With Swerve potentially adding another 12+ devices to our CAN Bus, it makes me wonder if I should pay more attention to these can bus extending products.
I know CTRE has a product as well for this. I’ve just been skeptical on it if it is really needed or if its a luxary.
Has anyone run into any can issues regarding large device usage?
Was for us at a point last year.
Since you can change what level of information is sent over CAN we turned off all the unnecessary feedback.
E.g. encoder position on a NEO used to power the intake rollers.
Ultimately it depends on your specific setup. We typically recommend total CAN bus utilization be kept below 90% when using CTR devices.
You can estimate what your bus util will be (at least for our products) using our documented defaults:
Generally speaking, if you aren’t going to hit 100% by default and can adjust status or control frames to stay below 90%, you should be OK.
If you’re going to be above 100% by default, you may need a CANivore or less devices on the bus. Adjustments to frame timings (via CAN commands) while your bus util is maxxed out on boot will likely not be applied correctly.
This is great info. Thank you. We basically have that exact SWERVE setup and will be planning to bring a few more SRXs on to the bus.
We had this problem last year early on in the season. We were maxing out the CAN bus utilization. Had to turn off or down a lot of the inputs that weren’t actually needed, like encoder values from many of the Falcons (we had CANCoders on the swerve units, for instance, so the steering Falcons’ encoders weren’t needed.) Once we got the optimization right, things worked a lot better.
I hate the idea of turning down performance but some things I’m sure you could.
Status 2, other than initial setup I don’t see why this needs to be fast. (at least for our implimentation) we basically set it in the compressor and then bail.
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