True Heading AIS-CTRX User manual

OPERATION & INSTALLATION
MANUAL
AIS-CTRX Class B AIS Transponder
Version 1.1E
© True Heading 2006
The manual may not in any aspect be copied without the prior authorization from True Heading AB.

AIS-CTRX Class B AIS Transponder Manual
TABLE OF CONTENTS
TABLE OF CONTENTS.............................................................................................. 2
REVISION .................................................................................................................. 5
INTRODUCTION ........................................................................................................ 6
GLOSSARY................................................................................................................ 7
CONDITIONS ............................................................................................................. 9
WARRANTY ............................................................................................................. 10
General.................................................................................................................. 10
Warranty conditions............................................................................................... 10
Warranty procedures ............................................................................................. 10
Other issues .......................................................................................................... 10
SUPPORT ................................................................................................................ 11
GENERAL NOTICE.................................................................................................. 12
LICENSING .............................................................................................................. 13
INFORMATION ABOUT AIS .................................................................................... 14
General.................................................................................................................. 14
Short technical description of AIS.......................................................................... 15
Limitations with AIS ............................................................................................... 16
PRODUCT SPECIFICATION ................................................................................... 17
Declaration of Conformity ...................................................................................... 18
INSTALLING THE AIS-CTRX UNIT ......................................................................... 19
Electrical Connections ........................................................................................... 19
Physical Mounting ................................................................................................. 20
PROGRAMMING THE TRANSPONDER ................................................................. 21
1.1E 2 LD2103

AIS-CTRX Class B AIS Transponder Manual
Field Programmer.................................................................................................. 21
USING THE TRANSPONDER.................................................................................. 22
Switching on .......................................................................................................... 22
Warning and Fault States ...................................................................................... 22
Data Port Messages .............................................................................................. 22
Information Transmitted and Received.................................................................. 23
Built in Test............................................................................................................ 23
LED Indicators ....................................................................................................... 23
Antennas ............................................................................................................... 24
MAINTENANCE ....................................................................................................... 25
SERIAL DATA INTERFACE ..................................................................................... 26
Power Connection / Data Connection.................................................................... 26
Serial Port Input/Output ......................................................................................... 26
Power Up Messages ............................................................................................. 26
VHF Data Link Messages (NMEA 0183 VDM) ...................................................... 26
VHF data link own vessel messages (NMEA 0183 VDO)...................................... 28
Regional Assignment Channel Assignment Message (NMEA 0183 ACA) ............ 28
Channel management information source messages (NMEA 0183 ACS)............. 29
AIS Alarm Messages (NMEA 0183 ALR, Text)...................................................... 29
ACK messages...................................................................................................... 30
ANTENNA CONNECTIONS ..................................................................................... 31
GPS Antenna......................................................................................................... 31
VHF antenna ......................................................................................................... 31
Antenna Types and Mounting................................................................................ 31
OPERATIONAL GUIDELINES FOR AIS-CTRX ....................................................... 32
FAQ .......................................................................................................................... 35
1.1E 3 LD2103

AIS-CTRX Class B AIS Transponder Manual
NOTES ..................................................................................................................... 37
DRAWINGS.............................................................................................................. 38
Packing List ........................................................................................................... 38
Fixing Template (NOT TO SCALE) ....................................................................... 39
General Arrangement ............................................................................................ 40
Cable Assemblies.................................................................................................. 40
APPENDIX A ANTENNAS AND ANTENNA MOUNTING ...................................... 42
GPS Antenna......................................................................................................... 42
VHF antenna for AIS use....................................................................................... 42
WARNINGS........................................................................................................... 42
1.1E 4 LD2103

AIS-CTRX Class B AIS Transponder Manual
REVISION
Version Date Responsible Approved Changes
P1.0E 2006-11-22 Anders Bergström Nils Willart Preliminary release
1.0E 2006-11-23 Anders Bergström Nils Willart First release
1.1E 2007-11-22 Anders Bergstrom Nils Willart Change of pictures
1.1E 5 LD2103

AIS-CTRX Class B AIS Transponder Manual
INTRODUCTION
We would like to thank you for choosing True Heading AB as supplier of your AIS-CTRX, AIS Class B
Transponder. The AIS-CTRX is a high quality AIS Class B Transponder using the latest technology.
AIS-CTRX makes it possible to receive information from ships, buoys, lighthouses, SAR helicopters,
Coastguard units, Pilot boats, Weather station etc. and to send information about your own ship to
others that are equipped with Automatic Identification System (AIS) transponders or receivers. SEE
AND BE SEEN
It is today, according to the IMO SOLAS regulation a requirement for all ships above 300 GT to carry
AIS. This means that a large number of ships and other types of navigational information providers will
be seen by your AIS-CTRX and contribute to enhanced safety in your navigation.
Picture 1 Real traffic scenario between Sweden and Bornholm (Denmark)
It is of utmost importance that you read this manual before you start to install and use your AIS-CTRX.
1.1E 6 LD2103

AIS-CTRX Class B AIS Transponder Manual
GLOSSARY
ACA (AIS) Regional Assignment Channel Assignment Message
ACK Acknowledgement
ACS (AIS) Channel management information source messages
AFSK Audio frequency-shift keying
ALR (AIS) Alarm Message
A to N Aid to Navigation
AIS Automatic Identification System
ATC Air Traffic Control
BIIT Built In Integrity Testing
BNC Bayonet fitting type RF connector
CSTDMA Carrier Sense Time Division Multiple Access
COG Course over Ground
CR Carriage Return
CS Carrier Sense
CSTDMA Carrier Sense TDMA
DC Direct Current
DGNSS Differential Global Navigation Satellite System
DGPS Differential Global Positioning System
DSC Digital Selective calling
ETA Estimated Time of Arrival
GALILEO European equivalent to GPS
GLONASS Global Navigation Satellite System
GNSS Global Navigation Satellite System
GMSK Gaussian Minimum Shift Keying
GPS Global Positioning Satellite / System
HF High Frequency
IMO International Maritime Organization
IEC International Electrotechnical Commission
LED Light Emitting Diode
LF Line Feed
LNA Low-noise amplifier
MF Medium Frequency
MKD Minimum Keypad and Display
MMSI Maritime Mobile Service Identity
MPE Maximum Permissible Exposure
NM Nautical Mile = 1852 m
NMEA National Marine Electronics Association
PC Personal Computer
1.1E 7 LD2103

AIS-CTRX Class B AIS Transponder Manual
PI Presentation Interface
RF Radio Frequency
RTCM Radio Technical Commission for Maritime Services Commission
RX Receive or Receiver
RFI Radio frequency interference
SAR Specific Absorption Rate
SELV Separated Extra Low Voltage
SMA Swedish Maritime Administration
SMS Short Message System
SOG Speed over Ground
SOLAS Safety Of Life At Sea
SOTDMA Self Organized Time Division Multiple Access.
SRM Safety Related Message
SRT Software Radio Technology
TDMA Time-division Multiple Access
TNC Threaded type BNC connector
TX Transmit or transmitter
UTC Universal Time Co-ordinated
VDM (AIS) VHF Data Link Messages
VDO (AIS) VHF data link own vessel messages
VHF Very High Frequency
VTS Vessel Traffic Services (Like ATC but for ships)
VSWR Voltage Standing Wave Ratio
1.1E 8 LD2103

AIS-CTRX Class B AIS Transponder Manual
CONDITIONS
Before you start using the AIS-CTRX product from True Heading AB it is important that you read and
fully understand the installation manual and its instructions. You should only proceed with the
installation if you are confident that you will be able to do so.
True Heading AB cannot be held liable for any injury or damage caused by, during or because of the
installation of AIS-CTRX. The AIS-CTRX is used at your own risk and it shall be remembered that AIS
and GPS data depends on the full co-operation of other users and systems.
AIS-CTRX is a navigation aid and works in co-operation with other similar systems like e.g. radar,
optical lookout etc. The AIS-CTRX installation should be inspected from time to time and checked on
its operational quality frequently by the user. Remember that navigation and life at sea always requires
proper seamanship and that the AIS-CTRX is not a replacement for such qualities.
NOT ALL VESSELS CARRY AIS. IT IS THEREFORE IMPORTANT TO KEEP PROPER LOOKOUT
AT ALL TIMES AND TO USE ALL AVAILABLE MEANS TO AVOID COLLISIONS AND
ACCIDENTS.
GPS MAY FROM TIME TO TIME INCLUDE ERRORS: THEREFORE, THE POSITION RECEIVED
FROM THE GPS BUILT IN TO AIS-CTRX SHALL ALWAYS BE VERIFED WITH OTHER
AVAILABLE MEANS.
1.1E 9 LD2103

AIS-CTRX Class B AIS Transponder Manual
WARRANTY
General
AIS-CTRX is developed and manufactured to meet high technical requirements and user demands. If
installed correctly and with regular maintenance your AIS-CTRX should provide you with several years
of operation and a very useful product. For further information provided in the manual and in this
information sheet please consult the place where you purchased the AIS-CTRX or direct to our
support.
Warranty conditions
- The warranty belongs to the person that purchased the product and cannot be handed over to a third
party or person.
- The warranty is not valid if serial number is missing, seals broken or if the AIS-CTRX has been
incorrect installed. Neither is the warranty valid if instructions for connection have not been followed,
faults caused by wrong usage, own made modifications or service made from none authorized service
stations.
- True Heading AB acknowledges that AIS-CTRX at delivery has been controlled and found
operational.
- True Heading AB agrees to repair or replace any faulty unit without any cost according to the
conditions set forth during a period of two (2) years from day of purchase.
- The warranty includes replacement or repair of faulty unit due to error in components or errors in
relation to the production of the product.
- The warranty covers costs for spares, labor, and return shipment. It does not include shipment from
to the repair facility.
- True Heading AB will never be liable under the warranty conditions for incorrect use, misuse, and
incidental, indirect or consequential damages of the AIS-CTRX.
- Proof of purchase is required for any warranty claim of the AIS-CTRX.
Warranty procedures
True Heading AB repairs and replaces faulty parts or units. The customer is responsible for transport
of the defect part or unit to True Heading or its retailer.
Warranty claims shall be made to the place where AIS-CTRX was purchased or direct to True
Heading AB through mail, fax or e-mail to our support department.
Other issues
Proper seamanship and common sense is applicable when using AIS-CTRX and the products shall
only be seen as a navaid. True Heading AB keeps the right to change the specification of the product
without prior notice.
IF YOU ARE NOT ABLE TO ACCEPT THE TERMS ABOVE, PLEASE RETURN THE AIS-CTRX TO
YOUR RETAILER FOR FULL CREDIT BEFORE OPENED AND USED.
1.1E 10 LD2103

AIS-CTRX Class B AIS Transponder Manual
SUPPORT
If you need support, please contact the closest reseller or the location where you acquired the product.
The manufacturer can also give support direct:
Email: [email protected] or Fax: [phone].
Please register your purchase of AIS-CTRX with True Heading AB by sending an e-mail to
[email protected] stating the serial number, date of purchase, your name, address and your
dealer’s name.
1.1E 11 LD2103

AIS-CTRX Class B AIS Transponder Manual
GENERAL NOTICE
The Automatic Identification System (AIS) unit mostly utilise a Global Navigation Satellite
System (GNSS) system such as e.g. GPS or GLONASS to determine position.
The accuracy of these systems is variable and can be affected by factors such as the
positioning of the antenna, the number of satellites available to determine a position and for
how long satellite information has been received.
It is desirable as often as possible to verify both your vessel’s AIS derived position data and
other vessels AIS derived position data with visual or radar based observations.
The compass safe distance of this unit is 0.5m or greater for 0.3° deviation.
1.1E 12 LD2103

AIS-CTRX Class B AIS Transponder Manual
LICENSING
IMPORTANT: In most countries the operation of an AIS unit is included under the vessels marine VHF
radio licence provisions. The vessel on to which the AIS unit is to be installed must therefore possess
a valid VHF radiotelephone licence which lists the AIS system and the vessel Call Sign and MMSI
number.
Please contact the relevant authority in your country for more information.
In accordance with our policy of continuous development and product improvement the AIS-CTRX
hardware and/or software may be upgraded from time to time and future versions of the AIS-CTRX
may therefore not correspond exactly with this manual.
When necessary upgrades to the product are made, these will be accompanied by updates or
addenda to this manual.
Please take time to read this manual carefully to understand its contents fully so that you can install
and operate your AIS system correctly.
Information contained in this manual is liable to change without notice.
True Heading AB disclaims any liability for consequences arising from omissions or inaccuracies in
this manual and any other documentation provided with this product.
© 2006 True Heading AB
1.1E 13 LD2103

AIS-CTRX Class B AIS Transponder Manual
INFORMATION ABOUT AIS
General
AIS (Automatic Identification System) is the name of a system that makes it possible for ships to
identify other ships and to monitor ship movements. The reason for implementing the AIS system is for
the mariner to obtain more information about ships in the vicinity than what radar is able to provide.
AIS gives e.g. information about a ships identity (name, call sign, IMO number and MMSI), size this
even for ships behind Island or bends that radar cannot detect.
AIS is used to enhance safety for life at sea, improve safety and efficiency in navigation and protect
the marine environment.
AIS-information transmitted from a ship contains of three (3) different main types:
- Static data that was programmed into the AIS equipment at installation and it only needs to be
changed if the ship changes its name, flag or undergoes a major refit where size or ship type is
changed;
- Dynamic data contains information that automatically is updated from ship sensors like the heading
from the Gyro, Position and speed from GNSS equipment. Also navigational status belongs to the
group of dynamic data but is updated manually by the crew; and
- Voyage related data that manually is updated by the crew along the voyage.
From the start AIS some times also was referred to as UAIS or as the 4S transponder system that
meant Ship to Ship and Ship to Shore.
IMO adopted 1998 a performance standard for AIS within the SOLAS requirement that described in
general how AIS should work. Below follows a brief description of the main requirements for AIS from
the performance standard:
•Automatically provide information to AIS land stations, other ships and airborne units e.g. SAR
helicopters about the ships identity, Type of ship, Position, Course, Speed, Navigational status
(e.g. under way using engine, at anchor) and other safety related information of importance.
•Be able to receive the same type of information from other ships.
•Be able to monitor and track other ships.
•Exchange information with land based AIS systems.
AIS is an automatic system that continuously and simultaneously transmits on two channels in the
maritime VHF frequency band.
AIS can handle several reports in a rapid consecutive flow. To accomplish these AIS uses a technique
called Self Organized Time Division Multiple Access (SOTDMA) that guarantees high transmission
safety and operational robustness.
AIS also allows for other types of information from e.g. sensors like Gyro, GPS and echo sounders etc.
to be transmitted automatically.
Important areas where AIS is used are:
•Information exchange between ships within VHF range (normally 20-30 NM) to enhance
safety at sea and to improve situation awareness.
1.1E 14 LD2103

AIS-CTRX Class B AIS Transponder Manual
•Information exchange between ships and AIS land stations as e.g. a VTS that controls and
monitors maritime traffic in an area.
•Automatic reporting in areas with mandatory reporting of different kinds.
•Exchange of safety related information between ships and between ships and land stations.
•Services like e.g. meteorological information in real-time from areas of importance, identity
and position of floating and fixed aids to navigation to improve identification and navigation.
How AIS Works
The marine Automatic Identification System (AIS) is a location and vessel information reporting
system. It allows vessels equipped with AIS to automatically and dynamically share and regularly
update their position, speed, course and other information such as vessel identity with similarly
equipped craft. Position is derived from a Global Navigation Satellite System (GNSS) network and
communication between vessels is by Very High Frequency (VHF) digital transmissions. A
sophisticated and automatic method of time sharing the radio channel is used to ensure that even
where a large number of vessels are in one location blocking of individual transmissions is minimised,
any degradation of the expected position reporting interval is indicated to the user and even if the unit
suffers extreme channel overload conditions it will always recover to normal operation.
AIS Classes
There are two classes of AIS unit fitted to vessels, Class A and Class B. In addition AIS base stations
may be employed by the Coastguard, port authorities and other authorised bodies. AIS units acting as
aids to navigation (A to N) can also be fitted to fixed and floating navigation markers such as channel
markers and buoys.
Class A units are a mandatory fit under the safety of life at sea (SOLAS) convention to vessels above
300 gross tons or which carry more than 11 passengers in International waters. Many other
commercial vessels and some leisure craft also fit Class A units.
Class B units are currently not a mandatory fit but authorities in several parts of the world are
considering this. Class B units are designed for fitting in vessels which do not fall into the mandatory
Class A fit category.
The AIS-CTRX is a Class B unit
Position Information Source
As noted above the marine AIS system uses position information derived from networks such as the
Global Positioning Satellite (GPS) or the Global Navigation Satellite System (GLONASS) in order to
determine the location of the AIS unit and thus the vessel to which it is fitted.
Short technical description of AIS
s, depending on the speed and AIS operates primarily on two dedicated VHF-frequencies (AIS1
– 161,975 MHz and AIS2 – 162,025 MHz). In areas where these two channels are not available, AIS
can automatically change to other alternatively available frequencies.
AIS uses two VHF radio channels, where the information is transmitted in short data packages or slots
in predefined and synchronized time frames. The dynamic information (position, speed, heading etc)
is transmitted in intervals from 2 s up to 10 maneuvers of the transmitting ship were the AIS is
mounted. Static and voyage related information (type of ship, size, cargo, destination etc.) is
1.1E 15 LD2103

AIS-CTRX Class B AIS Transponder Manual
transmitted every sixth minute or upon request from other units. Position, course and speed normally
are collected from the same sensor systems that provides the same information used in the navigation
e.g. in radars or ECDIS and this is normally based on GPS or DGPS. All ships within VHF coverage
will be able to receive AIS data and competent authorities that have installed networks with coastal
AIS coverage can receive the information. The capacity for the ships to report is defined by the IMO
performance standard to a minimum of 2000 data packages or slots per minute (see picture 2). ITU
(Technical Standard for the Universal AIS) has been kind to double this and has provided AIS with
4500 data packages or slots per minute. The transmission is based on the (SO)TDMA (Self-organized
Time Division Multiple Access) technique, that allows the system to overload with 400 till 500 % and
still give almost a 100 % message throughput between ships that are closer to each other than 8 to 20
nautical miles. In such case the system overloads targets far away will be discriminated in favor of
targets close to your own ship. In reality, the system capacity is unlimited and allows for a large
number of ships to communicate simultaneously.
Picture 2 The principle of AIS technology on the two radio channels.
Limitations with AIS
You should always be aware that all ship others ships and in particular pleasurecrafts, fishing boats,
warships and some coastal stations and VTS centers not will be equipped with AIS. Ships that have
been mandated to carry AIS can also under certain conditions turn of there AIS equipment at the
master’s disgrace. Therefore it is important to be aware that the information that AIS provides might
not be the full and complete picture of the situation around your ship.
Users of AIS must also be aware that transmission of false data can occur and that this will be
hazardous not only to your own ship but to other as well. The user is responsible for all data that is
entered into the system and for information provided by external sensors. The accuracy of received
AIS data is only as good as the information transmitted from the source of information.
You should always be aware that wrong configured or calibrated ship sensors (positions-, speed- or
heading sensors) could lead to that wrong information will be transmitted. Dangerous situations can
occur if faulty information is shown on another ship.
1.1E 16 LD2103

AIS-CTRX Class B AIS Transponder Manual
PRODUCT SPECIFICATION
Dimensions: 190 x 135 x 83 mm (L x W x H)
Weight: 1,45 kg
Power:
DC (9.6-15.6V)
Average power consumption 4W
Peak current rating 2A
GPS Receiver (AIS Internal): IEC 61108-1 compliant
Electrical Interfaces: RS232 38.4kBaud bi-directional
RS422 NMEA 38.4kBaud bi-directional
Connectors: VHF Antenna connector
GPS Antenna connector
RS232/RS422/Power
VHF Transceiver: 1 Transmitter, 2 Receivers
(One receiver time shared between AIS and DSC)
Frequency: 156.025 to 162.025 MHz
Output Power: 33dBm ± 1.5 dB
Channel Bandwidth: 25 kHz
Channel Step:
25 kHz
Modulation Modes: 25 kHz GMSK (AIS, TX and RX)
25 kHz AFSK (DSC, RX only)
Bit rate: 9600 b/s ± 50 ppm (GMSK)
1200 b/s ± 30 ppm (FSK)
RX Sensitivity: -107dBm 25 kHz (Message Error Rate 20%)
Co-Channel 10dB
Adjacent Channel 70dB
IMD 65dB
Blocking84dB
Environmental: IEC 60945, Operating Temperature: -25ºC to +55ºC
IEC 62287, Section 5, Cat c) exposed to the weather
1.1E 17 LD2103

AIS-CTRX Class B AIS Transponder Manual
Indicators: Power, TX timeout, status, pre-set (Safety Related
Message)SRMsent.
Operator Controls: Optional pre-set safety related message SRM)
transmit button (Not implemented)
Standards
This product complies with all the necessary standards under the European R&TTE directive for
Article 3.1(a), 3.1(b), 3.2 and 3.3(e). The following standards have been followed in pursuance of this:
IEC62287-1: 2006-03 Maritime navigation and radiocommunication equipment and systems – Class B
shipborne equipment of the automatic identification system (AIS) – Part 1: Carrier-sense time division
multiple access (CSTDMA) techniques
IEC60945: 2002-08 Maritime navigation and radiocommunication equipment and systems – General
requirements – Methods of testing and required test results
IEC61162-1: Maritime navigation and radiocommunication equipment and systems – Digital interfaces
– Part 1: Single talker and multiple listeners
IEC61108-1: GLOBAL NAVIGATION SATELLITE SYSTEMS (GNSS) – Part 1: Global positioning
system (GPS) -Receiver equipment - Performance standards, methods of testing and required test
results
EN 301 843-1 v2.1: Electromagnetic compatibility and Radio spectrum Matters (ERM);
Electromagnetic Compatibility (EMC) standard for marine radio equipment and services; Part 1:
Common technical requirements
EN 50383: 2002 Basic standard for calculation and measurement of electromagnetic field strength and
SAR related to human exposure from radio base stations and fixed terminal stations for wireless
telecommunications system (110MHz – 40GHz)
EN60950-1:2002 Information technology equipment – Safety – Part 1: General requirements
Declaration of Conformity
True Heading AB declares that this product is in compliance with the essential requirements and other
provisions of the R&TTE directive 1995/5/EC.
The product carries the CE mark, notified body number and alert symbol as required by the R&TTE
directive
The product is intended for sale in the following member states:
1.1E 18 LD2103

AIS-CTRX Class B AIS Transponder Manual
INSTALLING THE AIS-CTRX UNIT
WARNING: Do not connect the AIS-CTRX unit to mains (line) AC electrical supply, as an electric
shock or fire hazard could result.
CAUTION: Do not connect the AIS-CTRX unit to a DC supply exceeding 15.6 V or reverse the supply
polarity. Damage to the unit may result.
CAUTION: The AIS-CTRX unit is designed for operation in the temperature range -25 °C to +55 °C.
Do not install (or use) the AIS-CTRX unit in environments which exceed this range.
CAUTION: do not install the AIS-CTRX unit in an environment where it can be subject to excessive
exposure to water.
Electrical Connections
Warning: Only the RF,
data and power cables
provided with the AIS-
CTRX unit should be used
to connect antennas,
power and display devices
so as to maintain the
integrity of the enclosure.
Power Cable (or Power and Data Cable)
GPS Antenna Cable
VHF Antenna Cable
Please see the drawings
section of this manual for
details of the power, data and
RF cables supplied
Remove the top of the
transponder unit (eight
screws) as shown.
Using the two co-axial leads
supplied connect the down-
lead from a VHF antenna to
the VHF antenna port and
connect the down-lead of a
GPS antenna to the GPS
antenna port.
Please see Appendix A for
recommendations on
antennas and antenna
installation.
If an external display unit (chart plotter, PC etc) is to be used connect the supplied power and data
interface cable to the Power / NMEA port.
If an external display unit is not to be used connect the supplied power only interface cable to the
Power / NMEA port.
Locate the RF, power and/or data cables into the rubber grommets pushing them firmly to the base of
each slit. Each cable is pushed into the grommet slit which lies directly in front of the connector the
cable is connected to.
Replace the top of the transponder unit taking care to seat the cable grommets and the lid seal
correctly. Do not over-tighten the fixing screws.
1.1E 19 LD2103

AIS-CTRX Class B AIS Transponder Manual
If an external display unit is to be used (such as a chart plotter, PC serial terminal or other display
device) connect the user end of the data interface cable to the display device. Note that the software
in the display device must be configured for AIS operation AND to accept standard Class B operation
NMEA sentences. This external display unit software is not part of the AIS-CTRX transponder
package.
Connect a 12V DC supply (9.6-15.6V) capable of supplying 2A peak to the DC power lead (brown/red
= positive, black/blue=negative). It is recommended that the supply voltage be SELV in accordance
with EN 60950-1.
The case of the unit is not isolated from the negative terminal of the supply and therefore it is
recommended that the unit is not attached to metal parts of the vessel.
Physical Mounting
It is recommended that the unit is attached to a solid wooden surface with 20mm M3 self tapping
screws. A template for drilling pilot holes is shown on page 39.
1.1E 20 LD2103