GTU last year question papers
GUJARAT TECHNOLOGICAL UNIVERSITY
BE SEM-VII Examination-Nov/Dec-2011
Subject code: 170802
Subject Name: Industrial Automation
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q-1 (a) Draw block diagram of PLC. Explain each block in detail
(b) Explain in detail the following terminology with reference to process industry:
(i) Self regulation (ii) Control lag (iii) Dead Time (iv) Process Lag
Q-2 (a) Explain three mode controller (PID)
(b) (1) A stepper motor has a step angle = 3.6°. (1) How many pulses are required
for the motor to rotate through ten complete revolutions? (2) What pulse
frequency is required? for the motor to rotate at a speed of 100 rev/min?
(2) Advantages and Disadvantages of Automation
(b) (1) A 5m diameter cylindrical tank is emptied by a constant outflow of
1.0m3/min. A two position controller is used to open and close a fill valve
with an open flow of 2.0m3/min. For level control, the neutral zone is 1m and
the set point is 12m. (a) Calculate the cycling period (b) Plot the level vs. time.
(2) Explain basic block diagram of process control loop.
Q- 3 (a) Explain in detail with suitable diagram, Direct Digital Control
(b) Explain in detail the input-output module used in PLC.
Q-3 (a) Explain the block diagram of distributed control system.
(b) Explain supervisory digital control with suitable diagram.
Q-4 (a) With the importance of DCS in automation, Explain the hierarchical evolution
and functional distribution of DCS.
(b) Explain Timer and counter instructions for PLC with timing diagram.
Q-4 (a) Explain different types of displays in DCS.
(b) An integral controller is used for speed control with a set point of 12 rpm
within a range of 10 to 15rpm. The controller output is 22% initially. The
constant KI = -0.15% controller output per second per percentage error. If the
speed jumps to 13.5rpm, calculate the controller output after 2sec for a
Q- 5 (a) Explain following discontinuous controller modes
(i)Two position mode (ii) Multi position mode
(b) (1) Enlist types of network topology and explain any one with figure.
(2) A controlling variable is a motor speed that varies from 800-1750 rpm. If
the speed is controlled by a 25 to 50v dc signal, calculate (a) the speed
produced by an input of 38v and (b) the speed calculated as a percent of span.
Q-5 (a) Explain elements of ladder diagram and its application.
(b) To control the operation of tank for following steps:
(1) When start PB is pressed the whole system enable.
(2) Fill the tank up to middle level using valve 1.
(3) Fill remaining tank is valve 2
(4) Drain the tank using valve V3 when tank is full and Drain PB pressed.
(5) Start the heater when tank is full and stop when middle level is reached.
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