Two marks questions and answers

TWO MARKS QUESTIONS AND ANSWERS

1. What is fluidics ?

Fluidics is the technology that utilizes fluid flow phenomena in components and circuits to perform a wide variety of control functions.

2. What advantages does fluidics offer?

1. Fluidic devices offer exceptional thermal and physical stability and ruggedness.

2. They are completely insensitive to radiation, even of extremely high loads.

3. They are not affected by severe vibration and shock.

4. They are not susceptible to wear and tear.

3. At what pressures do fluidic devices function?

Normally fluidic devices function at pressures below 1 bar.

4. Where are fluidic control systems preferred than other control systems?

Fluidic control systems are preferred over other control systems in areas subject to nuclear radiation, magnetic flux, temperature extremes, vibration, and mechanical shock.

5. State the 'Coanda effect'.

"When a stream of fluid meets other stream, the effect is to change its direction of flow and effect is the fluid sticks to the wall."

6. Name four fluidic devices.

1. Bistable flip-flop,

2. Flip-flop with start-up preference,

3. SRT flip-flop,

4. OR/NOR gate.

7. What is a bistable flip-flop?

A bistable flip-flop provides controlled assurance as to which of the two output ports will deliver the power stream. It is normally used as a memory device.

8. What is a monostable device ?

A monostable device is required to perform monostable function which is analogous to spring return function. In this device, when the control signal is removed, the device will switch back to the favoured output.

9. When do you use a flip-flop with start-up preference?

A flip-flop with start-up preference is used in applications where a specific output is required when the power supply is first turned ON and all controls are OFF.

10. What is the use of truth table in logic devices ?

A truth table helps to describe the functioning of that particular logic device.“

11. What is a fluid sensor ?

A fluid sensor a device that senses a change in some parameter and as a result causes a related change in another parameter that can be recognized and interpreted. 

12. Name four fluid sensors that are used in fluid power systems.

1. Back-pressure sensor,

2. Cone-jet proximity sensor,

3. Interruptible-jet sensor, and

4. Contact sensing.

13. What are moving-part logic devices?

Moving-part logic (MPL) devices are miniature valve-type devices that perform switching operations in fluid logic systems by the action of internal moving parts.

14. What are the distinctive features that differentiates MPL devices from fluidic devices.

1. Very small in size and hence occupies less space.

2. Very fast response time.

3. Can be readily interfaced with electric and electronic circuits.

4. Longer life of elements.

15. Name few applications of MPL devices.

The MPL devices are well-suited for a wide range of applications in biomedical, environmental test equipment, textile machines, packaging machinery, computerised industrial automation, and portable systems.

16. What is a PLC?

A programmable logic controller (PLC) is a user-friendly electronic computer designed to perform logic functions such as AND, OR, or NOT for controlling the operation of industrial equipment and processes.

17. How do microprocessors differ from PLCs ?

The advantages of PLCs over microprocessors are given below:

1. PLCs are rugged and designed to withstand vibrations, temperature, humidity and noise.

2. The interfacing for inputs and outputs is inside the controller.

3. They are easily programmed and have an easily understood programming language.

18. List any four advantages that PLCs provide over electromechanical relay control systems.

1. PLCs are more reliable and faster in operation.

2. They are smaller in size and can be more readily expanded.

3. They require less electrical power.

4. They have very few hardware failure when compared to electromechanical relays.