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Total questions: 40
Worksheet time: 13mins
What is the main purpose of control modes in an automation system?
To measure tank levels
To define how a system reacts to an error signal
To regulate only temperature
To reduce mechanical load
An On–Off control mode functions by:
Providing a gradual change in output
Switching output fully ON or OFF
Adjusting output in proportion to error
Responding to error rate of change
Which control mode reduces steady-state error but may not remove it completely?
Proportional
Integral
Derivative
On–Off
The Integral (I) control mode is used to:
Respond to error rate
Correct accumulated errors
Increase proportional gain
Delay the signal output
The Derivative (D) mode mainly:
Eliminates steady-state error
Speeds up correction by reacting to error changes
Controls system pressure
Decreases temperature overshoot
Which control system combines P, I, and D actions for accuracy and stability?
On–Off control
PID control system
Manual feedback system
Cascade control
The P in a PID controller stands for:
Proportional
Pressure
Process
Power
In a PID pressure control system, what factor most affects its response?
Valve position
System volume and compressibility
Color of piping
Motor speed
In a level PID control of a closed tank, the measurement is affected by:
Hydrostatic pressure only
Vapor pressure and tank geometry
Temperature alone
Air pressure only
A flow PID control system is mainly used to:
Maintain constant pressure
Keep a steady flow rate under varying loads
Adjust boiler temperature
Control vessel trim
A temperature PID control regulates temperature by:
Adjusting air filters
Adjusting heating or cooling valves
Changing tank levels
Opening drain lines
Which factor affects temperature PID control performance?
Sensor response time and thermal inertia
Electric load
Pipe diameter
Pump rotation
Thermal inertia in temperature control refers to:
The resistance to temperature change
The speed of signal transmission
Electrical feedback delay
Valve mechanical wear
The sensor lag in a PID loop causes:
Immediate correction
Delay in detecting temperature changes
Increased pressure output
Reduced signal voltage
Which is a common application of temperature control onboard ships?
Lube oil cooling systems
Anchor windlass motor
Cargo crane
Bilge pump
A cascade control system uses:
Two or more controllers working together
A single feedback loop
Manual signal adjustment
Stepper motors only
In cascade control, the primary controller manages:
Secondary variable
Main process variable
Signal transmission
Actuator speed
The secondary (slave) controller in a cascade system:
Follows the master controller
Sets the main process set point
Works independently
Replaces proportional control
An example of cascade control onboard is:
Boiler feedwater level control
Temperature control of jacket cooling water with flow as secondary loop
Bilge pump pressure system
Generator frequency adjustment
The main advantage of cascade control is:
Faster correction of disturbances and improved stability
More complex hardware setup
Reduced signal transmission
Lower accuracy
An Electronic Engine Propulsion System primarily uses:
Mechanical governors
Electronic Control Units (ECUs)
Pneumatic valves only
Manual throttles
The use of ECUs in marine engines improves:
Emissions and fuel efficiency
Noise and vibration
Tank capacity
Propeller diameter
A key advantage of electronic propulsion automation is:
Need for constant manual operation
Integration with the ship’s IAS (Integrated Automation System)
Reduced diagnostic ability
Less control accuracy
Which function is handled by electronic fuel injection systems?
Manual speed control
Precise fuel delivery and timing
Constant-speed lubrication
Cooling of exhaust gas
Electronic propulsion systems improve safety by:
Ignoring sensor faults
Providing interlocks and alarms
Bypassing monitoring circuits
Increasing voltage fluctuations
LNG and Methanol require what special system condition?
High combustion pressure
Cryogenic storage and precise vapor control
Open deck ventilation
Electrical grounding only
The automation impact of biofuels mainly concerns:
Pump speed
Variable combustion characteristics
Fuel tank pressure
Lube oil type
Ammonia and hydrogen fuels require:
Flame monitoring and leak detection
High-temperature burners only
Reduced automation control
Standard fuel filters
For alternative fuels, automation ensures:
Safe handling and efficiency
Manual tank venting
Continuous burning only
Higher emissions
Why are accurate sensors vital for LNG systems?
They detect leaks and maintain vapor pressure
They reduce tank insulation
They control salinity
They increase thermal conductivity
The main purpose of instrument calibration is to:
Enhance signal strength
Ensure measurement accuracy
Increase operating voltage
Reduce instrument cost
Calibration compares instrument output with:
A. A known standard
B. The system’s error value
C. A fixed set point
D. A manual indicator
Common tools for calibration include:
Multimeter and pressure gauge
Fuel pump and air compressor
Screwdriver and hammer
Digital relay
During calibration, zero and span adjustments are made to:
Increase data rate
Correct measurement errors
Adjust pump output
Test electrical insulation
Ziegler–Nichols is a method used for:
Tuning PID controllers
Testing sensors
Adjusting relays
Checking fuses
Proportional gain (Kp) affects:
Signal noise
System responsiveness and stability
Sensor drift
Calibration accuracy
If integral time (Ti) is set too high, the system will:
Overshoot and oscillate
Become very slow
Improve accuracy instantly
Ignore feedback
The derivative time (Td) improves:
Temperature control
System stability and damping
Electrical grounding
Calibration data storage
Regular instrument adjustment ensures:
The system maintains desired set point
Uncontrolled process variations
Reduced loop response
Elimination of calibration need
Accurate calibration and tuning in marine automation ensure:
Efficient and safe operation of automated systems
Slower process control
More manual monitoring
Reduced reliability
