vissim信号控制器接口sc interface.pdf

VISSIMSignalControllerDLLInterfaceLK2007-01-23

ThisdocumentdescribeshowexternalcontrollerscanbeconnectedtoVISSIMthroughthe

newDLLinterface(availablesinceVISSIM4.10)tobeusedduringsimulationand/ortest

runs.

Introduction

Signalcontrollers(SCs)oftype“FixedTime”and“VAS”aresimulatedwithinVISSIM.All

otherSCsareexternalandeachonehasaprogramfileassignedtoit.Ifthisprogramfileisan

*.exetheoldDDEinterfaceisusedandoneinstanceofthis*.exeisstartedforeachSCusing

itduringasimulationrun.Iftheprogramfileisa*.dll,however,thenewDLLinterfaceis

used.Thismeansthatthe*.dllisloadedonlyonceforasimulationrunandhastohandlethe

controllerlogicanddataforallSCsthatitisassignedto.

Thecontrollerfrequency(usually1/s)defineshowmanycontrollertimesteps(passesthrough

thecontrollerlogic)musttakeplacepersimulationsecond.Itissetbytheexternalcontroller

duringtheinitializationsequence.ThesimulationresolutioninVISSIM(simulationtime

stepspersimulationsecond)mustbeamultipleofthecontrollerfrequency.Other

combinationsofvaluescauserun-timeerrors.(Example:Ifthesimulationresolutionis10and

thecontrollerfrequencyis2,VISSIMsimulates5simulationtimestepsbetweentwopasses

throughthecontrollerlogic.)

IneachcontrollertimestepVISSIMcontactsallcontrollerDLLsatofthecurrent

simulationtimestep.First,thecurrentsignalizationstatesanddetectordataofallSCsare

passedtotherespectiveDLLs.Second,theDLLsareaskedtocalculatenewdesiredsignal

stateswhicharesubsequentlypassedbacktoVISSIM.Dependingonparameterssetbythe

controllerlogic,eitherth