TECHNOLOGY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目录第1章绪论....................................................................................................................11.1选题背景............................................................................................................11.2选题依据............................................................................................................2第2章设计内容与要求............................................................................................32.1设计内容........................................................................................................32.1.1系统概述............................................................................................32.1.2设计的主要内容................................................................................42.1.3主要技术参数与技术指标................................................................42.2系统设计的功能要求........................................................................................4第3章系统方案设计................................................................................................63.1方案选择........................................................................................................63.2系统原理与组成................................................................................................73.2.1原理框图设计........................................................................................83.2.2系统原理分析........................................................................................9第4章系统的硬件电路设计....................
