Marine Control System & Instrumentation (Set 1)

Multiple Choice Questions

1. The controller set point of an automatic control system is 65°C. The valve closes when the output temperature reaches 70°C, and reopens when the temperature falls below 60°C. The type of positioning action in this controller is known as ____________.

2. In a pneumatic automation system, a unit producing a signal to govern the position of the controller of the measured variable, relative to the value of the measured variable, is said to have ____________.

3. If the loading air pressure for a diaphragm controlled valve drops below the designed operating pressure, the valve will ____________.

4. Every automated machinery plant must have an "engineer's assistance" alarm. Power for this alarm should be taken from the ____________.

5. The effect of "reset", when added to a proportional controller is to ____________.

6. Which of the following statements expresses the function of proportional-plus-reset action?

7. One disadvantage of proportional-position action is that ____________.

8. Filters are installed ahead of air line lubricators for the primary purpose of removing ____________.

9. The cylinder unloading mechanism used on low pressure air compressors is an example of which mode of control?

10. Which of the listed devices would be installed at a control system air pressure reducing station?