文献综述及外文文献翻译

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1、华中科技大学文华学院毕业设计（论文）外文文献翻译（本科学生用）题目：Plcbasedcontrolsystemforthemusicfountain学生姓名：_周训方___学号：060108011117学部（系）:信息学部专业年级:_06自动化（1）班_指导教师：张晓丹___职称或学位：助教__20年月日5外文文献翻译（译成中文1000字左右）：【主要阅读文献不少于5篇，译文后附注文献信息，包括：作者、书名（或论文题目）、出版社（或刊物名称）、出版时间（或刊号）、页码。提供所译外文资料附件（印刷类含封面、封

2、底、目录、翻译部分的复印件等，网站类的请附网址及原文】英文节选原文：CentralProcessingUnit(CPU)isthebrainofaPLCcontroller.CPUitselfisusuallyoneofthemicrocontrollers.Aforetimethesewere8-bitmicrocontrollerssuchas8051,andnowtheseare16-and32-bitmicrocontrollers.Unspokenruleisthatyou’llfindmostl

3、yHitachiandFujicumicrocontrollersinPLCcontrollersbyJapanesemakers,SiemensinEuropeancontrollers,andMotorolamicrocontrollersinAmericanones.CPUalsotakescareofcommunication,interconnectednessamongotherpartsofPLCcontrollers,programexecution,memoryoperation,over

4、seeinginputandsettingupofanoutput.PLCcontrollershavecomplexroutinesformemorycheckupinordertoensurethatPLCmemorywasnotdamaged(memorycheckupisdoneforsafetyreasons).Generallyspeaking,CPUunitmakesagreatnumberofcheck-upsofthePLCcontrolleritselfsoeventualerrorsw

5、ouldbediscoveredearly.YoucansimplylookatanyPLCcontrollerandseethatthereareseveralindicatorsintheform.oflightdiodesforerrorsignalization.Systemmemory(todaymostlyimplementedinFLASHtechnology)isusedbyaPLCforaprocesscontrolsystem.Asideform.thisoperatingsystemi

6、talsocontainsauserprogramtranslatedformaladderdiagramtoabinaryform.FLASHmemorycontentscanbechangedonlyincasewhereuserprogramisbeingchanged.PLCcontrollerswereusedearlierinsteadofPLASHmemoryandhavehadEPROMmemoryinsteadofFLASHmemorywhichhadtobeerasedwithUVlam

7、pandprogrammedonprogrammers.WiththeuseofFLASHtechnologythisprocesswasgreatlyshortened.Reprogrammingaprogrammemoryisdonethroughaserialcableinaprogramforapplicationdevelopment.Usermemoryisdividedintoblockshavingspecialfunctions.Somepartsofamemoryareusedforst

8、oringinputandoutputstatus.Therealstatusofaninputisstoredeitheras“1”oras“0”inaspecificmemorybit/eachinputoroutputhasonecorrespondingbitinmemory.Otherpartsofmemoryareusedtostorevariablecontentsforvariablesusedi