Current Indicator Training Session

Page 1: Introduction

  • Current Indicator: A device used to monitor and analyze water currents.

  • Master Systems In-House Training: Focuses on understanding and using current indicators effectively.

Page 2: Doppler Current Indicator

  • Definition: Also known as Acoustic Doppler Current Profiler (ADCP).

  • Functionality: Measures speed and direction of currents using sound waves throughout the water column.

Page 3: Principle of Current Indicator

  • Measurement Principle: Utilizes the Doppler effect of supersonic waves to gauge current.

  • Importance: Essential for troubleshooting and understanding operational principles of the device.

Page 4: Doppler Effect

  • Definition: The phenomenon where sound frequency changes based on the motion of the sound source and observer.

    • High-pitched: When the sound source approaches.

    • Low-pitched: When the sound source moves away.

  • Measurement Technique: Transmits sound towards an object; calculates relative speed based on frequency changes in reflected sound.

  • Application: In current measurement, sound is transmitted from a ship, with reflected waves used to analyze currents from plankton and other objects in the water.

Page 5: Water Tracking and Bottom Tracking Speeds

  • Water Tracking Ship Speed: Measures the relative speed of the ship against sea water.

    • Uses reflected waves from objects such as plankton.

  • Bottom Tracking Ship Speed: Determines the speed by analyzing reflected waves from the sea bottom.

  • Current Calculation: Current speed is derived by subtracting own ship speed from water tracking ship speed.

Page 6: Supersonic Beam

  • Beam Transmission: Emits supersonic beams at a 60-degree angle to measure currents and bottom tracking speeds in different directions.

  • Pulse Duration: Long pulse width (~10 times that of a fish finder) for enhanced measurement accuracy (5 to 30 ms).

  • Pair Beam System: Adopted to minimize errors due to ship motion.

Page 7: Current Measurement Process

  • Equipment Setup: A transducer installed on the ship's bottom for current measurement.

  • Measurement Steps:

    1. Transmit supersonic wave pulses downward at a 60-degree angle.

    2. Capture reflected wave from the current measurement layer and sea bottom.

    3. Calculate the water tracking ship speed using Doppler frequency from reflections.

    4. Use data to determine current speed by subtracting the water tracking speed from bottom tracking speed.

Page 8: Mechanism of Current Measurement

  • Working Steps:

    1. Transmit supersonic pulses in four directions from the ship.

    2. Extract reflected waves from the current measurement depth.

    3. Calculate relative speed to determine water tracking ship speed.

    4. Assess the time taken for sound to return to find current layer depth.

    5. Distinguish between weaker water reflections and stronger sea bottom reflections.

    6. Average measurements over time to stabilize current readings against noise and variations.

Page 9: Schematic Diagram

  • Components Overview:

    • LCD Monitors (NWZ-164, NWZ-211)

    • Signal cable connections for data transfer (5m each)

    • Sensors: GPS, Heading, Wind, Temperature (NMEA0183 compatibility)

    • Fish finder, signal processing, and ship power specifications.

Page 10: Major Parts of Current Indicator

  • Components Include:

    • JLN-652 Transducer (CFT-067B optional)

    • Power supplies and processors (NBA-5111, NJC-30)

    • Keyboard (NCH-603E) and monitors (NWZ-164 optional)

    • Matching box (NQD-2422 optional)

  • Specifications: Detailed dimensions of each component to aid in setup and maintenance.

Page 11: Conclusion

  • Acknowledgment: Final remarks to participants for their engagement in the training session.