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Recent activity in Instrumentation and Process Control

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GATE Chemical 2025 | Question: 52
The block diagram of a series cascade control system (with time in minutes) is shown in the figure. For $\tau_{l}=8 \: \mathrm{~min}$ and $K_{c}^{s}=1$, the maximum value...
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GATE Chemical 2025 | Question: 50
Consider a process with transfer function$$G_{p}=\frac{2 e^{-s}}{(5 s+1)^{2}}$$A first-order plus dead time $\text{(FOPDT)}$ model is to be fitted to the unit step proces...
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GATE Chemical 2026 | Question: 40
Consider three identical non-interacting first order processes in series, each having unit gain and a time constant of $2$ min. Tuning of proportional controller using cl...
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GATE Chemical 2026 | Question: 34
A control valve with hyperbolic characteristics has a turndown ratio (ratio of maximum flow to minimum controllable flow) of $50$. The flow rate through the valve at $70 ...
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GATE Chemical 2026 | Question: 15
A process exhibits an inverse response to a step input. Which of the following statements is/are necessarily TRUE about the process?Its transfer function has a positive z...
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GATE Chemical 2026 | Question: 2
In the P&ID shown below, which one of the following is the function of PAH in the process?to maintain a constant pressure in the vessel by throttling the pump outletto al...
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GATE Chemical 2025 | Question: 29
​​​​The first-order irreversible liquid phase reaction $A \rightarrow B$ occurs inside a constant volume $(V)$ isothermal CSTR with the initial steady state conditions sh...
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GATE Chemical 2025 | Question: 15
​​​​Choose the transfer function that best fits the output response to a unit step input change shown in the figure $\frac{(\alpha s+1) e^{-\theta s}}{\left(\tau_{1} s+1\...
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GATE Chemical 2025 | Question: 14
​​​​The vortex shedding meter is primarily used for measuringFluid Flow RateLiquid LevelFluid TemperatureFluid Pressure
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GATE Chemical 2024 | Question: 12
Consider the block diagram in the figure with control input $u$, disturbance $d$ and output $y$. For the feedforward controller, the ordered pair $(K, \alpha / \beta)$ is...
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GATE Chemical 2024 | Question: 13
​​​​​Consider the control structure for the overhead section of a distillation column shown in the figure. The composition controller (CC) controls the heavy key impurity...
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GATE Chemical 2024 | Question: 38
​​​​​​For the block diagram shown in the figure, the correct expression for the transfer function $G_{d}=\frac{y_{1}(s)}{d(s)}$ is$\frac{-G_{p 1} G_{c 2}}{\left(1+G_{c 1}...
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GATE Chemical 2024 | Question: 54
A $\text{PD}$ controller with transfer function $G_{c}$ is used to stabilize an open-loop unstable process with transfer function $G_{p}$, where\[G_{c}=K_{c} \frac{\tau_{...
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GATE Chemical 2024 | Question: 53
Consider the surge drum in the figure. Initially the system is at steady-state with a hold-up $\bar{V}=5 \mathrm{~m}^{3}$, which is $50 \%$ of full tank capacity, $V_{f u...
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GATE CH 2023 | Question: 25
A liquid surge tank has $F_{\text {in }}$ and $F_{\text {out }}$ as the inlet and outlet flow rates respectively, as shown in the figure below. $F_{\text {out }}$ is prop...
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GATE CH 2023 | Question: 45
Level $(h)$ in a steam boiler is controlled by manipulating the flow rate $(F)$ of the make-up (fresh) water using a proportional (P) controller. The transfer function be...
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GATE CH 2023 | Question: 44
A cascade control strategy is shown in the figure below. The transfer function between the output $(y)$ and the secondary disturbance $\left(d_2\right)$ is defined as$$G_...
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GATE CH 2023 | Question: 61
The outlet concentration $C_A$ of a plug flow reactor $\text{(PFR)}$ is controlled by manipulating the inlet concentration $C_{A 0}$. The following transfer function desc...
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GATE CH 2023 | Question: 62
The transfer function of a measuring instrument is$$G_m(s)=\frac{1.05}{2 s+1} \exp (-s) .$$At time $t=0$, a step change of $+1$ unit is introduced in the input of this in...
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GATE CH 2022 | Question: 14
Choose the option that correctly pairs the given measurement devices with the quantities they measure.$$\begin{array}{ccc} \hline\text{S No} & \text{Measurement Device} &...
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GATE CH 2022 | Question: 13
The appropriate feedforward compensator, $G_{ff}$, in the shown block diagram is$G_{ff} = \dfrac{2}{3}\dfrac{\left ( 8s + 1\right )}{\left ( 5s + 1\right )}$$G_{ff} = -\d...
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GATE CH 2022 | Question: 12
Liquid flowing through a heat exchanger $\text{(HX)}$ is heated. A bypass stream is provided to control the temperature of the heated exit stream. From the given plumbing...
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GATE CH 2022 | Question: 11
A control system on the jacket side of a reactor is shown in the figure. Pressurized water flows through the jacket to cool the reactor. The heated water flashes in the b...
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GATE CH 2022 | Question: 24
A process described by the transfer function $$G_{P}\left ( s \right ) = \frac{\left ( 10s +1 \right )}{5s + 1}$$ is forced by a unit step input at time $t = 0$. The outp...
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GATE CH 2022 | Question: 48
In the block diagram shown in the figure, the transfer function $G = \dfrac{K}{\left ( \tau s + 1 \right )}$ with $K 0$ and $\tau 0$. The maximum value of $K$ below whi...
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GATE CH 2022 | Question: 49
Consider the tank level control system shown in the figure, where the cross-section area of the tank is $A$. Assume perfect flow controllers $\text{(FC)}$. The level cont...
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GATE CH 2022 | Question: 50
Consider a single-input-single-output $\text{(SISO)}$ system with the transfer function $$G_{P}\left ( s \right ) =\frac{2\left ( s + 1 \right )}{\left ( \dfrac{1}{2} s +...
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GATE CH 2021 | Question: 11
Which of the following is $\text{NOT}$ a standard to transmit measurement and control signals?$4-20 \: \text{mA}$$3-15 \text{ psig}$$0-100\: \%$$1-5 \text{ VDC}$
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GATE CH 2021 | Question: 12
A feedforward controller can be used only ifthe disturbance variable can be measuredthe disturbance variable can be manipulatedthe disturbance variable can be ignoredregu...
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GATE CH 2021 | Question: 18
The inherent characteristics of the three control valves $P$, $Q$ and $R$ are shown in the figure.The $\text{CORRECT}$ option(s) is/are$P$ is a quick opening valve$Q$ is ...
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GATE CH 2021 | Question: 30
Which of these symbols can be found in piping and instrumentation diagrams?$(Q)$ and $(S)$ only$(P)$, $(Q)$ and $(R)$ only$(P)$, $(R)$ and $(S)$ only$(P)$, $(Q)$, $(R)$ a...
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GATE CH 2021 | Question: 31
It is required to control the volume of the contents in the jacketed reactor shown in the figure.Which one of the following schemes can be used for feedback control?Measu...
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GATE CH 2021 | Question: 32
Which of the following is $\text{NOT}$ a necessary condition for a process under closed-loop control to be stable?Dead-time term(s) must be absent in the open-loop transf...
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GATE CH 2021 | Question: 52
A system has a transfer function $G(s)= \dfrac{3e^{-4s}}{12s+1}$. When a step change of magnitude $M$ is given to the system input, the final value of the system output i...
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GATE CH 2021 | Question: 53
A person has a transfer function $G(s)= \dfrac{Y(s)}{X(s)} = \dfrac{20}{90000s^2+240s+1}$. Initially the process is at steady state with $x(t=0)=0.4$ and $y(t=0)=100$. If...
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GATE Chemical 2020 | Question: 23
Consider the following closed loop system with $G_p$ and $G_c$ as the transfer functions of the process and the controller, respectively.For a unit step change in the set...
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GATE Chemical 2020 | Question: 53
Consider the following closed loop system.$G_c, G_f$ , and $G_p$ are the transfer functions of the controller, the final control element and the process, respectively. $Y...
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GATE Chemical 2020 | Question: 52
Flow of water thorough an equal percentage valve is $900 \text{ litre } h^{-1}$ at $30 \%$ opening, and $1080 \text{ litre } h^{-1}$ at $35 \%$ opening. Assume that the p...
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GATE Chemical 2020 | Question: 8
Hot-wire anemometer is used for the measurement ofcompositionflowpressuretemperature
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GATE Chemical 2019 | Question: 12
A thermocouple senses temperature based on theNernst Effect Maxwell Effect Seebeck EffectPeltier Effect
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