基于PLC的水厂滤池控制系统 毕业论文外文翻译

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1、附录A：外文文献BasedonPLCcontrolsystemofwaterworkspondsThecontrolsystemofthecryogenicfacilityinthewaterworkspondssystemhasbeenreplacedbyemployingthePLC(ProgrammableLogicController)andSCADA(SupervisoryControlAndDataAcquisition)system.Theoriginalcontrolsystemwasconstructedabout20yearsagobys

2、pecifyingtheDCS(DistributedControlSystem)computertodealwith～400feedbackloops.Recently,troublesonthiscontrolsystemhaveincreasedduetoitsage-induceddeterioration.Tomaintainthehighreliabilityofthecryogenicfacility,anewcontrolsystemhasbeenplannedwiththePLCandSCADAsystems.Theirattractive

3、featuresincludehighmarketavailabilityandcost-effectiveness,however,theuseofPLCforsuchalargefacilitywith～400feedbackloopshasnotbeenestablishedbecauseofinsufficientprocessingcapabilityoftheearlyPLC.Meanwhile,therecentprogressinthePLCenablestousetheFBD(functionblockdiagram)programming

4、languagefor500functionblocks.ByoptimizingthefunctionblocksandconnectingthemintheFBDlanguage,thefeedbackloopshavebeensuccessfullyreplacedfromDCStoPLCwithoutasoftwaredeveloper.Moreover,anoscillationoftheliquidHelevel,whichoftenoccursduringthecooldownmodeofthecryopumps,canbeautomatica

5、llystabilizedbyeasilyaddinganewprocessprograminthePLC.Atpresent,thenewcontrolsystemhasworkedwell.Fiberwindingtensionisanimportantfactorinthemoldingtechniquesofcompositematerialwhichinfluencesthequalityofwindingproductdirectly,andthetensioncontrolisakeytechniqueinfiberwindingtechniq

6、ues.Thispaperintroducesaclosed-looptensioncontrolsystemwiththeprogrammablelogiccontroller(PLC)withfunctionmodulesasitscontrolkernel,thealternatingcurrent(AC)servomotorasexecuteelementandtheradius-followingdevicetoaccomplishthereal-timeradiuscompensation.Themechanismofthetensioncont

7、rolsystemisanalyzedandthenumericalmodelissetup.Thecompensationtechniqueoftheradiusofthescrollisanalyzed.Experimentalresultsshowthatthesystemiswellqualifiedwithhighcontrolprecisionandhighreactionspeed.Wateristhesourceoflife,watersupplynaturalrelationstothepeople'slivelihoodimportant

8、point,watersupplythatnoton