文档介绍：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 ordingtotherequirementofChina'surbanwatersupply,thispaperdesignsasetofwatersupplysystemoffrequeceycontrolofconstantvoltagebasedonPLC,andhavedevelopedgoodoperationmanagementinterfaceusingSupervisionControlandDatasystemismadeupofPLC,transducer,unitsofpumps,,,operationswitchadoptstheprincipleof”startfirststopfirst”.Thedetectionsignalofpressuresensorofhydraulicpressure,parisonoperation,so,controlfrequencyandtheexportvoltageoffrequencyconverter,etochangewatersupplyquantity,eventually,,withgroupformsoftwareconsummatelysystematicmonitoring,haverealizedoperationstatedevelopmenttoshowanddata,:Variablefrequencyspeed-regulatingConstant-pressurewatersupplyPLC目录第一章绪论.........................................................1...................................................1.............................2.........................................3第二章系统的理论分析及控制方案确定.................................4...................................4电动机的调速原理.......................................4变频恒压供水系统的节能原理.............................4...................................5控制方案的比较和确定...................................5变频概述...............................................6变频恒压供水系统的组成和原理图.........................7变频恒压供水系统控制流程...............................9水泵切换条件...........................................9第三章系统的硬件设计..............................................11..........................................11控制方案的比较和确定................