ABB DCS 系统 培训课程 系列讲座 Tasks

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1、CourseT530Chapter13Tasks13.1GeneralInformation13.1.1DescriptionThischapterdescribeswhatataskisandhowtosetpropertiesforit.13.1.2ObjectivesOncompletionofthischapteryouwillbeableto:·Describewhatataskis.·Setpropertiesforatask.13.1.3ReferenceDocumentationUsetheonlinehelp:Con

2、tentstab,GoOnlineandExecute>Execution13.23BSE022858/A2000/12/422:39:0013-5CourseT530Lesson1-Tasksinthetemplates13.1.1DescriptionThischapterdescribeswhatataskisandhowtosetpropertiesforit.13.1.2ObjectivesOncompletionofthislessonyouwillbeableto:·Describewhatataskis.·Setpro

3、pertiesforatask.13.1.3GeneralIntheProjectexploreroftheControlBuilderyouwillfindthreedefaultprograms,labeledProgram1connectedtothetaskFast,Program2connectedtothetaskNormalandProgram3connectedtothetaskSlow.Theprograms,containingthecode,arenotexecutedunlessa"workscheduler"

4、-atask-isconnectedandservesasan"engine"runningthecodeinthecontroller.13.1.4TaskpropertieswindowThesettingsofthetaskarechangedintheTaskPropertieswindow.3BSE022858/A2000/12/422:39:0013-5CourseT530Taskproperties13.1.1.1.1IntervalTimeTheintervaltimetheprogramisexecutedwithi

5、ssetintheTaskOverviewwindoworintheTaskPropertiesdialogbox.Defaultvaluesare50ms(Fast),250ms(Normal)and1000ms(Slow).Youcanchangethesevaluesatanytime.Forapriority-0task,theintervaltimecanbeaslowas1ms.Tasksofpriority1-5cannotbebelow10ms.Theresolutionis1ms.13.1.1.1.2OffsetAm

6、echanismusedtoavoidanunexpecteddelayoftheexecutionstarttime.SeeOffsetintheonlinehelpformoredetails.13.1.1.1.3PriorityTherearesixlevelsofpriority:TimeCritical,Highest,High,Normal,Low,andLowest,numberedfrom0to5.TimeCriticalhasthehighestpriority.Thetasksexecuteaccordingtop

7、riority.Ataskwithhigherprioritywillinterruptanytaskwithlowerpriority.Precisiontasksinterruptofanypointofexecutionbutothertasksinterruptatsomedistinctpoints.ThetaskprioritiescanbesetthroughtheSetPriorityfunction.13.1.1.1.4I/OcopyByusingtheradiobuttonsisitpossibletoselect

8、ifyouwanttomaketheI/Ocopybeforethetaskexecutesorafterthetaskexecutes.13.1.1.1.5DebugYoucansetupataskfornon-cyc