Japan Radio Co. JLN-740A User manual

General
1
Function of Each Components
2
Operation Method (JLN-740A/741A)
3
Menu Settings and Configurations
(JLN-740A/741A)
4
Operation Method (JLN-740N/741N)
5
Menu Settings and Configurations
(JLN-740N/741N
）
6
Operation Method (Option)
7
Setting by Using Menus (Option)
8
Installation Method
9
Maintenance and Inspection
10
After-Sales Service
11
Disposal
12
Specification
13
Menu list
APP A
Installation Drawings
APP B
Error due to the deviation from the
irradiation angle reference value
APP C
Spare Parts List
APP D
JLN-740A/740N
JLN-741A/741N
DOPPLER LOG
Instruction Manual

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i

z Safety Cautions z㻌
Cautions for High Voltage
High voltage of hundreds volts is used inside this equipment. Touching a component inside the
unit is very dangerous. Any person other than specialized maintenance staffs should not
maintain, inspect, or adjust the unit.
High voltages on the order of tens of thousand volts are most likely to cause instant deaths from
electrical shocks. At times, even voltages on the order of several hundred volts could lead to
electrocution. To defend against electrical shock hazards, do not put your hand into the inside of
apparatus. 
When you put in a hand unavoidably in case of urgent, it is strongly suggested to turn off the
power switch and allow the capacitors, etc. to discharge with a wire having its one end positively
grounded to remove residual charges. Before you put your hand into the inside of apparatus,
make sure that internal parts are no longer charged. Extra protection is ensured by wearing dry
cotton gloves at this time. Another important precaution to observe is to keep one hand in your
pocket at a time, instead of using both hands at the same time. It is also important to select a
secure footing to work on, as the secondary effects of electrical shock hazards can be more
serious. In the event of electrical shocks, disinfect the burnt site completely and obtain medical
care immediately.
Precautions for Rescue of Victim
of Electric Shock
When a victim of electric shock is found, turn off the power source and ground the circuit
immediately. If this is impossible, move the victim away from the unit as quick as possible without
touching him or her with bare hands. He or she can safely be moved if an insulating material such
as dry wood plate or cloth is used.
It is necessary to perform first aid immediately.
Breathing may stop if current flows through the respiration center of brain due to electric shock. If
the electric shock is not large, breathing can be restored by artificial respiration. A victim of electric
shock looks pale and his or her pulse may become very weak or stop, resulting in
unconsciousness and rigidity at worst.
7ZPNA3208

ii
Emergency Measures 
Method of First-Aid Treatment
Precautions for First-Aid Treatments
Apply artificial respiration to the person who collapsed, minimizing moving as much as
possible avoiding risks. Once started, artificial respiration should be continued rhythmically.
(1) Refrain from touching the patient carelessly as a result of the accident; the first-aider
could suffer from electrical shocks by himself or herself.
(2) Turn off the power calmly and certainly, and move the patient apart from the cable gently.
(3) Call or send for a physician or ambulance immediately, or ask someone to call doctor.
(4) Lay the patient on the back, loosening the necktie, clothes, belts and so on.
(5) (a) Feel the patient's pulse.
(b) Check the heartbeat by bringing your ear close to the patient's heart.
(c) Check for respiration by bringing your face or the back of your hand to the patient's
face.
(d) Check the size of patient's pupils.
(6) Opening the patient's mouth, remove artificial teeth, cigarettes, chewing gum, etc. if any.
With the patient's mouth open, stretch the tongue and insert a towel or the like into the
mouth to prevent the tongue from being withdrawn into the throat. (If the patient clenches
the teeth so tight that the mouth won't open, use a screwdriver or the like to force the
mouth open and then insert a towel or the like into the mouth.)
(7) Wipe off the mouth to prevent foaming mucus and saliva from accumulating.

iii
Flow of Cardiopulmonary Resuscitation (CPR)
A person is collapsing.
- Secure the safety of the surrounding area.
- Prevent secondary disasters.
Check for response.
-
Call while tapping the shoulder.
Breathing
Recovery position
- Lay the injured or
ill person on
his/her side and
wait for the arrival
of the emergency
services.
Not responding
Ask for help.
- Make an emergency call.
-
Ask to bring an AED.
Listen to the appeal of the
injured or ill person and give
the necessary first-aid
Responding
Not breathing
Give 2 rescue breaths; omissible Note(
1
)
Give CPR.
- 30 chest compressions
-
Give 2 rescue breaths; omissible Note(
1
)
Note
(
1
) Omission of rescue breathing:
If there is a fear of infection because the
injured or ill
person has an intraoral injury,
you are hesitant about giving mouth
-to-
mouth
resuscitation, or preparing the mouthpiece for
rescue breathing takes too long, omit rescue
breathing and proceed to the next step.
Open the airway.
-
Check for breathing.
Arrival of an AED
- Turn on the power.
- Use theAED by following its voice prompts.
Fitting of the electrode pads, etc.
Automatic electrocardiogram
analysis
- Do not touch the injured or ill
person.
Electric shock is needed.
Electric shock is not needed.
Delivery of electric shock
Resume CPR from chest
compressions by following the
voice prompts of the AED.
When the injured or ill
person has been
handed over to the
emergency services or
has started moaning or
breathing normally, lay
him/her on his/her side
in a recovery position
and wait for the arrival
of emergency services.
When to
stop CPR
A person is collapsing.
- Secure the safety of the surrounding area.
- Prevent secondary disasters.
The AED
automatically
analyzes the
heart rhythm
every 2 min.

iv
Specific Procedures for Cardiopulmonary Resuscitation (CPR)
1. Check the scene for safety to prevent secondary disasters
a) Do not touch the injured or ill person in panic when an accident has occurred. (Doing so may
cause electric shock to the first-aiders.)
b) Do not panic and be sure to turn off the power. Then, gently move the injured or ill person to a
safe place away from the electrical circuit.
2. Check for responsiveness
a) Tap the shoulder of the injured or ill and shout in the ear saying,
"Are you OK?"
b) If the person opens his/her eyes or there is some response or
gesture, determine it as "responding." But, if there is no response
or gesture, determine it as "not responding."
3. If responding
a) Give first-aid treatment.
4. If not responding
a) Ask for help loudly. Ask somebody to make an emergency call
and bring an AED.
• Somebody has collapsed. Please help.
• Please call an ambulance.
• Please bring an AED.
• If there is nobody to help, call an ambulance yourself.
5. Open the airway
a) Touch the forehead with one hand. Lift the chin with the two fingers
of the middle finger and forefinger of the other hand and push down
on the forehead as you lift the jaw to bring the chin forward to open
the airway. If neck injury is suspected, open the airway by lifting the
lower jaw.
6. Check for breathing
a) After opening the airway, check quickly for breathing for no more than
10 seconds. Put your cheek down by the mouth and nose area of the
injured or ill person, look at his/her chest and abdomen, and check the
following three points.
• Look to see if the chest and abdomen are rising and falling.
• Listen for breathing.
• Feel for breath against your cheek.
Are you OK?
Please call an
ambulance. Please bring an AED.

v
b) If the injured or ill person is breathing, place him/her in the recovery
position and wait for the arrival of the emergency services.
• Position the injured or ill person on his/her side, maintain a clear and
open airway by pushing the head backward while positioning their
mouth downward. To maintain proper blood circulation, roll him/her
gently to position them in the recovery position in the opposite
direction every 30 minutes.
7. Give 2 rescue breaths (omissible)
a) If opening the airway does not cause the injured or ill person to begin
to breathe normally, give rescue breaths.
b) If there is a fear of infection because the injured or ill person has an
intraoral injury, you are hesitant about giving mouth-to-mouth
resuscitation, or getting and preparing the mouthpiece for rescue
breathing takes too long, omit rescue breathing and perform chest
compressions.
c) When performing rescue breathing, it is recommended to use a
mouthpiece for rescue breathing and other protective devices to
prevent infections.
d) While maintaining an open airway, pinch the person's nose shut with
your thumb and forefinger of the hand used to push down the
forehead.
e) Open your mouth widely to completely cover the mouth of the injured or ill person so that no air
will escape. Give rescue breathing twice in about 1 second and check if the chest rises.
8. Cardiopulmonary resuscitation (CPR) (combination of chest compressions and
rescue breaths)
a) Chest compressions
1) Position of chest compressions
• Position the heel of one hand in the center of the chest, approximately between the nipples,
and place your other hand on top of the one that is in position.
Roll gently in the opposite
direction every 30 minutes.
CPR mask
Mouthpiece for rescue

vi
2) Perform chest compressions
• Perform uninterrupted chest compressions of 30
at the rate of about 100 times per minute.
While locking your elbows positioning yourself
vertically above your hands.
• With each compression, depress the chest wall to a depth of approximately 4 to 5 cm.
b) Combination of 30 chest compressions and 2rescue breaths
1) After performing 30 chest compressions, give 2rescue
breaths. If rescue breathing is omitted, perform only chest
compressions.
2) Continuously perform the combination of 30 chest
compressions and 2rescue breaths without interruption.
3) If there are two or more first-aiders, alternate with each other
approximately every two minutes (five cycles of
compressions and ventilations at a ratio of 30:2) without interruption.
9. When to stop cardiopulmonary resuscitation (CPR)
a) When the injured or ill person has been handed over to the
emergency services
b) When the injured or ill person has started moaning or breathing
normally, lay him/her on his/her side in a recovery position and wait
for the arrival of emergency services.
10. Arrival and preparation of an AED
a) Place the AED at an easy-to-use position. If
there are multiple first-aiders, continue CPR
until the AED becomes ready.
b) Turn on the power to the AED unit.
Depending on the model of the AED, you
may have to push the power on button, or
the AED automatically turns on when you open the cover.
c) Follow the voice prompts of the AED.
30 times
Compress
with these
parts (the
heels of
both
hands).
2 times
Turn on the power.

vii
11. Attach the electrode pads to the injured or ill person's bare chest
a) Remove all clothing from the chest, abdomen, and arms.
b) Open the package of electrode pads, peel the pads off and securely
place them on the chest of the injured or ill person, with the adhesive
side facing the chest. If the pads are not securely attached to the chest,
the AED may not function. Paste the pads exactly at the positions
indicated on the pads, If the chest is wet with water, wipe dry with a dry towel and the like, and
then paste the pads. If there is a pacemaker or implantable
cardioverter defibrillator (ICD), paste the pads at least 3cm away
from them. If a medical patch or plaster is present, peel it off and
then paste the pads. If the injured or ill person's chest hair is thick,
paste the pads on the chest hair once, peel them off to remove the
chest hair, and then paste new pads.
c) Some AED models require to connect a connector by following voice prompts.
d) The electrode pads for small children should not be used for children over the age of 8 and for
adults.
12. Electrocardiogram analysis
a) The AED automatically analyzes electrocardiograms. Follow the
voice prompts of the AED and ensure that nobody is touching the
injured or ill person while you are operating the AED.
b) On some AED models, you may need to push a button to analyze
the heart rhythm.
13. Electric shock (defibrillation)
a) If the AED determines that electric shock is needed, the voice
prompt saying, "Shock is needed" is issued and charging starts
automatically.
b) When charging is completed, the voice prompt saying, "Press the
shock button" is issued and the shock button flashes.
c) The first-aider must get away from the injured or ill person, make
sure that no one is touching him/her, and then press the shock button.
d) When electric shock is delivered, the body of the injured or ill person may jerk.
14. Resume cardiopulmonary resuscitation (CPR).
Resume CPR consisting of 30 chest compressions
and 2rescue breaths by following the voice
prompts of the AED.
Press the shock button.

viii
15. Automatic electrocardiogram analysis
a) When 2 minutes have elapsed since you resumed cardiopulmonary resuscitation (CPR), the
AED automatically analyzes the electrocardiogram.
b) If you suspended CPR by following voice prompts and AED voice prompt informs you that
shock is needed, give electric shock again by following the voice prompts.
If AED voice prompt informs you that no shock is needed, immediately resume CPR.
16. When to stop CPR (Keep the electrode pads on.)
a) When the injured or ill person has been handed over to the emergency services
b) When the injured or ill person has started moaning or breathing normally, lay him/her on his/her
side in a recovery position and wait for the arrival of emergency services.

ix
Contents
Safety Cautions ......................................................................................................... i
Emergency Measures............................................................................................... ii
Contents................................................................................................................... ix
Preface..................................................................................................................... xv
Pictorial Indication..............................................................................................................................xvi
Usage Precautions ...........................................................................................................................xvii
JLN-740A Overview of standard components................................................... xxiii
JLN-740N Overview of standard components................................................... xxiv
JLN-741A Overview of standard components.................................................... xxv
JLN-741N Overview of standard components................................................... xxvi
Abbreviations.......................................................................................................xxvii
Glossary............................................................................................................... xxix
How to use this manual........................................................................................ xxx
Chapter 1 General....................................................................................................................1-1
1.1 Functions ........................................................................................................................1-1
1.2 Features..........................................................................................................................1-2
1.3 Components....................................................................................................................1-4
1.4 Construction....................................................................................................................1-8
1.5 System Configuration ...................................................................................................1-18
1.5.1 JLN-740A System Configuration Diagram...............................................................1-18
1.5.2 JLN-740N System Configuration Diagram..............................................................1-19
1.5.3 JLN-741A System Configuration Diagram...............................................................1-20
1.5.4 JLN-741N System Configuration Diagram..............................................................1-21
Chapter 2 Function of Each Components................................................................................2-1
2.1 Main Display NWZ-510SDW (For JLN-740A/741A).......................................................2-1
2.2 Main Display NWZ-4640 (For JLN-740N/741N).............................................................2-2
2.3 Remote Display (Optional) NWZ-650SDR/840SDR ......................................................2-3
2.4 MID (Optional) NWZ-4610..............................................................................................2-4
2.5 Distance Counter (Optional) NWW-7 .............................................................................2-5
Chapter 3 Operation Method (JLN-740A/741A) ......................................................................3-1
3.1 Basic Operation..............................................................................................................3-2
3.1.1 Power Supply ON/OFF..............................................................................................3-2
3.1.2 Adjusting Brightness..................................................................................................3-4
3.2 Displaying Ship Speed/Accumulated Sailing Distance ..................................................3-5
3.2.1 Displaying Ship Speeds.............................................................................................3-5
3.2.2 Displaying theAccumulated Sailing Distance...........................................................3-6
3.3 Displaying Alert...............................................................................................................3-8
Chapter 4 Setting by Using Menus (JLN-740A/741A).............................................................4-1

x
4.1. Setting of NWZ-510SDW................................................................................................4-2
4.1.1. Main Menu.................................................................................................................4-2
4.1.2. Common Operation of Each Menu............................................................................4-4
4.1.3. Operation of Each Menu............................................................................................4-5
4.1.3.1. Touch Position Calibration..................................................................................4-5
4.1.3.2. Brightness Adjustment........................................................................................4-7
4.1.3.3. Date Setting........................................................................................................4-8
4.1.3.4. Confirming the system information...................................................................4-10
4.1.3.5. Advanced Settings of the details of the equipment at installation of this
equipment......................................................................................................... 4-11
4.1.3.6. Setting the number of decimal digits of a ship speed...................................... 4-11
4.1.3.7. Ship Speed Unit Settings .................................................................................4-12
4.1.3.8. Setting the upper limit and the lower limit for ship speed alerts......................4-13
4.1.3.9. SDME Advanced Settings................................................................................4-15
4.1.3.10. Alert List............................................................................................................4-15
4.1.3.11. Alert History......................................................................................................4-16
4.2. Alert...............................................................................................................................4-17
4.2.1. JLN-740AAlert list ...................................................................................................4-17
4.2.2. JLN-741AAlert list ...................................................................................................4-19
4.2.3. Sentence list that generates “ID sentence abnormal(PARSING FAIL)”..................4-20
Chapter 5 Operation Method (JLN-740N/741N)......................................................................5-1
5.1 Basic Operation..............................................................................................................5-2
5.1.1 Power Supply ON/OFF..............................................................................................5-2
5.1.2 Adjusting Brightness..................................................................................................5-4
5.2 Displaying Ship Speed/Accumulated Sailing Distance ..................................................5-5
5.2.1 Displaying Ship Speeds.............................................................................................5-5
5.2.2 Displaying theAccumulated Sailing Distance...........................................................5-6
5.3 Displaying Alert...............................................................................................................5-7
Chapter 6 Setting by Using Menus (JLN-740N/741N).............................................................6-1
6.1. Setting NWZ-4640..........................................................................................................6-2
6.1.1. Calling a main menu..................................................................................................6-2
6.1.2. Common operations of menus screens.....................................................................6-4
6.1.3. Operation of each menu............................................................................................6-5
6.1.3.1. Display setting....................................................................................................6-5
6.1.3.1.1. Adjusting contrast ........................................................................................6-5
6.1.3.1.2. Adjusting back light......................................................................................6-6
6.1.3.1.3. Setting a click sound....................................................................................6-6
6.1.3.1.4. Setting a display screen...............................................................................6-7
6.1.3.1.4.1. STEP1 Selecting a display screen.....................................................6-8
6.1.3.1.4.2. STEP2 Selecting a screen structure ..................................................6-9
6.1.3.1.4.3. STEP3 Selecting display contents ................................................... 6-11
6.1.3.1.5. Select a back light color.............................................................................6-14

xi
6.2. System setting ..............................................................................................................6-15
6.3. Language setting..........................................................................................................6-15
6.4. Alert setting...................................................................................................................6-15
6.5. Sensor setting...............................................................................................................6-16
6.6. Date and time setting....................................................................................................6-16
6.7. Alert history display.......................................................................................................6-16
6.8. Alert list display.............................................................................................................6-17
6.9. Alert...............................................................................................................................6-17
6.9.1 Alerts that occur in JLN-741N.......................................................................................6-18
6.9.2 Alerts that occur in JLN-741N.......................................................................................6-19
6.9.3 Sentence list that generates “ID sentence abnormal(PARSING FAIL)”...............6-20
6.9.4 Display of alert list · history screen...............................................................................6-21
6.10. Installation setting.........................................................................................................6-22
6.10.1System setting.......................................................................................................6-22
6.10.2 Language setting...................................................................................................6-23
6.10.3 Sensor setting .......................................................................................................6-23
6.10.4 Date setting...........................................................................................................6-23
Chapter 7 Operation Method (Option).....................................................................................7-1
7.1 Basic Operation..............................................................................................................7-2
7.1.1 Adjusting Brightness..................................................................................................7-2
7.2 Displaying Ship Speed/Accumulated Sailing Distance ..................................................7-4
7.2.1 Displaying Ship Speeds.............................................................................................7-4
7.2.2 Displaying theAccumulated Sailing Distance...........................................................7-5
7.3 Displaying Alert...............................................................................................................7-8
Chapter 8 Setting by Using Menus (Option)............................................................................8-1
8.1. Setting of NWZ-650SDR/840SDR..................................................................................8-2
8.1.1. Main Menu.................................................................................................................8-2
8.1.2. Operation of Each Menu............................................................................................8-4
8.1.2.1. Touch Position Calibration..................................................................................8-4
8.1.2.2. Brightness Adjustment........................................................................................8-5
8.1.2.3. Date Setting........................................................................................................8-6
8.1.2.4. Confirming the system information.....................................................................8-8
8.1.2.5. Advanced Settings of the details of the equipment at installation of this
equipment...........................................................................................................8-9
8.1.2.6. Display Mode Selection......................................................................................8-9
8.1.2.7. Ship Speed Unit Settings .................................................................................8-10
8.1.2.8. SDME Advanced Settings................................................................................ 8-11
8.1.2.9. SOG and STW selection..................................................................................8-12
8.2. Setting of NWZ-4610....................................................................................................8-12
Chapter 9 Installation Method..................................................................................................9-1
9.1 Installation of the Main Display and Distribution Processor...........................................9-2
9.2 Installation of the Transducer Mounting .........................................................................9-3

xii
9.3 Connection Diagram.......................................................................................................9-4
9.3.1 JLN-740A inter-connection diagram..........................................................................9-4
9.3.2 JLN-740N inter-connection diagram..........................................................................9-5
9.3.3 JLN-741A inter-connection diagram..........................................................................9-6
9.3.4 JLN-741N inter-connection diagram..........................................................................9-7
Chapter 10 Maintenance and Inspection.................................................................................10-1
10.1 Routine Maintenance....................................................................................................10-1
10.2 Countermeasures forAbnormalities and Faults...........................................................10-2
10.3 Repair unit.....................................................................................................................10-2
10.4 Troubleshooting............................................................................................................10-3
Chapter 11 After-Sales Service................................................................................................ 11-1
11.1 Requesting Repair........................................................................................................11-1
11.2 Recommendation of Inspection and Maintenance....................................................... 11-2
Chapter 12 Disposal.................................................................................................................12-1
Chapter 13 Specification..........................................................................................................13-1
13.1. General Specification....................................................................................................13-1
13.1.1. JLN-740A.................................................................................................................13-1
13.1.2. JLN-740N.................................................................................................................13-1
13.1.3. JLN-741A.................................................................................................................13-2
13.1.4. JLN-741N.................................................................................................................13-2
13.2. JLN-740A/741AMain Display NWZ-510SDW..............................................................13-3
13.2.1. Display Unit..............................................................................................................13-3
13.2.2. Electrical Specifications...........................................................................................13-3
13.2.3. Environmental Requirements ..................................................................................13-3
13.2.4. Mechanical Specifications .......................................................................................13-3
13.2.5. External Interface.....................................................................................................13-4
13.3. JLN-740N/741N Main Display NWZ-4640 ..........................................................................13-5
13.3.1. Display Unit..............................................................................................................13-5
13.3.2. Electrical Specifications...........................................................................................13-5
13.3.3. Environmental Requirements ..................................................................................13-5
13.3.4. Mechanical Specifications .......................................................................................13-5
13.3.5. External interface.....................................................................................................13-5
13.4. Distribution Processor NQA-7040 ................................................................................13-6
13.4.1. Electrical Specifications...........................................................................................13-6
13.4.2. Environmental Requirements ..................................................................................13-6
13.4.3. Mechanical Specifications .......................................................................................13-6
13.4.4. External Interface.....................................................................................................13-6
13.5. Signal Processor NJC-70S...........................................................................................13-7
13.5.1. Electrical Specifications...........................................................................................13-7
13.5.2. Environmental Requirements ..................................................................................13-7
13.5.3. Mechanical Specifications .......................................................................................13-7
13.6. Transducer mounting NKF-547....................................................................................13-8

xiii
13.6.1. Electrical Specifications...........................................................................................13-8
13.6.2. Environmental Requirements ..................................................................................13-8
13.6.3. Mechanical Specifications .......................................................................................13-8
13.7. Transducer mounting (Option) NKF-531E....................................................................13-9
13.7.1. Electrical Specifications...........................................................................................13-9
13.7.2. Environmental Requirements ..................................................................................13-9
13.7.3. Mechanical Specifications .......................................................................................13-9
13.8. Remote Display (Optional) NWZ-650SDR.................................................................13-10
13.8.1. Display Unit............................................................................................................13-10
13.8.2. Electrical Specifications.........................................................................................13-10
13.8.3. Environmental Requirements ................................................................................13-10
13.8.4. Mechanical Specifications .....................................................................................13-10
13.9. Remote Display (Optional) NWZ-840SDR................................................................. 13-11
13.9.1. Display Unit............................................................................................................ 13-11
13.9.2. Electrical Specifications......................................................................................... 13-11
13.9.3. Environmental Requirements ................................................................................ 13-11
13.9.4. Mechanical Specifications ..................................................................................... 13-11
13.10. MID (Optional) NWZ-4610 ..................................................................................13-12
13.10.1. Display Unit ....................................................................................................13-12
13.10.2. Electrical Specifications..................................................................................13-12
13.10.3. Environmental Requirements.........................................................................13-12
13.10.4. Mechanical Specifications..............................................................................13-12
13.11. JLN-740A/N Data Format....................................................................................13-13
13.11.1. IEC 61162-1 Input/Output Data......................................................................13-13
13.11.1.1.Output data.....................................................................................................13-13
13.11.1.2.Input data........................................................................................................13-16
13.11.2. IEC 61162-450 I/F ..........................................................................................13-19
13.12. JLN-741A/N Data Format....................................................................................13-20
13.12.1. IEC 61162-1 Output Data...............................................................................13-20
13.12.1.1. Output data.................................................................................................13-20
13.13. About Chinese version RoHS.............................................................................13-22
Appendix A Menu list..................................................................................................................A-1
A.1 Display menu list (NWZ-510SDW, NWZ-650SDR/NWZ-840SDR).................................A-1
A.2 Display menu list (NWZ-4640).........................................................................................A-6
A.3 Maintenance software menu list....................................................................................A-10
Appendix B Installation Drawings...............................................................................................B-1
Appendix C Error due to the deviation from the irradiation angle reference value....................C-1
C.1 Errors by hull motions........................................................................................................C-1
Appendix D Spare Parts List.......................................................................................................D-1

xiv
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xv
Preface
Thank you for purchasing the Japan Radio Co., Ltd.
JLN-740A/740N/741A/741N Doppler Log. This equipment is an SDME (Speed
and Distance Measuring Equipment), complying with the regulations of IMO
(International Marine Organization), measures and displays wide-range ship
speed through the water.
• Please read all safety precautions, pictorial indication and manual carefully
before using your equipment to ensure safe and proper use.
• Please keep this instruction manual handy for future reference. Doing so
will allow you to understand and to be prepared for any contingency.

xvi
Pictorial Indication 
Meanings of Pictorial Indication
Various pictorial indications are included in this manual and
are shown on this equipment so that you can operate them
safely and correctly and prevent any danger to you and / or
to other persons and any damage to your property during
operation. Such indications and their meanings are as
follows.
Please understand them before you read this manual:
!
DANGER This indication is shown where incorrect equipment
operation due to negligence may cause death or serious
injuries.
!
WARNING This indication is shown where user is supposed to be in
danger of being killed or seriously injured if this indication
is neglected and this equipment is not operated correctly.
!
CAUTION
This indication is shown where user is supposed to be
injured or any property damage is supposed to occur if
this indication is neglected and this equipment is not
operated correctly.
Examples of Pictorial Indication
Electric Shock
The mark represents CAUTION (including DANGER and
WARNING).
Detailed contents of CAUTION ("Electric Shock" in the example
on the left) is shown in the mark.
Disassembling
Prohibited
The mark represents prohibition.
Detailed contents of the prohibited action ("Disassembling
Prohibited" in the example on the left) is shown in the mark.
Disconnect
the power plug
!
The mark represents instruction.
Detailed contents of the instruction ("Disconnect the power plug"
in the example on the left) is shown in the mark.
Warning Label There is a warning label on the top cover of the equipment.
Do not try to remove, break or modify the label.

xvii
Usage Precautions 
DANGER
Never remove the cover of this equipment.
Touching the high-voltage section inside may cause an electric shock.
Before conducting inspection, maintenance or parts replacement, make sure
to turn off the power and breaker.
Failure to comply may cause an electric shock, fire or an equipment fault.
Make sure to turn the breaker off since voltage is still outputted from the
distribution processor even after the displays are turned off.
Failure may result in equipment failure, or death or serious injury due to
electric shock.
Do not touch the equipment with hands or gloves wet with water.
Otherwise, an electric shock or a malfunction may occur.

xviii
Customers shall never attempt to check or repair the inner of the equipment.
Checking or repair by an unqualified person may cause a fire or an electric
shock.
Do not attempt to disassemble or tamper with this equipment.
A fire, an electric shock, or a malfunction may occur.
For maintenance, inspection of the internal section of the equipment, request
the service to the store, nearest JRC agent, JRC marine service department,
sales department, regional office, branch or sales office.
In case you find smoke, unusual odor or extreme high heat coming from the
equipment, turn off the power and breaker immediately, unplug the power
supply cable from an electric outlet, and contact the store, nearest JRC
agent, JRC marine service department, sales department, regional office,
branch or sales office.
Keeping the equipment in operation under such condition may cause fire or
an electric shock.
The Doppler log must be used strictly as navigation aid equipment only.
The final decision on navigation must be made by the pilot.
If the final decision is made based on the information displayed by the
Doppler log only, an accident such as collision or grounding may occur.
This equipment must not be used by anyone except the ship’s crews and
specialized maintenance staff.
Failure to comply may result in misuse.
Do not use this equipment under any power supply voltage other than the
voltage that is indicated.
Failure to comply may result in fire, an electric shock, or an equipment fault.
Do not place a glass or cup containing water, etc., or a small metal object on
this equipment.
If water or such object gets inside, a fire, an electric shock, or a malfunction
may occur.