National Instruments PXI-8461 Computer Hardware User Manual


 
Appendix B Cabling Requirements for PXI-8460 Low-Speed CAN
PXI-846x and NI-CAN for Windows NT B-4 ni.com
Cable Specifications
Cables should meet the physical medium requirements specified in
ISO 11519-2, shown in Table B-2.
Belden cable (3084A) meets all of those requirements, and should be
suitable for most applications.
Number of Devices
The maximum number of devices depends on the electrical characteristics
of the devices on the network. If all of the devices meet the requirements
of ISO 11519-2, at least 20 devices may be connected to the bus. Higher
numbers of devices may be connected if the electrical characteristics of
the devices do not degrade signal quality below ISO 11519-2 signal level
specifications.
Table B-2. ISO 11519-2 Specifications for Characteristics of a CAN_H
and CAN_L Pair of Wires
Characteristic Value
Length-related resistance 90 m/m nominal
Length-related capacitance:CAN_L and ground,
CAN_H and ground, CAN_L and CAN_H
30 pF/m nominal