_Prescaler_1); // ADC_CLK=2MHz, SamplingTime=8us ADC_SamplingTimeConfig(ADC1, ADC_Group_SlowChannels, ADC_SamplingTime_16Cycles); // Enable ADC1 ADC_Cmd(ADC1, ENABLE); // Enable ADC1 Channel 14 ADC_ChannelCmd(ADC1, ADC_Channel_14, ENABLE); // Start ADC1 Conversion using Software trigger ADC_SoftwareStartConv(ADC1); while (ADC_GetFlagStatus(ADC1, ADC_FLAG_EOC) == RESET); val = ADC_GetConversionValue(ADC1); ADC_Cmd(ADC1, DISABLE); CLK_PeripheralClockConfig(CLK_Peripheral_ADC1, DISABLE); return val; }

5.初始化IO

void NTC_Init(void) { // PB4, ADC1_IN14 GPIO_Init(GPIOB, GPIO_Pin_4, GPIO_Mode_In_FL_No_IT); }

6.取得温度

// 参数：返回温度整数部分，返回温度小数部分 // 返回：是否获取温度成功 bool NTC_GetT(int8_t *t_z, uint8_t *t_f) { uint16_t adc_val; uint8_t idx; const uint16_t *pt; adc_val = NTC_ADCConv(); idx = NTC_SearchTable(adc_val); if (idx == 0xff) { return FALSE; } pt = cNTCTable + idx; *t_z = idx + NTC_TABLE_T_FIRST; *t_f = (*pt - adc_val) * 10 / (*pt - *(pt + 1)); return TRUE; }

采样电阻值和实际温度值对应（两个数组影射）

#define Res1 10000 //10K #define BValue 3950 float Rt,Voltage,Temperature; #define TEMP_NUM 241 int nuiTempTab[TEMP_NUM]= { 95337,92655,90058,87540,85100,82736,80444,78222,76068,73980, 71955,69992,68088,66241,64449,62712,61026,59390,57803,56263, 54769,53318,51911,50544,49217,47929,46679,45464,44285,43140, 42027,40947,39897,38878,37887,36924,35989,35080,34196,33337, 32503,31691,30902,30135,29389,28664,27959,27273,26605,25956, 25325,24711,24113,23532,22966,22415,21879,21357,20850,20355, 19874,19406,18950,18506,18073,17652,17242,16842,16453,16074, 15704,15345,14994,14652,14319,13995,13679,13371,13070,12777, 12492,12213,11942,11677,11419,11168,10922,10683,10449,10222, 10000,9783,9571,9365,9164,8967,8776,8588,8406,8228,8054,7884, 7718,7556,7398,7244,7093,6946,6802,6662,6525,6391,6260,6132, 6007,5885,5766,5650,5536,5425,5316,5210,5106,5004,4905,4808, 4714,4621,4530,4442,4355,4270,4187,4106,4027,3950,3874,3800, 3727,3656,3587,3519,3452,3387,3323,3261,3200,3140,3082,3025, 2969,2914,2860,2808,2756,2706,2657,2608,2561,2515,2470,2425, 2382,2339,2297,2256,2216,2177,2139,2101,2064,2028,1992,1958, 1924,1890,1857,1825,1794,1763,1733,1703,1674,1646,1618,1591, 1564,1537,1512,1486,1461,1437,1413,1390,1367,1344,1322,1300, 1279,1258,1238,1218,1198,1178,1159,1141,1122,1105,1087,1070, 1053,1036,1019,1003,988,972,957,942,927,913,899,885,871,858, 845,832,819,806,794,782,770,759,747,736,725,714,703,693,683, 672,663, }; int trueTempTab[TEMP_NUM]= { -200,-195,-190,-185,-180,-175,-170,-165,-160,-155, -150,-145,-140,-135,-130,-125,-120,-115,-110,-105, -100,-95,-90,-85,-80,-75,-70,-65,-60,-55,-50,-45, -40,-35,-30,-25,-20,-15,-10,-05,00,05,10,15,20,25, 30,35,40,45,50,55,60,65,70,75,80,85,90,95,100,105, 110,115,120,125,130,135,140,145,150,155,160,165,170, 175,180,185,190,195,200,205,210,215,220,225,230,235, 240,245,250,255,260,265,270,275,280,285,290,295,300, 305,310,315,320,325,330,335,340,345,350,355,360,365, 370,375,380,385,390,395,400,405,410,415,420,425,430, 435,440,445,450,455,460,465,470,475,480,485,490,495, 500,505,510,515,520,525,530,535,540,545,550,555,560, 565,570,575,580,585,590,595,600,605,610,615,620,625, 630,635,640,645,650,655,660,665,670,675,680,685,690, 695,700,705,710,715,720,725,730,735,740,745,750,755, 760,765,770,775,780,785,790,795,800,805,810,815,820, 825,830,835,840,845,850,855,860,865,870,875,880,885, 890,895,900,905,910,915,920,925,930,935,940,945,950, 955,960,965,970,975,980,985,990,995,1000, }; int CalcTemp(int nuiResVal) { int temperature; int k; int m; int nuiTempMin = 0; int nuiTempMax = TEMP_NUM; int nuiMidVal = 0; while(nuiResVal >= nuiTempTab[nuiTempMax]) { nuiMidVal = (nuiTempMax + nuiTempMin) / 2; if((nuiMidVal == nuiTempMin) || (nuiMidVal == nuiTempMax)) { break; } if(nuiResVal >= nuiTempTab[nuiMidVal]) { nuiTempMax = nuiMidVal; } else { nuiTempMin = nuiMidVal; } } if (nuiResVal == nuiTempTab[nuiTempMin]) { return trueTempTab[nuiTempMin]; } if (nuiResVal == nuiTempTab[nuiTempMax]) { return trueTempTab[nuiTempMax]; } k = nuiTempTab[nuiTempMin] - nuiTempTab[nuiTempMax]; m = (trueTempTab[nuiTempMax] - trueTempTab[nuiTempMin]) * (nuiResVal - nuiTempTab[nuiTempMax]) / k; temperature = trueTempTab[nuiTempMin] + m; return temperature; } Voltage=(float)ADC_ConvertedValue*(3.3/4096); Rt=(Res1*(float)ADC_ConvertedValue)/(4096-(float)ADC_ConvertedValue); Temperature = CalcTemp(Rt); printf("\r\n 电压值%f \r\n",Voltage); printf("\r\n 电阻值%f \r\n",Rt/1000); printf("\r\n AD值%d \r\n",ADC_ConvertedValue); printf("\r\n 温度值%f\r\n",Temperature/10);

【本文地址】

公司简介

联系我们