小区变频恒压供水控制系统设计.doc

兰州理工大学毕业设计(论文)PAGE\*MERGEFORMATIIITECHNOLOGY摘要本设计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。本系统包含五台水泵电机，它们分别实现对生活用水、消防用水的提供和对排污水的排放。采用变频器实现生活用水泵和消防用水泵的软启动和变频调速。压力传感器检测当前水压信号，经过压力变送器送入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'surbanwatersupply,thispaperdesignsasetofwatersupplysystemoffrequececontrolofconstantvoltagebasedonPLC,andhavedevelopedgoodoperationmanagementinterfaceusingSupervisionControlandDataAcquisition.ThesystemismadeupofPLC,transducerunitsofpumps,pressuresensorandcontrolmachineandsoon.Thissystemisformedbythreepumpgenerators,andtheyformthecirculatingrunmodeoffrequencyconversion.Withgeneralfrequencyconverterrealizeforthreephasepumpgeneratorsoftstartwithfrequencycontrol,operationswitchadoptstheprincipleof”startfirststopfirst”.Thedetectionsignalofpressuresensorofhydraulicpressure,viaPLCwithsetvaluebycarryoutPIDcomparisonoperation,so,controlfrequencyandtheexportvoltageoffrequencyconverter,andthentherotationalspeedthatchangespumpgeneratorcometochangewatersupplyquantity,eventually,itisnearbytomaintainpipenetpressuretostabilizewhensetvalue.ThroughworkcontrolmachinetheconnectionwithPLC,withgroupformsoftwareconsummatelysystematicmonitoringhaverealizedoperationstatedevelopmenttoshowanddata,reporttothepoliceinquiry.KeyWords:variablefrequencyspeed-regulating,constant-pressurewatersupply,PLC目录TOC\o"1-3"\h\uHYPERLINK\l"_Toc359158624"第1章绪论PAGEREF_Toc359158624\h1HYPERLINK\l"_Toc359158625"1.1选题背景PAGEREF_Toc359158625\h1HYPERLINK\l"_Toc359158626"1.2选题依据PAGEREF_Toc359158626\h2HYPERLINK\l"_Toc359158627"