How are Kp, L, and tau typically estimated from a step-response for PID tuning?

• A. From the peak overshoot only.
• B. From the process reaction curve using the tangent method: L is the delay before the tangent, tau is the time from end of L to the tangent intersection with the axis, and Kp is the steady-state gain from input to output.
• C. From frequency response alone.
• D. From the final value of the output.

Answer: (B)