WorksheetsOn-Off Controller in Marine Engineering
Total questions: 15
Worksheet time: 8mins
Which of the following best describes the operation of an On-Off controller in a marine boiler system?
The fuel valve opens partially depending on error magnitude.
The fuel valve is either fully open or fully closed.
The controller adjusts fuel continuously in proportion to error.
The controller delays operation until steady-state is reached.
In a ship's water tank system controlled by an On-Off controller, the solenoid valve operates in which manner?
Gradual opening and closing based on flow demand.
Continuously variable flow adjustment.
Fully open or fully closed positions only.
Opens at half capacity to avoid overflow.
What phenomenon occurs when an On-Off controller repeatedly overshoots the setpoint in a marine oven temperature control?
Dead time
Steady-state error
Hunting
Drift
Hysteresis in an On-Off controller for marine heating systems is primarily used to:
Eliminate steady-state error completely.
Reduce frequent switching near the setpoint.
Increase proportional control range.
Improve continuous signal variation.
A thermostat with a setpoint of 70°C and hysteresis of 1°C will switch ON at what temperature?
69°C
70°C
71°C
72°C
The main disadvantage of using On-Off controllers in marine applications is:
They are too complex to design.
High cost of implementation.
Continuous oscillation around the setpoint.
They cannot work with solenoid valves.
In a marine refrigeration system, On-Off control is most suitable for:
Fine-tuned temperature control.
Systems requiring precise stability.
Sluggish systems with large time constants.
Variable proportional load changes.
Which of the following graphs best represents the output of an On-Off controller?
Smooth proportional curve.
Linear increasing slope.
Step-like square waveform.
Exponential decay curve.
Deadband in On-Off control systems prevents:
Continuous cycling around the setpoint.
Hysteresis adjustments.
Output overshoot reduction.
Energy efficiency improvement.
What will happen if the deadband in an On-Off controller is too small?
System remains stable for long time.
Switching frequency increases significantly.
Overshoot is completely eliminated.
Controller output becomes continuous.
Which marine engineering system typically uses On-Off control due to simplicity and cost effectiveness?
Ship propulsion system
Cargo handling cranes
Electric heaters for cabins
Radar tracking system
Which control characteristic is missing in an On-Off controller compared to PID control?
Hysteresis
Deadband
Proportional adjustment
Two-step switching
If hysteresis in a marine oven control is increased, what will happen?
Switching frequency decreases, overshoot increases.
Switching frequency increases, overshoot decreases.
Both switching and overshoot decrease.
Both switching and overshoot increase.
A water level control system on a ship uses differential pressure switches. The switch activates when:
Flow rate decreases.
Pressure at the bottom of the tank reaches a threshold.
Pump speed increases.
Controller detects steady-state error.
Which statement is TRUE regarding On-Off control in marine systems?
Provides precise proportional control.
Minimizes actuator wear due to switching.
Simple, inexpensive, and suitable for basic systems.
Eliminates steady-state error completely.
