I have a problem with the CAN Bus shield 2.0
My other CAN bus devices are not seeing CAN messages from the CAN bus shield.
I checked the signalling and I do see CAN H to CAN L voltage toggling but clamped at 2 volts max.
My other CAN bus tool is CAN-H to CAN-L will toggle at around 4 volts differential.
The Seeed studio shield 2 V difference range seems to be clamped at 2V. Its very flat at the two volt level.
This is not a problem, 2 volts is working fine. My problem was in the cable wiring.