The offset introduced by proportional controller with gain Kc in response of first order system can be reduced by ____________________?

Related Mcqs:

1. A proportional controller with a gain of Kc is used to control a first order process. The offset will increase, if________________?

   A. Kc is reduced
   B. Kc is increased
   C. Integral control action is introduced
   D. Derivative control action is introduced

2. Suppose that the gain, time constant and dead time of a process with the following transfer function: Gc(s) = 10 exp( – 0.1s)/(0.5s + 1) are known with a possible error of ± 20% of their values. The largest permissible gain Kc of a proportional controller needs to be calculated below taking the values of process gain, time constant and dead time as________________?

   A. 8, 0.6, 0.08
   B. 12, 0.6, 0.12
   C. 8, 0.6, 0.12
   D. 12, 0.4, 0.08

3. If response of a control system is to be free of offset and oscillation, the most suitable controller is_________________?

   A. Proportional controller
   B. Proportional-derivative (PD) controller
   C. Proportional-integral (PI) controller
   D. Proportional integral-derivative (PID) controller

4. Find the ultimate gain and frequency for a proportional controller in the case of a process having the transfer function Gp(s) = 1/(4s + 1)(2s + 1)(s + 1) ?

   A. w = 1/√14, Kc = 45/7 √14
   B. w = √(7/6), Kc = 46/3
   C. w = 1, Kc = 13
   D. w = √(7/8), Kc = 45/4

5. An ideal PID controller has the transfer function [1 + (1/0.55) + 0.25]. The frequency at which the magnitude ratio of the controller is 1, is________________?

   A. 0.5/0.2
   B. 0.2/0.5
   C. 0.2 × 0.5
   D. 1/√(0.2 × 0.5)

6. In a closed loop system, the process to be controlled is an integrating process with transfer function 1/2s. The controller proposed to be used in an integral controller with transfer function 1/T1s. When a step change in set point is applied to such a closed loop system, the controlled variable will exhibit__________________?

   A. Overdamped response
   B. Underdamped response
   C. Undamped response
   D. Unstable response

7. The transfer function for an ideal proportional plus reset controller (reset time T) is_______________?

   A. Kc[1 + (1/TS)]
   B. Kc(1 + TS)
   C. Kc/(1 + TS)
   D. Kc/[1 + (s/T)]

8. Response of a system to a sinusoidal input is called _____________ response?

   A. Impulse
   B. Unit step
   C. Frequency
   D. None of these

9. Which of the following controllers has maximum offset ?

   A. P-controller
   B. P-I controller
   C. P-D controller
   D. P-I-D controller

10. The transfer function for a PID controller is (where, η i is the integral (reset) time and ηD is the derivative time.) ?

    A. Kc(1 + ηis + ηD ). s
    B. Kc[1 + (1/ηis) + ηD . s)
    C. Kc(1 + ηis + (1/ηD . s)
    D. None of these