List of top Instrumentation and Process Control Questions

In the block diagram shown in the figure, the transfer function $G=\dfrac{K}{(\tau s+1)}$ with $K>0$ and $\tau>0$. The maximum value of $K$ below which the system remains stable is \(\underline{\hspace{2cm}}\) (rounded off to two decimal places).

Consider a single-input-single-output (SISO) system with the transfer function \[ G_p(s)=\frac{2(s+1)}{\left(\frac{1}{2}s+1\right)\left(\frac{1}{4}s+1\right)} \] where the time constants are in minutes. The system is forced by a unit step input at time $t=0$. The time at which the output response reaches its maximum is \(\underline{\hspace{2cm}}\) minutes (rounded off to two decimal places).
A process described by the transfer function \[ G_p(s) = \frac{10s + 1}{5s + 1} \] is forced by a unit step input at time $t = 0$. The output value immediately after the step input (at $t = 0^+$) is \(\underline{\hspace{2cm}}\) (rounded off to the nearest integer).

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? 
 

Which of these symbols can be found in piping and instrumentation diagrams? 

The inherent characteristics of three control valves P, Q and R are shown in the figure. 

The CORRECT option(s) is/are 
 

A system has a transfer function
\[ G(s) = \frac{3e^{-4s}}{12s^2 + 1} \] When a step change of magnitude M is given to the system input, the final value of the system output is measured to be 120. The value of M is \(\underline{\hspace{1cm}}\) .
A process has a transfer function
\[ G(s) = \frac{Y(s)}{X(s)} = \frac{20}{90000s^2 + 240s + 1} \] Initially the process is at steady state with \( x(t = 0) = 0.4 \) and \( y(t = 0) = 100 \). If a step change in \( x \) is given from 0.4 to 0.5, the maximum value of \( y \) that will be observed before it reaches the new steady state is \(\underline{\hspace{1cm}}\) (round off to 1 decimal place).
Which of the following is NOT a necessary condition for a process under closed-loop control to be stable?
Which of the following is NOT a standard to transmit measurement and control signals?
A feedforward controller can be used only if: