四川职业技术学院毕业设计（论文）第页共NUMPAGES34页摘要本文介绍了恒压供水的基本原理以及系统构成的基础，说明了可编程控制器（PLC）在恒压供水系统中所担任的角色。从系统的整体设计方案和实际需求分析开始，紧密的联系实际生活的需要，力求做到使系统运行稳定，操作简便，解决实际中问题，保证供水安全、快捷、可靠。恒压供水保证了供水质量，以PLC为主机的控制系统丰富了系统的控制功能，提高了系统的可靠性。关键字:PLC；恒压供水；变频器AbstractThisarticleintroducedtheconstantpressurewatersupply'sbasicprincipleaswellasthesystemconstitution'sfoundation,showedtheprogrammablecontroller(PLC)therolewhichholdsthepostintheconstantpressurewatersupplysystem.Startfromsystem'soveralldesignplanandtheenergydemandanalysis,thecloserelationpracticallife'sneed,makeseveryefforttoachievecausesthesystemsoperationtobestable,theoperationissimple,thesolutionrealissue,theguaranteewatersupplysecurity,isquick,isreliable.Theconstantpressurewatersupplyhadguaranteedthewatersupplyquality,asmainengine'scontrolsystemhasenrichedsystem'scontrolfunctiontakePLC,enhancedsystem'sreliability.keywords:PLC;Constantpressurewatersupply;Frequencychanger目录TOC\o"1-3"\h\z\uHYPERLINK\l"_Toc220394275"目录PAGEREF_Toc220394275\h2HYPERLINK\l"_Toc220394276"前言PAGEREF_Toc220394276\h4HYPERLINK\l"_Toc220394277"第一章恒压供水原理及工艺PAGEREF_Toc220394277\h5HYPERLINK\l"_Toc220394278"1.1本课题的研究意义PAGEREF_Toc220394278\h5HYPERLINK\l"_Toc220394279"1.2工艺要求PAGEREF_Toc220394279\h5HYPERLINK\l"_Toc220394280"1.3系统的组成和基本工作原理PAGEREF_Toc220394280\h5HYPERLINK\l"_Toc220394281"第二章PLC概述PAGEREF_Toc220394281\h6HYPERLINK\l"_Toc220394282"2.1PLC组成PAGEREF_Toc220394282\h6HYPERLINK\l"_Toc220394283"2.1.1PLC的组成PAGEREF_Toc220394283\h6HYPERLINK\l"_Toc220394284"2.1.2PLC的定义PAGEREF_Toc220394284\h7HYPERLINK\l"_Toc220394285"2.1.3PLC的特点PAGEREF_Toc220394285\h7HYPERLINK\l"_Toc220394286"2.1.4PLC的性能指标PAGEREF_Toc220394286\h7HYPERLINK\l"_Toc220394287"2.1.5PLC的分类PAGEREF_Toc220394287\h8HYPERLINK\l"_Toc220394288"2.2PLC工作原理PAGEREF_Toc220394288\h8HYPERLINK\l"_Toc220394289"2.2.1循环扫描PAGEREF_Toc220394289\h8HYPERLINK\l"_Toc220394290"2.2.2PLC的编程结构功能图