JRC JLR-20 User Manual (English)

Questions and Answers:

E
Elizabeth WilliamsJul 30, 2025
How to troubleshoot power issues on a JRC Marine GPS System?
- D
  David ReynoldsJul 30, 2025
  If the JRC Marine GPS System does not turn on, there could be several reasons. First, ensure the ship junction box or the power supply equipment is providing power by checking their respective cablings. If the cabling is fine, inspect the fuses connected to the power cable and the power supply equipment; replace them if blown. If the issue persists, the display unit switch might be broken, and you should consult with JRC or an affiliate.
C
Carla MillerAug 3, 2025
What to do if my JRC Marine GPS System is not receiving data from external devices?
- J
  Joseph BowenAug 3, 2025
  If your JRC Marine GPS System isn't receiving data from external devices, the issue might stem from the serial cable's polarity, so check the polarity of the cable. Also, verify that the interface settings are correctly configured. Finally, confirm that the entered commands are supported by checking the commands and version.
C
Charles CookAug 7, 2025
Why is my JRC JLR-20 not transmitting data to external devices?
- D
  davidwarrenAug 8, 2025
  If the JRC Marine GPS System is not transmitting data to external devices, first ensure that the output settings have been properly configured. Also, verify that the configured channel is correct. If problems persist, the DISP-DPU or connector board might be broken, requiring you to consult with JRC or an affiliate.
B
Bryan BlankenshipAug 11, 2025
What causes no sensor reception on a JRC JLR-20 Marine GPS System?
- L
  Lynn BrownAug 12, 2025
  If your JRC Marine GPS System isn't receiving data from its sensor, the sensor connection cable might be cut, so check the connection cable. If the cable is intact, the sensor itself might be broken, in which case you should consult with JRC or an affiliate.
D
Donna KennedyAug 16, 2025
What to do if the LCD display is not working on my JRC JLR-20 Marine GPS System?
- G
  Gloria FordAug 16, 2025
  If the LCD display of your JRC Marine GPS System is blank, it could indicate that the LCD display is broken. In this case, you should consult with JRC or an affiliate.
M
Ms. Brenda HunterAug 20, 2025
Why is there no alarm sound on my JRC Marine GPS System?
- R
  robert55Aug 20, 2025
  If the alarm sound is not working on your JRC Marine GPS System, the buzzer might be broken. You should consult with JRC or an affiliate.
L
Laura McmahonAug 25, 2025
How to enable the click sound on a JRC JLR-20?
- J
  jennifer28Aug 25, 2025
  If you are not hearing a click sound on your JRC Marine GPS System, the key press sound may be turned off. To resolve this, refer to section 5.3.1.3 for setting the key press sound.

JRC JLR-20 Specifications

General

Brand	JRC
Model	JLR-20
Category	Marine GPS System
Language	English

Summary

Foreword

Before Commencing the Operation

Symbols

Explains various symbols used in the manual for safety and operation.

Precautions Upon the Operation

Appearance of the Equipment

Standard Equipment

Details the standard components included with the JRC GPS Compass JLR-20/30.

Section 1 Equipment Overview

1.1 Functions

Describes the primary purpose and capabilities of the GPS compass system.

1.2 Features

Lists the key characteristics and advantages of the GPS compass.

1.3 Configuration

Details the standard and optional equipment included with the JLR-20 and JLR-30 models.

1.4 Construction

Provides dimensional drawings and mass specifications for the NWZ-4700 Display Unit.

1.5 System Diagram

Illustrates the overall system connectivity and data flow between components.

Section 2 Installation

2.1 Sensor Installation

Guides on selecting an optimal location and installing the GPS compass sensor unit.

2.2 Display Unit Installation

Instructions for mounting the NWZ-4700 display unit, including bracket and flush mount options.

2.3 Cable Connection

Details the rear panel connectors and their functions for various unit connections.

Section 3 Names and Functions of Each Unit

3.1 NWZ-4700 Display Unit

Identifies and explains the controls and display elements of the NWZ-4700 unit.

3.2 NNN-20/30 Sensor Unit

Illustrates the components of the NNN-20/30 sensor unit, including antennas and processor.

Section 4 Display

4.1 Display Screen

Overview of the different screen displays available on the unit, such as Compass, Navigation, and Turn Rate.

4.1.1 Compass Screen

Details the graphical representation of the ship's heading on various compass screen formats.

4.1.2 Bow Heading Screen

Explains the numerical display of the ship's heading and related data.

4.1.3 Navigation Screen

Describes the display of latitude and longitude obtained from GPS positioning.

4.1.4 Turn Rate Screen

Illustrates the display of the ship's rate of turn, including graphic and numerical formats.

4.1.5 Water Speed / Ground Speed Screen

Shows how ship speeds (STW, SOG) and current data are displayed.

4.1.6 Configuration Screen

Details how to access the main menu for system configuration.

Section 5 Operation

5.1 Menu List

Provides a comprehensive list of all available menu options and their settings.

5.2 Basic Operation

Covers fundamental operations like powering the unit on and off.

5.2.1 Turning the Unit On

Step-by-step guide for powering on the equipment and initiating system startup.

5.2.2 Turning the Unit Off

Procedure for safely powering down the GPS compass unit.

5.2.3 Adjusting the Backlight

Instructions for setting the display brightness to one of four levels.

5.2.4 Adjusting the Contrast

Guide to adjusting the display contrast through 13 levels.

5.2.5 Stopping the Alarm Buzzer

How to silence audible alarms when they occur.

5.2.6 Changing the Display

Explains how to cycle through different screen displays using the DISP key.

5.2.7 Displaying Satellite Information

Details how to view satellite positions and signal levels on the display.

5.2.8 Alarm History Display

Describes how to view a log of past alarm events.

5.3 Main Menu

Accessing and navigating the main menu to check or change system settings.

5.3.1 Display Settings

Configuring display parameters like contrast, brightness, and buzzer settings.

5.3.1.1 Adjusting the Contrast

Step-by-step guide to adjust the LCD contrast from 1 to 13 levels.

5.3.1.2 Brightness Settings (DIMMER)

Setting the display brightness to various levels: maximum, typical, and minimum.

5.3.1.3 Click Sound Settings (CLICK SOUND)

Enabling or disabling the audible click sound for key presses.

5.3.1.4 Display Reversing Setting (REVERSING MODE)

Option to reverse display colors (normal, reverse 1, reverse 2).

5.3.2 Setting the Heading (HEADING)

Configuration options for heading measurement, including restoration, backup, and offset.

5.3.3 GPS Configuration (GPS)

Settings for GPS mode, HDOP, smoothing, and RAIM accuracy level.

5.3.3.1 Initial Settings (INITIALIZATION)

Procedure for setting initial GPS receiver parameters like latitude, longitude, and date.

5.3.4 SBAS Settings (SBAS)

Configuration options for Satellite-Based Augmentation System (SBAS) modes and search.

5.3.5 Beacon Settings (BEACON)

Settings for selecting beacon stations, bit rate, frequency, and displaying beacon information.

5.3.6 System Settings

System configuration for time difference, date/time display, datum, speed units, and ROT range.

5.3.7 Data I/O Settings (DATA I/O)

Configuring data input/output settings for external devices, including NMEA and NSK formats.

5.3.8 Checking the Version

Displays the software version information for the unit, sensor, and GPS receivers.

5.3.9 Others Settings

Miscellaneous settings for current layer and data number.

5.3.10 Language Settings (LANGUAGE)

Option to change the display language of the unit.

5.4 Maintenance Menu

Accessing the maintenance menu for advanced diagnostics, demo, reset, and software updates.

5.4.1 Antenna Check

Provides sensor status and allows confirmation of heading, roll, pitch, and GPS reception.

5.4.2 Input Check

Monitors data input from sensor or other ports, allowing verification of data reception.

5.4.3 Self-Diagnosis (DIAGNOSIS)

Performs self-diagnosis tests on the display unit, sensor, and LCD.

a. Display Unit Self-Diagnosis (DISPLAY UNIT)

Details the self-diagnosis results for the display unit's ROM, RAM, SIO, and buzzer.

b. Sensor Self-Diagnosis (SENSOR)

Reports the self-diagnosis results for the sensor's controller, ROM, RAM, FRAM, and antenna.

c. Screen Self-Diagnosis (LCD)

Checks for dead pixels on the LCD by cycling screen colors.

5.4.4 Demo

Runs a demonstration mode to simulate equipment operation, requiring sensor connection.

5.4.5 Product Type Configuration

Configures the unit type (main/sub), enters serial numbers, and checks default settings.

5.4.6 Master Reset (RESET)

Restores all unit and sensor settings to their factory default values.

5.4.7 Software Update (SOFT UPDATE)

Procedure for updating the unit's software via a connected computer.

Section 6 Maintenance and Inspection

6.1 General Maintenance and Inspection

Provides guidelines for routine cleaning and securing of parts to maintain equipment.

6.2 Alarms

Lists alarm messages, their contents, and potential causes for troubleshooting.

6.3 Troubleshooting

Offers guidance on identifying and resolving common problems with the GPS compass system.

6.3.2 Repair Unit

Lists replaceable units and their corresponding models for repair purposes.

6.3.3 Regular Replacement Parts

Identifies parts that require periodic replacement, like LCD units and batteries.

Section 7 After-Sales Service

7.1 Warranty

Outlines the standard warranty period and terms for the equipment.

7.2 Repair Parts Stocking Period

Information on the availability of functional repair parts after production discontinuation.

7.3 When Requesting Service

Provides instructions on what information to provide when requesting service or repairs.

7.4 Recommended Checks and Inspections

Advises on additional inspections and maintenance to ensure long-term performance.

Section 8 Disposal

8.1 Disposal of the Equipment

Guidelines for safely disposing of the GPS compass equipment according to local regulations.

8.2 Disposal of Used Batteries

Instructions for the proper and safe disposal of the unit's lithium battery.

Section 9 Specifications

9.1 DISPLAY UNIT (NWZ-4700)

Lists technical specifications for the NWZ-4700 display unit, including panel, power, and environment.

9.1.5 External Interfaces

Details serial transmission and contact signal specifications for connecting external devices.

9.2 SENSOR UNIT (NNN-20/30)

Provides electrical specifications, environmental ratings, and dimensions for the sensor unit.

Appendix

Appendix 1 List of Geodetic Systems

A table mapping screen display codes to corresponding geodetic systems.

Related product manuals

JRC JLR-20 User Manual

Table of Contents