内蒙古科技大学毕业设计说明书（毕业论文）
基于虚拟仪器的热电偶检定系统
—数据采集及处理系统
摘 要
热电偶是广泛应用于工业和科研领域中的一种测温传感器，作为现代检测技术和仪器仪表工业的主要工具，它的准确与否直接关系到制造商与用户的经济利益。为了确保热电偶温度计测温的准确性，不仅在出厂时要对它进行严格检定，而且在随后的使用中还要进行周期性检定。随着计算机在各个领域中的发展和广泛应用，标准热电偶检定工作也由过去传统的人工手动操作，发展到现在的计算机自动检定，即采样、控制、数据处理、显示、保存、打印检定记录等整个过程都可由计算机来完成，解决了热电偶手动检定数据计算繁琐、误差较大、检定过程耗费时间长的问题，使标准热电偶整体检测水平得到了相应的提高。
基于上述形势，本论文利用现代计算机控制技术和数据采集技术，以及丰富的软、硬件资源，论述了一种新型的标准热电偶计算机自动检定系统的研制方法。系统选用先进的集成数据采集卡和功能强大的LabVIEW虚拟仪器技术，构建了一种新型热电偶自动检定系统。此系统界面友好，操作灵活方便，而且可移植性和重用性强。
关键词：热电偶；自动检定；数据采集；虚拟仪器
内蒙古科技大学毕业设计说明书（毕业论文）
The Calibration System of Thermocouples Based on Virtual Instrument – Data Acquisition and Processing System
Abstract
Thermocouple is a sort of temperature sensor, which is used extensivly in industry and scientific field. As the important means of temperature measurement and industry in the modern society,its accuracy directly relates the economy benefits of the manufacturers and the users. To ensure the thermocouple’s veracity, it must be calibrated strictly before it leave factory, and be calibrated periodically in the process of use it.With the further developing and wide application for computer in the various fields, the calibrating work for standard thermocouple has being developed from the past traditional manual operation to automation. Computer can complete the calibrating inculding sampling、controlling、processing data、displaying、saving and printing calibrating records. So the automatic calibration system not only resovlved a series of problems such as detailed data-calculating,major errors,time-wasting and so on,but also improved the technique.
Based on above-mentioned situations, this thesis makes use of morden computer contorl and data acquisition technology with abundant software and hardware resources ,and expounds the research of a new kind of automatic calibration system.The system uses the advanced DAQ and the powerful function LabVIEW virtual instrument technology,which designs the new automatic calibration system for thermocouple. It has friendly interface, and can be operated conveniently , moreover, it can be transplanted and repeated used.
Key words: Thermocouple; Automatic test; Data acquisition; Virtual Instrument
内蒙古科技大学毕业设计说明书（毕业论文）
目 录
摘 要 ......................................................................................................................................... I Abstract ......................................................................................................................................II 第一章 绪论 .............................................................................................................................. 1
1.1 课题的研究背景及发展概况 ..................................................................................... 1 1.2 课题研究的主要内容 ................................................................................................. 4 第二章 虚拟仪器的基本知识 .................................................................................................. 5
2.1 虚拟仪器基本概念 ..................................................................................................... 5 2.2 虚拟仪器发展方向 ..................................................................................................... 9 第三章 热电偶简介 ................................................................................................................ 11
3.1 热电偶基本概念与测温原理 ................................................................................... 11
3.1.1 热电偶的基本概念 ........................................................................................ 11 3.1.2 热电偶的测温原理 ........................................................................................ 15 3.2 标准热电偶的检定 ................................................................................................... 16 3.3 热电偶检定的数据处理 ........................................................................................... 18 第四章 基于虚拟仪器的热电偶自动检定系统的设计 ........................................................ 19
4.1 系统总体设计 ........................................................................................................... 19 4.2 炉温控制系统设计 ................................................................................................... 20 4.3 数据采集系统设计 ................................................................................................... 22
4.3.1 数据采集原理 ................................................................................................ 22 4.3.2 数据采集系统的实现 .................................................................................... 23
第五章 热电偶检定系统的硬件配置 .................................................................................... 24
内蒙古科技大学毕业设计说明书（毕业论文）
5.1 DAQ系统设计 .......................................................................................................... 24
5.1.1 信号调理卡 .................................................................................................... 24 5.1.2 数据采集卡 .................................................................................................... 25 5.1.3 DAQ硬件配置 ............................................................................................... 25 5.2 热电偶检定炉 ........................................................................................................... 26 5.3 JKH-C2型可控硅移相触发器/调压器 ..................................................................... 27 5.4 零点恒温器 ............................................................................................................... 29 5.5 计算机配置 ............................................................................................................... 29 第六章 热电偶检定系统的软件设计与开发 ........................................................................ 30
6.1 软件系统的整体设计 ............................................................................................... 30 6.2 软件设计 ................................................................................................................... 31
6.2.1 登陆系统子VI ............................................................................................... 31 6.2.2 初始设置子VI ............................................................................................... 33 6.2.3 预警系统子VI ............................................................................................... 34 6.2.4 数据采集子VI ............................................................................................... 36 6.2.5 数据记录与读取子VI ................................................................................... 38 6.2.6 温度曲线子VI ............................................................................................... 38 6.2.7 误差与修正曲线子VI ................................................................................... 40 6.3 检定结果分析 ........................................................................................................... 41 第七章 总结 ............................................................................................................................ 43 参考文献 .................................................................................................................................. 44 附录A总系统前面板 .............................................................................................................. 46 附录B总系统数据流程图 ...................................................................................................... 47
内蒙古科技大学毕业设计说明书（毕业论文）
致谢 .......................................................................................................................................... 48