There could be a few different problems.
Is the speed for the 8473 set the same as your bus?
Is the 8473 wired correctly?
Do you need a termination resistor?
Do you have the correct resistor?
Are you using the bus monitor in MAX to check for traffic?
Is the speed for the 8473 set the same as your bus? YES
Is the 8473 wired correctly? YES
Do you need a termination resistor? YES
Do you have the correct resistor? YES This is on a functioning vehicle. The CAN bus is certainly there and doing stuff.
Are you using the bus monitor in MAX to check for traffic? YES and it does not see any messages or frames.
I am expecting to find out that this is a software problem. What I would like is a an example LabVIEW program that automatically detected
the CAN bus operation and figured out the set up details. As it stands MAX is telling me there is no CAN bus traffic when I know there is.
Any suggestions and what to try next?
If you go into Help > Find Example and then click on the search tab and enter CAN there will be all the examples. There is a CAN Receive.vi that is pretty basic, you just set the baud rate and interface. Is is similar to the bus monitor in MAX.
You could double check the resistance of the wires at the 8473. You might have accidently put in an extra resistor which could be doing bad things.
If the ohms are correct you could put a scope on the wires to see if you have a clean CAN signal, or if you have a bad connection to the car.
There also might be a self test for the 8473 if you right click on the CAN channel that you can try. I know that if you do not close the network interface properly on the PCI CAN card, you sometimes have to reset it before it will work again.
Thanks for all the suggestions. I tried flipping the H and L wires, no joy. And the example Recieve.vi, no joy.
Then I got an electrical engineer to take a look. He blinked once and said "You're on the wrong connector. Tap off the eight pin connector
instead of the ten pin connector."
I did and now the Receive.vi is pulling in lots of CAN messages.
Thanks again for your suggestions. John Kirk
We have all been there. Glad you have it working.