硬件设计

（末尾附文件）

1．采用AT89C51单片机作为控制器，分别对温度采集、LCD显示。
2．温度测量模块采用K\热电偶与MAX6775相结合可实现冷端温度补偿高分辨率测量
3．显示用液晶显示屏显示实时温度值。
4. 系统结构如图2.4。

　硬件组成原理
本系统硬件主要由热电偶温度采集电路、MAX6675温度处理电路、89C51单片机控制电路和LCD显示电路，报警电路组成。
首先通过键盘设定温度范围，存储在24C02C存储器里，热电偶采用分度号为K的热电偶，为了减少外界信号的干扰通过双绞线跟MAX6675芯片直接相连接。MAX6675芯片通过SPI串行接口传输数据，采用的89C51单片机对带有冷端补偿的温度转换芯片MAX6675进行控制。本系统设计还具有报警的特点，当所测量的温度低于所设置的温度下限或者高于所设置的温度上限时报警电路发出警报。显示电路由89C51单片机通过1602液晶显示屏(LCD)进行显示，显示的是当前设置温度的上限与下限，以及热电偶测温的温度。

仿真图1： LCD1602为显示器，MAX1241为数据采集芯片； 可设置温度上下限，超出范围后蜂鸣器报警

仿真图2 LCD1602为显示器，MAX6775为数据采集芯片；可设置温度上下限，超出范围电机将被正反驱动且相应的LED会亮起

程序设计

#include<reg51.h>
#include<intrins.h> //包含_nop_()函数定义的头文件
#include<absacc.h>
#define uchar unsigned char
#define uint  unsigned int
#define LCD1602_DW XBYTE[65023]
#define LCD1602_CW XBYTE[64767]
#define LCD1602_CR XBYTE[65279]
sbit DOUT=P1^5;
sbit SCLK=P1^6;
sbit CS=P1^7;
uint aaaa,aa,cc;//储存A/D转换后的值
uchar num;
uint a,b,c;
sbit p10=P1^0;//按键端口
sbit p11=P1^1;//按键端口
sbit p12=P1^2;//按键端口
sbit p30=P3^0;//蜂鸣器接口
uint code table1[]={	0,3,6,9,10,15,18,21,23,26,29,32,35,38,41,44,47,50,53,56,59,62,65,68,71,74,78,81,84,87,90,93,96,99,102,105,108,112,115,118,121,124,127,130,134,137,140,143,146,149,153,156,159,162,165,169,172,175,178,181,185,188,191,194,198,201,204,207,211,214,217,220,224,227,230,233,237,240,243,246,250,253,256,260,263,266,270,273,276,280,283,286,290,293,296,300,303,306,310,313,316,320,323,326,330,333,336,340,343,346,350,353,356,360,363,366,370,373,376,380,383,387,390,393,397,400,403,407,410,413,417,420,424,427,430,434,437,440,444,447,451,454,457,461,464,467,471,474,477,481,484,487,491,494,497,501,504,508,511,514,518,521,524,528,531,534,538,541,544,548,551,554,558,561,564,567,571,574,577,581,584,587,591,594,597,600,604,607,610,614,617,620,624,627,630,633,637,640,643,646,650,653,656,659,663,666,669,673,676,679,682,686,689,692,695,699,702,705,708,711,715,718,721,724,728,731,734,737,741,744,747,750,754,757,760,763,766,770,773,776,779,783,786,789,792,796,799,802,805,809,812,815,818,821,825,828,831,834,838,841,844,847,851,854,857,860,864,867,870,873,877,880,883,886,890,893,896,899,903,906,909,913,916,919,922,926,929,932,935,939,942,945,949,952,955,958,962,965,968,972,975,978,981,985,988,991,995,998,1001,1005,1008,1011,1014,1018,1021,1024,1028,1031,1034,1038,1041,1044,1048,1051,1054,1058,1061,1064,1068,1071,1074,1078,1081,1084,1088,1091,1094,1098,1101,1104,1108,1111,1114,1118,1121,1124,1128,1131,1135,1138,1141,1145,1148,1151,1155,1158,1161,1165,1168,1171,1175,1178,1182,1185,1188,1192,1195,1198,1202,1205,1209,1212,1215,1219,1222,1225,1229,1232,1236,1239,1242,1246,1249,1252,1256,1259,1263,1266,1269,1273,1276,1279,1283,1286,1290,1293,1296,1300,1303,1307,1310,1313,1317,1320,1324,1327,1330,1334,1337,1341,1344,1347,1351,1354,1358,1361,1364,1368,1371,1375,1378,1381,1385,1388,1392,1395,1398,1402,1405,1409,1412,1415,1419,1422,1426,1429,1433,1436,1439,1443,1446,1450,1453,1456,1460,1463,1467,1470,1474,1477,1480,1484,1487,1491,1494,1497,1501,1504,1508,1511,1515,1518,1521,1525,1528,1532,1535,1539,1542,1545,1549,1552,1556,1559,1563,1566,1569,1573,1576,1580,1583,1587,1590,1594,1597,1600,1604,1607,1611,1614,1618,1621,1624,1628,1631,1635,1638,1642,1645,1649,1652,1655,1659,1662,1666,1669,1673,1676,1680,1683,1686,1690,1693,1697,1700,1704,1707,1711,1714,1717,1721,1724,1728,1731,1735,1738,1742,1745,1748,1752,1755,1759,1762,1766,1769,1773,1776,1779,1783,1786,1790,1793,1797,1800,1804,1807,1811,1814,1817,1821,1824,1828,1831,1835,1838,1842,1845,1849,1852,1855,1859,1862,1866,1869,1873,1876,1880,1883,1887,1890,1893,1897,1900,1904,1907,1911,1914,1918,1921,1925,1928,1931,1935,1938,1942,1945,1949,1952,1956,1959,1963,1966,1969,1973,1976,1980,1983,1987,1990,1994,1997,2001,2004,2007,2011,2014,2018,2021,2025,2028,2032,2035,2039,2042,2045,2049,2052,2056,2059,2063,2066,2070,2073,2076,2080,2083,2087,2090,2094,2097,2101,2104,2108,2111,2114,2118,2121,2125,2128,2132,2135,2139,2142,2145,2149,2152,2156,2159,2163,2166,2170,2173,2176,2180,2183,2187,2190,2194,2197,2201,2204,2207,2211,2214,2218,2221,2225,2228,2231,2235,2238,2242,2245,2249,2252,2256,2259,2262,2266,2269,2273,2276,2280,2283,2286,2290,2293,2297,2300,2304,2307,2310,2314,2317,2321,2324,2328,2331,2334,2338,2341,2345,2348,2352,2355,2358,2362,2365,2369,2372,2375,2379,2382,2386,2389,2393,2396,2399,2403,2406,2410,2413,2416,2420,2423,2427,2430,2434,2437,2440,2444,2447,2451,2454,2457,2461,2464,2468,2471,2474,2478,2481,2485,2488,2491,2495,2498,2502,2505,2508,2512,2515,2519,2522,2525,2529,2532,2536,2539,2542,2546,2549,2552,2556,2559,2563,2566,2569,2573,2576,2580,2583,2586,2590,2593,2596,2600,2603,2607,2610,2613,2617,2620,2623,2627,2630,2634,2637,2640,2644,2647,2650,2654,2657,2661,2664,2667,2671,2674,2677,2681,2684,2687,2691,2694,2698,2701,2704,2708,2711,2714,2718,2721,2724,2728,2731,2734,2738,2741,2744,2748,2751,2754,2758,2761,2765,2768,2771,2775,2778,2781,2785,2788,2791,2795,2798,2801,2805,2808,2811,2815,2818,2821,2825,2828,2831,2835,2838,2841,2844,2848,2851,2854,2858,2861,2864,2868,2871,2874,2878,2881,2884,2888,2891,2894,2898,2901,2904,2907,2911,2914,2917,2921,2924,2927,2931,2934,2937,2941,2944,2947,2950,2954,2957,2960,2964,2967,2970,2973,2977,2980,2983,2987,2990,2993,2997,3000,3003,3006,3010,3013,3016,3019,3023,3026,3029,3032,3036,3039,3042,3045,3049,3052,3055,3058,3061,3064,3067,3071,3074,3077,3080,3082,3085,3088,3091,3094,3096,3099,3102,3104,3106,3109,3111,3113,3115,3117,3119,3121,3123,3125,3126,3128,3130,3131,3132,3134,3135,3136,3138,3139,3140,3141,3142,3143,3144,3145,3146,3147,3148,3149,3150};
uint code table2[]={	52,51,50,49,48,47,46,45,44,43,42,41,40,39,38,37,36,35,34,33,32,31,30,29,28,27,26,25,24,23,22,21,20,19,18,17,16,15,14,13,12,11,10,9,8,7,6,5,4,3,2,1,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144,145,146,147,148,149,150,151,152,153,154,155,156,157,158,159,160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181,182,183,184,185,186,187,188,189,190,191,192,193,194,195,196,197,198,199,200,201,202,203,204,205,206,207,208,209,210,211,212,213,214,215,216,217,218,219,220,221,222,223,224,225,226,227,228,229,230,231,232,233,234,235,236,237,238,239,240,241,242,243,244,245,246,247,248,249,250,251,252,253,254,255,256,257,258,259,260,261,262,263,264,265,266,267,268,269,270,271,272,273,274,275,276,277,278,279,280,281,282,283,284,285,286,287,288,289,290,291,292,293,294,295,296,297,298,299,300,301,302,303,304,305,306,307,308,309,310,311,312,313,314,315,316,317,318,319,320,321,322,323,324,325,326,327,328,329,330,331,332,333,334,335,336,337,338,339,340,341,342,343,344,345,346,347,348,349,350,351,352,353,354,355,356,357,358,359,360,361,362,363,364,365,366,367,368,369,370,371,372,373,374,375,376,377,378,379,380,381,382,383,384,385,386,387,388,389,390,391,392,393,394,395,396,397,398,399,400,401,402,403,404,405,406,407,408,409,410,411,412,413,414,415,416,417,418,419,420,421,422,423,424,425,426,427,428,429,430,431,432,433,434,435,436,437,438,439,440,441,442,443,444,445,446,447,448,449,450,451,452,453,454,455,456,457,458,459,460,461,462,463,464,465,466,467,468,469,470,471,472,473,474,475,476,477,478,479,480,481,482,483,484,485,486,487,488,489,490,491,492,493,494,495,496,497,498,499,500,501,502,503,504,505,506,507,508,509,510,511,512,513,514,515,516,517,518,519,520,521,522,523,524,525,526,527,528,529,530,531,532,533,534,535,536,537,538,539,540,541,542,543,544,545,546,547,548,549,550,551,552,553,554,555,556,557,558,559,560,561,562,563,564,565,566,567,568,569,570,571,572,573,574,575,576,577,578,579,580,581,582,583,584,585,586,587,588,589,590,591,592,593,594,595,596,597,598,599,600,601,602,603,604,605,606,607,608,609,610,611,612,613,614,615,616,617,618,619,620,621,622,623,624,625,626,627,628,629,630,631,632,633,634,635,636,637,638,639,640,641,642,643,644,645,646,647,648,649,650,651,652,653,654,655,656,657,658,659,660,661,662,663,664,665,666,667,668,669,670,671,672,673,674,675,676,677,678,679,680,681,682,683,684,685,686,687,688,689,690,691,692,693,694,695,696,697,698,699,700,701,702,703,704,705,706,707,708,709,710,711,712,713,714,715,716,717,718,719,720,721,722,723,724,725,726,727,728,729,730,731,732,733,734,735,736,737,738,739,740,741,742,743,744,745,746,747,748,749,750,751,752,753,754,755,756,757,758,759,760,761,762,763,764,765,766,767,768,769,770,771,772,773,774,775,776,777,778,779,780,781,782,783,784,785,786,787,788,789,790,791,792,793,794,795,796,797,798,799,800,801,802,803,804,805,806,807,808,809,810,811,812,813,814,815,816,817,818,819,820,821,822,823,824,825,826,827,828,829,830,831,832,833,834,835,836,837,838,839,840,841,842,843,844,845,846,847,848,849,850,851,852,853,854,855,856,857,858,859,860,861,862,863,864,865,866,867,868,869,870,871,872,873,874,875,876,877,878,879,880,881,882,883,884,885,886,887,888,889,890,891,892,893,894,895,896,897,898,899,900,901,902,903,904,905,906,907,908,909};
void delay1(uint z)
{for(z=0;z<10;z++)_nop_();
}
//判忙函数
void WHILE_BUSY()						 
{while((bit)(LCD1602_CR&128));//读回DB7的值，为DB7=1时则等待 。
}
void LCD1602_init()
{ WHILE_BUSY();//判忙，不忙继续写指令LCD1602_CW=56;//写指令，8位接口，双行显示，5*7字符WHILE_BUSY();//判忙，不忙继续写指令LCD1602_CW=1;//清屏WHILE_BUSY();//判忙，不忙继续写指令LCD1602_CW=6;//地址计数自动加一WHILE_BUSY();//判忙，不忙继续写指令LCD1602_CW=12;//开显示
}
uint read_max1241()
{uint voltage=0;		 //存放12位数字量uchar cont12=12;	     //12位CS=1;SCLK=0;CS=0;while(DOUT==0);       //转换结束SCLK=1;SCLK=0;while(cont12--){SCLK=1;              //SCLK上升沿数据稳定并读出voltage<<=1;    if(DOUT==1)voltage+=1;SCLK=0;}	 CS=1;return voltage;
}

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文件地址

链接：https://pan.baidu.com/s/1g35SOgoVfOdbluOuerBwNg
提取码：z5q5

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