[FrankJ]

The D (derivative) term helps to compensate for short term disturbances. Its effect decays over time. It can have a destabilizing influence on the loop. It is generally the last term to determined if it is used at all. Generally a properly tuned loop will have a little overshoot & oscillation decaying to 0 in 2-4 oscillations. I am not sure how you tune a loop without the load connected.

The jags use a 32 fixed point integer for the constants--16.16. one bit for sign, 15 bits lefts of the decimal point, 16 bit right of the decimal point.