Instrumentation - May 2016
MU Chemical Engineering (Semester 6)
Total marks: --
Total time: -- INSTRUCTIONS
(1) Assume appropriate data and state your reasons
(2) Marks are given to the right of every question
(3) Draw neat diagrams wherever necessary 1(a) Describe various performance characteristics of measuring instruments. 8 marks
1(b) A thermocouple gives an output of 0.4 mV for each degree change in temperature. What will be the word length required when its output passes through an analogue-to-digital converter if temperatures from 0 to 200°C are to be measured with a resolution of 0.5°C? 8 marks
1(c) A DAQ card of 16-bit resolution and 20-60mA along current loop is used to record above atmospheric pressures. Even a slight change in pressure (-1 Pa) needs to be detected. What is the maximum absolute pressure that can be measured? What is the analog input to mA for a pressure change of 10 kPa? 8 marks
2(a) A component manufacture constructs certain resistance to be anywhere between 1.14KΩ and 1.26KΩ and He classifies them to be 1.2Ω resistors.
What is the absolute error? What tolerance should be stated? 8 marks
2(b) A stepper motor has a 30-teeth gear with a 5° angle of tum per step. For a desired rotational speed of 200 rpm, what input pulse rate (in pulses per second) is required? 8 marks
2(c) Write in short control valve characteristics. 8 marks
3(a) The plate separation of a parallel plate capacitor was changed from 5 inches to 3 inches. Will the capacitance increase or decrease? What is the percent change in capacitance? 8 marks
Write short notes on3(b)(i) Rupture Discs 8 marks
3(b)(ii) Bourdon tube pressure gauge 8 marks
3(b)(iii) Ultrasonic method for Level Measurement 8 marks
4(a) Explain Wheatstone bridge in detail. 8 marks
4(b) A Platinum resistance thermometer has a resistance of 100Ω at 0°C and the value of temperature coefficient of resistance is 0.00385. In operation the resistance is 101Ω calculate the temperature. 8 marks
Write short notes on4(c)(i) Layers of protection analysis (LOPA) methods 8 marks
4(c)(ii) Basic Process control scheme with Diagram. 8 marks
5(a) The output of a thermocouple measuring temperatures from 20°C to 180°C is linearly represented by the standard current range of 4-20 mA. Then,
(i) What is the current at 110°C?
(ii) What temperature does a current of 8.4 mA represent?
(iii) What is the current at 130°C?
(iv) What temperature does a current of 10mA. 8 marks
5(b) Explain importance of calibration also explain calibration of Rotameter. 8 marks
5(c) Explain data acquisition and conversion system. 8 marks
Write short notes on (any four)6(a) Signal conditioning 8 marks
6(b) Capacitive type sensing element 8 marks
6(c) Hot wire anemometer 8 marks
6(d) Piezo electric sensing element 8 marks
6(e) Electromagnetic flow meter. 8 marks