It is the number of times/minute that the effect of proportional position action upon the final control element is repeated by proportional speed floating action.
There are two ways of expressing reset action:
1 . Reset time and 2. Reset Rate
1. Reset Rate : It is commonly expressed as a number of “repeats” per minute. It is determined by dividing.
a) Travel of final control element ( Value stroke ) in one minute as a result of the effect of proportional
speed floating action.
b) The travel as a result of the effect of proportional position action with the same deviation in both cases.
2. Reset Time : It is the time interval by which the rate is commonly expressed in minutes. It is determined by subtracting.
a) The time required for a selected motion of the final control element resulting from combined effect of the proportional position plus rate action.
b) The time required for the same motion as a result of the effect of proportional position action alone with the same rate of change of controlled variable in both cases or expressed in another way. It is the time lead in terms of air pressure on the control value produced by rate action compared with proportional position action for the same rate of change of actual measurement in both cases.