Tuning" a control loop is the adjustment of its
control parameters (gain/proportional band,
integral gain/reset, derivative gain/rate) to the
optimum values for the desired control response.
The optimum behavior on a process change or
set point change varies depending on the
application. Some processes must not allow
an overshoot of the process variable from the
set point. Other processes must minimize the
energy expended in reaching a new set point.