新型便携式电子称的设计摘要现代社会的发展，对称重技术提出了更高的要求。目前，台式电子秤在商业贸易中的使用已相当普遍，但存在较大的局限性：体积大、成本高、需要工频交流电源供应、携带不便、应用场所受到制约。现有的便携秤为杆秤或以弹簧压缩、拉伸变形来实现计量的弹簧秤，居民用户使用的是国家已经明令淘汰的杆秤。多年来，人们一直期待测量准确、携带方便、价格低廉的便携式电子秤投放市场。本文设计了一种便携式电子秤，论述了仪器的工作原理，介绍了仪器的误差来源与误差分配，给出了仪器电路设计与软件流程，探讨了仪器的工程设计技术。针对电容式称重传感器非线性影响大的问题，提出并建立了电容式称重传感器的非线性影响模型与校正模型，为便携式电子秤的低成本准确称量奠定了理论基础。便携式电子秤主要由电源、称重传感器、单片机、键盘/开关、LCD显示器等部分构成。主要技术指标为：称量范围0～10kg；分度值0.01kg；精度等级Ⅲ级；电源DC1.5V。仪器的技术指标参考了目前国内市场上使用最多、国内外产量最大的电子衡器的技术指标，其合理性无疑加大了产品投放市场后的竞争能力。仪器主要功能有自检、去皮、计价、累计、单价设定、过载报警和欠压提示等。仪器若不进行称量操作，5分钟后自动进入休眠模式，降低电源消耗。新型便携式电子秤体积小、计量准确、携带方便、操作简单、称量速度快，并集质量称量功能与价格计算功能于一体，能够满足商业贸易和居民家庭的使用需求，具有广阔的应用前景。关键词：便携式电子秤；电容式称重传感器；非线性校正；PIC16F877单片机；误差分配；工程设计AbstractThedevelopmentofthemodernsocietyhasputforwardhigherrequestonweighingtechnology.Thedesk-topelectronicscaleshavebeengreatapplicationincommercialtrade,buttheyhavemanyshortcomingssuchaslargevolume,highcost,ACsupplypowerandnotcoveniencetocarry,sotheyarerestrictedtouse.Theusualportablescalesareleverscaleswhicharemostlyusedbyresidents,andspringbalancewhichmeasurethroughcompressionordrawingofspring.Theyarebeingrejectedfortheirbigmeasuringerrors.Peoplehavebeenexpectingcheapportableelectronicscaleswhichcanmeasureaccuratelyandbecarriedconvenientlyformanyyears.Thisthesisdesignsnew-typeportableelectronicscales.Itdiscussestheinstrumentalworkingprinciple,andintroducesitserrorsourcesandhowtodistributetheerror.And,theinstrumentalcircuit,software-flow-chartandengineeringdesigningtechnologyarepresented.Becausecapacitanceweighingsensorisofbadnon-linearity,theauthorputforwardandsetupamathsmodeltorevisenon-linearity,whichestablishesthetheorybasisfortheinstrumenttomeasureaccuratelyandbelow-cost.Theportableelectronicscalesconsistofpower,weighingsensor,microchip,keyboard/switch,LCDandetc.Itstechnicalindictorsinclude10kgmaximalmeasuringrange,10gdivisionvalue,Ⅲprecision,1.5Vworkvoltage.Itstechnicalindictorsrefertotheindictorsoftheelectriconicmeasuringtoolsofmostpopularityinthemarketsandoflargeoutputathomeandboard,sotheinstrumentisstrengthenedthecompetitivepowerafterputtingonmarkets.Itpossessesmanyintelligentfunctions,suchasshelling,lack-of-powerdisplay,overloadalarm,unitpriceenactement,accumulationcomputation,self-calibratingandetc.Itcan“sleep”automaticallyinfiveminutesifitisnotmeasuring.New-typeportableelectronicscalescanmeasuremassrapidlyandaccuratelyandcommunicatevalue.Furthermore,itissmall,simplystructured,easytooperateandconvenienttocarry.Theinstrumentisabletomeettheneedsofcommercialtradeandresidents,soitsapplicationhasabrightfuture.KeyWords:PortableElectronicScales;CapacitanceWeighingSensor;Non-linearityRevision;MicrocontrollerPIC16F877;Errordistribution;EngineeringDesign第1章绪论质量是测量领域中的...
