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.Theoriginalcontrolsystemwasc

2、onstructedabout20yearsagobyspecifyingtheDCS(DistributedControlSystem)computertodealwith～400feedbackloops.Recently,troublesonthiscontrolsystemhaveincreasedduetoitsage-induceddeterioration.Tomaintainthehighreliabilityofthecryogenicfacility,anewcontrolsyste

3、mhasbeenplannedwiththePLCandSCADAsystems.Theirattractivefeaturesincludehighmarketavailabilityandcost-effectiveness,however,theuseofPLCforsuchalargefacilitywith～400feedbackloopshasnotbeenestablishedbecauseofinsufficientprocessingcapabilityoftheearlyPLC.Me

4、anwhile,therecentprogressinthePLCenablestousetheFBD(functionblockdiagram)programminglanguagefor500functionblocks.ByoptimizingthefunctionblocksandconnectingthemintheFBDlanguage,thefeedbackloopshavebeensuccessfullyreplacedfromDCStoPLCwithoutasoftwaredevelo

5、per.Moreover,anoscillationoftheliquidHelevel,whichoftenoccursduringthecooldownmodeofthecryopumps,canbeautomaticallystabilizedbyeasilyaddinganewprocessprograminthePLC.Atpresent,thenewcontrolsystemhasworkedwell.Fiberwindingtensionisanimportantfactorinthemo

6、ldingtechniquesofcompositematerialwhichinfluencesthequalityofwindingproductdirectly,andthetensioncontrolisakeytechniqueinfiberwindingtechniques.Thispaperintroducesaclosed-looptensioncontrolsystemwiththeprogrammablelogiccontroller(PLC)withfunctionmodulesa

7、sitscontrolkernel,thealternatingcurrent(AC)servomotorasexecuteelementandtheradius-followingdevicetoaccomplishthereal-timeradiuscompensation.Themechanismofthetensioncontrolsystemisanalyzedandthenumericalmodelissetup.Thecompensationtechniqueoftheradiusofth

8、escrollisanalyzed.Experimentalresultsshowthatthesystemiswellqualifiedwithhighcontrolprecisionandhighreactionspeed.Wateristhesourceoflife,watersupplynaturalrelationstothepeople'slivelihoodimportantpoint,watersupplythatnoton