可编程控制器毕业论文外文翻译

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1、拟建中的阜阳市中国XXXX国际服装城依托中国XX国际服装城，拟建成为皖西北地区规格最高、规模最大、商务及功能最优的现代化、国际化服装专业市场，建设规模占地约128亩，建筑面积约25万平方米，项目总投资约5亿元人民币。经过1--2年的开发建设，能达到正常运营期的中国XX.XX国际服装城将吸纳全国和世界各地的经销商、代理商企业物流总部等500—1000家，预计年交易额实现68亿元人民币，每年实现税收8000—10000万元人民币，每年实现利润1.68亿元人民币，实现就业和创业人员约2万以上。B：外文文献及译文SystemBlockDiagramAP

2、rogrammableControllerisaspecializedcomputer.Sinceitisacomputer,ithasallthebasiccomponentpartsthatanyothercomputerhas;aCentralProcessingUnit,Memory,InputInterfacingandOutputInterfacing.AtypicalprogrammablecontrollerblockdiagramisshowninFigure1.Figure1ProgrammableControllerBlo

3、ckDiagramTheCentralProcessingUnit(CPU)isthecontrolportionofthePLC.Itinterpretstheprogramcommandsretrievedfrommemoryandactsonthosecommands.InpresentdayPLC'sthisunitisamicroprocessorbasedsystem.TheCPUishousedintheprocessormoduleofmodularizedsystems.Memoryinthesystemisgenerally

4、oftwotypes;ROMandRAM.TheROMmemorycontainstheprograminformationthatallowstheCPUtointerpretandactontheLadderLogicprogramstoredintheRAMmemory.RAMmemoryisgenerallykeptalivewithanon-boardbatterysothatladderprogrammingisnotlostwhenthesystempowerisremoved.Thisbatterycanbeastandardd

5、rycellorrechargeablenickel-cadmiumtype.NewerPLCunitsarenowavailablewithElectricallyErasableProgrammableReadOnlyMemory(EEPROM)whichdoesnotrequireabattery.Memoryisalsohousedintheprocessormoduleinmodularsystems.Inputunitscanbeanyofseveraldifferenttypesdependingoninputsignalsexp

6、ectedasdescribedabove.Whenpowerisappliedtoaprogrammablelogiccontroller,thePLC’soperationconsistsoftwosteps:(1)updateinputsandoutputsand(2)solvetheladder.ThefirstthingthePLCdoeswhenitbeginstofunctionisupdateI/O.Thismeansthatalldiscreteinputstatesarerecordedfromtheinputunitand

7、alldiscretestatestobeoutputaretransferredtotheoutputunit.Registerdatagenerallyhasspecificaddressesassociatedwithitforbothinputandoutputdatareferredtoasinputandoutputregisters.Theseregistersareavailabletotheinputandoutputmodulesrequiringthemandareupdatedwiththediscretedata.Si

8、ncethisisinput/outputupdating,itisreferredtoasI/O.AftertheI/Oupdatehasbeena