This article is about QUESTION & ANSWERS FOR CONTROL SYSTEM_DCS_P&ID and focusing to the engineers, technicians and supervisors. You will find lot of documents related to this article. Just navigate our website www.paktechpoint.com and find more articles. Please! Do not forget to subscribe our You tube channel also. Thanks in Advance.
PLEASE SUBSCRIBE OUR PAKTECHPOINT YOUTUBE CHANNEL
QUESTION & ANSWERS FOR CONTROL SYSTEM_DCS_P&ID
1. Which component determines that the temperature is below the set point?
Sensor
Transmitter
Controller
Final
control element
control element
2. What are the components of a typical industrial two-position control feedback loop?
Two-position controller, sensor, transmitter, and final control element
Two-position controller, sensor, receiver, and first stage element
Control valve, transmitter, and receiver
Two-position controller, sensor, transmitter, and set-point reference
3. A heating system using a two-position control turns on when:
The room temperature remains constant for 24 hours
The room temperature falls below a set point
The feedback loop fails to send the signal
The feedback loop fails to open the valve
4. One characteristic of the two-position control is
It is a simple system with continuously modulating valve signal
It is a system that eliminates oscillations
It is a simple system with an on and off position
It is a simple system that yields a constant controlled variable
5. In a two-position control, which component detects changes in the controlled variable?
Solenoid valve
Final control element
Pressure switch
Sensor
6. In a two-position control what causes oscillations in the controlled variable?
The system cannot Select the reason why a two- position control causes oscillations in the respond
immediately to changes in the controlled variable response time of the sensor is too fast to control oscillations.
immediately to changes in the controlled variable response time of the sensor is too fast to control oscillations.
The valve reacts too slowly to changes in the controlled variable.
7. The system does not respond to changes in the controlled variable?
The system does not respond to changes in the controlled variable.
The system cannot respond immediately to changes in the controlled variable.
The response time of the sensor is too fast to control oscillations.
The valve reacts too slowly to changes in the controlled variable.
8. Which of the following statements about a two-position control is correct?
The valve reacts tooslowly to changes in the controlled variable
The response time of the sensor is too fast to control oscillations
The system cannot respond immediately to changes in the controlled variable
The system does not respond to changes in the controlled variable
9. Identify the correct reason that the
two-position control causes oscillations in the controlled variable.
two-position control causes oscillations in the controlled variable.
The response time of the sensor is too fast to control oscillations
The valve reacts too slowly to changes in the controlled variable
The system does not respond to changes in the controlled variable
The system cannot respond immediately to changes in the controlled variable
10. In order to keep boiler pressure within tolerable limits it is best to use :
Two-position control
Proportional control
Fuel flow control
Derivative control
11. Changes in proportional control action are expressed as
An input ratio
An output range
A gain factor
A sensitivity response
12. In the proportional control mode, the final element:
Can be positioned at any point within the throttling range
Can be positioned at three discreet points
Cannot be changed
Can only be positioned on or off
13. The final control element in the proportional control mode:
Can be positioned at three discreet points
Can be positioned at any point within the throttling range
Cannot be changed
Can only be positioned on or off
14. In the proportional control mode, oscillations are minimized because:
Integral control is used
There are multiple offsets programmed
A finer degree of control is possible than the on-off mode
Thesensor is more accurate than in the two-position position
15. Proportional control action provides:
Immediate control
On-off control
Intermittent control
Continuous control
16. What is one relationship between a change in the controlled variable and a proportionally controlled valve?
An increase in the controlled variable causes the valve to contract towards the closed position
An increase in the controlled variable causes the valve to expand towards the fully opened position
A decrease in the controlled variable causes the valve to contract towards the closed position
A decrease in the controlled variable creates no change in the valve
17. One of the relationships between a change in the controlled variable and a proportionally controlled valve is:
An increase in the controlled variable causes the valve to expand towards the fully opened position
An increase in the controlled variable causes the valve to contract towards the closed position
A decrease in the controlled variable causes the valve to contract towards the closed position
A decrease in the controlled variable creates no change in the valve
18. In a proportionally controlled system, when the valve contracts towards the closed position the controlled variable must have:
Reached the offset
Decreased
Increased
Oscillated
19. In a proportionally controlled system, when the valve expands towards the fully opened position the controlled variable must have:
Reached the offset
Increased
Oscillated
Decreased
20. Which of the following statements is correct concerning proportional band and gain?
A wide proportional band produces a less sensitive response
A narrow proportional band produces a less sensitive response
A low gain corresponds to a more sensitive response
A high gain corresponds to a less sensitive response
21. The relationship between proportional band and gain is:
Directly proportional
Inversely proportional
An integral relationship
A derivative relationship
22. What is the relationship between proportional band and gain?
A narrow proportional band has a low gain and a wide band has a high gain
The amount of band width and the amount of gain are the same
A wide proportional band has a low gain and a narrow band has a high gain
The amount of band width and the amount of gain are unrelated
23. Which of the following statements best describes the relationship between proportional band and gain?
A narrow proportional band has a low gain and a wide band has a high gain amount of band width and the amount of gain are the same
The amount of band width and amount of gain are unrelated
A wide proportional band has a low gain and a narrow band has a high gain
24. Excessive proportional action results in:
Offset
Gain
Banding
Oscillation
25. An advantage of a PID controller is:
It responds rapidly to upsets
It canbe used with flow control processes
It controls for offset
It prevents oscillation
26. Offset is best defined as:
The difference between the set point and the controlled variable
The width of the proportional band
The setamount of oscillations in a given time frame
The derivative of the set point value and the controlled variable
27. The best definition for the term offset is:
The width of the proportional band
The difference between the set point and the controlled variable
The setamount of oscillations in a given time frame
The derivative of the set point value and the controlled variable
28. Choose the best description of offset.
Thevalue of the set point with inherent fluctuations
The unnecessary deviation from the set point over time
The difference between the set point and the controlled variable
The derivative of the set point value and the controlled variable
29. The term offset as it applies to proportional control systems is:
The value of the set point with inherent fluctuations
The unnecessary deviation from the set point over time
The derivative of the set point value and the controlled variable
The difference between the set point and the controlled variable
30. Integral action continues to provide additional control:
As long as the offset is present
Until the offset is present
After the control elements are corrected
As long as the proportional band is 50% or less
31. Integral action performs checking, adjusting, and rechecking:
Until deviations shut down the system
Until the process returns to the set point
After the controlled variable returns to the set point
Until proportional control takes over
32. Repeated control action is a characteristic of:
Gain
Derivative
Integral action
Proportional band
33. The main purpose of integral action is to:
Monitor the set point
Provide intermittent control in the throttling range
Maintain proportional band/gain ratios
Provide continuous control until the variable is back at the set point
34. PID control is useful in processes that:
Are slow to respond and need more control
Are fast responding and need little control
Need constant stabilizing
Need no control
35. The function of PID control is to :
Overcome flow control deviations
Provide efficient and accurate means of automatic control
Reposition the final control element when signal is interrupted
Provide the best means of manual control
36. The most complex process control mode is the:
Derivative
Integral
PID
Proportional
37. Which control mode prevents overshoot andreduces oscillations?
Two-position
Integral
Derivative
PID