Home › MCQs › BioTechnology › Question #10592
Back to Questions
BioTechnology QUESTION #10592
Question 1
A PID controller adjusts a manipulated variable based on:
  • Proportional, Integral, and Derivative terms of the error signal $\varepsilon$✔️
  • The current set point value only
  • Open-loop feed-forward predictions of substrate consumption
  • Only the derivative of the error to predict future deviations
Correct Answer Explanation
The PID controller output is: $y = y_0 + K_P\left[\varepsilon + \dfrac{1}{\tau_I}\int \varepsilon\, dt + \tau_D \dfrac{d\varepsilon}{dt}\right]$ where:
  • P (Proportional): responds to current error magnitude
  • I (Integral): eliminates steady-state offset by integrating past error
  • D (Derivative): anticipates future error from the rate of change
Tuning $K_P$, $\tau_I$, and $\tau_D$ is done experimentally (e.g. Ziegler-Nichols method).