Unexplained intermittent CAN / 2CAN Jaguar problems at GSR

[nuttle]

Not to pile on, but in case this may help either another team or anyone working on these problems:


- If you try to use an indexed encoder with the closed-loop PID control feature of the Jags, I'm pretty sure this won't work (based on our experiences). The issue here is probably that the index mark causes the encoder count to be reset once per revolution, and the PID logic doesn't expect this behavior, since it is not a continuous count but a count that essentially wraps around at a certain point. You can get around this by disconnecting the index pin -- certainly worth a try if this applies to you. You'll have to rely on the encoder being at zero when things start up, or doing something else to reference the count.


- If you are using PID, stuttering could certainly be caused by not having the P/I/D coefficients set correctly.

- I second the recommendation not to crimp an RJ connector directly to the solid leads coming from a resistor; this is not as reliable as making a short pigtail using cable that is designed for use with these connectors and soldering the terminator resistor to this.
- If you use a 2CAN, the 2CAN webpage is helpful for seeing how things are behaving. In particular, it provides error counters that can help validate wiring and basic communications connectivity.