Just a guess due to lack of supplied info, but perhaps first set the master ofset to mid range. then set the master gain so that the speed range is correct for the master then set the master offset for the correct start frequency. next repeat above for the slave, only set the ofset to speed match the motors at either mid point for lowest deviation over full span or set for match at desired operating speed this will have more deviation at one end but closest match over desired operating range. Finaly test across range and tweak if not in spec. hope this helps Terry