Hardware functional, but CAN messages not received by PC

[SchlumbergerMan]

I recently moved a desktop CAN card from my office to a computer in the lab to replace a slow laptop. The laptop has a PCMCIA CAN card and communicates properly over the CAN bus. I installed LabWindows v6.0, then installed NI-CAN v2.2, shut down the desktop, installed the PCI card, booted up, the auto-hardware install ran. Using MAX, I did a self-test, which passed, but when I boot up the tool on the other end of the CAN bus, the bus spy on MAX does not register any CAN messages. The card previously worked on my office desktop and the tool communicates properly with the laptop. I tried uninstalling everything and reinstalling using a different PCI slot in the desktop but it is still non-functional. I also checked the connection cable but it is working properly. I am installing the latest NI-CAN update v2.3, which is the newest version compatible with my v6.0 of CVI, but doubt this will solve the problem as I was running the old version of NI-CAN on the laptop and it functioned correctly. I am all out of ideas...

[biker2000]

Hi,

Could that be a problem with the baud rate? The Channel API and the tools in MAX (e.g. the BusMonitor/bus spy) use the default baud rate that is set in MAX (right-click on the CAN port » Properties). When NI-CAN gets installed (and there is no existing version of NI-CAN found on the system), the default baud rate is set to 125 kbaud, however, you might have changed that on your office desktop to a different value.
This does not apply, if you use the Frame API as you have to explicitly set the baud rate when calling ncConfig.

-B2k

[SchlumbergerMan]

Thanks for the reply. I have resolved the issue, it turned out to be a resistance problem on the CAN bus, a simple 120Ohm resistor fixed the problem...and to think how many times I re/un-installed that card/software.