毕业设计(论文)-基于AT89S51单片机的电子称设计

摘要称重技术自古以来就被人们所重视，作为一种计量手段，广泛应用于工农业、科研、交通、内外贸易等各个领域，与人民的生活紧密相连。目前，商用电子秤的使用非常普及，逐渐会取代传统的杆秤和机械案秤。电子秤是电子衡器中的一种，衡器是国家法定计量器具，是国计民生、国防建设、科学研究、内外贸易不可缺少的计量设备，衡器产品技术水平的高低，将直接影响各行各业的现代化水平和社会经济效益的提高。因此，称重技术的研究和衡器工业的发展各国都非常重视。通过分析近年来电子衡器产品的发展情况及国内外市场的需求，电子衡器总的发展趋势是小型化、模块化、集成化、智能化；其技术性能趋向是速率高、准确度高、稳定性高、可靠性高；其功能趋向是称重计量的控制信息和非控制信息并重的“智能化”功能；其应用性能趋向于综合性和组合性。本文是基于AT89S51单片机的一种电子称重设备的设计说明。论文首先简要叙述了电子秤的主要背景以及总体的设计方式；然后详细阐述了数字电子秤的设计流程，以及硬件系统和软件系统的设计，并给出了硬件电路的设计细节。本系统主要分为四大部分，信号前级为称重传感器和放大滤波电路，电阻应变式称重传感器，利用全桥测量原理，将重力信号转换成电信号来测量。单片机为主要部件，完成数据处理和对各个部分的控制，通过对电路输出电压和标准重量的线性关系，建立具体的数学模型，将电压量纲（V）改为重量纲（g）。人机界面部分由六位LED管显示与4×4位矩阵键盘组成，可以由键盘控制显示重量和价钱等信息。关键字：电子秤；称重传感器；AT89S51单片机；A/D转换器；LED数码管AbstractWeighingtechnologyfromtimeimmemorialattention,asameasurementmethod,widelyusedinindustry,scientificresearch,transportation,andtradefields,andpeople'slivesarecloselylinked.Atpresent,theuseofelectroniccommercialverypopular,andgraduallywillreplacethetraditionalGanChengandmachinery.Electronicisakindofelectronweighingapparatus,instrumentsisthenationallegalmeasuringinstruments,livelihood,nationaldefense,scienceresearch,domesticandforeigntradeindispensablemeasureequipment,instruments,producttechnicallevelwilldirectlyinfluencethefromallwalksoflifeandsocialmodernizationleveleconomicbenefit.Therefore,weighingtechnologyresearchanddevelopmentofallindustrialinstrumentsveryseriously.Weighinginrecentyearsthroughanalysisofelectronicproductsandthedevelopmentofdomesticandinternationalmarketdemand,electronicweighingtheoveralldevelopmenttrendissmallandmodular,integrated,intelligent;theirtechnicalperformancetrendrateishigh,highaccuracy,stabilityHigh,highreliability,itsfunctionisweighingmeasurestendtocontrolinformationandnon-controlinformationboththeintelligentfunctionsofitsapplicationperformancetendtobecomprehensiveandcombinationsof.ThisarticleisbasedonAT89S51ofanelectronicweighingequipmentdesign.Itfirstlybrieflydiscussesthemainbackgroundandelectronicoveralldesign,Andthenexpoundsthedigitalelectronicdesignprocess,andthehardwareandsoftwaredesignofthesystemisgiven,andthehardwarecircuitdesigndetails.Thistypeofdigitalelectronicweigheriskeen,correctandconvenienttouse.Itshuman-computerinterfacehasagoodinteractivefunctionanditcanbeusedinvarycircumstances,suchasfamilyandshoppingmall,etc.Keywords:anelectronicscale;Weighingtransducer;AT89S51;A/Dconverter;LEDdigitaltubeI目录1绪论...........................................................................................错误!未定义书签。1.1电子称重器背景介绍.........................................................错误!未定义书签。1.2现状及其发展动态............................................................................................12系统方案的设计......................................................................................................22.1称重器的工作原理............................................................................................22.2电子称重器的设计思路....................................................................................22.3系统总体设计方案论证与选择........................................................................32.4各模块功能的方案论证与选择........................................................................32.4.1称重传感器模块..........................................................错误!未定义书签。2.4.2前置信号处理模块......................................................................................42.4.3A/D转换器..................................................................................................72.4.4键盘及显示模块..........................................................错误!未定义书签。2.5本章小结...........................................................................................................83硬件电路设计........................................................................................................103.1系统主控电路的设计......................................................................................103.1.1单片机芯片AT89S51介绍........................................................................103.1.2单片机引脚说明........................................................................................113.1.3AT89S51的最小系统电路构成.................................................................133.2数据处理部分电路设计..................................................................................133.2.1传感器和外围放大电路设计...................................................................133.2.2A/D转换芯片与AT89S51单片机接口电路设计....................................143.3显示电路设计..................................................................................................153.4键盘电路设计..................................................................................................163.5硬件抗干扰措施.................................................................错误!未定义书签。3.6本章小结..........................................................................................................184系统软件设计........................................................................................................18II4.1主程序设计......................................................................................................184.2A/D转换