How can I get a USB-8473 to work at >125kbps?

[diarmaede]

All,

I am using an NI USB-8473 high speed CAN card.  I've plugged in into a known-good CAN port in a network that works fine at 500kbps with other CAN devices.

When I run the 8473 at 125Kbps, it works fine.  When I run it faster than that, it does not work.  It does not read CAN data, although the CAN LED does flash before an error (3FF6206B or other) is generated.  When I try to write to the bus at speeds above 125K, the device appears to attempt to write once, then stop functioning.

Any help would be greatly appreciated.

Thanks!

[JB]

• Although the network works with another interface at 500kbps, please check if your cabling meets the requirements for High-Speed CAN (page 4-4 of the NI-CAN Hardware and Software Manual).
• Do you use proper cable termination as mentionned at page 4-5 of above linked document ?
• Has the "know-good CAN port" an onboard 120 ohm termination resistor ?

[diarmaede]

Cabling meets all requirements for High Speed CAN and works with other CAN hardware.  Termination resistors are 120K.

Thanks for your input.

- Forbes

[JB · Accepted solution]

120KΩ or 120Ω ?

[diarmaede]

At this juncture, I must quote the famous philosopher, Homer, not once, but twice.

Quote #1:  "D'OH!!!"  You mean orders of magnitude are important?!

Quote #2:  "Woohoo!"  Problem solved.

Thanks for making me see the obvious.

Cheers,

Forbes