基于RS485的变送器通信模块设计 6.docx

绵阳师范学院2019届本科毕业设计（论文）PAGE\*MERGEFORMATIV基于RS485的变送器通信模块设计摘要：以往的变送器大多是模拟量输出，模拟量因受电源的限制，其数据表达是有限的且抗干扰能力弱。总线技术的发展使得变送器的数字量输出成为一大发展趋势，采用数字量输出的变送器数据表达比模拟量更精确，且抗干扰能力更强。RS485总线支持多点数据通信方式，可对共模干扰进行抑制。总线的信号收发装置具有良好的灵敏度，可检测的电压范围较广，因此传输信号可在较远的距离上得到有效恢复。基于此可知RS485总线在工程现场得到了大量应用。因此研究设计基于RS485的变送器通信模块，使得传统变送器的数字量传输成为可能，具有较强的实用价值。关键词：变送器、RS485总线、通信模块DesignoftransmittercommunicationmodulebasedonRS485Undergraduate：CaozhenSupervisor:LiaoMeiyingAbstract:Inthepast,mostofthetransmitterswereanalogoutputs.Theanalogoutputswerelimitedbythepowersupply,sothedataexpressionwaslimitedandtheanti-interferenceabilitywasweak.Thedevelopmentofbustechnologymakesthedigitaloutputofthetransmitterbecomeabigdevelopmenttrend.Thedataexpressionofthetransmitterusingdigitaloutputismoreaccuratethantheanalogone,andtheanti-interferenceabilityisstronger.RS485busUSEShalf-duplexcommunication,supportsmulti-pointdatacommunication,adoptsbalancedtransmissionanddifferentialreception,andcaneffectivelysuppresscommonmodeinterference.Inaddition,thebustransceiverhashighsensitivityandcandetectvoltageaslowas200mv,sothetransmissionsignalcanberecoveredbeyondkilometers.Becauseoftheseadvantages,RS485bushasbeenwidelyusedinengineeringfield.Therefore,theresearchanddesignofthetransmittercommunicationmodulebasedonRS485makesthedigitaltransmissionofthetraditionaltransmitterpossibleandhasstrongpracticalvalue.Keywords:transmitter,RS485bus,communicationmodule目录TOC\o"1-3"\h\uHYPERLINK\l_Toc31875绪论PAGEREF_Toc318751HYPERLINK\l_Toc12111研究背景及意义PAGEREF_Toc121111HYPERLINK\l_Toc3880研究目的PAGEREF_Toc38801HYPERLINK\l_Toc32469发展现状PAGEREF_Toc324691HYPERLINK\l_Toc231241.方案设计PAGEREF_Toc231242HYPERLINK\l_Toc326901.1RS485介绍PAGEREF_Toc326902HYPERLINK\l_Toc4411.2RS232与R