GATE BT Instrumentation and Process Control PYQs & Answers

Questions 1–10 of 10. Imported answers require independent review unless marked reviewed.

The transfer function of a Proportional-Integral (PI) controller

is given by

where

is the controller gain,

is the controller integral time constant and

is the Laplace variable. The role of the integral component of the controller is to ____________.

Your answerChoose one option.

integrate the difference between the process and manipulated variable

integrate the difference between the set point and disturbance variable

integrate the difference between the set point and the measured variable

integrate the difference between the input and output variable

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In the open-loop process shown in the figure, the input

, the transfer function

and the output

are given in the Laplace domain in terms of the Laplace variable s. For this process, which of the following is true?

(where

, are the magnitude of the input, the characteristic time and the gain for the process, respectively)

Your answerChoose one option.

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A thermometer measuring body temperature follows a first-order response with a time constant of 40 seconds. The instrument will reach 95% of its steady-state output at __________ seconds.

(Round off to the nearest integer)

Your answerChoose one option.

120

160

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The output

of a first-order process is governed by the following differential equation

where

is a non-zero time constant,

is the gain and

is the input with

Assume

. The transfer function for this process (consider

as the independent variable in the Laplace domain)

Your answerChoose one option.

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The transfer function of a process is

, where

is the gain and

is the time constant. This is a ________ process.

Your answerChoose one option.

first order

multi-capacity

purely capacitive

second order

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A proportional controller is used to control the temperature of an autoclave from 60 °C to 130 °C. If the proportional band setting of the controller is 25%, the proportional gain value is ____________.

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Which of the following statements are CORRECT for a controller? P. In a proportional controller, a control action is proportional to the error Q. In an integral controller, a control action is proportional to the derivative of the error R. There is no “offset” in the response of the closed-loop first-order process with a proportional controller S. There is no “offset” in the response of the closed-loop first-order process with a proportional-integral controller

Your answerChoose one option.

P and Q only

P and R only

P and S only

Q and S only

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The process and instrumentation diagram for a feedback control strategy to maintain the level (

) of a liquid by regulating a valve (

) in a tank is shown below.

is inlet liquid flow rate,

is outlet liquid flow rate,

is the liquid level transmitter,

is the liquid level controller,

is the setpoint value of the liquid level,

is the measured value of the liquid level and

is the valve pressure.

The manipulating variable(s) is/are

Your answerChoose one option.

only

and

only

and

only

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Which one of the following statements is CORRECT about proportional controllers?

Your answerChoose one option.

The initial change in control output signal is relatively slow

The initial corrective action is greater for larger error

They have no offset

There is no corrective action if the error is a constant

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Match the instruments in Group I with the corresponding measurements in Group II.

Group I P. Manometer Q. Rotameter R. Tachometer S. Haemocytometer

Group II

Agitator speed

Pressure difference

Cell number

Air flow rate

Your answerChoose one option.

P-4, Q-1, R-2, S-3

P-3, Q-4, R-1, S-2

P-2, Q-4, R-1, S-3

P-2, Q-1, R-4, S-3

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GATE BT Instrumentation and Process Control PYQs

How to practice Instrumentation and Process Control

Question 15

Question 36

Question 42

Question 43

Question 12

Question 64

Question 41

Question 13

Question 41

Question 42