Re: Can I branch the CAN to go to two separate places?
 

True but knowing all the points of failure and liking to know things usually does not play well with a 6 week build. There are many examples of KISS in FIRST builds.

Re: Can I branch the CAN to go to two separate places?
 

I've never had a terribly good sense of time, did I miss the game release again? Crap, I hate it when I do that.

Re: Can I branch the CAN to go to two separate places?
 

LOL, yeap it is almost bag and tag already.
Time for robot delivery heroics!:D

Seriously, not to discourage those who have the time and motivation but there is nothing wrong with the recommended way. So most of those I know that made Jaguars work and other interesting unusual CAN things on an FRC robot (including my Propeller based CAN ESC) leveraged the off season, or knowledge acquired by someone off season, or even knowledge and resources outside of FRC channels.

It is wonderful to give that extra dimension, but as the complexity climbs you leave the common denominator behind. FIRST picked a design for the CAN bus that should make everyone work in the 6 week build season and then made sure to build process around it. We should acknowledge potential alternatives exist but not create a situation where the CSA job requires a CAN BERD/BERD in the spare parts kit.

Re: Can I branch the CAN to go to two separate places?
 

The CRio Canbus was RS232 to the first jaguar. That limited throughput to the CRio to 9600 BPS. There were significant programming gotchas on the CRio Canbus implementation. For instance it didn't do well with being loaded with more data than the throughput could handle. I think many issues blamed on Jaguars and wiring was actually programming. Anyway as a system the Canbus Jaguars were problematic. The current Roborio/Talon SRX is way better.

By standard, the maximum recommended stub length is .3 M. Which limits star configurations. Although with the short bus length of your typical FRC robot, you can get away with a lot, but I would stick to the standard. TI has a good application paper on CANBUS here.

Re: Can I branch the CAN to go to two separate places?
 

Agreed there were a lot of issues programming could have addressed with the Jaguars and cRIO, and software fixes have been released to the RoboRIO and accessories, but it is hard on students trying to learn programming to address that sort of thing especially with the time it takes to reload test code into the cRIO and to some extent the RoboRIO.

Programmers without deep hardware/firmware familiarity and knowledge often face these kind of issues when they do embedded work and robotic systems. It becomes extremely important to have clear disclosure and support.

In a way, more CAN devices puts pressure and focus on the system providers to find, resolve and support lest we accumulate risk. I am much more comfortable with how we use CAN now.

Re: Can I branch the CAN to go to two separate places?
 

I agree completely. I didn't mean to sound as if I was throwing programmers under the bus.

It is one of those gotchas that you do have to look for in real life. Which generally made PWM a better choice unless you really needed something that canbus gave you.

Re: Can I branch the CAN to go to two separate places?
 

You just move a jumper. They made it pretty easy!