What is the exact message you are getting? There are a lot of simple things this could be.
Are you saying that the entire can bus network fails when you plug your servo in causing a complete failure, or just that the servos stop communicating properly and there is an error?
If the issue is localized to just the servos and the rest of the system is still talking, then check to make sure you have your pitch ID jumper in and that it is pinned out correctly. If you don't they have a conflict and it causes issues.
If you are having a
complete can bus failure you will want to start trouble shooting your can bus.
Here is a quick can bus troubleshooting procedure that I train our staff to do.
1. Ensure that both termination points are plugged in. Test the resistance between can bus hi and can bus low at any LRU except the termination points.
- If you read 60Ω then your can bus is properly terminated, move on to step 2
- If you read 120Ω then your can bus is not terminated. This can be an unplugged termination LRU, a break in the line, or a missing termination block or jumper. Start by checking the termination jumpers. If those are in the correct pins then there is a break in the can bus up stream somewhere. If you have any break points in the system, start by checking those. From there you will need to check continuity LRU by LRU
- If you read 40Ω or less then you have too many terminations. Check to see if you have any of the 9 pin termination block installed.
2. In your case, you seem to be having a localized issue with the servos. I would do the following: Once you have established that your can bus is properly terminated start by removing power from the servos. If the can bus starts working with the servos plugged in, but turned off, check to see if you have can bus hi and low flip-flopped at one end.
3. If pulling power from the servos doesn't change anything then we move onto a bit more involved troubleshooting. unplug every LRU on the can bus
except your PFD and 2 termination points. If the system works (green check mark on those three units on the system info page) then you need to turn the system off and add one LRU back, repeating this cycle, until the can bus breaks - that unit is your issue and it is almost certainly a pinout error on the can bus wires.
4. If the can bus is not talking when brought down to its base components and you have confirmed that it is correctly terminated, then start by checking the can bus pinout at the PFD and both termination points. There is likely a pin out error at one of those units.
5. If none of the above works then the next most likely issue is a short to either can bus hi or low or a short between hi and low. This can be a bear to find. start by unplugging
every can bus LRU and termination block. Once they are all unplugged check the Hi and Low against ground. If you detect continuity from either wire to ground there is a short to ground. If you have continuity from hi to low then they probably got soldered together at some point. With this type of failure it is usually faster to replace the entire can bus rather than to identify a specific point. ... Though it can be super frustrating to do this - its usually a last resort.
I'm sure that this is WAY more information than you need, but I wanted to type out a more thorough can bus trouble shooting guide for anyone who might stumble across it in the future.
