a) Briefly explain THREE (3) differences between open loop system and closed loop system. You need draw diagrams to illustrate your answers. (CLO1) [5 Marks]

b) Explain all elements in the typical process control closed loop system (CLO1) [4 Marks]

c) The temperature of steam distillation plant is controlled by On-Off controller. The heater is located at the bottom of the distillation tank with RTD is used to monitor the temperature of the plant. (CLO1)

i. Draw a block diagram indicating all the components and variables in the system. [4 Marks]

ii. Briefly explain the operation of ON-OFF controller in this application. [4 Marks]

iii. List TWO (2) advantages and TWO (2) disadvantages of ON-OFF controller. [4 Marks]

iv. Suggest TWO (2) improvement could be made to the system to prolong the life of the heater. [4 Marks]