3~电气工程与自动化专业外文文献英文文献外文翻译plc方面.doc

外文原文(复印件)A:FundamentalsofSingle-puterThesingle-puterandtheintegratedcircuitarguablythetowmostsignificantinventionsofthe20thcentury[1].Thesetowtypesofarchitecturearefoundinsingle-,-5A-1,othersfollowthephilosophy,eneral-putersandmicroprocessors,ofmakingnologicaldistinctionbetweenprogramanddatamemoryasinthePrincetonarchitecture,-5A--puterintoasingledevice,asshowninFig3-5A-&-5A-1AHarvardtypeInput&-5A--5A-(ROM).ROMisusuallyforthepermanent,non--,(orintendedforusewith)/-chipROM[2];therecanstillbeasignificantsavinginI/'piggy-back'EPROM(ErasableprogrammableROM)socketsordeviceswithEPROMinsteadofROM。ThesedevicesarenaturallymoreexpensivethanequivalentROMdevice,-volumeapplicationswheretheyprovidetheadvantagesofasingle-chipdevice,intermsofon-chipI/O,etc.,withtheconvenienceofflexibleuserprogra