Simrad ITI TRAWL SYSTEM - SERIAL DATA COMMUNICATION REV A, ITI TRAWL SYSTEM Instruction Manual

Simrad ITI Trawl System

Serial data communication and
NMEA 0183 message description

111110 10 00101 0101 010
010101001 00010100011
010101010 00101010100

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

E 2003 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 [e-mail].

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

2

ITI TRAWL SYSTEM, BASIC PRINCIPLE

3

ITI 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 befound 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

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Document logistics

Rev Date Written Checked Approved

A 23.09.03 GM KRA KRA
B
C
D

(The original signatures are recorded in the company’s logistic database.)

Rev Comments

A Original issue.
B
C
D

To assist us in making improvem ents to the product and tothis 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 inte nded 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
electronicmarinedeviceshas been implemented inthe ITI system.

The most common way of connecting electronic equipment is to
use serial lines.

A more powerful way of integrating, is the Ethernet standard with
highersignalling capacity.The softwarerequiredto communicate
over the Ethernet is included in theITI system, however astandard
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.

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2 ITI TRAWL SYSTEM, BASIC PRINCIPLE

The Simrad ITI wireless trawl positioning and monitoring system
is designedto improvecontrol andefficienc y inpelagic andbottom
trawling. Small robust battery powered sensors mounted on the
trawl, transmit important information to the vessel on request.

• The ITI providesthe skipper with exact position ofthe 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’s philosophyis to 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

Settingup a three wire TwinRig system isa question of findingthe
balance point between a number of f orces. 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 toadjustthe Twin Rig correctlyand henceoptimise
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

(Cd6891)

Theclump positionrelative toa straightline betweenthe doorswill
affect the geometryof 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 a ddition, the
angle between the true course over ground (VTG) and the straight
line between the doors are calculated and displayed.

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The figure above shows that the trawl is 3_ off port side. The doors
and theclump arenot 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 maxi mum door spread and a square tow, the middle wire
should be paid out 1.3 meter.

Note The trawl geometry iscomparedto the course over groundshowing

94

_

with 90_being optimum.

Both tra wl 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 i s 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 reduce d integration
costs.

The quality of the transmission data depends on:

• sea condition

• depth

• temperature layers

• multipath

• most important -the noiselevel 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.

Theappropriatefilteringanddisplayalgorithm usedby Simradfor
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 there fore emphasise, to any one who a re using the ITI
data, to design an application specific filtering and adding
”artificial intelligence” to the use of- and interpreting the data
received.

We wil l 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. Ifspecial agreements aremade, Simradcan supplylog
files recorded during actual towings for test and simulation
purposes.Beyond that, Simrad havelimited capacityto assistusers
of the ITI data in their application.

The use of the ITI data is the users responsibility and Simrad
disclaim re sponsibility for any consequences of using data from
the 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

ETHERNE T REMOTE CONTROL MONITO R

CE NTRO NIX

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:

• Auxiliaryequipment like Winch control system, Track plotter,
data logger etc.

If port C is not used bythe sonar the port might be used for optional
output of the Trawl position (GLL) to an auxiliary plotter. Port A,
B and Chave 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 avail able 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 li ne D

Navigator

Serial li ne A

Echosounder

Serial li ne B

Aux

Serial li ne 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 inthe 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 independe nt on
whether SONAR OUTPUT has been activated.

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Received message

All messages listed in table 2 can be received at any time without
activating them from the menu. Asde scribed above, by settingthe
NMEA TRANSFER command to ON, all messages received on
Ethernet will be transmitted out onserial port B, and vice versa. “-

-” means any character will be accepted.

Serial li ne D

Navigator

Serial li ne A

Echosounder

Serial line B

Aux

Serial li ne 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

A RS-232 Echo sounder NMEA 0183

B RS-422 - Winch control

- Track plotter

- Data logger

NMEA 0183

C RS-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.

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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 femaleand requirea male connectorfortheserialcable.

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.

• The nextthree letters indicate 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> (CarriageReturn)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.

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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 offseteast of Greenwich.

@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 m etres 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 t rue bearing to the target (i.e. relative t o 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.

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@IITPC,x,M,y,M,z,M<cr><lf>Trawl Position in Cartesian c o-ordinates

TPC represents the Trawl Position in Cartesian co-ordinates.

x,M isthe horizontaldistancein metresfrom vessel centre line. Value

is positive if trawl is on starboard side, negative if on port side.

- requires an active depth sensor on the trawl or manual set
depth, if not the slant range will be presented.

y,M is the horizontal distance in metres from the transducer to the

trawl along the vessel’s centre line. The value will normally be
positive as the trawl is usually behind the vessel.

- requires an active depth sensor on the trawl or manual set
depth, if not the slant range will be presented.

z,M is the depth of the trawl in metres belowthe surface.the value is

normally positive.

- requires an active depth sensor on the trawl or manual set
depth, if not the depth field will be empty.

$IIGLL,ddmm.hhh,N,dddmm.hhh,W ,hhmmss.ss,A*hh<cr><lf>
Trawl Position in Latitude and Longitude

GLL represents the trawls Geographical Latitude and Longitude.

- requires GLL input from a nav. Receiver.

ddmm.hhh,N is the Latitude, Deg.Min.Hundredths, N=North, S=South.

dddmm.hhh,W is the longitude, Deg.Min.Hundredths, W=West, E=East.

hhmmss.ss UTC of position (time stamp, fraction of seconds void).

- requires ZDA input from GPS for accurate timestamp.

A valid

- never invalid, terminates output after one minute without
GLL input from a nav. Receiver.

$IIDBS,,,xxxx.x,M,,*hh<cr><lf>Depth of trawl Below Surface

DBS represents Depth of the trawl Below the Surface.

xxxx.x,M is the depth in metre s (0 - 2000). The fields for depth in feet and

fathoms are empty.

- requires an active depth sensor on the trawl.

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$IIMTW,-xx.x,C*hh<cr><lf> Water temperature at the trawl

MTW represents the Meteorological Temperature in the Water.

xx.x is the water temperature (° C) measured at the trawl.

(Sign prefix only if minus.) Range from -5° Cto+30° C.

C means the value is in ° Celsius.

- requires an active temperature sensor on the trawl.

@IIHFB,x.x,M,y.y,M<cr><lf>
Trawl Headrope to Footrope and Bottom (Trawl Eye/Height sensor 1)

HFB represents the distances from the Headrope to the Footrope and

Bottom.

x.x,M is the distance in me tres from headrope to footrope (0 - 100 m).

y.y,M is the distance in metres from headrope to bottom (0 - 100 m).

@IIHB2,x.x,M,y.y,M<cr><lf>
Trawl Headrope to Footrope and Bottom (Height sensor 2)

HB2 represents the distances from the Headrope to the Footrope and

Bottom.

x.x,M is the distance in metres from headrope to footrope (0 -- 100 m).

y.y,M is the distance in metres from headrope to bottom (0 -- 100 m).

@IITDS,x.x,M<cr><lf> Trawl Door Spread 1

TDS represents the Trawl Door Spread 1 distance.

x.x,M is the spread distanc e in metres (0 - 300 m)

- if invalid, nullfields will be transmitted

- filtered values if sensorfilter is on.

@IITS2,x.x,M<cr><lf> Trawl Door Spread 2

TS2 represents the Trawl Door Spread 2 distance.

x.x,M is the spread distanc e in metres (0 -300 m)

- if invalid, nullfields will be transmitted

- filtered values if sensorfilter is on.

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$PSIMTH,x.x,M,y.y,M*hh<cr><lf>
Trawl Headrope to Footrope and Bottom (Trawl Eye/Height sensor 1)

TH represents the distances from the Headrope to the Footrope and

Bottom.

x.x,M is the distance in me tres from headrope to footrope (0 - 100 m).

y.y,M is the distance in metres from headrope to bottom (0 - 100 m).

$PSIMTE,xx%y,xx%y,xx%y,xx%y,xx%y,xx%y,xx%y,xx%y,xx%y,xx%y,a,x.x,M,
Gx,gx,Vx.x *hh<cr><lf> Trawl Eye, Echo telegram, fish detection

TE carries the echo readings from fish detection and the sensor set

up parameters (type of trawl, range gain etc).

x.x% per cent of samples above threshold for the 10 echo cells.

y average level (1-7) of the xx %. Data skipped if cell is empty or

not available.

a B/P Bottom/Pelagic 10 cells. b/p: bottom/pelagic 5 cells.

x.x,M total range, 2,5 – 50 m of fish detec tion range.

Gx Gain setting, coarse.

gx g1 – g7 gain setting fine.

Vx.x Version of Trawl Eye Sensor software.

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$PSIMSn,xxxx,M,xxxx,M,yyy.y,T,xxx.x,M,hhmmss*hh<cr><lf>

nn=1Spread1 (port trawl door when Twin Rig)

n=2 Spread2 (starboard trawl door when Twin Rig)

xxx,M slant range in metres to sensor

- filtered values

- decimals not used.

xxx,M horizontal range in metres to sensor

- unfiltered values

- nullfields if depth-sensor not activated (will calculate
horizontal range with m anual set de pth)

- decimals not used.

yyy.y,T true bearing (deg.re l.north) to sensor

- requires gyro input for reliable data.

xxx.x,M spread measurement in metres (door to door or door to middle

weight)

- if invalid values nullfields will be transmitted

- filtered values if sensorfilter is on.

hhmmss time of transmission (time of Spread interrogation)

- requires ZDA input from GPS for accurate timestam.

$PSIMHn,xxxx,M,xxxx,M,yyy.y,T,z z.z,M,zz.z,M,hhmmss*hh<CR> <LF>

n -n=1height 1 sensor or trawl eye

-n=2height 2 sensor

xxxx,M Slant range in meters to sensor

- filtered values

- decimals not used.

xxxx,M horizontal range in metres to sensor

- unfiltered values

- nullfields if depth-sensor not activated (will calculate
horizontal range with manual set depth

- decimals not used.

yyy.y,T true bearing (deg.rel.north) to sensor

- requires gyro input for reliable data.

zz.z,M height in metres from headrope to footrope, 0 - 50 m.

zz.z,M height in metres from headrope to bottom, 0 - 100 m

- if invalid values nullfields will be transmitted.

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$PSIMGn,xxxx,M,xxxx,M,yyy.y,T,yz .z,D,hhmmss*hh<CR><LF>

n n=1 grid 1 sensor

n=2 grid 2 sensor

xxxx,M slant range in metres to sensor

- filtered values

- decimals not used.

xxxx,M horizontal range in metres to sensor

- unfiltered values

- nullfields if depth-sensor not activated (will calculate
horizontal range with manual set depth

- decimals not used.

yyy.y,T true bearing (deg.rel.north) to sensor

- requires gyro input for reliable data.

zz.z,D angle of grid, 0-90 degrees

- if invalid values nullfields will be transmitted.

$PSIMCA,xxxx,M,xxxx,M,yyy.y,T,x,y,z,hhmmss*hh<CR><LF>

CA catch sensor (bearing and range only to activated sensor with

lowest number).

xxxx,M slant range in metres to sensor

- filtered values

- decimals not used.

xxxx,M horizontal range in metres to sensor

- unfiltered values

- nullfields if depth-sensor not activated (will calculate
horizontal range with manual set depth

- decimals not used.

yyy.y,T true bearing (deg.re l.north) to sensor

- requires gyro input for reliable data.

x catch1 sensor: 0=off, 1=on, 2=not activated/no answer.

y catch2 sensor: 0=off, 1=on, 2=not activated/no answer.

z catch3 sensor: 0=off, 1=on, 2=not activated/no answer.

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$PSIMDE,xxxx,M,xxxx,M,yyy.y,T,zzzz.z,M,a,hhmmss*hh<CR> <LF>

DE depth sensor

x.x,M slant range in metres to sensor

- filtered values

- decimals not used.

x.x,M horizontal range in metres to sensor

- unfiltered values

- nullfields if depth-sensor not activated (will calculate
horizontal range with manual set depth

- decimals not used.

y.y,T true bearing (deg.rel.north) to sensor

- requires gyro input for reliable data.

zzzz.z,M water depth in metres, 0-2000 metres

- if invalid values nullfields will be transmitted.

a Indicate the menu selected position of the sensor

a=p port , a=c centre, a=s starboard.

$PSIMTM,xxxx,M,xxxx,M,yyy.y,T,zz.z,C,a,hhmmss*hh<CR><LF>

TM temperature sensor

xxxx,M slant range in metres to sensor

- filtered values

- decimals not used.

xxxx,M horizontal range in metres to sensor

- unfiltered values

- nullfields if depthsensor not activated(will calculate
horizontal range with manual set depth

- decimals not used.

yyy.y,T true bearing (deg.re l.north) to sensor

- requires gyro input for reliable data.

zz.z,C water temperature in -5 to 30 degrees Celsius

- if invalid values nullfields will be transmitted.

a Indicate the menu selected position of the sensor

a=p port, a=c centre, a=s starboard.

Acombi sensor (depth/temperature) will generate both the DEand
TM sentences. The temperature, depth or combi sensor must be
used to showt he range to the remote spread sensor if the geometry
of the trawl system shall be calculated.

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$PSIMMW,xxxx.x,M,xxxx.x,M,yyy.y,T,z.z,M,y.y,D,c,hhmmss*hh<cr><lf>

xxxx.x,M slant range in metres to mi ddle weight (clump)

- filtered values.

xxxx.x,M horizontal range in metres to middle weight

- unfiltered values

- nullfields if depth-sensor not activated (will calculate
horizontal range with manual set depth).

yyy.y,T true bearing (deg.re l.north) to middle weight

- requires gyro input for reliable data.

z.z,M signed deviation in metres (if deviation positive, then middle

weight further out than door-door line)

- an offsetto the deviation may be set inthe trawl setup inorder
toget thedeviationnearzero when the trawlgeometryisideal.
A positive offset will shorten the mid weight wire

- a mid weight filter, filtering the signed deviation, is found in
the trawl setup.

About the mid weight filter:

- the mw filter calculates from unfiltered horizontal ranges for
mw filter setting of 1 to 5 and if active depth sensor on trawl

- the mw filter calculates from filtered horizontal ranges for
mw filter setting of 6 to 10 and active depth sensor on trawl

- the mwfilter calculatesfrom filtered slant ranges if noactive
depth sensor on trawl.

y.y,D “starboard angle” bet ween true GPS course (or heading if no

GPS) and the “Door-Door Line” of the trawl (0° < y.y < 180°).

c status of data, primarily middle weight deviation status

A: OK

B: OK but ambiguous

(± on deviation, presented range complies with positive
deviation, i.e. the larger range possibility)

C: Uncertain (angle based calculations)

D: Uncertain and ambiguous

E: Invalid data, required sensors not active

V: Invalid data, throw away

W: Invalid and ambiguous.

hhmmss time of transmission

(time of Middle weight deviation calculations)

- requires ZDA input from GPS for accurate timestamP.

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Note $PSIMMW will be sent whenclump position undated, only. Update

of the new angle parameter due only to change of course, is not
supported!

@IITFI,x,y,z<cr><lf> Trawl Filling

TFI represents Trawl Filling.

x,y,z are the catch 1, 2 and 3 messages

(off = 0, on = 1, no answer = 2).

@IITTS,x,M,y,P,z,M<cr><lf> Trawl To Shoal distance

TTS represents the Trawl To Shoal distance.

x,M is the horizontal distance in metres from the trawl to the shoal in

a direction normal to the vessel’s centre line. The value will be
positive if the shoal is on the starboard side of the trawl,
otherwise negative.

y,M is the horizontal distance in metres from the trawl to the shoal is

thedirectionof the vessel’s centre line. The valuewillbepositive
if the shoal is ahead of the trawl, negative if the shoal is behind
the trawl.

z,M is the vertical distance in metres from the trawl to the shoal. The

value will be positive if the trawl is above the shoal, negative i f
the trawl is below the shoal. The sign will be shown only i f the
value is negative.

Note This sent ence requires the @SSTPP sentence from a scanning

sonar, an active depth sensor on the trawl and gyro input on both
sonar and ITI.

$SDDBS,x.x,f,y.y,M,z.z,F*hh<cr><lf> Sounder Depth Below Surface

SD represents Sounder Depth.

DBS represents Depth of water Below Surface.

x.x,f is the depth in feet.

y.y,M is the depth in metres.

z.z,F is the depth in fathoms

- only depth in meters will be transmitted

- this is a filtered copy of external echosounders depth.

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@IIDAD,x.x,M,x.x,M<cr><lf> Depth of trawl Ascend/Descend

DAD represents Depth Ascend Descend.

x.x,M represents Depth of trawl in metres.

x.x,M represents change of depth in metres per minute, negative

number if ascending.

Note This sentence requires an active depth sensor on the trawl.

$IIZDL,hhmmss.ss,x.x,a*hh<cr><lf> Time and Distance to Variable Point

→ The point is here the position sensor on the trawl which normally

is the mid weight sensor on double trawl.

hhmmss.ss Time to point, 00 to 99 hours minutes and seconds.

x.x distance to point in nautical miles.

a type of point.

C: Collision

T: Turning point

R: Reference/general -usedbyITI

W: Wheelover

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An example of NMEA output from port B:

@IITPT,3089,M,175,P,0375.5,M

@IITPC,00162,M,3085,M,0375,M

@IIHFB,007.6,M,012.0,M

$PSIMTH,007.6,M,012.0,M*19

$IIGLL,5924.462,N,01030.048,E,062216,A*38

@IITTS,-0154,M,03256,M,-0121,M

$IIVTG,,,358,M,03.7,N,,*62

$IIZDA,062216.00,02,01,1999,01,00*7B

@IIHB2,008.7,M,008.8,M

@IITDS,105.5,M

$PSIMS1,3021,M,2998,M,177.0,T,105.5,M,062217*5A

@IITS2,118.9,M

$PSIMS2,3021,M,2998,M,172.6,T,118.9,M,062218*55

@IITFI,1,1,0

@IIDAD,0375.6,M,-001.9,M

$IIMTW,03.5,C*15

$PSIMMW,3018.3,M,2996.3,M,174.9,T,0000.8,M,A,062220*7C

$SDDBS,,,0187.5,M,,*1A

$IIDBS,,,0375.6,M,,*01

$PSIMTE,,29%4,60%3,98%7,97%7,,97%6,97%4,97%2,46%1,B,8.0,M,G1,g7,V3.08*52

$PSIMH1,1557,M,1512,M,189.9,T,008.1,M,015.0,M,143842*25

$PSIMH2,1557,M,1512,M,189.9,T,007.0,M,015.0,M,143843*29

$PSIMS1,1556,M,1511,M,193.1,T,090.2,M,143844*5C

$PSIMDE,1557,M,1512,M,189.9,T,0372.0,M,c,143847*4F

$PSIMTM,1558,M,1513,M,189.9,T,03.9,C,s,143849*45

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NMEA Input to ITI

$SDDBS,x.x,f,y.y,M,z.z,F*hh<cr><lf> Sounder Depth Below Surface

SD represents Sounder Depth.

DBS represents Depth of water Below Surface.

x.x,f is the depth in feet.

y.y,M is the depth in metres.

z.z,F is the depth in fathoms.

Note Only one of the depth values is required.

$--DBT,,,y.y,M,,*hh<cr><lf> Sounder Depth Below Transducer

-- Means: accept any combination.

DBT represents the Depth of water Below the Transducer.

x.x,M is the depth in metres.

@SSTPP,x,M,y,P,z,M,nn*hh<cr><lf> Position of target or marker

SS represents Receive from Scanning Sonar.

TPP represents Target Position in Polar co-ordinates.

x,M is the horizontal range in metres to the target.

y,P is the bearing to the target relative to the vessel’s heading

- requires gyro input on both Sonar and ITI for reliable data.

z,M is the target’s depth in metres below the surface.

nn is the target identification code: 0 means echo target tracked, 10

means position tracked.

$--GLL,ddmm.hh,N,dddmm.hh,W*hh<cr><lf> Geographical position

-- is the code for the type of system used. -- will be OM if Omega,
LC if Loran-C, GP if GPS, DE if decca etc.

GLL represents Geographical Latitude, Longitude.ddmm.hh,N is the

latitude position in Deg.Min.Hundredths, N=North, S=South.

dddmm.hh,W is the longitude position, Deg.Min.Hundredths, W= West,

E=East.

Note The ITI system wi ll only use the ZDA sentence for time input.

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$--VTG,,,x.x,M,y.y,N,,*hh<cr><lf> Vessel course and speed

-- is the code for the type of system used. -- will be OM if Omega,
LC if Loran-C etc.

VTG is the abbreviation for Vessel Track Ground.

x.x,M is the track bearing, in degrees magnetic.

y.y,N is the speed, with resolution 0.1 knots.

@TAWWL,x,M,y,M<cr><lf> Winch Wire Length

TA is the identification code.

WWL represents Winch Wire Length.

x,M is the wire length to starboard trawl door, resolution 1 m.

y,M is the wire length to the port trawl door, resolution 1 m.

@TAWWT,x.x,T,y.y,T<cr><lf> Winch Wire Tension

TA is the identification code.

WWT represents Winch Wire Tension.

x.x,T is the starboard wire tension, resolution 0.1 ton.

y.y,T is the port wire tension, resolution 0.1 ton.

$--ZDA,hhmmss.ss,dd,MM,yyyy,xx,xx*hh<cr><lf>Time & Date

hh is the hours.

mm is the minutes.

ss is the seconds and parts of seconds.

dd is the day’s date.

MM is the month.

yyyy is the year.

xx is the local time zone etc. (not used by ITI).

Note The ITI system will not use othersentences thanthe ZDA sentence

for time input.

$--HDM,x.x,M*hh<cr><lf> Heading, Magnetic

x.x,M is the heading in degrees magnetic.

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$--HDT,x.x,T*hh<cr><lf> Heading, True

x.x,T is the heading in degrees relative to true north.

$--HDG,x.x,,,,*hh<cr><lf> Heading, Deviation & Variation

x.x this is the magnetic sensor heading, in degrees.

Telegram from Winch Syncro 2020

This telegram carries the length of trawl wires as measured at the
winches.

Though the sentence is not an approved NMEA 0183 sentence, its
format complies with most of the “NMEA rules”.

$WMSYN,xxx.x,c,xxx.x,c,xxx.x,c,xx.x,T,xx.x,T,xx.x,T*hh<cr><lf>

Sentence identifier

Starboard Wire Length

Mid Wire Length

Port Wire Length

m - meter, F - Fathom, f - feet

Starboard Wire Tension
[tons]

Mid Wire Tension [tons]

Port Wire Tension [tons]

(Cd6887 )

Note The ITI will not present the mid wire tension and mid wire length

References:

National Marine Electronic Association NMEA0183.

Standard for interfacing marine electronic devices.

Ve rsion 2.20, January 1, 1997.

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7 NMEA – ABBREVIATIONS, ITI AUX MENU

SELECTIONS

In the AUX menu selections only the NMEA start code are
indicated.

The different codes with comments are as follows:

IIZDA

Time & date of ITI system

IIGLL Geographical position of trawl
IITPT Trawl position true vessel
IIMTV Water temperature at the trawl
IIHFB Distance trawl headrope to footrope and bottom,

Height Sensor 2

PSIMTH Distance trawl headrope to footrope and bottom, Trawl Eye,

Height Sensor 1

IIHB2 Height 2
IITDS +IITS2 Trawl door spread Sensor1 and Sensor2
PSIMS1 +

PSIMS2

Range, bearing and distance Spread 1 and Spread 2

IITFI Trawl filling
IITPC Trawl position in Cartesian coordinates
IITTS Trawl to shoal distance
IIVTG Vessel course over ground and speed
IIDBS Depth of trawl below surface
IIDAD Depth Ascend / Descend
SDDBS Sounder depth below surface
PSIMTE Trawl Eye, echo readings and sensor setup
PSIMMV Range, bearing, signed deviation and status Middle weight

E 2003 Simrad AS

ISBN 82-8066-013-5

Simrad AS
Strandpromenaden 50
Box 111
N-3191 Horten

Telephone: [phone]
Facsimile: [phone]

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