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GATE 2019 BT – Question 51

Fundamentals of Biological Engineering · Process Control: Measurement devices, valves, first and second order systems, feedback and feed forward control, P, I and D controllers and tuning · 2 marks · Multiple choice

Which proportional-controller statement is CORRECT?

  1. Initial control-output change is relatively slow.
  2. Initial corrective action is greater for a larger error.
  3. There is no offset.
  4. Constant error produces no corrective action.

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Correct answer: (B) Initial corrective action is greater for a larger error.

Explanation

For proportional control, $u-u_0=K_pe$. With a fixed nonzero gain, output change is directly proportional to error, so a larger error gives greater corrective action, B. The response is not inherently delayed; constant error can produce constant action, and proportional control can retain steady-state offset.

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