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摘要随着微电子技术的应用，市场上使用的传统称重工具已经满足不了人们的要求。为了改变传统称重工具在使用上存在的问题，在本设计中将智能化、自动化、人性化用在了电子秤重的控制系统中。本系统主要由单片机来控制，测量物体重量部分由称重传感器及A/D转换器组成，加上显示单元，此电子皮带秤具备了功能多、性能价格比高、功耗低、系统设计简单、使用方便直观、速度快、测量准确、自动化程度高等特点。本系统以89C51单片机为主控芯片，外围附以称重电路、显示电路、键盘电路等构成智能称重系统电路板，从而实现自动称重系统的各种控制功能。可以说,此设计所完成的电子皮带秤很大程度上满足了应用需求。当被称物体放置在秤体的秤台上时，其重量便通过皮带秤体传递到称重传感器，传感器随之产生力－电效应，将物体的重量转换成与被称物体重量成一定函数关系(一般成正比关系)的电信号(电压或电流等)。此信号由放大电路进行放大、经滤波后再由模/数（A/D）器进行转换，数字信号再送到微处器的CPU处理，CPU不断扫描键盘和各种功能开关，根据键盘输入内容和各种功能开关的状态进行必要的判断、分析、由仪表的软件来控制各种运算。运算结果送到内存贮器，需要显示时，CPU发出指令，从内存贮器中读出送到显示器显示，或送打印机打印。一般地信号的放大、滤波、A/D转换以及信号各种运算处理都在仪表中完成。关键词：89C51单片机称重传感器A/D转换器LED显示器ABSTRACTWiththeapplicationofmicro-electronicstechnology,traditionponderationinstrumentusedinmarkethasbeennotsatisfactionwithhunmanrequirementsalready.Inordertomakeupforthetraditionalapparatusshortcoming,weimprovetheapparatus'scontrolsystemwithintelligenceandautomation.Thissystemismainlycontrolledbymicrocontroller,thesectionofheightmeasurementaccomplishbysupersonicsensor,thesectionofweightmeasurementaccomplishbyweightsensorandA/Dtransformer,thisapparatushavemanycharacteristicsuchashavingmorefunction,consumelessenergy,smallandmoveeasily,lowprice,measureprecisely,thespeedisquick,automaticworkwithoutpeopleandsoon.Thesystemismainlycontrolledbythemicrocontroller89C51,theperipheryisconsistofthecircuitofclockandcalendar,thecircuitofmeasureheightandweight,thecircuitofdisplayandprint,allofthesecomprisethecircuitboardoftheintelligentapparatusofheightandweight.Itcanachieveallfunctionoftheapparatus.Whenhewascalledintheobjectsplacedonthescale,theweightandbeltscalesbodythroughtoweighingtransducer,sensorgenerateselectricityeffect-theweightoftheobject,willbeconvertedtoacertainweightcalledobjects(generalfunctionrelationisproportionaltotherelationshipbetweensignal(the)voltageorcurrent,etc.).Thissignalbyamplifyingcircuit,theamplificationbyfilter/(A/D)device,digitalsignalsintotinyplaceofCPU,CPUscanningswitch,allsortsoffunctionsandkeyboardaccordingtovariousfunctionsandkeyboardinputswitchtojudge,analysis,bythesoftwaretocontrolallkindsofinstruments.ComputationalresultsshowedthatneedtoCunZhuQiinsidewhentheCPU,frominsideCunZhuQiinstructioninreadingtodisplay,orsendtheprinter.Generally,thesignalfilter,A/Dconversionandsignalprocessingvariousoperationsininstrumentation.Keywords:89C51singlechipponderation–sensorA/DconverterLEDdisplay目录1前言..........................................................................................................................11.1电子皮带秤与称重技术简介...............................................................................................11.2电子皮带秤的组成.................................................................................................................11.2.1电子皮带秤的基本结构................................................................................11.2.2电子皮带秤的工作原理................................................................................21.3设计思路...................................................................................................................................22系统方案论证与选型...................................................................................................42.1控制器选择..............................................................................................................................42.2系统检测部分的硬件选择...................................................................................................52.2.1传感器的选择................................................................................................52.2.2放大电路选择................................................................................................62.2.3A/D转换器的选择.........................................................................................72.2.4键盘处理部分方案论证..............................................................................122.3显示电路选择部分..............................................................................................................133系统硬件设计...............................................................................................................143.1微分处理器的发展..............................................................................................................143.2X5045EEPROM存储芯片介绍..........................................................................................153.374LS374芯片和74LS145芯片介绍...............................................................................173.4主控电路硬件设计..............................................................................................................184系统软件设计...............................................................................................................194.1程序的总体设计..................................................................................................................194.2系统主程序实现..................................................................................................................194.3子程序设计................................................................................................................