National Instruments PCI-8430 User Manual

BiasResistors
AnRS-485transmissionlineentersanindeterminatestateifnonodes
aretransmittingonit.Thisindeterminatestatecancausethereceiversto
receiveinvaliddatabitsfromnoisepickeduponthecable.Topreventa
linefromreceivingthesedatabits,thetransmissionlinecanbeforced
intoaknownstatebyinstallingtwobiasresistorsatonenodeonthe
transmissionline.Doingsocreatesavoltagedividerthatforcesthe
voltagebetweenthedifferentialpairtobegreaterthan200mV,the
thresholdvoltageforthereceiver.FormoreinformationaboutRS-485
biasresistors,refertoUsingYourSerialHardware.

National Instruments PCI-8430 Specifications

General

Brand	National Instruments
Model	PCI-8430
Category	Computer Hardware
Language	English