S7-300CPU的三种启动方式的区别.doc

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1、Whatisthedifferencebetweenarestart(warmrestart),coldrestartandhotrestartofaS7-400CPU?HidepartnumberDisplaypartnumberPartnumber:Description:BeforeaS7-400CPUorCPU318-2startsprocessingtheuserprogramafterswitch-on,astartupprogramisprocessed.Inthestartupprogram,youcandefine

2、specificpresettingsforyourcyclicprogrambyprogrammingstartupOBsaccordingly.Therearethreetypesofstartup: StartupmodeBriefdescriptionRestart(warmrestart)Programprocessingstartsanew.Retentivedataisretained.ColdrestartCurrentdataisdiscardedandprogramprocessingbeginsagainwit

3、hthestartvalues.HotrestartOncepowerisresumed,theprogramcontinuesatthepointatwhichitwasinterrupted.Inoperatingmode"STARTUP":·TheprogramisprocessedinthestartupOB(OB100forrestart(warmrestart),OB101forhotrestartandOB102forcoldrestart).·Time-andalarm-controlledprogramproces

4、singisnotpossible.·Timesareupdated.·Theruntimemeterruns.·Thedigitaloutputsonsignalmodulesareblocked,butcanbesetviadirectaccess.Restart(warmrestart):Fig.01Inarestart(warmrestart),programprocessingrestartsatthebeginningoftheprogramwitha"basicsetting"ofthesystemdataanduse

5、raddressareas.·Theprocessimageandthenon-retentivemarkers,timersandcountersarereset.Retentivemarkers,timersandcounterseachretaintheirlastvalidvalue.Alldatablocksparameterizedwiththeproperty"NonRetain"areresettotheloadedvalues.Theotherdatablockseachretaintheirlastvalidva

6、lue.·Programprocessingstartsagainatthebeginning(startupOBorOB1).·Ifthepowersupplyisinterrupted,awarmrestartisonlypossibleinbufferedmode.IfyouareoperatingyourCPUwithoutbackupbattery,theCPUisautomaticallyresetcompletelyandthenrestarted(warmrestart)whenyouswitchonorpowerr

7、eturnsafteraPOWEROFF.Arestart(warmrestart)isalwayspermissibleunlessthesystemdemandsanoverallreset.Inthefollowingcasesonlyarestart(warmrestart)ispossibleafter:·Overallreset.·LoadingoftheuserprogramintheSTOPmodeoftheCPU.·USTACK/BSTACKoverflow.·Interruptionoftherestart(wa

8、rmrestart)throughPOWEROFForviamodeswitch.·Exceedingofparameterizedinterruptiontimelimitforrestart.Orderofoperationsfo