基于虚拟仪器的加热炉温控系统设计

中文摘要I摘要本论文要做的课题是基于虚拟仪器的加热炉温控系统设计，要求加热炉温度稳定在80℃，允许有±1℃的误差。本论文采用美国NI公司虚拟仪器开发软件LabVIEW8.5开发出一套低温电加热炉温度控制系统。系统具体设计方案如下：由传感器测得的炉温信号经过变送环节送给数据采集卡，采集卡对信号进行A/D转换后传输至虚拟仪器，虚拟仪器中的PID算法对信号处理后产生控制信号，再经过采集卡D/A转换后输出控制PWM波产生电路，改变PWM波占空比，产生的PWM波经过光耦MOC3041控制双向可控硅的通断，以此改变加在电阻上的电压，达到温控目的。本论文首先按照上述设计方案设计了硬件电路，接着进行系统软件的设计。经过简单的实验，系统可以正常采集数据并显示。关键词：虚拟仪器，LabVIEW，温控系统，过零调功，PWMAbstractIIAbstractThetaskofthispaperistodesignatemperaturecontrolsystembasedonvirtualinstrumentofthefurnace.Andtherequirementsofthefurnacetemperatureisstableat80℃,allowederrorof±1℃.ThispaperadoptedLabVIEW8.5,asoftwaretodevelopthevirtualinstrumentofNIcompanyinAmerica,developedasetoftemperaturecontrolsystemoflow-powerelectricheating.Thesystemdesignareshowedasfollows:thetemperaturesensorssendthesignaloftemperaturechangetothedataacquisitioncardbytransmitter,thenthesignalwillbeconverttodigitalsignalandbesendtothevirtualinstrumentbythedataacquisitioncard,andthenthevirtualinstrumentwilloutputcontrolsignalafterbeprocessedbyPIDalgorithm,andthecontrolsignalwillbeconverttoanalogsignalbythedataacquisitioncardandoutputtocontrolPWMwavesproducecircuittochangethedutycycleofPWMwaves,thenthePWMwaveswillcontrolthebidirectionalthyristorthroughopticalcouplerMOC3041tochangethevoltageinresistancesothatthetemperaturewillbechanged.Thispaperdesignedthehardwarecircuitinaccordancewiththeabovedesignscheme,followedbythedesignofthesystemsoftware.Afterasimpleexperiment,thesystemcanacquireanddisplaythedatasnormally.Keywords:virtualinstrument,LabVIEW,temperaturecontrolsystem,zero-crossingpoweradjustment,PWM目录III目录摘要.........................................................................................................IABSTRACT(英文摘要)...............................................................................Ⅱ目录.........................................................................................................Ⅲ第一章绪论................................................................................................11.1课题的研究的目的和意义............................................................................11.2国内外发展状况............................................................................................11.3本设计要做的工作........................................................................................3第二章虚拟仪器及LabVIEW简介.............................................................42.1虚拟仪器的基本概念....................................................................................42.2虚拟仪器的特点及应用................................................................................42.3LabVIEW的含义...........................................................................................52.4LabVIEW的发展...........................................................................................62.5LabVIEW的结构............................................................................62.6LabVIEW的优势...........................................................................................6第三章系统总体方案及硬件电路设计.........................................................73.1系统总体方案................................................................................................73.2硬件电路设计................................................................................................73.2.1传感器的选型...........................................................................73.2.2数据采集卡的选型...................................................................93.2.3PWM波产生电路的设计..........................................................113.2.4交流过零触发PWM脉宽调功原理..........................................12第四章温控系统软件设计..........................................................................144.1登录系统设计................................................................................................144.2数据采集及处理控制模块的设计................................................................174.2.1温度信号的采集.......................................................................174.2.2采集数据的处理.......................................................................19目录IV4.2.3PID控制信号的产生.................................................................224.3数据存储模块................................................................................................244.3.1数据存入文本文件...................................................................244.3.2数据存入TDMS文件..............................................................254.4历史数据查看模块.........................................................................264.4.1文本文件查看方式..................................................................264.4.2TDMS文件查看方式................................................................284.5打印模块........................................................................................394.6网络通信模块................................................................................304.6.1DataSocket的数据传输............................................................314.6.2在Web上发布程序.................................................................334.7加热炉温控系统的集成..........................................................