摘要随着人民生活水平的日趋提高，新技术和先进设备的应用，使给供水设计得到了发展的机遇。于是选择一种符合各方面规范、卫生安全而又经济合理的供水方式，对我们给供水设计带来了新的挑战。本系统采用PLC进行逻辑控制，采用带PID功能的变频器进行压力调节，系统存在工作可靠，使用方便，压力稳定，无冲击等优越性。本设计恒压变频供水设备由PLC、变频器、传感器、低压电气控制柜和水泵等组成。通过PLC、变频器、继电器、接触器控制水泵机组运行状态,实现管网的恒压变流量供水要求。设备运行时,压力传感器不断将管网水压信号变换成电信号送入PLC,经PLC运算处理后,获得最佳控制参数,通过变频器和继电器控制元件自动调整水泵机组高效率地运行。供水系统的监控主要包括水泵的自动启停控制、供水压力的测量与调节、系统主管道水压的；系统水处理设备运转的监视、控制；故障及异常状况的报警等。现场监控站内的控制器按预先编制的软件程序来满足自动控制的要求，即根据供水管的高/低水压位信号来控制水泵的启/停及进水控制阀的开关，并且进行溢水和枯水的预警等。文中详细介绍了所选PLC机、变频器、传感器的特点、各高级单元的使用及设定情况，给出了系统工作流程图、程序设计流程图及设计程序。关键词：可编程控制器变频器传感器1ABSTRACTIncompanywiththeimprovementofpeople’slivingstandard,theapplicationofnewtechniqueandadvancedequipmentprovideanewdevelopmentforthedesignofwatersupply.Itisachallengeforustoselectawayofwatersupplywithhighstandard,secureandhealthy,economical,andreasonable.ThissystemadoptsPLClogiccontrol,andtransducerwithPIDfunctiontoadjustthepressure,whichpresentsmanyadvantages,suchashighreliability,convenienceinuse,stabilityinpressure，andwithoutimpact.ThedesignismadeofProgrammableLogiccontroller，transducer,sensor,lowpressurecontrolmanufacturetank,etc.Throughtransducerandrelay,contactorcontrolpumpingunitrunningstatus,thepipenetworkachievestotherequirementofconstantpressurevariableflow-ratewatersupply.Whentheequipmenton-the-fly,pressuregaugewithoutintermissiontranslatesthepipenetworkhydraulicpressuresignaltoelectricalsignalentermicrocomputer,andthroughmicrocomputer’arithmeticprocessing,obtainsoptimalcontrolparameter.Thedampressbeforehandmadeupsoftwareprogramcamesatisfactionselfgoverningoblige，namelyonthebasisofhighorlow-watersignalcamecontrolradialdiffuserinfluentvalve’sswitch,andproceedoverfullandlowwater’sgradefromwatertankandpondbackofthemonitorprimeincluderadialdiffuserautomatismopenceasedam,waterlevelflow,manmetricmeasuringandregulate；usewaterflow,displacement'measure；watertreatmentequipmentlocomotiveputincontrol；waterqualitydetection；waterconservationprogramcontrol；malfunctionanderrorstate'entergradeu