表5.2 E型热电偶温度曲线数据处理(a) 截取数据(x,y) ( 0 ,0 ) (11.1199,0.6603) (24.9140,1.4748) 求得的(k,b)值 —— (0.05938,0) (0.05905,0.00370) 截取数据(x,y) (263.8429,18.2483) (278.1772,19.3379) (293.2072,20.4633) (312.4124,21.9995) (339.4713,24.0961) (357.9673,25.5664) (378.2661,27.1992) (388.5059,28.0277) (403.3234,29.1975) (418.6228,30.4322) (431.3058,31.4688) (466.9868,34.3310) (485.3941,35.7954) (493.6641,36.4611) (509.7465,37.7738) (525.9030,39.0783) (540.0750,40.2581) (553.8872,41.3418) (577.1954,43.2471) 求得的(k,b)值 (0.077996, -2.33047) (0.07601, -1.80732) (0.07488, -1.49115) (0.07999, -2.98998) (0.07748, -2.20710) (0.07949,-2.88945) (0.08044, -3.22786) (0.08091, -3.40623) (0.07895, -2.64375) (0.08070, -3.35171) (0.08173, -3.78245) (0.08022, -3.12898) (0.07956, -2.82032) (0.08050, -3.27677) (0.08162, -3.83344) (0.08074, -3.38390) (0.08325, -4.70242) (0.07846, -2.11598) (0.08174,-3.9350) (41.5665,2.5092) (0.06211,-0.07278) (53.6208,3.2720) (0.06328, -0.12114) (65.9120,4.0675) (0.06472, -0.19840) (80.8246,5.0269) (0.06433, -0.17294) (90.4945,5.6585) (0.06532, -0.25225) (109.7177,6.9701) (120.8203,7.7391) (131.0263,8.4395) (143.1633,9.2770) (0.06823, -0.51594) (0.06926, -0.62928) (0.06863, -0.55235) (0.06900, -0.60182) (155.852,10.1906) (0.07200, -1.03091) (168.402,1.1042) (180.539,11.9722) (196.936,13.1790) (0.07279, -1.15430) (0.07152, -0.93953) (0.07360, -1.31514) (208.408,14.0275) (0.07397, -1.38786) (234.589,16.0023) (249.299,17.1140) (0.07543, -1.69216) (0.07557, -1.72632)
表5.3 E型热电偶温度曲线数据处理(b) 截取数据(x,y) 求得的(k,b)值 截取数据(x,y) 求得的(k,b)值 (598.7770,44.9775) (628.3034,47.3576) (651.9522,49.2434) (669.1011,50.6274) (682.6408,51.6979) (704.2806,53.4480) (726.1569,55.1794) (748.4532,56.9621) (761.9314,58.0299) (785.3031,59.8729) (798.7812,60.9235) (812.9558,62.0404) (831.4865,63.4521) (848.3578,64.7923) (864.3993,66.0432) (0.08018,-3.03209) (0.08061,-3.28945) (0.07974,-2.74450) (0.08070,-3.37233) (0.07906,-2.27427) (0.08087,-3.51008) (0.07915,-2.29230) (0.07995,-2.88045) (0.07922,-2.33353) (0.07886,-2.05300) (0.07795,-1.34043) (0.07880,-2.01716) (0.07618,0.10806) (0.07944,-2.59842) (0.07798,-1.36179) (886.3455,67.7209) (894.4194,68.3358) (911.5947,69.6709) (933.4675,71.3399) (943.4797,72.0903) (952.7813,72.8050) (964.7959,73.6911) (984.1743,75.1633) (990.2462,75.6207) (1000.0000,76.358) —— —— —— —— —— (0.07645, -0.03670) (0.07616, 0.21773) (0.07773, -1.19075) (0.07630, 0.11183) (0.07495, 1.37785) (0.07684, -0.40314) (0.07375, 2.53554) (0.07597, 0.39441) (0.07533, 1.02484) (0.07559, 0.76695) —— —— —— —— —— 全部的数据处理利用MATLAB 的“X=A\\B”函数进行。下面给出进行数据处理的
例子,
>> format long >> A=[0 1;11.1199 1] A =
0 1.00000000000000 11.11990000000000 1.00000000000000
>> B=[0;0.6603] B =
0 0.66030000000000
>> X=A\\B X =
0.05938003039596 0
>> A=[11.1199 1;24.9140 1] A =
11.11990000000000 1.00000000000000 24.91400000000000 1.00000000000000
>> B=[0.6603;1.4748] B =
0.66030000000000 1.47480000000000
经过上述的分段折线化方法对E型热电偶非线性校正后,可以得到较高的精确
度,同时相较于方案二由于是对温度—毫伏曲线进行全部的校正,因此其适用于整个量程,且不需要很多的数学知识便可解决。
5.2 系统软件设计
1.主程序流程图
整个系统的软件由A/D采集、DS1302时钟程序、HD7279显示程序等几部分组成。其整个系统的流程图如图5.5所示。
开 始
2.键盘、显示子程序流程图
结 束 进行采集 LED显 示 温度路数? 键值=59、60 判断值 按键? N 复 位 Y 键值=61 键值=62 时钟值 结 束 图5.5 主程序流程图
图5.6为HD7279工作流程图。
结 束 LED显示 与CPU通讯 按 键 ? Y N 闪 烁 复 位 开 始 判断键值 图5.6 HD7279工作流程图
5.3 本章小结
本章主要介绍了E型热电偶的线性化处理方法—分段折线化的处理方法,采
用MATLAB对E型热电偶的分度表进行曲线拟合,而后在曲线上分段截取线段求取k,b值。在软件设计中作出了整个系统的软件流程图,同时给出了TLC2543的软件实例。