基于PLC的水厂滤池控制系统 毕业论文外文翻译.doc.doc

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1、附录A：外文文献BasedonPLCcontrolsystemofwaterworkspondsThecontrolsystemofthecryogenicfacilityinthewaterworkspondssystemhasbeenreplacedbyemployingthePLC(ProgrammableLogicController)andSCADA(SupervisoryControlAndDataAcquisition)system.Theoriginalcontrolsystemwasconstructedabout20yearsa

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

3、attractivefeaturesincludehighmarketavailabilityandcost-effectiveness,however,theuseofPLCforsuchalargefacilitywith～400feedbackloopshasnotbeenestablishedbecauseofinsufficientprocessingcapabilityoftheearlyPLC.Meanwhile,therecentprogressinthePLCenablestousetheFBD(functionblockdiag

4、ram)programminglanguagefor500functionblocks.ByoptimizingthefunctionblocksandconnectingthemintheFBDlanguage,thefeedbackloopshavebeensuccessfullyreplacedfromDCStoPLCwithoutasoftwaredeveloper.Moreover,anoscillationoftheliquidHelevel,whichoftenoccursduringthecooldownmodeofthecryop

5、umps,canbeautomaticallystabilizedbyeasilyaddinganewprocessprograminthePLC.Atpresent,thenewcontrolsystemhasworkedwell.Fiberwindingtensionisanimportantfactorinthemoldingtechniquesofcompositematerialwhichinfluencesthequalityofwindingproductdirectly,andthetensioncontrolisakeytechn

6、iqueinfiberwindingtechniques.Thispaperintroducesaclosed-looptensioncontrolsystemwiththeprogrammablelogiccontroller(PLC)withfunctionmodulesasitscontrolkernel,thealternatingcurrent(AC)servomotorasexecuteelementandtheradius-followingdevicetoaccomplishthereal-timeradiuscompensatio

7、n.Themechanismofthetensioncontrolsystemisanalyzedandthenumericalmodelissetup.Thecompensationtechniqueoftheradiusofthescrollisanalyzed.Experimentalresultsshowthatthesystemiswellqualifiedwithhighcontrolprecisionandhighreactionspeed.Wateristhesourceoflife,watersupplynaturalrelati

8、onstothepeople'slivelihoodimportantpoint,watersupplythatnoton