[techhelpbb]

The good news...I know for a fact what you're trying to do works.

Now why it's not working for you:

Couple of things come to mind you might want to check.

Make sure you have A and B of the quadrature encoder in the right place in the wiring. Do this first. If there's anything wrong in the mechanism or wiring there's no point in tuning it won't end well. You can check those encoders if you hook them to the cRIO.

As you're tuning for a set point of RPM (velocity):
Try setting your P gain (Kp) to 0.1 or less and raising your I gain (Ki) between 0.001 and 0.1. If your mechanism can be perfectly driven by the ideal discrete time version of that Jaguar PID loop (in other words it's a near match to some of the assumptions that math makes) you might not need much P gain (Kp) at all (in theory very little or none). If P gain (Kp) is too high it'll oscillate (what you might be calling chatter) and sometimes you can move it up slowly from 0.1 to 0.3 for example and it'll work (you'll hit hard oscillation if you go up say 50%-80% more)...but then when you set it directly to 0.3 it will immediately oscillate when it starts the motor moving from a dead stop.

Try tuning the mechanism off the floor assuming it's a drive mechanism.

Not sure about your encoder setting issue haven't looked at that setting myself will ask the students.
UPDATE: We have our quadrature encoders running as quadrature encoders.
Perhaps A or B is not really connected?