基于PLC控制的变频恒压供水系统本文首先调研了国内部分城市的供水系统现状，在此基础上提出了基于PLC控制的变频恒压供水系统。恒压自动供水系统主要组成包括：可编程控制器、控制盒、变频器以及传感器。在恒压供水速度控制系统中，三个水泵使用变频器设置功率频率f，从而实现发动机转速控制N，从而改变水泵的功率曲线。具有恒定水压的变频技术自动控制系统的控制单元主要从三个阶段发展，从继电器到接触器再到单片机，再到目前使用的PLC。同时，还通过速度控制来控制变频器，该速度控制的多个端用于模拟输入控制，然后到达专用变频器。由于调节器和变频器的不断改进，低消耗量的城市供水变得简单高效，对于供水系统的控制过程也实现了自动化。使用编程软件创建PID控制器以控制供水系统中的压力，并将PID控制器集成到PLC中。控制器可以通过处理实际测得的压力值以及与设定值的偏差来实时控制变频器的输出频率和电压。目的是改变水泵电机的速度和水泵出口处的流量，以便自动调节整个供水压力，保持压力接近设定值。关键词：PID；PLC；恒压供水；变频器AbstractThisarticlecombinesthebasicsituationofthewatersupplysysteminsome1citiesinourcountry,andproposesavariablefrequencyandconstantpressurewatersupplysystembasedonPLCcontrol.Themaincomponentsoftheconstantpressureautomaticwatersupplysysteminclude:programmablecontroller,controlbox,frequencyconverterandsensor.Intheconstantpressurewatersupplyspeedcontrolsystem,thethreewaterpumpsusethefrequencyconvertertosetthepowerfrequencyf,soastorealizetheenginespeedcontrolN,therebychangingthepowercurveofthewaterpump.Thecontrolunitofthevariablefrequencytechnologyautomaticcontrolsystemwithconstantwaterpressureismainlydevelopedfromthreestages,fromrelaytocontactortosingle-chipmicrocomputer,andthentothecurrentlyusedPLC.Atthesametime,thefrequencyconverterisalsocontrolledbyspeedcontrol.Multipleendsofthespeedcontrolareusedforanaloginputcontrol,andthenreachthededicatedfrequencyconverter.Duetothecontinuousimprovementofregulatorsandfrequencyconverters,low-consumptionurbanwatersupplyhasbecomesimpleandefficient,andthecontrolprocessofthewatersupplysystemhasalsobeenautomated.UseprogrammingsoftwaretocreateaPIDcontrollertocontrolthepressureinthewatersupplysystemandintegratethePIDcontrollerintothePLC.Thecontrollercancontroltheoutputfrequencyandvoltageoftheinverterinrealtimebyprocessingtheactualmeasuredpressurevalueandthedeviationfromthesetvalue.Thepurposeistochangethespeedofthepumpmotorandtheflowrateattheoutletofthepumpsoastoautomaticallyadjusttheentirewatersupplypressureandkeepthepressureclosetothesetvalue.Keywords：PID；PLC；ConstantPressureWaterSupply；；Inverter目录1绪论..........................................................................................................................11.1研究背景........................................................................................................11.2变频技术恒压供水系统的国内外研究现状................................................11.3变频恒压供水系统特点及其安全性讨论....................................................21.4本课题的主要研究内容................................................................................32供水系统的控制方案......................................42.1变频恒压供水系统节能原理.........................................................................42.2变频恒压控制的调节过程.............................................................................42.3变频恒压供水系统的控制方案.....................................................................5...
