毕业论文（设计）题目：基于PLC控制的高精度液位控制系统的设计姓名：濮孝金学号：122120018专业：机械电子工程年月摘要在工农业生产过程中，经常需要对水位进行测量与控制，而日常生活中应用到的水位控制也相当广泛。在以往水塔液位控制系统中，常规继电器的频繁操作容易导致机械磨损，不方便更新和维护，不能满足人们的实际需求；另外，随着人口的递增和生活条件的提高，人们用水的需求量也日益增加。为了提高液位控制系统的质量和效率，节约能源，本次模拟水塔液位控制系统的装置考虑结合可编程逻辑控制器，继电器和传感器等技术，实现液位控制系统的自动控制。本设计使用西门子S7-300PLC可编程控制器作为液位控制系统的核心，配合硬件与软件实现液位控制池液位动态平衡，过高、过低水位报警等功能。主要的实验方法是在水箱上安装一个自动水位测量装置，通过水位变送器检测水箱实际液位并将该液位反馈到PLC控制器，经A/D转换后，所得数据与PLC内部设定数据进行比较，控制器处理数据并发送相应指令改变电机的转速从而控制抽水速率，改变进水量，使水位稳定地保持在设定值附近。此外，通过液位标定计算出控制器输出PIW数值与实际水位的关系，就可以在触摸屏上直观显示实时水位情况。实验结果表明本设计能较好地完成自动液位控制的功能。关键词：水塔液位控制，水位控制，继电器，PLCAbstractInthecourseofroutineindustrialandagriculturalproductionwetheneedtomeasurethewaterlevelandcontrolit.Furthermoreeverydaylevelcontrolapplicationsarequiteextensive,suchashydropower,watertowersandotherwatercontrol.Accordingtothewatersupplysysteminthepast,frequentoperationtowerswillproducemechanicalwearofconventionalrelayconvenientmaintenanceandupdates,thatmeansitcannotmeettheactualneedsofthepeople,andwithGradualgrowthofpopulationandlivingconditions,thedemandforwaterisalsoincreasing.Inordertoimprovethequalityofthewatersupplysystem,energyconservation,soIconsidereduseaprogrammablelogiccontroller,relayandsensortechnology,withhardwareandsoftwaretoachievelowwaterlevelalarm,warningswitchbetweenworkandproceduresmanual/automatictodesignpracticallevelcontroltowerscheme.Icompletedthesetupofthissimulationusingthetankwatertower,basedonSiemensS7-300PLCprogrammablecontrollertankwaterlevelcontrolsystemasthecore.Icompletedawatertanktocompletetheperformancecapabilityaimingatdoinganeedsanalysis.Themainexperimentalmethodusedistoinstallanautomaticwaterlevelmeasuringdeviceonthetank.ThelevelsensordetectingthewatertanktomeasuretheactualwaterlevelandthecontrolmoduletosendinformationtothePLC,viaA/Dconversion,thedataobtainediscomparedwiththesetlevel,thecontrollerprocessesthedataandsendstheappropriatecommandstocontrolthemotorspeedchangepumpingrate,thewaterlevelmaintainedintheproperposition.ThanTouchscreencompletestheleveldisplay,faultalarminformationdisplay,real-timeandhistoricalcurvecurvesshow.Ifthewaterlevelislowerorhigherthanthesetvalue,thehazardwarningsignalwillbeissuedInthispaper,PLCautomaticwatersupplysystembasedongoodexecutionprocesslevelcontrol.Keywords:towerwater;waterlevelcontrol;relays;PLC目录第一章绪论.......................................................................................................................1§1.1研究背景........................................................................................................1§1.2PLC的产生与发展.........................................................................................21.2.1PLC的产生................................................................................................21.2.2PLC技术的发展......................................
