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1、摘要随着我国社会经济的发展,城市建设发展十分迅速,同时也对基础设施建设提出了更高的要求。城市供水系统的建设是其中的一个重要方面,供水的可靠性、稳定性、经济性直接影响到用户的正常工作和生活。随着人们对供水质量和供水系统可靠性要求的不断提高,利用先进的自动化技术、控制技术以及通讯技术,设计出高性能、高节能、能适应供水厂复杂环境的恒压供水系统成为必然趋势。本系统包含三台水泵电机,它们组成变频循环运行方式。采用变频器实现对三相水泵电机的软启动和变频调速,运行切换采用“先启先停”的原则。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
2、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,PLC,组态软件-56-ABSTRACTAsChina'ssocialandeconomicdevelopment,urbanconstructionanddevelopmentveryquickly,butalsotheconstructionofinfrastructurefacilitieshasputforwardhigherrequirements.Citywate
3、rsupplysystemconstructionisoneoftheimportantaspectsofthewatersupplyreliabilityandstability,theeconomyofadirectimpactontheuser'snormalworkandlife.Aspeopleonthewaterqualityandwatersupplysystemsinthecontinuousimprovementofreliabilityrequirements,theuseofadvancedautomationtechnology,controlt
4、echnologyandcommunicationtechnology,designahigh-performance,high-energy,watersupplyplantstoadapttothecomplexenvironmentofconstantpressurewatersupplySystemsbecomeaninevitabletrendThissystemisformedbythreepumpgenerators,andtheyformthecirculatingrunmodeoffrequencyconversion.Withgeneralfrequ
5、encyconverterrealizeforthreephasepumpgeneratorsoftstartwithfrequencycontrol,operationswitchadoptstheprincipleof”startfirststopfirst”.Thedetectionsignalofpressuresensorofhydraulicpressure,viaPLCwithsetvaluebycarryoutPIDcomparisonoperation,so,controlfrequencyandtheexportvoltageoffrequencyc
6、onverter,andthentherotationalspeedthatchangespumpgeneratorcometochangewatersupplyquantity,eventually,itisnearbytomaintainpipenetpressuretostabilizewhensetvalue.ThroughworkcontrolmachinetheconnectionwithPLC,withgroupformsoftwareconsummatelysystematicmonitoring,haverealizedoperationstatede
7、velopmenttoshowanddata,reporttothepoliceinquiry.Keywords:variablefrequencyspeed-regulating,constant-pressurewatersupply,PLC,supervisioncontrolanddataacquisition.-56-目录1绪论11.1课题的提出51.2变频恒压供水系统的国内外研究现状.................................................61.2.1变频调速技术的国内外发展与现状...