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黑龙江大学本科生毕业论文论文题目：数字式电容位移传感器的研究与设计学院：电子工程年级：2007级专业：自动化姓名：李瑶学号：20075181指导教师：毛琳2011年5月7日I摘要由于具有结构简单、动态特性好、能实现非接触式测量等优点，电容位移传感器广泛应用于超精密加工、高精度定位、超精密测量等领域。现有电容位移传感器普遍采用测头与测量电路分立式设计，信号传输电缆的寄生电容等分布参数对传感器的分辨力、稳定性等性能影响显著，因此信号传输距离受到严重限制。如何保证电容模拟信号传输的稳定性以及减少漂移，就成了影响电容传感器性能的关键。为了完成对电容量的测量，本文设计了一个脉冲宽度调制电路，将电容量的变化转化为不同宽度的脉冲，然后用单片机的定时器功能检测出来并通过数码管显示出来。再运用PROTEL99SE将设计的电路制成电路板。关键字电容；传感器；数字式；脉冲宽度调制；Protel99SEIIAbstractWiththeadvantagesofsimplestructure,dynamiccharacteristicsandnon-contactmeasurement,capacitancedisplacementsensorhasbeenwidelyusedinthedomainsofprecisionmachining,highprecisionorientationandultraprecisionmeasurement.Themeasuringcircuitofcapacitancedisplacementsensoriscommonlysetoutoftheprobe.Sotheparasiticcapacitanceofthecableinfluencestheresolutionandstabilityofthesensor.Thesignaltransmissiondistanceisseverelyrestricted.Therebyhowtoensurethestabilityofanalogsignalstransmissionandhowtoreducethezerodrift,hasbecomethekeywhichinfluencestheperformanceofthecapacitancesensor.Tocompletethemeasurementofelectricalcapacity,thepaperdesignsapulsewidthmodulationcircuitthatchangesthecapacitanceintoadifferentpulsewidthwhichcanbedetectedbyMCUtimerfunctionsanddisplayedthroughdigitaltube.ThenusingPROTEL99SEmakesthedesignoftheprintedcircuitboard.KeywordsCapacitance;sensor;Digital;Pulsewidthmodulation;Protel99SE目录摘要..........................................................................................................................................IAbstract....................................................................................................................................II前言.........................................................................................................................................1第1章数字式电容式位移测量仪的原理介绍...................................................................21.1电容传感器的原理......................................................................................................21.1.1变极距型电容传感器........................................................................................31.1.2变面积型电容传感器........................................................................................41.1.3电容式角位移传感器........................................................................................41.1.4变介电常数型电容式传感器............................................................................51.2电容位移传感器测量方法对比..................................................................................61.2.1运算放大器式电路...........................................................................................71.2.2差动脉冲调宽电路...........................................................................................81.2.3调频电路..........................................................................................................101.2.4二极管双T型电路..........................................................................................101.2.5AC桥路式测量电路........................................................................................111.3电容式传感器的特点及发展趋势............................................................................121.3.1电容传感器的特点..........................................................................................121.3.2电容式传感器的发展方向..............................................................................14第2章数字式电容式位移测量仪的电路设计..................................................................152.1测量电路的设计........................................................................................................152.1.1单片机最小系统..............................................................................................152.1.2stc89c51引脚功能介绍...................................................................................162.1.3电平转换电路..................................................................................................182.1.4按键及电源接口电路的设计..........................................................................192.2电容传感器的电路设计............................................................................................202.2.1检测电路的设计..............................................................................................202.2.2555定时器的介绍...........................................................................................232.3显示电路的设计........................................................................................................242.3.1CD4511介绍....................................................................................................252.4单片机软件设计........................................................................................................26第三章PROTEL99SE制作电路板......................................................................................303.1PROTEL99SE...........................................................................................................303.1.1PROTEL99SE简介........................................................................................303.1.2Protel99SE软件的一些使用方法..................................................................303.1.3PROTEL99SE软