# Instrumentation and Process Control GATE-2015

**Q 1**. Match the output signals as obtained from four measuring devices in response to a unit step change in the input signal.

**Q 2.** The transfer function for the disturbance response in an open-loop process is given by G_d^{open}\left(s\right) . The corresponding transfer function for the disturbance response in a closed-loop feedback control system with proportional controlled is given by G_d^{closed}\left(s\right) . Select the option that is ALWAYS correct {O[G(s)] represents order of transfer function G(s)}:

**Q 3.** Which one of the following transfer functions, upon a unit step change in the disturbance at t = 0, will show a stable time domain response with a negative initial slope (i.e., slope t = 0):

**Q 4.** The block diagram for a process with feedback control for output deviation variable h is shown in the figure below. All transfer functions are given with pre-factor of *s* in minutes. A unit step change is made in the set-point at t = 0. The time required for *h* to reach 50% of its ultimate value, in minutes (up to two decimal places), is: __________________

**Q 5.** Consider a control system with the open loop transfer function given by:

In the above function, pre-factor of s is in minutes and K_{c}is the gain of proportional controller. The frequency for phase margin of 30^{o} is 4.04 rad/min. The value of K_{c} for a gain margin of 1.7 (up to one decimal place) is _______________.