摘要本论文根据中国城市小区的供水要求，设计了一套基于PLC的变频调速恒压供水系统,并利用组态软件开发良好的运行管理界面。变频恒压供水系统由可编程控制器、变频器、水泵机组、压力传感器、工控机等构成本系统包含三台水泵电机，它们组成变频循环运行方式。采用变频器实现对三相水泵电机的软启动和变频调速，运行切换采用“先启先停”的原则压力传感器检测当前水压信号，送入PLC与设定值比较后进行PID运算，从而控制变频器的输出电压和频率，进而改变水泵电机的转速来改变供水量，最终保持管网压力稳定在设定值附近。通过工控机与PLC的连接，采用组态软件完成系统监控，实现了运行状态动态显示及数据、报警的查询关键词：变频调速，恒压供水，可编程控制器，组态软件ABSTRACTAccordingtotherequirementofChina'surbanwatersupply,thispaperdesignsasetofwatersupplysystemoffrequeceycontrolofconstantvoltageIbasedonPLC,andhavedevelopedgoodoperationmanagementinterfaceusingSupervisionControlandDataAcquisition.ThesystemismadeupofPLC,transducer,unitsofpumps,pressuresensorandcontrolmachineandsoon.Thissystemisformedbythreepumpgenerators,andtheyformthecirculatingrunmodeoffrequencyconversion.Withgeneralfrequencyconverterrealizeforthreephasepumpgeneratorsoftstartwithfrequencycontrol,operationswitchadoptstheprincipleof”startfirststopfirst”.Thedetectionsignalofpressuresensorofhydraulicpressure,viaPLCwithsetvaluebycarryoutPIDcomparisonoperation,so,controlfrequencyandtheexportvoltageoffrequencyconverter,andthentherotationalspeedthatchangespumpgeneratorcometochangewatersupplyquantity,eventually,itisnearbytomaintainpipenetpressuretostabilizewhensetvalue.ThroughworkcontrolmachinetheconnectionwithPLC,withgroupformsoftwareconsummatelysystematicmonitoring,haverealizedoperationstatedevelopmenttoshowanddata,reporttothepoliceinquiry.Keywords:variablefrequencyspeed-regulating,constant-pressurewatersupply,ProgrammablelogicController,supervisioncontrolanddataacquisitionII目录摘要...................................................................................................................IABSTRACT....................................................................................................II第1章绪论.....................................................................................................11.1课题的提出.........................................................................................11.2PLC概述.............................................................................................11.2.1可编程控制器的定义...............................................................11.2.2西门子S7-200PLC简介...........................................................21.3本课题的主要研究内容.....................................................................3第2章系统的理论分析及控制方案确定.....................................................42.1变频恒压供水系统的理论分析.........................................................42.1.1电动机的调速原理...................................................................42.1.2变频恒压供水系统的节能原理...............................................42.2变频恒压供水系统控制方案的确定.................................................72.2.1变频恒压供水系统的组成及原理图.......................................72.2.2变频恒压供水系统控制流程.................................................112.2.3水泵切换条件分析.................................................................12第3章系统的硬件设计..............
VIP
