基于RS-485总线的开关量采集模块设计

安徽工程科技学院毕业设计（论文）基于RS-485总线的开关量采集模块设计摘要RS－485是现在使用十分广泛的一种布网方式。随着数字技术的发展和计算机日益广泛的应用，现在一个系统往往由多台计算机或测控点组成，需要解决多站、远距离通信的问题。在计算机自动控制系统急速发展的今天，特别是考虑到现场总线已经普遍地渗透到自动控制的各个领域的现实，现场总线必将成为电工自动控制领域主要的发展方向之一。本文设计了一种基于RS-485总线的开关量采集模块，属于实践性课题。该模块主要运用于工业现场的开关量采集，系统以AT89C52单片机作为系统的控制器，以转换接口芯片SN75LBC184实现RS-485通信标准，通过四片光耦TP521-4对16路开关量采集线路进行处理，用DC/DC电源模块WR24S5对系统进行供电。在系统设计时，考虑到工业现场的复杂环境，采用了抗干扰措施。系统采用看门狗技术解决了飞程序和死循环，软件程序的设计也考虑了抗干扰措施，尽量选用低功耗器件，此部分选用X5045。在系统设计时，考虑到工业现场的复杂环境，软件程序的设计考虑了抗干扰措施，尽量选用低功耗器件并且所有输入、输出采用光藕隔离。系统工作可靠，功耗低，具有一定的应用价值。关键词：现场总线；单片机；抗干扰如需此论文Word版本，单片机程序/单片机技术支持，请访问:嵌入式应用软件园。嵌入式应用软件园，版权所有，请勿转载/销售。-2-2DesignofDigitalsignalInputModuleBasedonRS-485BusAbstractRS-485isthepresentusestheverywidespreadonekindtospreadanettheway.Alongwithdigitaltechnique'sdevelopmentandthecomputerdaybydaywidespreadapplication,nowasystemofteniscomposedofmanycomputersortheobservationspot,needstosolvethemulti-stations,theremotecommunicationquestion.Todaywhichdevelopsrapidlyinthecomputerautomaticcontrolsystem,speciallyconsideredthefieldbusalreadygenerallyseepedtotheautomaticcontroleachdomainreality,thefieldbuswillcertainlytobecomeoneofelectricianautomaticcontroldomainmaindevelopmentdirections.ThisarticlehasdesignedonekindbasedontheRS-485mainline'sswitchquantitygatheringmodule,belongstothepracticaltopic.Thismodulemainlyutilizesinindustrysceneswitchquantitygathering,thesystemtakessystem'scontrollerbyat89C52monolithicintegratedcircuit,TransformsconnectionchipSN75LBC184torealizetheRS-485correspondencestandard,carriesonprocessingthroughfourlightpairTP521-4to16groupswitchquantitygatheringline,carriesonthepowersupplywithDC/DCpowersourcemoduleWR24S5tothesystem.Whensystemdesign,consideredindustryscenecomplexenvironment,hasusedtheanti-jammingmeasure.Thesystemusedthewatch-dogtechnologytosolveflewtheprocedureandtheendlessloop,thesoftwareroutinedesignhadalsoconsideredtheanti-jammingmeasure,selectedthelowpowerlosscomponentasfaraspossible,thispartselectedX5045.Whensystemdesign,consideredtheindustryscenethecomplexenvironment,softwareroutine'sdesignhadconsideredtheanti-jammingmeasure,selectsthelowpowerlosscomponentasfaraspossible,andallinputs,theoutputusethelightlotusrootisolation.Thesystemoperationreliable,thepowerlossislow,hascertainapplicationvalue.Keywords:Fieldbus;Microcontroller;Anti-jamming嵌入式应用软件园，版权所有，请勿转载/销售。-3-3目录引言..............................................................................................................................................7绪论..............................................................................................................................................8第1章方案论证.........................................................................................................................10第2章系统硬件设计................................................................................................................122.1信号处理电路...................................................................................................................122.1.1AT89S52特性描述......................................................................................................122.1.2AT89S52晶振连接电路.............................................................................................152.2485通信电路....................................................................................................................152.2.1RS-485.........................................................................................................................162.2.2RS-485注意问题........................................................................................................162.2.3SN75LBC184P...............................................................................................................172.3信号采集电路...................................................................................................................202.3.1光耦的参数.................................................................................................................202.3.2TLP521-4的内部结构图...........................................................................................202.3.3引脚介绍.....................................................................................................................212.3.4TP521-4温度与集电极功耗曲线.............................................................................212.4看门狗电路........................................................................................................................212.4.1X5045概述..................................................................................................................212.4.2X5045产品特性..........................................................................................................222.4.3X5045的工作原理......................................................................................................232.4.4X5045的操作指令......................................................................................................252.5电源模块.........................................................