1. Select a process variable (pressure / temperature / level / flow) and conduct a literature survey to determine recent developments in process instrumentation field. Identify any one novel instrument and explain in detail the working of the instrument. Description should include neat diagram, principle of working and the source of literature (to be attached).
2 . (a) The RTD has specifications of R = 500 Ω and α = 0.003/°C at 260 °C. The dissipation constant is given as PD = 25 mW/°C. This transducer is to be used to measure 260 to 315.6°C. Signal conditioning will provide a 0 to 5 Volt output for this temperature range and the system accuracy must be ± 0.056 °C. The bridge is excited with a 5 V source and assume R3 = 1 kΩ. Develop the signal conditioning circuit diagram.
(b) Develop the designed circuit using breadboard in the laboratory. Available thermal sensor can be used in the circuit. Discuss the effect of resistors on calibration of the sensor with specific emphasis on the sensitivity of the instrument.
Q2
A two capacity process tank is to be analyzed using proportional and integral controllers. A process could be a steam jacketed kettle as shown in Figure.1.Water is heated continuously by the steam flow and it is proposed to use a controller to regulate the steam flow. The steam flow is essentially depending upon to the valve opening which is controlled by TC. The temperature of the water in the kettle is measured using a RTD sensor and transmitted to the controller.
Analysis & Design aspect:
1. Assume appropriate time constants and other design parameters.
2. Study the possible step response of the system with proportional(P), and integral(I) controllers.
3. Evaluate the stability using Rouths Hurwartz criterion and obtain the range of K value for the stability under various controllers.
4. Evaluate the relative stability of the system with P and I controllers.
5. Make recommendations for the overall design with various time constant and design parameters.