National Instruments PCI-8430 - Page 25

PXIKits
ThePXIserialhardwaregivesyouavarietyofsolutionsforserial
communication.TheRS-232boards(PXI-8430,PXI-8432,PXI-8420,and
PXI-8422)workwiththeRS-232protocol.TheRS-485boards(PXI-8431,
PXI-8433,PXI-8421,andPXI-8423)workwiththeRS-422andRS-485
protocols.YoucanusetheRS-232portsforserialcommunicationupto
distancesof50ft.YoucanconnecttheRS-485portstoupto31devices
usingserialcablelengthsupto4,000ft.
Additionally,thePXIserialboardsareavailableintwo-port,four-port,
eight-port,and16-portversions.Thetwo-portversionsuseDB-9
connectors.Thefour-portversionsuse10-positionmodularjacksto
provideallfourconnectionsonasinglefrontpanel.Optionalcable
accessoriesconvertthe10-positionmodularjackstoeitherDB-9orDB-
25connectorswithstandardpinouts.Theeight-portversionsuseadapter
cablestoconvertthe68-pinconnectorontheboardtoeightDB-9
connectors.ThePXI-8430/16usestwoadaptercablestoconvertthetwo
68-pinconnectorsontheboardto16DB-9connectors.ThePXI-8420/16
usesabreakoutboxtoconvertthe100-pinconnectorontheboardto16
DB-9connectors.Throughoutthishelpfile,PXIserialboardsreferstoall
versionsofthePXIserialboards.
TheisolatedPXIboardsaredesignedforapplicationsinharsh
environments.Isolatedportsprovidereliablecommunicationinsituations
involvinggroundloopsfromdifferentgroundlevelsorhighcommon
modevoltageinducedonthelinesinnoisyenvironments.Nonisolated
portsmaynotprovidereliablecommunicationinthosesituations.The
isolationbetweeneachcommunicationportandthehostPCensuresthe
safeoperationofthePCandthedevicesconnectedtootherportsonthe
sameboard,incaseofaccidentalhighvoltagesorlinesurgeson
communicationlines.
TheRS-232portsareDTE.IntheRS-232specification,DataTerminal
Equipment(DTE)andDataCommunicationsEquipment(DCE)referto
thetypesofequipmentoneitherendofaserialconnection.Ingeneral,
DTEandDCErefertocomputerequipmentandmodems,respectively.
FormoreinformationaboutcablingaRS-232porttootherdevices,refer
toRS-232DTEvs.DCE.
TheRS-485portssupportfourhardwaretransceivercontrolmodesfor