Question if anyone has any thoughts that may help us. We are having an issue with our CAN Bus. We currently have 8 spark maxes on our bus, our rio and our REV power distribution board. We are not seeing all 8 devices when we plug in on the bus. We either see the Rio and 6 of our sparks or we see the power distribution board and 2 of our sparks. We have checked our CAN wires and they seem to all be connected and they are daisy chained together. Is there anything else that could cause this issue or should we just start testing wire by wire.
Check wire by wire there is most likely a connection not fully seated or a set of flipped wires. You can also use the rev client plugged in to each device and see where it jumps from one bus to next.
So i can see where the disconnect is and I have checked the wire visually and it looks good, I guess the next step then is just to switch out those two wires then.
Try plugging in with only one device at a time and add them back in one by one to see if one devices messes up the whole bus.
You could use a voltimeter to find which one has abnormally low voltage. Also consider looking at the CAN status lights. The ones that aren’t either pink or blue are the ones you want to look at
For your daisy chain, is the roborio the start/end and the PDH/PDP the other start/end or are they are in the middle of the chain?
roborio is the start and PDH/PDP is the end. Right now only thing is the middle is the 6 sparks. No pcm wired in yet.
Two other questions then, on the PDH/PDP is the CAN jumper in the on position?
If so does your sparks have the CAN wiring where they have extra loop of wire?
If so I would pull the breakers in the PDH/PDP for the sparks and then check that both the PDH/PDP and the roborio show up. Then add the breakers for the sparks back one at a time checking to see what effect each spark has on the CAN network.
I am not in the shop at the moment but will definitely check when I can get down there. Thanks for the advice.
I assume that you are plugging into different devices to see the different outcomes.
I think your statement likely says there is something wrong in the wiring between the 6th and 7th spark max in your can wire chain. I would verify you have green to green yellow to yellow. Have good connections. If you are using lever style connectors make sure you are not just clamping on insulation and not wire. If all that fails try replacing the can wire between the two.
Thanks, and yes, different devices provide different outcomes. We will test and see, but I suspect we may be clamped on insulation or have a bad wire. We have already confirmed green to green and yellow to yellow.
1 Like
It sounds like a bad wire. I am assuming you have the Rio on one end and the PD at the other and using them for the termination resistor. Measure the resistance at one end of the bus or the other. The resistance should be 120ish ohms with one resistor or 60 ish with both resistors.
When everything is right Can works pretty good. But little things can break it. Get you most OCCD person you got and teach him(her) to QA your canbus.
This topic was automatically closed 365 days after the last reply. New replies are no longer allowed.