User manual

Reference ILX34-AENWG ♦ Point I/O Platform
User Manual Wireless POINT I/O Adapter
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Page180of209 ProSoftTechnology,Inc.
 September19,2011
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6.2.3 Use of the Common Industrial Protocol (CIP)
TheILX34‐AENWGadapterusestheCommonIndustrialProtocol(CIP).CIPistheapplicationlayer
protocolspecifiedforEtherNet/IP,theEthernetIndustrialProtocol,aswellasforControlNetand
DeviceNetnetworks.Itisamessage‐basedprotocolthatimplementsarelativepathtosenda
messagefromtheproducingdevicein
asystemtotheconsumingdevices.
 Theproducingdevicecontainsthepathinformationthatsteersthemessagealongthe
properroutetoreachitsconsumers.Sincetheproducingdeviceholdsthisinformation,
otherdevicesalongthepathsimplypassthisinformation;theydonotneedtostoreit.
This
hasthefollowingsignificantbenefits.
 Youdonotneedtoconfigureroutingtablesinthebridgingmodules,whichgreatlysimplifies
maintenanceandmodulereplacement.
 Youmaintainfullcontrolovertheroutetakenbyeachmessage,whichenablesyoutoselect
alternativepathsforthesameenddevice.
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Understand Messaging
Class3(ExplicitMessage)requeststhroughtheILX34‐AENWGadaptertoaspecificPOINTI/O
modulemaynotalwaysreceivearesponsefromtheI/Omodules.InthecasewheretheI/O
moduledoesnotreplytotherequest,theadapterrespondswithanerrorcodeindicatinga
timeout.
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6.2.4 Specify the Requested Packet Interval (RPI)
TheRPIistheupdateratespecifiedforaparticularpieceofdataonthenetwork.TheRPIcanbe
specifiedfortheadapterandincludealloftheI/Omodulescommunicatingthroughit(usinga
rack‐optimizedconnection)orspecifiedforaparticularmodule(usingdirectconnection).
Whenyouadd
amoduleoranadaptertotheI/Oconfigurationofacontroller,youmustenter
theRPIasaparameter.Thisvaluespecifieshowoftentoproducethedataforthatdevice.For
example,ifyouspecifyanRPIof50ms,itmeansthatevery50msthedevice
shouldsenditsdata
tothecontrollerorthecontrollershouldsenditsdatatothedevice.
UseRPIsonlyfordevicesthatexchangedata.Forexample,aControlLogixEtherNet/IPbridge
moduleinthesamechassisasthecontrollerdoesnotrequireanRPI,becauseitisnotadata‐
producing
memberofthesystem.Itsuseisonlyasabridgetoremoteracks.
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