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.Theoriginalcontrolsystemwasconstructedabout20yearsagob

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

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

4、amminglanguagefor500functionblocks.ByoptimizingthefunctionblocksandconnectingthemintheFBDlanguage,thefeedbackloopshavebeensuccessfullyreplacedfromDCStoPLCwithoutasoftwaredeveloper.Moreover,anoscillationoftheliquidHelevel,whichoftenoccursduringthecooldownmodeofthecryopumps,canbeau

5、tomaticallystabilizedbyeasilyaddinganewprocessprograminthePLC.Atpresent,thenewcontrolsystemhasworkedwell.Fiberwindingtensionisanimportantfactorinthemoldingtechniquesofcompositematerialwhichinfluencesthequalityofwindingproductdirectly,andthetensioncontrolisakeytechniqueinfiberwind

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

7、etensioncontrolsystemisanalyzedandthenumericalmodelissetup.Thecompensationtechniqueoftheradiusofthescrollisanalyzed.Experimentalresultsshowthatthesystemiswellqualifiedwithhighcontrolprecisionandhighreactionspeed.Wateristhesourceoflife,watersupplynaturalrelationstothepeople'slivel

8、ihoodimportantpoint,watersupplythatnoton