应变式传感器称重系统的设计

菏泽学院HezeUniversity本科生课程设计（论文）题目应变式传感器称重系统的设计姓名任青瑞学号2013174271院系蒋震机电工程学院专业自动化指导教师侯建华职称副教授应变式传感器称重系统的设计１传感器与检测技术课程设计任务书及成绩评定专业自动化设计题目应变式传感器称重系统的设计学生姓名任青瑞学号2013174271指导教师侯建华职称副教授一、设计的主要内容（技术指标）与要求1主要内容本文设计了一种以AT89C51单片机为核心，包括ADC0809类型转换器的压阻应变片式压力传感器的重力测量系统。精度高，输出特性的线性好，工作性能稳定、可靠。2设计要求：（1）了解应变桥的工作原理；（2）应用应变桥的调节电路和A/D转换；（3）使用单片机读取转换值并用数码管显示；（4）测量范围是0—2000g。进度安排：第一阶段查阅相关文献第二阶段确立多个方案，选择最优方案第三阶段针对方案进行硬件电路设计并调试第四阶段针对方案进行软件设计并调试第五阶段总结报告，写论文成绩评定设计成绩：指导教师：年月日菏泽学院本科传感器与检测技术课程设计２目录摘要„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„1关键字„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„1Abstract„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„1Keywords„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„1引言„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„21应变式传感器称重系统设计方案„„„„„„„„„„„„„„„„„„„„„21.1设计要求„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„21.2设计思路„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„22硬件设计„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„22.1单片机模块„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„22.2电源模块„„„„„„„„„„„„„„„„„„„„„„„„„„„„„42.3传感器电路模块„„„„„„„„„„„„„„„„„„„„„„„„„„„42.4A/D变换电路模块„„„„„„„„„„„„„„„„„„„„„„„„„„42.5数码管显示模块„„„„„„„„„„„„„„„„„„„„„„„„„„„53软件设计„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„63.1程序设计语言的选用„„„„„„„„„„„„„„„„„„„„„„„„„63.2软件程序的设计„„„„„„„„„„„„„„„„„„„„„„„„„„„64调试校准„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„74.1实物连线„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„74.2系统调零„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„84.3量程调节„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„8个人总结„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„8参考文献„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„8附录„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„„9应变式传感器称重系统的设计３应变式传感器称重系统的设计自动化专业学生任青瑞指导教师侯建华摘要：本文设计一种以AT89C51单片机为核心，包括ADC0809类型转换器的压阻应变片式压力传感器的重力测量系统。简要介绍了压阻应变片式压力传感器电路的工作原理以及A/D变换电路的工作原理，完成了整个实验对于压力的采样和显示。与其它类型传感器相比，压阻应变片式压力传感器有以下特点：测量范围广，精度高，输出特性的线性好，工作性能稳定、可靠，能在恶劣的化境条件下工作。由于压阻应变片式压力传感器具有以上优点，所以它在重力测试技术中取得十分广泛的应用。关键字：压阻应变片式传感器；AT89C51单片机；ADC0809；数码管TheDesignofStrainGaugeSensorWeighingSystemAutomationprofessionalstudentRenQingruiTutorHouJianhuaAbstract:ThispaperintroducesakindofdifferentialpressuremeasuringsystemwithAT89C51singlechipmicrocomputerasthecore,includingthediffusionsiliconpressureresistancetypepressuresensorofADC0809typeconverter.ThispaperbrieflyintroducestheworkingprincipleofthediffusionsiliconpressuresensorcircuitandtheworkingprincipleoftheA/Dconversioncircuit,andcompletesthesamplinganddisplayofthepressureinthewholeexperiment.Comparedwithotherkindsofsensors,thediffusedsiliconpressureresistancetyperesistancestraintypesensorhasthefollowingcharacteristics:widemeasuringrange,highprecision,goodoutputcharacteristicsoflinear,stableperformance,reliable,canworkunderthebadenvironmentconditions.Becauseoftheaboveadvantages,thediffusionsiliconpressureresistancetypepressuresensorhasaverywiderangeofapplications.Keywords:Pressureresistancestraingaugesensor;AT89C51;ADC0809;digitaltube菏泽学院本科传感器与检测技术课程设计４引言物料计量是工业生产和贸易流通中的重要环节。称重装置或衡器是不可缺少的计量工具。随着工农业生产的发展和商品流通的扩大，衡器的需求也日益增多，过去沿用的机械杠杆秤己不能适应生产自动化和管理现代化的要求。而传感器技术和电子技术的迅速发展，电子称重技术日趋成熟，逐步取代了机械秤。快速、准确、操作方便、消除人为误差、功能多样化等方面已成为现代电子称重技术的主要特点。现代电子称重装置的应用已遍及到国民经济各领域，取得了显著的经济效益。同时对称重仪表的要求也越来越高，要求仪表有更高抗干扰能力、更高的精度。而压力传感器技术在诸多领域中相对而言最为成熟。根据工作原理的不同，压力传感器通常可以分为机械膜片、硅膜片电容性、压电性、应变性、光纤、霍尔效应、压阻式压力传感器等。压阻式传感器又包括扩散硅型和应变片型传感器，压阻应变片式传感器由于具有结构简单、可微型化、输出信号大、精度高、分辨率高、频响高、低功耗、体积小、工作可靠等突出特点而在压阻式压力传感器市场中占据更大的份额。本次设计采用压阻应变片传感器。1应变式传感器称重系统设计方案1.1设计要求(1)了解应变桥的工作原理；(2)应用应变桥的调节电路和A/D转换；(3)使用单片机读取转换值并用数码管显示；(4)测量范围是0—2000g。1.2设计思路在设计之前，先准备好编程软件，原理图设计软件，相关元器件，焊接工具，导线若干，应变传感器模块等。然后查阅资料，绘制电路图，绘制完成后生成PCB图，进行元器件的布局，不断改进。布局要美观合理，避免信号干扰。绘制完成后进行电路板的印刷，然后进行元器件的焊接，最终完成整个应变式传感器称重系统的硬件系统，然后进行软件编程，编写A/D转换和数码管显示的程序。确定完成整个应变式传感器称重系统后进行调试。2硬件设计应变片传感器称重系统的设计，采用金属丝电阻应变片式压力传感器，采集的信号通过A/D转换器实现从模拟到数字的转换，再经过AT89C51芯片处理，在LED数码管上显示所要的结果。应变片传感器称重系统总框图如图2-1所示。2.1单片机模块在众多的51系列单片机中，要算ATMEL公司的AT89C51、AT89S51更实用，因应变式传感器称重系统的设计５图2-1应变片传感器称重系统总框图为它不但和8051指令、管脚完全兼容，而且其片内的4K程序存储器是FLASH工艺的，这种工艺的存储器用户可以用电的方式瞬间擦除、改写，一般专为ATMELAT89xx做的编程器均带有这些功能。显而易见，这种单片机对开发设备的要求很低，开发时间也大大缩短。写入单片机内的程序还可以进行加密，这又很好地保护了你的劳动成果。再者，AT89C51、AT89S51目前的售价比8051还低，而且还有稳定，充足的货源。AT89C51系列单片机的内部结构是各种逻辑单元及其之间的互连构成的。其主要由中央处理器（CPU）、程序存储器（ROM）、数据存储器（RAM）、串行接口、并行I/0接口、定时/计数器、中断系统等几大单元，以及数据总线、地址总线和控制总线组成。AT89C51单片机特点能与MCS-51兼容，有4K字节可编程闪烁存储器，寿命能够达到1000写/擦循环，数据可以保留时间长达10年，全静态工作：0Hz-24MHz，三级程序存储器锁定，128×8位内部RAM，32可编程I/O线，两个16位定时器/计数器，5个中断源，可编程串行通道，低功耗的闲置和掉电模式，片内振荡器和时钟电路。所以AT89C51符合本次设计的主控芯片。AT89C51接线如图2-2所示。图2-2AT89C51接线图压力采集信号处理A/D转换AT89C51显示HI电源菏泽学院本科传感器与检测技术课程设计６2.2电源模块应变式传感器称重系统需要＋5V电源，所以该系统的电源可以由普通的手机充电器来代替。手机充电器中既包含了降压模块，又有交直流转换模块，可以提供稳定的＋5V直流电源，而且手机充电电源非常常见，完全可以满足要求。2.3传感器电路模块传感器是一种能够感受规定的被测量的信息，并按照一定规律转换成可用输出信号的器件或装置，通常由敏感元件、转换元件、测量电路三部分组成。传感器技术是现代信息技术的三大支柱之一，其应用的数量和质量已被国际社会作为为衡量一个国家智能化、数字化、网络化的重要标志。应变片传感器称重系统采用压阻式应变片传感器。用应变片测量受力时，将四片应变片采用全桥形式接入测量电路应变片在外力作用下发生机械形变时。在外力作用下，被测对象表面产生微小机械变形时，金属电阻丝受力F作用时长度变化，横截面积相应改变，电阻率因晶格变化等因素的影响而改变，故起电阻值变化，这就是金属的电阻应变效应。应变片敏感栅也随同变形，其电阻值发生相应变化。通过转换电路转换为相应的电压或电流的变化，可以得到被测对象的应变值，而根据应力应变关系，可以测得应力值。通过弹性敏感元件，将位移、力、力矩、加速度、压力等物理量转换为应变，因此可以用应变片测量上述各量，从而做成各种应变式传感器。在设计中直接将应变片作为电阻连接到传感器模块中，组成传感器。本设计选用金属电阻式应变片如图2-3所示。图2-3金属箔式应变片结构图2.4A/D转换电路模块ADC芯片型号很多，在精度、速度和价格方面千差万别，较为常见的ADC主要有逐次逼近型、双积分型和电压—频率变换型三种。我们选用逐次逼近型，即ADC0809。它由±5V电源供电，片内带有锁存功能的8路模拟多路开关，片内具有多路开关的地址译码器和锁存电路、高阻抗斩波器、稳定的比较器，256Ω电阻T型网络和树状电子开关以及逐次逼近寄存器。输出具有TTL三态锁存缓冲器，可直接接到单片机数据总线应变式传感器称重系统的设