Simrad ITI TRAWL SYSTEM - SERIAL DATA COMMUNICATION REV... User manual

Simrad ITI Trawl System
Serial data communication and
NMEA 0183 message description
111110 10 00 1010101010
01010100100010100011
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10101001100001111.................
Instruction manual

Simrad ITI Trawl system
Serial data communication and
NMEA 0183 message description
Instruction manual
857--164777 / Rev.A

Note
Simrad AS makes every effort to ensure that the information contained within this
document is correct. However, our equipment is continuously being improved and
updated, so we cannot assume liability for any errors which may occur.
Warning
The equipment to which this manual applies must only be used for the purpose for which
it was designed. Improper use or maintenance may cause damage to the equipment or
injury to personnel. The user must be familiar with the contents of the appropriate manuals
before attempting to operate or work on the equipment.
Simrad AS disclaims any responsibility for damage or injury caused by improper
installation, use or maintenance of the equipment.
Copyright
E2003 Simrad AS
ISBN 82-8066-013-5
The information contained within this document remains the sole property of Simrad AS.
No part of this document may be copied or reproduced in any form or by any means, and
the information contained within is not to be communicated to a third party, without the
prior written consent of Simrad AS.
Support
For support on your Simrad equipment, consult your local dealer, visit www.simrad.com,
or contact us directly at [email protected].
Simrad AS
Strandpromenaden 50
Box 111
N-3191 Horten
Telephone: [phone]
Facsimile: [phone]
A L W A Y S A T T H E F O R E F R O N T O F T E C H N O L O G Y

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Sections
This book is the Instruction manual manual for the ITI system.
1INTRODUCTION
2ITI TRAWL SYSTEM, BASIC PRINCIPLE
3ITI GEOMETRY FOR TWIN RIG
4 RESPONSIBILITY
5 SERIAL LINES
6 NMEA 0183 MESSAGES, DEFINITIONS
7NMEA–
ABBREVIATIONS, ITI AUX MENU SELECTIONS
(Cd6911)
M/S simrad Echo, our research and demonstration vessel

Simrad ITI
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Remarks
References
Further information about the ITI system supplied may be found in the following manuals:
•ITI Installation manual
•ITI Trawl Eye Instruction manual

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Contents
1INTRODUCTION 1..........................................
2 ITI TRAWL SYSTEM, BASIC PRINCIPLE 2................
3ITIGEOMETRYFORTWINRIG 3..........................
4 RESPONSIBILITY 5........................................
5 SERIAL LINES 6............................................
Transmitted messages 6..........................................
Received message 8.............................................
Serial line configuration and pin allocations 9.........................
Serial port pin assignments 10......................................
6 NMEA 0183 MESSAGES, DEFINITIONS 11.................
Message description 11............................................
NMEA output from ITI 12.........................................
NMEA Input to ITI 23.............................................
Telegram from Winch Syncro 2020 25...........................
7 NMEA – ABBREVIATIONS, ITI AUX MENU SELECTIONS 26

Simrad ITI
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Document logistics
Rev Date Written Checked Approved
A23.09.03 GM KRA KRA
B
C
D
(The original signatures are recorded in the company’s logistic database.)
Rev Comments
AOriginal issue.
B
C
D
To assist us in making improvements to the product and to this manual, we would welcome
comments and constructive criticism. Please send all such - in writing or by e-mail - to:
Simrad AS
Documentation Department
P.O.Box 111
N-3191 Horten
Norway
or e-mail:
[e-mail]

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1INTRODUCTION
Note This document is intended for software engeneers. It is to be used
for writing codes in order to communicate with the ITI system.
With the rapid development of marine electronic devices, it has
become necessary to develop a standardised interface protocol for
exchanging data between devices regardless of the device
manufacturer. The NMEA 0183 standard protocol for interfacing
electronic marine deviceshas been implemented in the ITIsystem.
The most common way of connecting electronic equipment is to
use serial lines.
A more powerful way of integrating, is the Ethernet standard with
higher signalling capacity. The software required to communicate
over the Ethernet is included in the ITI system, however a standard
ITI does not include the hardware required.
A dedicated interface/display board containing the Ethernet
hardware must be installed.
→Please refer to the Simrad ITI Installation Manual, Appendix 1
page 3 – 17 for more details.
The ITI system has four serial lines available for external
equipment connection.
→Please refer to page 6 for more details.

Simrad ITI
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2 ITI TRAWL SYSTEM, BASIC PRINCIPLE
The Simrad ITI wireless trawl positioning and monitoring system
is designedto improvecontrol andefficiency inpelagic andbottom
trawling. Small robust battery powered sensors mounted on the
trawl, transmit important information to the vessel on request.
•The ITI provides the skipper with exact position of the gear and
what is happening in and around the trawl. It also provides all
crucial information for an effective, profitable and responsible
fishing.
•The ITI is a modular system. From a basic unit of one sensor,
the ITI system can be extended to a complete and advanced
instrument package according to the customers requirements.
Distance and
Speed sensor
Trawl Eye
Depth and
Temperature Sensor
Catch Sensor
Simrad’sphilosophy isto reduce integration costsand increase the
benefit of our products to let data from the ITI be available for
integration with external equipment like chart plotters, winch
control systems etc.

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3 ITI GEOMETRY FOR TWIN RIG
Setting up a three wire Twin Rig system isa questionof findingthe
balance point between a number of forces. The adjustment of the
centre warp is very critical. This is one of the reason for the
positioning of the clump, and hence the balance of forces between
the doors and the warp and sweeps being so critical to get a square
tow.
•The ITI Geometry System provides the skipper with crucial
information to adjust the Twin Rig correctly andhenceoptimise
the efficiency of both trawls during the tow.
The ITI Geometry System is based on measurements of the
distance from the vessel to both trawl doors and to the clump. In
addition, the distances between each door and the clump are
measured based on transponders attached to the clump. Based on
these range measurements, the geometry of the Twin Rig is
calculated with high accuracy since all measurements are relative
to each other.
1.3
30
28
310 307 309
(C d6891)
The clump position relative to a straightline betweenthedoorswill
affect the geometry of the trawl. To get a square tow, the deviation
from the straight line position should be close to zero.
This is a focus point for the ITI Geometry System. In addition, the
angle between the true course over ground (VTG) and the straight
line between the doors are calculated and displayed.

Simrad ITI
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The figure above shows that the trawl is 3_off port side. The doors
and the clump are not lined up correctly with door/clump distances
of 28 and 30 meter. The distances to the trawl doors are 310 and
309 meter and distance to the clump is 307 meters. In order to
obtain maximum door spread and a square tow, the middle wire
should be paid out 1.3 meter.
Note The trawl geometry is compared to the course over ground showing
94
_ with 90 _ being optimum.
Both trawl heights are 3,2 meter and the Trawl Eye echogram
shows that the port trawl has good bottom contact but for the
moment, with a few fishes in the opening. One Catch Sensor is
mounted on the port cod end. The trawl is 6:20 min. behind the
vessel, the clump has a light bottom contact ascending 0,4 m/min.
Depth below the vessel is 120 meter and the temperature at the
trawl is 5,8_C. In addition, heading, speed and Lat./Long. are
displayed.
The ITI Geometry for Twin Rig will be implemented in the ITI
topside software, version 5.20 or above.
(Cd6 893 )
The picture shows a Twin Rig trawl with the Trawl Eye echogram
showing the trawl opening.

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4 RESPONSIBILITY
Simrad’s philosophy is to let data from our ITI Trawl System be
available for integration with external equipment like chart
plotters, winch control systems etc. We are convinced that this will
increase the benefit of the product and lead to reduced integration
costs.
The quality of the transmission data depends on:
•sea condition
•depth
•temperature layers
•multipath
•most important - the noise level from the propeller because you
are receiving the signals from astern.
Compared to serial line data communication channel, the
hydroacoustic transmission channel is far more unstable with data
errors and intermittent interruption of the data transmission as a
result.
The appropriate filteringand display algorithm used by Simrad for
displaying the data on a CRT, might not be the optimum for
applications, which are using the data as part of input parameters
for controlling or regulating winches etc.
Simrad will therefore emphasise, to any one who are using the ITI
data, to design an application specific filtering and adding
”artificial intelligence” to the use of- and interpreting the data
received.
We will not involve ourselves in applications using our data but
any user will have access to the data from the ITI as described in
this manual. If special agreements are made, Simradcan supplylog
files recorded during actual towings for test and simulation
purposes. Beyond that, Simrad have limited capacitytoassistusers
of the ITI data in their application.
The use of the ITI data is the users responsibility and Simrad
disclaim responsibility for any consequences of using data from
the ITI.

Simrad ITI
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5 SERIAL LINES
The ITI system has four (female) serial ports, A, B C and D. All
message transferred via these serial lines are based on the NMEA
0183 format protocol.
A
B
C
D
ETHERNET REMOTE CONTROL MONITOR
C ENT RO N IX
TD-L TD-R
230 V mains supply
Gyro-compass,
l og, etc.
(Cd4346)
Port A, C and D have the following dedicated functions:
•Port A for connection to an echo sounder
•Port C to a sonar
•Port D to a navigator.
Port B is dedicated for:
•Auxiliary equipment like Winch control system, Track plotter,
data logger etc.
If port C is not used by the sonar the port might be used for optional
output of the Trawl position (GLL) to an auxiliary plotter. Port A,
B and C have two-way communication while port Donly has input
data. All four serial lines can receive telegrams without being
activated from the menu.
Ports A, B and C must be activated from the menu before any
messages being transmitted.
Transmitted messages
A NMEA telegram will be transmitted when its data has been
updated. Each individual parameter available on the serial line B
(AUX) can be turned ON or OFF from the menu.
Individual parameters can not be set ON or OFF on serial lines A
and C. These two serial lines have been allocated for interfacing
to Echo sounder and Sonar respectively, and all parameters on any
of these two lines are either activated or not activated.
No parameters are transmitted out on serial port D.

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Serial line D
Navigator Serial line A Echosounder Serial line B Aux Serial line C Sonar Ethernet Aux
$IIDBS
@IIHFB
@IIHB2
$IIZDL
@IITDS
@IITS2
@IIHFB
$IIMTW
@IITFI
@IITPT
@IITPC
@IITTS
$IIGLL
$IIVTG
$SDDBS
$IIDBS
@IIHB2
@IIDAD
$PSIMT
$PSIMTH
$PSIMMW
$PSIMS1
$PSIMS2
$IIZDA
$PSIMH1
$PSIMH2
$PSIMG1
$PSIMG2
$PSIMCA
$PSIMDE
$PSIMTM
@IITDS
@IITS2
@IIHFB
$IIMTW
@IITFI
@IITPT
@IITPR
$IIDBS
@IIDAD
@IIHB2
@IITDS
@IITS2
@IIHFB
$IIMTW
@IITFI
@IITPT
$IIGLL
@IIDAD
@IIHB2
@IITPC
Table 1 Transmitted messages
Table 1 shows the different parameters that can be transmitted by
ITI when activated in the menu.In addition,all messagesreceived
on serial line B can be transferred out on Ethernet.
This transfer facility is activated from the command:
NMEA TRANSFER.
Optionally $IIGLL (trawl position) is available on Port C. This
require the parameter TEST2 to be set to 8 (Menu /
SYSTEMSETUP / TRAWL EYE), and is then independent on
whether SONAR OUTPUT has been activated.

Simrad ITI
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Received message
All messages listed in table 2 can be received at any time without
activating them from the menu. As described above, by settingthe
NMEA TRANSFER command to ON, all messages received on
Ethernet will be transmitted out on serial port B, and vice versa. “-
-” means any character will be accepted.
Serial line D
Navigator Serial line A Echosounder Serial line B Aux Serial line C Sonar Ethernet Aux
$----GLL
$----VTG
$----ZDA $SDDBS
$----DBT
$----GLL
$----VTG
$SDDBS
$----DBT
$----HDT
$----HDM
$----HDG
$----ZDA
@SSTPP
@TAWWL
@TAWWT
$WMSYN
$----HDT
$----HDM
$----HDG
@SSTPP
$----GLL
$----VTG
$SDDBS
$----DBT
$----HDT
$----HDM
$----HDG
$----ZDA
@SSTPP
@TAWWL
@TAWWT
$WMSYN
Table 2 Received messages

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Serial line configuration and pin allocations
→Refer to drawing no. 824-108590, ITI Installation manual.
The four serial port (female) connectors are found on the
transceiver unit plug panel, located in the bottom of the cabinet.
The serial lines can be configured electrically as follows:
•Port A can be configured as RS-232 or RS-422.
•Ports B and C are standard RS-232 serial lines only.
•Port D can be configured as RS-232, RS-422 or current loop.
Table 3 gives an overview of the different ways of configuring the
serial lines electrically, and the dedicated use of each line.
Port Possible
configurations
ITI port allocation Format
ARS-232 Echo sounder NMEA 0183
BRS-422 - Winch control
- Track plotter
- Data logger
NMEA 0183
CRS-232 Sonar NMEA 0183
D - RS-232
-- RS-422
-- 20 mA Current loop
Navigator NMEA 0183
Table 3 Possible serial port configurations and allocations
→Refer to the ITI installation manual for further information
regarding configuration port A and D.

Simrad ITI
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Serial port pin assignments
The ITI system is designed to communicate over serial interfaces
where control signals are not required. The connectors in the
cabinetare femaleandrequirea male connector forthe serialcable.
Table 4 shows the pin assignments for port B (and C) available on
the ITI transceiver cabinet.
Pin Name Description
1
2
3
4
5
6
7
8
9
RX DA2
TX DA2
GND
RT SA2
CT SA2
Receive data RS-232 NMEA RX A
Transmit data RS-232 NMEA TX A
Signal ground RS-232 NMEA RX/TX B
Request to send RS-232
Clear to send RS-232
Table 4 Pin assignments - ports B and C
Note The RS-232 inputs of port A-D do not meet the optoisolation
requirements of the NMEA standard and precautions should be
taken thereafter.
→Refer to the ITI Installation manual for pin assignments of port A
and D.

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6 NMEA 0183 MESSAGES, DEFINITIONS
Messages transmitted and received on serial lines or Ethernet are
all based on the NMEA 0183 data format protocol.
The main characteristics are as follows:
•RS-422A asynchronous serial line
•4800 baud
•8 data bits
•No parity
•One or more stop bits
•All data coded in ASCII code
•Optional ”X-OR” checksum
All messages start with either; “$” or “@”.
Telegrams starting with “$” do fully comply with the NMEA0183
data format protocol.
•All other telegrams are in accordance with an old proprietary
“Simrad standard.” They start with @, but otherwise they
follow the main characteristics listed below.
•The next two letters (Talker identifier) indicate which system
is transmitting the messages. Simrad ITI System uses II as a
talker identifier.
•Thenextthree lettersindicate thetype ofmessage. Thetelegram
may consist of many data fields separated by commas. A field
may be empty, and then only the separating commas are
transmitted, also called nullfields.
•Each message ends with <cr> (Carriage Return)and <lf> (Line
Feed). For all message starting with ”$” the checksum *hh is
included in compliance with version 2.20 of the NMEA 0183
standard, - no checksum on ”@” sentences.
Throughout this document, all telegrams with II as the Talker
identifier, and telegrams with the proprietary code PSIM,are
originated by ITI and transmitted to other equipment. All
telegrams with other Talker identifiers are received by ITI from
external equipment.
Message description
Below you will find the message description for ITI topside
software version 5.30 or above. The different types of telegrams
are not listed in consecutive order.
Note The *hh check sum, <cr> carriage return and <lf> line feed are
not described for each sentence.

Simrad ITI
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NMEA output from ITI
$IIVTG,,,xxx,M,yy.y,N,,*hh<cr><lf>Vessel course and speed
→requires input from a nav. Receiver.
VTG represents the Vessel Track over the Ground.
xxx,M is the track bearing, in degrees magnetic.
yy.y,N is the speed in knots relative to ground.
$IIZDA,hhmmss.ss,dd,MM,yyyy,xx,xx*hh<cr><lf> Time & Date of ITI
→equals UTC ± 5 seconds if GPS connected.
hh is the hours
mm is the minutes
ss.ss is the seconds and parts of seconds
dd is the day’s date
MM is the month
yyyy is the year
xx,xx is the local time zone (hh,mm) positive offset east ofGreenwich.
@IITPT,xxxx,M,y,P,zzzz.z,M<cr><lf> Trawl Position True vessel
TPT represents the True Trawl Position relative to the vessel.
xxxx,M is the horizontal range in metres to the target (0 - 4000 m).
- requires an active depth sensor on the trawl or manual set
depth, if not the slant range will be presented.
yyy,P Is the true bearing to the target (i.e. relative to north).
(Resolution 1°.)
- requires gyro input for reliable data.
zzzz.z,M is the depth in metres of trawl below the surface (0 - 2000 m).
- requires an active depth sensor on the trawl or manual set
depth, if not the depth field will be empty.