Question

What type of controller is commonly used to regulate temperature in a bioreactor?

• A. PID controller
• B. ON/OFF controller
• C. Bang-bang controller
• D. Proportional controller

Hint:

• ON/OFF (Bang-Bang) Controller Simple, but causes oscillations.
• Proportional (P) Controller Reduces error, but may have steady-state offset.
• Proportional-Integral (PI) Controller Eliminates steady-state error, but can slow response or increase overshoot.
• Proportional-Integral-Derivative (PID) Controller Combines benefits of P, I, and D actions for good stability, accuracy (no offset), and transient response. Widely used for process control.

Answer 1

The Correct Option is A

In biotechnology, particularly in processes involving bioreactors, maintaining precise temperature control is essential for optimal microbial or cellular activity. One of the most effective devices used for this task is the PID controller. Let's explore why the PID controller is preferred:

• PID Controller: The acronym "PID" stands for Proportional, Integral, and Derivative, which are the three control actions used in this type of controller. Each action operates as follows:
  • Proportional (P): This component controls the gain of the system. It adjusts the output proportionally to the error—the difference between the desired setpoint and the actual process variable.
  • Integral (I): This part addresses the accumulated offset that may arise from the proportional control action. It works by integrating the error over time, which helps to eliminate the steady-state error.
  • Derivative (D): This component predicts the future trend of the error by calculating its rate of change, thus providing a damping action which minimizes overshoot and improves system stability.

The combination of these three actions in a PID controller results in a robust control mechanism that efficiently regulates temperature with minimal fluctuations and steady performance. Given its precise and stable temperature regulation capability, the PID controller is commonly used in bioreactors, ensuring high-quality production and efficiency of the biological processes.

Correct Answer: PID controller