National Instruments NI 9853 Operating Instructions Manual

Also see for NI 9853: Getting started guide Getting started guide

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National Instruments NI 9853 Operating Instructions Manual Manual pdf 13 page image

© National Instruments Corp. 13 NI 9853 Operating InstructionsTermination ResistorsThe termination resistors (Rt) should match the nominalimpedance of the CAN cable, and therefore comply with the valuesin Table 4.Cable LengthsThe allowable cable length is affected by the characteristics of thecabling and the desired bit transmission rates. Detailed cable lengthrecommendations can be found in the ISO 11898, CiA DS 102, andDeviceNet specifications.ISO 11898 specifies 40 m total cable length with a maximumstub length of 0.3 m for a bit rate of 1 Mb/s. The ISO 11898specification says that significantly longer cable lengths may beallowed at lower bit rates, but each node should be analyzed forsignal integrity problems.Table 4. Termination Resistor SpecificationCharacteristic Value ConditionTermination resistor, Rt 100 Ω min,120 Ω nominal,130 Ω maxMinimum powerdissipation: 220 mW