Brother TC-225 / TC-229 adventure!

ok ill look at that tonight.

its not offset from 0 - at least not very visibly in the scope. its just resonating on the down motion.

That makes sense to me. There is more resistance going up than, down, so more P is needed going up, but it causes overshoot going down. Using the scope try to compare the following error for an up and down moves. (Do a short incremental jog in both directions, to try to get both moves showing on the scope at one time.) Try to adjust the bias to get the following error as close to the same on both moves as you can.

oh, i think i see what yer saying. ill try these things tonight.

thanks.

Bias does nothing at all useful. Ff2 clamps error to below .001 but resonance is there still.

To be useful as a counterbalance, bias must be used with torque mode drives
(so the bias is in the proper units, force in this case)

You might also improve tuning a bit by tuning the drives velocity loop

That makes sense. There's nothing on the drive I can see to tune... It's of course fine on the old control. There is no documentation of any kind for it.

Right now it's basically tracking well but with intermittent resonance above 100ipm or so

Thanks