PicoQuant MultiHarp 150 - Setting up White Rabbit Connections

PicoQuantGmbH MultiHarpSoftwareV.3.1.0.0
WR Console Output
TheWRPCisinternallyrunninganembeddedsoftwarethatprovidesacommandconsolethatinprinciplebe
accessedlikeusingaterminal.ThecurrentimplementationintheMultiHarpfirmwareandsoftwaredoesnotal-
lowfullaccesstothisconsole.However,thegroupofcontrolsdescribedhereprovidesreadaccesstothecon-
soleoutput.IfthetickboxAuto-RefreshischeckedtheWRconsoleoutputisperiodicallyrefreshed.Note
thattheWRPC’sconsoleoutputisprovidingmeaningfulstatusinformationonlywhentheWRPCisrunningand
hasreceivedthecommandguiwhichstartstheWRPCmonitor.
6.8.2. Setting up White Rabbit Connections
Asoutlinedabove,usingWhiteRabbitasaclocksourcefortheMultiHarprequiresestablishingaWRconnec-
tion.Thefollowingdescribesthenecessarystepstosetupsuchaconnectionbytheexampleofapointtopoint
WRconnectionbetweentwoMultiHarpdevices.
AsafirststepitisalwaysnecessarytoswitchtheWRlinkon(startingtheembeddedWRPCsoftware).Thisis
donebyclickingthebuttonLinkOnintheWRdialogofbothdevices.Inordertoseeifthisissuccessfulitis
advisabletohavetheautomaticstatusrefreshenabled.Itmaytakeafewsecondsuntilthelinkisestablished.
NowyoucanselecttheWRmodeofonedeviceasmasterandtheotherasslave.ThenclickthebuttonSet
Modeineachdevice’sWRdialog.ObservethestatusdisplayandwaituntilthePTPstatusswitchestoMAS-
TERandSLAVErespectively.Theconsoleoutputshouldnowsay“LockedCalibrated”ingreenlettersonboth
sidesandontheslavesidetheservostateshouldeventuallyswitchto“TRACK_PHASE”.TheWRconnection
isnowestablishedandyoucaninspecttheconsoleoutput,e.g.,tocheckthetimingaccuracybetweenthetwo
devicesorotherconnectionstatistics.FordetailspleaserefertotheWRPCmanual.
AftertheWRconnectionisestablisheditispossibletosetthecurrenttimeofthemastersideasthecommon
timeformasterandslave.ThiscanbedonebyclickingthebuttonSetTimeatthemaster.Notethatthistime
isobtainedfromtheoperatingsystem(asUTC).Thisisonlyasaccuratew.r.t.trueUTCastheaccuracyofthe
master’sWindowsclocksetting.MoreaccuratetimecanbeobtainedbyusingtheGrandMastermode,which,
however,requiresanaccuratetimesourcesuchasaGPS/GLONASSreceiver,anatomicclockorsimilar,con-
nectedtotheMultiHarpviathe10MHzclockreferenceandPPSinputsatthebackofthehousing.Notehow-
ever,thatsuchfunctionalityisnotyetconvenientlysupportedbytheMultiHarpsoftware.Seriousworkinthisdi-
rectionshouldusetheMultiHarpprogramminglibraryandcustomsoftware.Inpracticeitisprobablymorecon-
venienttouseadedicatedcommercialgrandmasterintheWRnetwork.
WhentheWRconnectionisestablishedand(optionally)theWRtimehasbeenset,theWRdialogcanbe
closedandWRcanbeselectedasthereferenceclocksourcefortheMultiHarp.Notethatthechoiceofmaster
versusslaveintheclocksourceselectionmustmatchtheroleofmaster/slaveoftheWRconnection.
ForregularuseoftheWRconnectionitisrathercumbersometoperformthedescribedconnectionprocedure
manuallyeachtime.Instead,itispossibletoplaceanappropriateinitializationscriptinmasterandslavesothat
itisautomaticallyexecuteduponpower-up.Anexamplefortheslavesidemaylookasfollows:
ptpstop
sfpdetect
sfpmatch
modeslave
ptpstart
gui
Theonlydifferenceforthemastersideissettingmodemaster (or modegm forgrandmaster).Please
notethatthelastlineguiisnotstrictlynecessaryinagenericWRPCnode.However,duetotheMultiHarp‘s
currentimplementationitisrequiredbecausetheWRPCmonitoroutputisusedtoretrievestatusinformationfor
therelatedprogramminglibraryfunctionsandthestatusinformationprovidedintheWRdialog.Formoredetails
onthescriptcommandspleaserefertotheWRPCdocumentation.
Sofar,onlyapointtopointWRconnectionbetweentwoMultiHarpdeviceswasdiscussed.Itisalsopossibleto
connectaMultiHarpwithsomeotherWRnodeandacrossWRnetworkswitches.Sofarthiswastestedwiththe
“SPECboard”andtheWRswitchesfromSevenSolutions.PleasecontactusifyouwishtooperatetheMulti-
HarpwithotherWRhardwareorinamorecomplexnetworksothatwecanadviseorconsultwiththevendor.
Furthermore,someadvancedusesofWRsuchasremoteexperimentcontrolandjointactionofmultiplede-
vicesarenotyetfullyimplemented.Welookforwardtocollaboratewithinterestedusersaswellassuppliersin
ordertoextendandimprovetheMultiHarp‘sWRinteroperabilityandfunctionality.Pleasegetintouch.
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