AME 11 End of Unit – SVE Study

AME 11 End of Unit Quiz

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State the reasons for fitting a pneumatic process valve with a feedback positioner.

D) A feedback positioner is fitted to provide a backup control signal in case the primary control system fails, ensuring the valve remains operational.

C) A feedback positioner is fitted to reduce the overall power consumption of the valve actuator, improving energy efficiency.

A) A feedback positioner is fitted to monitor the valve position and provide real-time correction signals to ensure the valve remains at the desired position, improving accuracy and stability in the process control.

B) A feedback positioner is fitted to increase the air pressure supplied to the actuator, which helps in enhancing the overall force applied to the valve.

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Describe the effect of increasing the controller gain with respect to the steady-state tank level when the outflow is increased in a float and lever proportional system.

C) The steady-state tank level will decrease more slowly in response to the increased outflow.

B) The steady-state tank level will oscillate more and be less stable.

A) The steady-state tank level will become more stable and closer to the setpoint.

D) The steady-state tank level will remain unchanged regardless of the controller gain.

3 / 12

In an On-Off control system, what happens when the controlled variable exceeds the set point?

D) The system remains inactive until the variable drops significantly.

C) The system increases the output to correct the error.

B) The system switches off the output to bring the variable back to the set point.

A) The system modulates the output to gradually reduce the variable.

4 / 12

Explain derivative action in control terms.

D) Derivative action is the component of the control system that maintains the steady-state error by constantly adjusting the control output proportionally.

B) Derivative action describes the process of integrating the accumulated error over time to adjust the control output.

A) Derivative action involves adjusting the control output based on the rate of change of the error, aiming to predict future errors and reduce overshoot.

C) Derivative action adjusts the control output based on the proportional deviation from the setpoint, with no regard to the rate of change.

5 / 12

Define the term Proportional Action.

B) Proportional action integrates the error over time to adjust the control output, aiming to eliminate steady-state error.

A) Proportional action adjusts the control output based on the magnitude of the error, where the output is directly proportional to the difference between the setpoint and the actual value.

D) Proportional action uses a fixed output level regardless of the error magnitude to maintain system stability.

C) Proportional action predicts future errors by adjusting the control output based on the rate of change of the error.

6 / 12

Describe using control block diagram terms how a governor maintains the speed of a diesel engine driving a generator.

A) The governor adjusts the fuel input based on the difference between the desired speed setpoint and the actual engine speed (feedback), using a proportional-only control block.

C) The governor uses a manual control block to adjust the engine speed directly without feedback, ensuring the engine speed remains constant regardless of load changes.

B) The governor compares the actual engine speed to the desired speed setpoint and uses a proportional-integral-derivative (PID) control block to adjust the fuel input and maintain the engine speed.

D) The governor uses a feedback loop where the actual engine speed is compared to a fixed reference value, adjusting the fuel input based on a simple on-off control block.

7 / 12

How is the level in a water tank controlled by a float and lever proportional system?

D) The lever controls the water level by switching between two fixed positions—completely open or completely closed.

A) The float rises with the water level, causing the lever to close a valve, stopping the inflow of water when the desired level is reached.

B) The float sinks as the water level rises, which directly activates a pump to remove excess water from the tank.

C) The float rises with the water level, opening a valve to allow more water into the tank.

8 / 12

How can the gain of a control system be increased or decreased?

B) Increase the gain by increasing the integral time; decrease the gain by reducing the integral time.

A) Increase the gain by reducing the proportional band; decrease the gain by increasing the proportional band.

D) Increase the gain by reducing the setpoint; decrease the gain by increasing the setpoint.

C) Increase the gain by adding derivative control; decrease the gain by removing derivative control.

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Describe the effect of excessive Derivative Action.

C) Excessive Derivative Action can result in a system that quickly reaches the setpoint without overshooting or oscillating.

D) Excessive Derivative Action can decrease the system’s overall response time and improve its accuracy in maintaining the setpoint.

B) Excessive Derivative Action can cause the system to become overly sensitive to noise, leading to oscillations and instability.

A) Excessive Derivative Action can lead to a sluggish response time and an increase in steady-state errors.

10 / 12

How does hysteresis improve the performance of an On-Off control system?

B) It prevents rapid cycling by creating a dead zone between switching on and off.

C) It allows the system to adjust output continuously.

A) It increases the switching frequency of the system.

D) It enables the system to predict and correct future errors.

11 / 12

Explain the purpose of Integral Action.

C) Integral action predicts future errors by adjusting the control output based on the rate of change of the error.

B) Integral action integrates the error over time to eliminate steady-state error, ensuring that the system eventually reaches the setpoint.

D) Integral action maintains a constant output level regardless of the error to keep the system stable.

A) Integral action adjusts the control output based on the magnitude of the error, aiming to quickly correct deviations from the setpoint.

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2. Which of the following is a typical application of an On-Off control system?

C) Pressure regulation in a hydraulic system.

A) Speed control of a variable frequency drive.

D) Flow control in a proportional valve system.

B) Temperature control in a household thermostat.

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