To shorten the range you must improve the conversion / gearing - This is so you get better conversion and the servo now is controlling to 1/ 1000 of a unit not 1/10 of a unit I think it is possible to adjust this parameter but I have never had to on a 300 system. If you are happy with the scaling then you probably have a tuning issue Stationary is the motor 'humming'? Allen bradley kinetix 300 u..