FLEX热备方案.docx

FLEX热备方案.docx

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FLEX热备方案

FlexLogixBackuponDeviceNet

ApplicationNote

FlexLogix的DeviceNet网络备份

应用说明

March2003

2000303

1.FlexLogixbackupondevicenetOverview综述3

1.1TypicalApplications典型应用3

1.1.1PowerGeneration发电3

1.1.2RemoteRTUforSCADA远程终端的管理控制的数据采集3

1.1.3SmallProcess小过程3

1.2DeviceNetTechnologyUsed驱动技术应用3

1.3SystemREquirements系统需求3

1.4ArchitecturalOverview结构总貌5

1.4.1HowFlexLogixBackupworks如何工作5

2.developingtheFlexLogixBackupapplication备份应用的发展6

2.1accessingBackupconfigurationfromtheuserprogram从用户程序访问备份结构6

2.2BackupHeartbeatconfiguration备份心跳结构6

2.3Readingbackupstate读备份规定6

2.4readingbackupstatus读备份状况6

2.5ExamplegetAttributeSingleMSGinstruction获得单MSG指令属性的例子7

2.6ExampleSetAttributeSingleMSGInstruction设置单MSG指令属性的例子9

2.7ExampleLaddertoenablebackupmode梯形图使能备份模式的例子11

2.8ConfiguringtheScanlistsinprimaryandsecondary在第一和第二处理器配置扫描列表15

2.9Tipsfordevelopmentanddebugging发展和调试15

3.powerupandsystemstartup上电和系统启动16

3.1Examplesteptoqualifyabackupsystem逐步限制备份系统的例子16

3.2usingledsforstatus利用二极管的状态17

4.FAQ常见问题18

5.ControlLogixandflexLogixcomparison比较20

1.FlexLogixbackupondevicenetOverview综述

FlexLogixBackuponDeviceNetisasimple,low-cost,backupsystemtargetedtowardssmallerapplicationswhichrequirefastswitchoversfromPrimarytoSecondaryprocessor.NoadditionalHWorspecialSWisrequired.FlexLogixBackupisfasterthanaSWimplementedswitchover（i.e.inhibit/uninhibit）andlowercostthanControlLogixRedundancyonControlNet.

FlexLogix的DeviceNet网络的备份是一种简单、低成本。

备份系统针对的是要求快速从第一处理器切换到第二处理器的小的应用场合。

不需要额外的HW或专门的SW设备。

FlexLogix备份切换速度比SW快、比ControlLogix的ControlNet冗余网低成本。

1.1TypicalApplications典型应用

IngeneralBackupcapabilitywillfulfilltwogeneralrequirements:

一般而言完成工作需要2个普通要求:

-MinimizeDownTimeincaseofProcessorfailure（sameprograminbothprocessors）.

-处理器故障的最小停机时间（相同的程序在2个处理器里）

-MitigateRiskofchangesadverselyaffectingtheapplication（useold,provenprograminoneprocessorandnew,untestedprograminotherprocessor）.Incasethenewuntestedprogramcausesaproblem,aforcedswitchovercanbemadetotheolderprovenprogramwithoutre-downloadingtheprogram.

-减小应用程序改变的相对影响（在一个处理器中用旧的证明过的程序，另一个中使用未测试过的程序）。

万一新的程序引起故障，强制切换能切换到旧的程序。

1.1.1PowerGeneration发电

FlexLogixBackupisidealforpowergenerationapplicationswhichrequirealow-costbackupprocessortominimizedowntime.Atypicalapplicationwouldinvolveusingaredundantpairofprocessorstocontroltheswitchgears,orforstandbyorpowercogeneration.

1.1.2RemoteRTUforSCADA远程终端的管理控制的数据采集

SincemanyRTU（RemoteTerminalUnit）applicationsforSCADA（SupervisoryControlAndDataAcquisition）arelocatedinremotelocations,backupprocessorsarerequiredsincethemeantimetorepairmaybequitelong.

1.1.3SmallProcess小过程

Insmallprocessapplicationswhereenvironmentalcontroliscritical（e.g.lossoftemperaturecauseswholebatchtobethrownaway）,abackupprocessorisrequiredtoavoidlossofthewholebatchincaseofprocessorfailure（e.g.powerfailure）.

1.2DeviceNetTechnologyUsed驱动技术应用

TheAllen-BradleytechnologybehindthebackupfunctionalityistheabilitytohaveSharedDeviceNetMastershipofslaveI/Odevices.TypicallywithDeviceNetonlyasinglemastermayexistonthenetworkforanyparticularslave.WithSharedDeviceNetMastership,asimplebackupsystemcanbeimplemented.TheheartbeatcommunicationsbetweenPrimaryandSecondarydetermineswhichscanneristhemasterandwhichscannerisinstandby.ThetechnologyisnotuniquetoFlexLogixbutcurrentlythe1788-DNBOistheonlyDeviceNetscannerwhichsupportsthisfeature.

1.3SystemREquirements系统需求

RSLogix5000andFlexLogixFWrevisionmustbev10orhigherataminimum.

-FlexLogixFWmustbeatv10orhigherfor1788-DNBOsupport

-FlexLogixFWmustbeatv11orhigherfor1788-ENBTsupport

-1788-DNBOFWmustbeat2.Xorhigher

TheDeviceNetnetworkshouldbesetupwithboththeprimaryandsecondary1788-DNBOnodeaddressessetto0.Node1shouldbereservedforthesecondaryscanner.（Itisalsopossibletousehighernodenumberssuchas10and11,or30and31,butnot62and63.）

AllI/OandoperatorinterfacesthatarerequiredtobebackedupmustbeonDeviceNet.

1.4ArchitecturalOverview结构总貌

1.4.1HowFlexLogixBackupworks如何工作

Refertothepreviouspicture.以上图片提到的

-Bothprocessors/scannerssimultaneouslyreceiveallinputs

-2个控制器/扫描器同时接受所有输入

-BothprocessorsexecuteinparallelbutareNOTsynchronized.

-2个控制器并行执行但是不同步

-OnlyPrimarysendsOutputstoI/Odevices.（Avirtualswitchinthe1788-DNBOsisusedtoswitchoutputsbetweenPrimaryandSecondary.）

-只有主控制器送输出到I/O驱动（在1788-DNBOs有一个虚假的切换用于在主、从控制器切换输出）。

-Afterfailureorforcedswitchover,Outputsareautomaticallyswitchedby1788-DNBOfromPrimarytoSecondary

-故障或强制切换时，输出会自动通过1788-DNBO进行主、从切换。

TheswitchoversofastthattheI/Odoesnottimeout.TheI/Oisunawarethatredundantprocessors/scannersexistandisunawareoftheswitchover.

切换给I/O是非常快的，不需要时间。

冗余的控制器和扫描器切换，I/O是不会觉察的。

2.developingtheFlexLogixBackupapplication备份应用的发展

2.1accessingBackupconfigurationfromtheuserprogram从用户程序访问备份结构

BackupmodeisenabledfromtheUserProgramwithafewsimpleladderrungs（orequivalent）.Thefirstandmostcriticalstepistosetthebackup“heartbeat”constantinsidetheDeviceNetscanner,whichdeterminestheswitchovertime（2xheartbeat）andenablesthebackupfeature.Bydefaulttheheartbeatisinitializedtozero,whichdisablesthebackupmodesotheUserProgrammustsettheheartbeattoanon-zerovaluetoenablebackupmode.

2.2BackupHeartbeatconfiguration备份心跳结构

Theheartbeatisinmultiplesof8ms（i.e.8,16,24,etc.）witharecommendedvalueof16-48msformostapplications.Thisresultsinaswitchoverof32-96ms（butdoesn’tincludeprocessorscandelays）.Ifmultiplesof8arenotusedfortherequestedheartbeat,thenthescannerwillusethenexthighersupportedheartbeatvalue,whichcanbereadfromthescanner.

心跳是8ms的倍数（如：

8，16，24等），最多的应用推荐值是16到48ms。

是切换时间为32-96ms（但是不包括扫描器延迟）。

假如8ms的倍数不是用来要求心跳，扫描器会用更大的、能从扫描器读数据的支持心跳值。

TheheartbeatsettingwithintheDeviceNetscannerisaccessedbyusingtheGenericMessageInstructionandtheSet/GetAttributeSingleservicetoScannerClass0x90+Instance0x01+Attribute0x12withanINTdatatype.Whenthescannerdetectsachangeintheheartbeat,itwillresetitselfandusethenewconfiguration.

2.3Readingbackupstate读备份规定

Thebackupstateofthescannercanbeobtained（e.g.primaryorsecondary）usingtheGetAttributeSingleservicetoScannerClass0x90+Instance0x01+Attribute0x13withaSINTdatatype.

扫描器备份规定能获得（第一或第二）使用获得单一的扫描服务特征类：

0=Disabled不能

1=PrimaryScanner主扫描器

2=BackupScanner备用扫描器

3=InvalidPrimaryNodeAddress（e.g.can'tbe62or63）故障主节点地址

4=FaultedBackupScanner-CRCFailure-（e.g.ScanListsdon'tmatch）故障备用扫描器（校验故障）

5=FaultedBackupScanner-BackupNodeNumberFailure（e.g.BackupnotPrimary+1）故障备用扫描器，备份节点数值故障

6=BackupScannerPendingPrimaryDetection备用扫描器未发现主扫描器

254=AttemptingPrimaryAccess尝试主访问

255=AttemptingBackupAccess尝试备用访问

Thebackupstateisusefulfordebugormoresophisticatedbackupschemes.

2.4readingbackupstatus读备份状况

AdditionalstatusbitsarealsoavailableusingtheGetAttributeSingleservicetoScannerClass0x90+Instance0x01+Attribute0x14withaSINTdatatype.附加的状况位也可用来获得扫描服务唯一属性。

Bit0=NoBackupScannerDetected没有备用扫描器

Bit1=PrimaryScannerforcingIDLE（BackupinRUNbutPrimaryinIDLE）主扫描器强制空闲

2.5

ExamplegetAttributeSingleMSGinstruction获得单MSG指令属性的例子

ScreenshotsofaexampleGetAttributeSingleMSGinstruction.Current_HeartbeatisanINT.

2.6

ExampleSetAttributeSingleMSGInstruction设置单MSG指令属性的例子

ScreenshotsofaexampleSetAttributeSingleMSGinstruction.Config_HeartbeatisaINT.

2.7ExampleLaddertoenablebackupmode梯形图使能备份模式的例子

AnexampleladderprogramusingtheGetandSetAttributesservicestoenableBackupScannerisshownbelow.

2.8ConfiguringtheScanlistsinprimaryandsecondary在第一和第二处理器配置扫描列表

ThekeytoeasilyconfiguringtheredundantDeviceNetscannersistoconfigurethemseparatelywithonlyasinglescanneronthenetworkatatime.Inorderforbackuptowork,bothscanlistsmustbeidentical.

2.9Tipsfordevelopmentanddebugging发展和调试

Ingeneralitisalsoagoodideatodevelopanddebugtheentireapplicationwithonlytheprimaryprocessorandscannerpresent.Whentheapplicationistotallyverified,thendownloadtheprogramandexactsamescanlisttothesecondary,withouttheprimarybeingpresent.Verifythatthesecondaryisalsofunctioningproperly,andthenbothprimaryandsecondarycanbeaddedtothenetworkatthesametime.

NOTE:

NoconfigurationparametersareenteredfromRSNetworxforDeviceNetorRSLogix5000toenableBackup.AllconfigurationoccursintheUserProgram.Almostyourentireapplication（e.g.exceptforafewladderrungs）canbedevelopedwithoutknowledgethattheapplicationwillhaveabackupprocessorandscanner.

3.

powerupandsystemstartup上电和系统启动

3.1Examplesteptoqualifyabackupsystem逐步限制备份系统的例子

ThefollowingexamplestepsdescribethesequenceofeventstakentoconfigureaFlexLogixBackupsystem.

1）PutallbackedupI/OandoperatorinterfacesonDeviceNetusingnodeaddresses2andhigher.

2）ConnectaFlexLogixprocessorwitha1788-DNBOscanneronthenetwork.Setthenodeaddressto0.Powerupthecontrollerandnetwork.

3）UsingRSNetWorxforDeviceNet,downloadascanlisttothe1788-DNBOtoallowcommunicationtoslavedevicesonnetwork.Thiscouldbeafreshlymadeconfigurationorapreviouslycreatedproject.Ifafreshconfiguration,makesu