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1、摘 要导热系数是表征物质热传导性质的物理量，材料结构的变化与所含杂质的不同对导热系数值都有明显的影响。导热系数作为衡量建筑材料保温性能，表征料传热能力的重要指标一直为人们所重视，材料的导热系数经常需要由实验具体测定，目前大多使用电位差计和电流计来人工测定计算导热系数，其缺点是自动化程度低、通用性差、调节过程复杂、测试结果容易受到人为因素的影响。随着我国经济和科学技术的发展，新产品、新材料不断涌现，工业、农业、建筑、地质、等部门对新产品、新材料的导热系数测量越来越多，精度要求也越来越高，面对科研、生产的高要求，用微机和智能控制方法构成的一种新型的数字测控系统十分必要，智能导热系数的测控系统提高了
2、保温材料特性测试的自动化和智能水平，同时提高了测量的效率和测试的精度，减轻了人员的劳动强度。本次设计的任务是智能导热系数测试仪测控系统的设计。本测控系统主要功能是通过加热模块对被测保温（绝热）材料的两侧进行加温。当两侧温度达到稳定时，形成稳定的温差。该温差形成一个稳定的热流通过被测材料。根据此温差和材料的几何尺寸等参数和计算公式就可计算得出该材料的导热系数。因此，本设计任务主要包括：材料两侧的温度测量、温度控制、稳温状态的判定和导热系数的计算、被测材料几何参数的输入、导热系数结果的显示等。通过任务分析、方案比较确定和电路设计，较好的实现了导热系数测试仪测控系统的设计任务。关键词：微型处理器，导
3、热系数，智能，温度控制，功率驱动AbstractThe coefficient of transmitting heat is described as a physics context which tokens the heat conduction character of material. The coefficient value of transmitting heat is strongly affected by the changing of material construction and the different impurity which the materia
4、l contains. The coefficient of transmitting heat, as the important index which measures the heat preservation function of the building materials and tokens the transmitting heat ability which the material has, is paid more attentions all the time. The coefficient of transmitting heat of the material
5、 is always requested to be measured in experiment. Nowadays the electric potential difference counts and the galvanometer are used to measure the coefficient of transmitting heat in most case, which exists some shortcomings: the low automation degree , the bad performance in general use, the complic
6、acy regulate process ,the measure results are easily influenced by artificial factors. Along with the development of the economy and science technique in our country, there present a lot of new products and new materials. In the industrial agricultural department, and building departments, more and
7、more measurements are needed to obtain the coefficient of transmitting heat of the new product, the measuring accuracy is requested to be higher. In the face of the requirement for scientific research and industrial production, it is quite necessary to design a new digital measuring system with the
8、microcomputer and the intelligence control technique. Intelligent system which measures the coefficient of transmitting heat improves the automation and intelligence level. At the same time, it improves the measure efficiency and the test accuracy, alleviates the personnels labor strength. The task
9、of this design is to design and finish a measure system which contains a intelligent machine measuring the coefficient of transmitting heat.It mainly designs to collect the temperature of the material which is to be measured with thermo-element on the condition that the temperature controlling modul
10、e makes the measuring condition reaching a stably level .And then amplifier, convert it from analog to digital, deliver it and the conduct in the whole controlling module, then convert the processed signal from digital to analog signal, control the heating efficiency. Then it designs the communicati
11、on between the upper and below computer and the communicating bus among each module, and so on. Finally we finish the task which contains the measure of the coefficient of transmitting heat which the material have, and the manifestation of the data result with CRT. And whats more, the measure result
12、 could be printed out from the printer at any time.By the designing of the each module above, we complete the measuring function of the machine which measures the coefficient of transmitting heat, and obtain quite a good result which we look forward to. The design result proves that the measuring sy
13、stem with high intelligence and automation level improves the intelligence and automation level in measuring the characters of the preserving heat material, meantime, improves the measure efficiency and the test accuracy. Key word: MCU, The coefficient of transmitting heat, intelligence, Temperature
14、 controlling目 录第一章、绪论第二章、导热系数的测试方法和测试原理21导热系数的测试方法211 稳态方法测量法212动态（瞬时）测量法22导热系数的测试原理23影响绝热材料导热系数的主要因素第三章、专用电炉的设计第四章、智能导热系数测试仪硬件系统的设计 41 上位机42 下位机421 模/数转换器422 数/模转换器423 温度传感器424 信号放大电路425 温度控制电路第五章、智能导热系数测试仪软件系统的设计51软件功能分析52面板设计及软件程序框图第六章、系统通信的设计61 系统总线的简介62上下位机之间的通信总线的选择与实现63 PI总线的特点和PI-BIU的设计流程第七章
15、、智能导热系数测试仪整机操作说明结语与谢辞参考文献第一章、绪论 导热系数作为衡量建筑材料保温性能，表征料传热能力的重要指标一直为人们所重视，材料的导热系数经常需要由实验具体测定，目前大多数的人工测定计算导热系数，其缺点是自动化程度低、通用性差、调节过程复杂、测试结果容易受到人为因素的影响。因此，没有先进的计算机技术，复杂的测控系统是难以实现的。本设计属于典型的稳态法平板式导热系数测定法 对试块和专用电炉的应用来讲，符台无限大平板式稳态测量原理，满足稳态傅立叶导热公式的应用条件。电炉设计合理，尤其其升温速率很快，这样可以缩短测量周期，是本仪器的特色之一。固为使用了微机技术，可对各种金属、非金属进
16、行 测量。其量程广泛，是本仪器特色之二。固为在单片机上使用了LabVIEW 软件包，不仅实现了软件代替硬件的原则，而且极大降低了编程时间。两个月底层编程时间可以缩减到十天，而且程序易于修改和链接本仪器从压一次“自动升温”虚拟按键开始，直至打印出测量结果，全部实现微机自调和管理，无需人工干预。可知，本设计是一套复杂的闭环测控系统。总之，本仪器是一台高质量，高速度和全自动化的新产品，在各行各业中有广泛的应用前景。第二章、导热系数的测试方法和测试原理 21 导热系数的测试方法211 稳态方法测量法热流法导热仪：将厚度一定的方形样品（通常长宽各30cm，厚10cm）插入于两个平板间，设置一定的温度梯度。使用校正过的热流传感器测量通过样品
