CAN cabling request

[vickyb4]

Hello,

I’m looking at setting up a CAN multi-node network and I was hoping NI would be able to help me out with your products.
I have around 4 nodes with 9 pin DSUB connectors. I would like to know:

1) Which cable to use as the BUS and how I would go about connecting nodes to the bus.
2) What are the lengths of the wires that you provide?
3) Can I use CAN CableY or a T-adapter to Tap into the Bus to add an extra Node?
4) Can I request for gender change of the connectors on the CAN-cable-0 or the Can-Cable-y ?

Thank you,
Vivek Bhaskar
University of Illinois at Chicago

[biker2000]

Hello Vivek Bhaskar,

National Instruments does not sell CAN or DeviceNet cables. You would need to get cables from a different source (e.g. search www.belden.com for the term 'DeviceNet' or build your own cables).

For your other question:
(3) Yes, the CAN bus there are 'T's allowed however, the length of the 'T' (the stub length) is limited and depends on the baud rate.
"ISO 11898 specifies 40 m total cable length with a maximum stub length of 0.3 m for a bit rate of 1 Mb/s. The ISO 11898 specification says that significantly longer cable lengths may be allowed at lower bit rates, but each node should be analyzed for signal integrity problems." (NI-CAN Hardware and Software Manual, May 2004 Edition)

You can probably double the stub length when you cut the baud rate in half on a properly terminated network. However, that allows only for 2.4m at a bit rate of 125 kb/s and I would avoid planning for so long stub lengths in general.

If someone knows a good source for CAN cables, please post it here!

-B2k