Introduction to Marine Automation Terminologies
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What is the primary purpose of instrumentation in marine automation?

  • To solely provide mechanical assistance to operators
  • To measure, control, and observe various processes (correct)
  • To eliminate the need for human operators
  • To automate only financial transactions

    • Which statement accurately describes a closed loop system?

  • It uses continuous feedback for accuracy. (correct)
  • It operates without any feedback.
  • It relies entirely on human oversight.
  • It is simpler than an open loop system.

    • What does the term 'set point' refer to in a control system?

  • Any disturbance variable that affects the system
  • The desired value of a controlled variable (correct)
  • The actual value measured in the system
  • The maximum allowable deviation from normal operation

    • Which element directly measures process variables in a control system?

    <p>Primary element</p> Signup and view all the answers

    What role does the final control element play in the control system?

    <p>It changes the manipulated variable to correct the process.</p> Signup and view all the answers

    Which of the following is a characteristic of open loop systems?

    <p>They lack feedback mechanisms.</p> Signup and view all the answers

    Which type of device is a Bourdon tube?

    <p>A primary element for pressure measurement</p> Signup and view all the answers

    What is the role of the diaphragm in pressure measurement?

    <p>It creates a partition and responds to pressure changes.</p> Signup and view all the answers

    What is the primary function of a strain gauge?

    <p>To change resistance in proportion to pressure</p> Signup and view all the answers

    Which pressure unit is most commonly used in the English system?

    <p>PSI</p> Signup and view all the answers

    What type of device is a U-tube manometer primarily used for?

    <p>Local indication of pressure</p> Signup and view all the answers

    Which device generates a small electrical signal proportional to the force exerted?

    <p>Piezoelectric transducer</p> Signup and view all the answers

    What standard output does a pressure transmitter typically give?

    <p>4 to 20 mA</p> Signup and view all the answers

    How is the capacitance of a variable capacitance transducer affected?

    <p>By the distance between its plates</p> Signup and view all the answers

    For level measurement in SI units, which measurement units are commonly used?

    <p>Millimeters and centimeters</p> Signup and view all the answers

    What is the role of a level switch in a measurement system?

    <p>To cut-off electrical signals during emergencies</p> Signup and view all the answers

    What method do differential pressure flowmeters use to measure flow rate?

    <p>By inferring flow rate from pressure drop across an obstruction</p> Signup and view all the answers

    Which type of flowmeter physically traps fluid to measure flow rate?

    <p>Displacement or volumetric flowmeter</p> Signup and view all the answers

    What does the accuracy rating of an instrument indicate?

    <p>The limit of errors not to exceed under specified conditions</p> Signup and view all the answers

    What types of devices are included under velocity flowmeters?

    <p>Turbine and vortex shedding flowmeters</p> Signup and view all the answers

    Which of the following is NOT a component of the calibration process?

    <p>Validating the precision of the instrument</p> Signup and view all the answers

    In terms of accuracy, what does the term 'FS' stand for?

    <p>Full Scale</p> Signup and view all the answers

    What is the purpose of a calibrator in the calibration process?

    <p>To serve as the standard of comparison</p> Signup and view all the answers

    Which of the following statements about precision is true?

    <p>It measures the conformity of repeated readings from the instrument</p> Signup and view all the answers

    What standard output range does a level transmitter typically provide?

    <p>4 to 20 mA</p> Signup and view all the answers

    Which unit is NOT commonly used for temperature measurement?

    <p>Joule</p> Signup and view all the answers

    Which device serves as a local reference for temperature measurement?

    <p>Bimetallic device</p> Signup and view all the answers

    What is the output signal of a thermocouple measured in?

    <p>Millivolts</p> Signup and view all the answers

    How does the resistance of an RTD change with temperature?

    <p>Increases with temperature</p> Signup and view all the answers

    Which equation represents volumetric flow rate?

    <p>$Q = v imes A$</p> Signup and view all the answers

    Which of the following is a correct expression of temperature conversion from Celsius to Fahrenheit?

    <p>$F = 9/5 (C) + 32$</p> Signup and view all the answers

    What does mass flow rate specifically measure?

    <p>Mass or weight of fluid per unit time</p> Signup and view all the answers

    What is the conversion factor from US gallons per day (gpd) to cubic meters per second (m3/s)?

    <p>4.39 x 10^-8</p> Signup and view all the answers

    How does one convert liters per minute (liter/min) to imperial gallons per minute (Imp gpm)?

    <p>Multiply by 0.22</p> Signup and view all the answers

    What is the conversion factor from cubic feet per minute (cfm) to liters per second (liter/sec)?

    <p>1.699</p> Signup and view all the answers

    If you have a flow of 6333.3 m3/h, what is the equivalent flow in imperial gallons per day (Imp gpd)?

    <p>5277.8</p> Signup and view all the answers

    To convert from US gallons per minute (US gpm) to cubic meters per hour (m3/h), what factor is required?

    <p>7.48</p> Signup and view all the answers

    When converting liter/h to m3/s, which factor is used?

    <p>0.001</p> Signup and view all the answers

    What is the conversion from cubic meters per minute (m3/min) to imperial gallons per minute (Imp gpm)?

    <p>316.7</p> Signup and view all the answers

    Which of the following corrects a common mistake when converting US gpd to liters per hour?

    <p>Multiply by 3.785</p> Signup and view all the answers

    Study Notes

    Introduction to Marine Automation - Terminologies

    • Instrumentation: A collection of devices used for observation, measurement, and control.
    • Control System: A system used to regulate a process, monitor it, or indicate when desired results are achieved.
    • Automation: Automatically controlling a system using instruments to balance supply and demand.
    • Mechanization: Providing machinery to assist human operators with physical tasks.
    • Open Loop System: A control loop without feedback, a simple system.
    • Closed Loop System: A control loop with continuous feedback, more accurate but complex.
    • Controlled Variable: The variable within a system that is controlled. This variable often has a set point.
    • Set Point: The desired value for the controlled variable.
    • Manipulated Variable: The variable changed to adjust the system and correct the process.
    • Disturbance Variable: Any variable that can disrupt the process. Examples include ambient temperature.
    • Primary Element: The device that measures variables in a system such as sensors or instruments.
    • Secondary Element: The device that processes the signal from the primary element and sends a signal to the final control element.
    • Final Control Element: The device that changes the manipulated variable to correct the process, often control valves.

    Types of Control Systems

    • Diagrams illustrating open and closed loop systems are included, showing the process, manipulated variable (MV), process variable (PV), measuring element, indicator/recorder (open loop) and controller set point (SP), manipulated variable, and corresponding flow back to the controller in a closed loop system.

    Process Variables

    • Diagrams highlighting the manipulated variable, controlled variable, and disturbance variable within a process.

    Components of a Typical Control System

    • Diagrams outlining the final control element, controller, secondary element, primary element, and sensor within the process.

    Function of Components in Control System

    • Diagrams show how the manipulated variable (MV) is compared to the set value (SV) which computes and then adjusts the MV to control the process value (PV).

    Principles of Process Measurements - Pressure Measurements

    • Primary Elements:
      • Bourdon Tube: Used in ordinary pressure gauges, available in C-type, helical, and spiral variations for different applications.
      • Diaphragm: A rubber device creating a partition between areas, responding to applied pressure.
      • Bellows: A device expanding or contracting due to pressure.
    • Diagrams of each primary pressure element are included, visually depicting their structure and principle of operation.

    Principles of Process Measurements - Continued

    • Strain Gauges: Devices changing resistance proportionally to pressure, increasing resistance with increased pressure.
    • Piezoelectric Transducers: Quartz crystal devices producing a small electrical signal proportional to the pressure applied.
    • Variable Capacitance Transducers: Two-plate device where capacitance changes with plate distance, directly proportional to pressure.

    Units of Pressure

    • A table converting various pressure units (psi, kPa, inH2O, mmH2O, inHg, mmHg, bar, kg/cm², gm/cm²) is included.

    Local Reference for Pressure Measurement

    • Pressure gauges and U-tube manometers are used for pressure measurement and verification.

    Remote Control for Pressure Measurement

    • Pressure switches and transmitters measure pressure and send signals to the controller, often with alarm signals included.

    Level Measurements

    • Level can be measured in units like millimeters, centimeters, meters, or percentages in the SI system. Inches, feet, and percentages are used in the English system.
    • Local references like sight glass and sounding tape are used to measure and verify levels.

    Remote Control for Level Measurement

    • Level switches and transmitters are used; sometimes they act as emergency switches. Output signals are often 4 to 20 mA or 0.2 to 1.0 Bar.

    Temperature Measurements

    • Temperature is measured using Celsius (°C) in SI units, and Fahrenheit (°F) in ANSI system. Other units include Kelvin and Rankine.
    • Local references such as bimetallic devices, fluid expansion devices, infrared, or change-of-state devices (thermometers) are used to measure temperature.

    Remote Control for Temperature Measurement

    • Temperature switches and transmitters are used for remote temperature measurement, with the signals sent to a controller. These devices can be used to cut off electrical signals when a predefined limit is exceeded, using thermocouples and RTDs (Resistance Temperature Detectors).

    Flow Measurements

    • Flow can be measured using volumetric flow rate (volume of fluid per unit time) or mass flow rate (mass or weight per unit time).
    • Typical units for flow rate include pounds per hour.
    • A table converts various flow units.

    Instrument Calibration - Terminologies

    • Calibration: Determining an instrument's uncertainty or accuracy by comparing it to a known standard.
    • Calibrator: The instrument used as the known standard in calibration.
    • Accuracy: How close an indicated value is to the recognized or ideal value.
    • Accuracy Rating: Maximum permissible errors under specific conditions (often expressed as a percentage or +/- value).
    • Precision: Reproducibility of measurements.
    • Rangeability: The ability of an instrument to change its range/scale.
    • Traceability: The ability to link a measurement to known standards.
    • Sensitivity: Smallest measurable change in a measured quantity.

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    Related Documents

    Basic Marine Automation Handout PDF

    Description

    Explore key terminologies in marine automation, including instrumentation, control systems, and various types of loops. This quiz will deepen your understanding of automation processes and their components. Perfect for those looking to enhance their knowledge in marine technology.

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