Section 1 Introduction; Function; Feature - JRC JLR-7900 Quick Reference

Section 1 Introduction

1.1 Function

1) MID
The Multi Information Display (MID) is the display unit that receives NMEA data items from
various sensors to display them.
The screen can be split to up to 4 areas for use. Only necessary information can be displayed
by selecting data to be displayed in the areas.
There are three modes in which six screens can be registered, and up to 18 screens can be
registered.
2) Doppler Log (JLN-205MK2)
The JRC Model JLN-205MK2 Doppler Log is an equipment for measuring accurately the true
speed and run of a ship, utilizing the Doppler shift of ultrasonic signals, which are radiated from a
trnsducer into sea water downward obliquely to the bow and stern sides, then scattered and
reflected in the sea water. The transducer is mounted on the hull bottom.
This equipment measures a relative speed to seawater from the hull bottom within 3m.
Therefore, ship's speed corresponding to the output of a main engine can be obtained without
containing the speed such as the currents. The ship's speed error margin caused by the change
in the water line doesn't occur because the transmission and the reception of the pulse are done,
and it excludes the signal in the vicinity of the bottom of a ship. Moreover, because the dual beem
method to launch the ultrasonic wave signal in two directions (fore and aft) is adopted, the ship's
speed error margin because of the change in the trim is greatly reduced.
This equipment offers measured information to other equipment such as radar and ECDIS.
3) GPS Navigator (JLR-7900/JLR-7600)
The GPS navigator operates around-the-clock to measure the position with high accuracy
anywhere in the world and in all weather conditions by using the GPS satellites. In addition, the
GPS navigator can increase the accuracy of position fixing by receiving correction data from the
DGPS beacon station and SBAS satellites.

1.2 Feature

The equipments have the following features:
1) MID
・Display of various NMEA data items
・Selection of display contents and screen layout
・Distribution of power supply in daisy chain mode
・Selection of display screen in each mode
・Sharing of data and interlocking of dimmer between display units at RS-485 interface
2) Doppler Log (JLN-205MK2)
・Ship's speed through the water
・Free of errors due to hull motions
・Reliable compact transducer
3) GPS Navigator (JLR-7900/JLR-7600)
・Availability of three output ports
・Improvement of operability by using various menus
・Built-in SBAS function
・Built-in RAIM function
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