Building our networks and beginning to program. CAN1 seems to work reliably to transmit and receive from all modules attached. But CAN2 doesn’t seem to be working at all from either ADU or PMU. It’s built similar to CAN1, so I’m assuming the physical structure is fine.
Is there a way to see/know what/when either ADU or PMU is actually transmitting on CAN2?
Connect your USBtoCAN to CAN2 and you can see what data is being transmitted.
You can also use the receiving device CAN input with live data checked to see what a specific channel is seeing.
Upload your project files and we can take a look if there’s a simple setting missing. CAN2 needs messages or inputs in the software, as well as the wiring correct obviously.
Outline what functionality you’re using CAN 2 for
You can check your logs for CAN bus errors. Search for the CAN2 error channel.
If you have any errors on the CAN bus, you have to fix them.
It can be because of devices with different speeds, frame ID conflicts, incorrect bus termination (2x120 ohm), or general electrical issues.
Update on this.
I wired in an On/On switch between Can1 and Can2 and the USB/CAN module. This allows me to switch between the two BUS lines in Light Client. With that I can see that my CAN2 is now working, except when I turn on my Sentinel Video system. Initially we found it was running 1MBS vs 500kbs that is our CAN2. We are now running a Beta version of code to change the speed, but when that module is turned on it crashes our CAN2. In theory it’s not transmitting, so more troubleshooting is required, but now I can see CAN2 on LightClient.
Here’s the switch we used.
Do you have two 120-ohm resistors on the second bus?
And don’t use the one in USBtoCAN if you switch it between buses.
You need 2x120 ohm with or without USBtoCAN connected.
The module doesn’t have to transmit anything to break the bus.
Every module on the CAN bus confirms every frame it receives, and that confirmation will break the bus if the module is set to a different speed.
It seems their beta software is not working at 500 kbps exactly.
Do you have some devices that have to be at 500 kbps?
Maybe you can switch the CAN 2 to 1 Mbps and use the official firmware for the video system?
We’re running “non essential” modules on CAN2, which includes ABS and Power Steering, both of which run 500. The Sentinel (video live stream module) is already wired in and I don’t feel like ripping the harness apart to swap it to CAN1 now!
The harness is terminated with a 120ohm resistor at the ABS pump (front of car) and an internal resistor at our Roof Light LED controller (rear of car, near Sentinel). The Sentinel does have CAN output wires to add a terminator if needed, so i might just terminate that and turn off the switchable terminater on the other module.
Isolate things to make sure.
Connect only the video system and USBtoCAN on the bench and check with the Light Client if you have errors at 500 kbps.
Or disconnect the modules from the second bus in the car, so there is only a video system and USBtoCAN.
If there are errors, the video system is not working correctly.