SPEED LOG
JRC JLN-740/JLN-741

Doppler Log

  • Highly accurate speed and distance log

  • Proprietary bubble detection

  • Precise navigation during berthing

  • BAM compliant alert handling
Product Information
Description

 

The JLN-740 series is a single axis water SDME compliant with the IMO MSC.96 (72) standard, required on all internationally voyaging ships exceeding 300 GT. Boasting never-before-seen accuracy for speed measurement, the JLN-740 is also installed with our company’s proprietary bubble detection function, which informs you when measurement accuracy is impaired due to air bubble contact.

The JLN-740 series utilizes digital signal processing, which, coupled with optimizations to existing speed measurement waveforms and the reliability of ship bottom mounting, has resulted in water speed measurement with accuracy up to 0.03kn or 0.3% in all models (measured at fixed speeds) That accuracy of information allows for highly fuel-efficient speeds, which means faster voyages with less waste. Along with improved speed measurements, the series also has greatly improved ship speed tracking, relaying all the information you need for precise navigation during berthing.

 

Touch operation

With just one physical power button, the 5-inch color main display and 6.5 and 8.4-inch for the remote displays are operated by touch operation. The touch screens can be easily read during daylight but also in darkness, with excellent clarity, even when viewed from a wide angle. All displays feature dimmable backlighting and have a graphical user interface is logical, easy to use and consistent throughout. All displays are designed for the industrial environment found onboard of ships, ensuring years of problem free operation.

 

Precise Ship Speed Tracking

The JLN-740 series uses digital signal processing and optimized speed measurement waveforms to achieve an accuracy of up to 0.03 knots or 0.3%. This high accuracy enables more fuel-efficient speeds, leading to faster voyages with reduced waste. Additionally, improved speed tracking provides precise navigation during berthing operations.

 
 
 Bubble Detection
 

The JLN-740 series features proprietary JRC technology that detects when bubbles contact the transducer, signaling reduced measurement accuracy on the display. This alert allows users to take corrective action by visually inspecting the device on the ship’s bottom to confirm the source of the issue.

 

Specifications

NAME DOPPLE LOG
MODEL JLN-740A JLN-740N JLN-741A JLN-741N
IMO approved Yes
Operating system Dual-beam pulse Doppler system
Operating frequency 2MHz
Measurement scale -10.00 to 40.00kn
Sailing display range Model A: 0 to 999999.99NM. Model N: 0 to 99999.99NM (NWW-7: to 9999.99NM with Distance Counter
Water speed 3.0 m deeper than the transducer surface
Ship speed accuracy 1% of the speed of the ship, or 0.1kn whichever is greater
Total distance accuracy 1% of the distance run by the ship in 1hr or 0.1 nautical miles in each hour whichever is greater
Speed indication kn or m/s
Display Technical panel 5.1 inch-LCD (400×900 pixels 4.5 inch monochrome LCD Touch panel 5.1 inch-LCD (480×800 pixels 4.5 inch monochrome LCD
Input interface
(IEC-61162-1)
GPS: RMC, ZDA (clock adjustment)
Signal output 8 ports NMEA0183 Ver1.5, 2.1, 2.3, 4.0 or IEC61162-1: VBW, VLW 2 ports IEC61162-1 :
VBW, VLW
1 ports IEC61162-1 :
VBW, VLW
I/O interface Analog display: 2 ports
Log pulse : 2 ports
(Photocoupler signal 200pulse / NM, Max. 30V, 10mA)
Distance Counter (NWW-7): 1 port
Remote Display (NWZ-650SDR /NWZ-840SDR),
Multi Information Display (NWZ-4610) : Total 2 ports
LAN I / O for RMS : 1 ports
Alarm (Power · Speed · System) output : 1 port each
Serial I /O for alarm : 1 port
Dimmer : serial I / O:1 port · Analog Input : 1 port
Power supply
Voltage
AC100 / 230V (±10%)
Power
consumption
AC100V : 50W (60VA) Less than, AC230V : 50W (150VA) Less than
Environmental
requirements
(excl. transducer)
Temperature range : -15 to 55℃ (operating)
Relative humidity : 0 to 93% (non condensing)

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