Recently I captured some BUS activity of a Cummins QSX15 (KOEO), the point of the exercise was basically CAN sniffing as I'm playing with a project to make myself I very basic scan tool for J1939(so during inspections I can hook up a hand held device to check for codes instead of getting out and setting up a laptop based scan tool....and just to play ). I wanted to get a capture to reverse engineer the SPN conversion method.
What I captured amazed me! The wave form was so terrible after checking my equipment and setup serval times I didn't believe the engine would run or defiantly not communicate, to the extend that I even said to my boss I thought/think there was/is a fault, well I defiantly don't think this is normal??(don't have a similar setup to to compare to.)
This would eliminate the sporadic nature we see at CAN Hi from our intrusion with the Scope
i.e. we must ensure our connection to the network is not responsible for the structure we see on CAN Hi
I hope this helps and I look forward to the outcome
I've seen people recommend utilizing the high-impedance probes a few times on CAN Bus signals. I'd love to see a write-up from Pico about these probes, specifically it would be nice to have something that is comparing screenshots showing the effect on the trace between a standard probe and a high-impedance probe.