[de_]

Thanks for all the input. We tried a number of combinations but gravity combined with the realities of a no-backturn gearbox (which leads to significant jumping going downwards as the backturn pins engage and disengage as the motor is turned on or off or reverses direction, we went back to KISS (dropped the PID code) and currently just go full speed up to within 5% of the target and power off. The no-backturn motor keeps us there. We did something similar going downwards but I believe are not going full power down. So far so good ...

I suspect a generic PID algorthim is aimed at systems that has largely symetrical responses on either side of the target but we were highly assymmetrical (especially with the anti-backlash) making a single set of tuning parameters hard pressed to do a good job in both directions