p.25:
of integral control in response to large errors, such as those caused by step inputs.  I address the issue of controller overshoot due to the integration of  large error signal later in this chapter.

p.30
An integral term eliminates steady-state errors in the plant response.  The K_i gain of the integral term is ussually set to a small value

p.31
integral term eliminates steady-state errors in the response

p.32
Integrator windup is the result of integrating a large error signal during periods when

p.34
instead of PID control.

p.38
The weights applied to each of these terms are called the proportional, integral, and derivative gains, respectively.