Jeremy,
Here is some fundamental information about the CAN bus. I’m not sure if this has anything to do with your problem, but it may help you eliminate the bus as the problem.
The CAN bus is only two wires plus a shield (ground) wire. They are designated CAN Lo, CAN Hi, and ground. Kanardia uses a cable with an RJ45 jack for convenience. They have two pin-out configurations, one which carries power along with the CAN bus, and one which does not. Both diagrams are attached.
An important component of any CAN bus is that each end is terminated with a 120 Ohm resistor. The bus is linear and central nodes don’t get a resistor, only the ends of the bus do. Because these resistors are arranged in parallel, the resistance across the CAN Hi and CAN Lo wires should be 60 Ohms with both ends connected. If you disconnect just one end, the resistance across the CAN Lo and CAN Hi wires should be 120 ohms. And of course with both ends disconnected there should be no conductivity between these wires.
I looked at the Kanardia manual for the DAQU and is has a built in resistor/terminator, so it’s intended to be one of the ends of the bus. However, the Digi Display requires a plug in resistor to be installed if this is one of the two ends of the bus. They do this so that when you have multiple components you can decide where the end of the line will be and place the resistor there. So you will want to make sure you have that resistor in place wherever the second end of the bus is. See attachments below.
