基于PLC变频恒压供水控制系统设计.doc

石家庄铁道学院毕业设计(论文)49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。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。本系统包含四台水泵电机它们组成变频循环运行方式。采用变频器实现对四相水泵电机的软启动和变频调速。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PLCABSTRACTAccordingtotherequirementofChina'surbanwatersupplythispaperdesignsasetofwatersupplysystemoffrequeceycontrolofconstantvoltagebasedonPLCandhavedevelopedgoodoperationmanagementinterfaceusingSupervisionControlandDataAcquisition.ThesystemismadeupofPLCtransducerunitsofpumpspressuresensorandcontrolmachineandsoon.Thissystemisformedbythreepumpgeneratorsandtheyformthecirculatingrunmodeoffrequencyconversion.Withgeneralfrequencyconverterrealizeforthreephasepumpgeneratorsoftstartwithfrequencycontroloperationswitchadoptstheprincipleof”startfirststopfirst”.ThedetectionsignalofpressuresensorofhydraulicpressureviaPLCwithsetvaluebycarryoutPIDcomparisonoperationsocontrolfrequencyandtheexportvoltageoffrequencyconverterandthentherotationalspeedthatchangespumpgeneratorcometochangewatersupplyquantityeventuallyitisnearbytomaintainpipenetpressuretostabilizewhensetvalue.ThroughworkcontrolmachinetheconnectionwithPLCwithgroupformsoftwareconsummatelysystematicmonitoringhaverealizedoperationstatedevelopmenttoshowanddatareporttothepoliceinquiry.Keywords:Variablefrequencyspeed-regulatingConstant-pressurewatersupplyPLC目录第一章绪论.........................................................11.1课题的提出...................................................11.2变频恒压供水系统的国内外研究现状.............................21.3本课题的主要研究内容.........................................3第二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..............