AB 冗余系统内存使用详解

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1、Page5of5UnderstandControlLogixRedundancyMemoryUsageCreationDate:6-30-04DISCLAIMERBecauseofthevarietyofusesforthisinformation,theuserofandthoseresponsibleforapplyingthisinformationmustsatisfythemselvesastotheacceptabilityofeachapplicationanduseoftheprogram.InnoeventwillAllen-BradleyCompanyberespons

2、ibleorliableforindirectorconsequentialdamagesresultingfromtheuseorapplicationofthisinformation.Theillustrations,chartsandexamplesshowninthisapplicationnoteareintendedsolelytoillustratetheprinciplesofprogrammablecontrollersandsomeofthemethodsusedtoapplythem.Particularlybecauseofthemanyvariablesandr

3、equirementsassociatedwithanyparticularinstallation,Allen-BradleyCompanycannotassumeresponsibilityorliabilityforactualusebasedupontheillustrationsusedandapplications.Allen-BradleyCompanyassumesnopatentliabilitywithrespecttouseofinformation,circuits,equipment,orsoftwaredescribedinthistext.Reproducti

4、onofthecontentsoftheapplicationnote,inwholeorinpart,withouttheexpresswrittenconsentoftheAllen-BradleyCompanyisprohibited.DocumentPurposeThisdocumentisnotamanualortrainingmaterial,butanApplicationNote,whichcouldbeusefulinhelpingaRockwellAutomationcustomerwithunderstandingControlLogixRedundancymemor

5、yusage.IntendedAudienceThisdocumentistobeusedbyRockwellAutomationemployees/customerssupportingandsellingControlLogixRedundancy.V1.0Page5of5ConceptofApplicationNoteInaControlLogixcontroller(L55andL6X)therearetwoseparateareasofmemory,I/Omemoryanddataandlogicmemory.WhenRedundancyisenabled,certainarea

6、sofmemorywillapproximatelydoubleinusage;thoseareI/Omemoryanddatamemory.Wewilldiscusswhytheseareasofmemorydouble.FirstletuslookatanexampleusinganL55M13toillustrate:Non-RedundantSystem:I/Omemory:Total208KbytesUsed75KbytesDataandLogicmemory:Total1.5MegUsed250Kbytesdataand250KbyteslogicNowwhenRedundan

7、cyisenabledtheamountofI/Omemoryanddatamemorywilldouble.RedundantSystem:I/Omemory:Total208KbytesUsed125KbytesDataandLogicmemory:Total1.5MegUsed500Kbytesdataand250KbyteslogicAnotherexampleoftheI/Oanddatamemorydoubl