基于PLC变频恒压供水系统设计.doc

摘要在城市化进程迅速的今天城市的居住形式主要是生活小区那么小区供水系统的建设就显得尤为重要。而且随着城市用水量不断增加对供水系统的建设提出了更高的要求。供水的经济性、可靠性、稳定性直接影响到小区住户的正常生活和工作。本系统是针对居民生活用水而设计的一套由变频器、PLC、水泵机组等设备组成的自动变频恒压供水控制系统。该系统将PLC、变频器、相应的传感器和执行机构有机地结合起来并发挥各自优势能够最大程度满足需要具有运行稳定、操作简单和高效节能等特点。该系统对变频器内置PID模块参数进行预置通过压力传感器对水压的反馈构成闭环控制系统；PID模块根据用水量的变化调节水泵的输出流量实现恒压供水并达到有效节能的目的。本文首先介绍了采取变频调速方式实现恒压供水相对于传统的阀门控制恒压供水方式的节能原理；其次对水泵机组的各种供水状态及转换的条件、水泵由变频转工频运行方式的切换过程进行分析着重研究并提出了基于PLC和变频器的恒压供水系统的方案并给出了硬件设计和PLC控制程序设计。关键词：PLC、变频调速、恒压供水AbstractIntoday'srapidurbanizationurbanlivingismainlylivingquartersthentheconstructionofresidentialwatersupplysystemisparticularlyimportant.Andwiththegrowingurbanwaterdemandwatersupplysystemstheproposedhigherrequirements.Economicsofwatersupplyreliabilityandstabilitytothedistrictresidentsdirectlyaffectedthenormallifeandwork.ThesystemisdesignedforhouseholdwatersetbythefrequencyconverterPLCwaterpumpandotherequipmentconsistingofautomaticconstantpressurewatersupplycontrolsystem.SystemPLCfrequencyconverterthecorrespondingsensorsandactuatorstogetherorganicallyandplaytheirrespectiveadvantagesthecontrolsystemeasytooperatenotonlytothegreatestextenttomeettheneedsofstabilityandsecurityofitsoperatingperformancesimpleandconvenientmodeofoperationandthecompleteandthoughtfulfeatureswillmakewatersavingwatersavinglaborsavinghighefficiencyhigh-qualityfinalrunreliableenergy-savingpurposes.Thispaperintroducesthewaytoachievefrequencycontrolconstantpressurewatersupplyvalvecontrolcomparedtoconventionalenergy-savingprincipleofconstantpressurewatersupply.Converterbuilt-inPIDmoduleonthepresetparametersusinghydraulicpressuresensorfeedbackclosedloopsystem.AccordingtochangesinwaterconsumptiontoPIDregulationmodebyadjustingthepumpoutputflowconstantpressurewatersupplyandefficientenergy.Thenitanalyzesthestateofpumpunitsandconver