MagLog User`s Manual

MagLog User`s Manual
Data Acquisition Software
25479-01 Rev.N
User’s Guide
2190 Fortune Drive, San Jose, Ca 95131 USA
Phone: (408) 954-0522
Fax: (408) 954-0902
Software Installation and Registration Procedure
This program is the newest version of our standard MagLog or MagLogLite™
logging package. It now includes a Configuration Wizard that will step the user
through set up of the G-877, G-881 and G-880 Marine Magnetometer and G-823A
or G-823B airborne/basestation systems. This software is in continual
development, so make sure you check our website regularly for the latest version.
For instance, a features such as Survey Playback and Print on Anomaly enable
high-speed anomaly detection and location.
Important! A software key (Dongle) or serial number copy protects these
versions of MagLog and MagLogLite. You must follow the procedure
below in order to enable the version that you purchased, either MagLog or
1. Install MagLog or MagLogLite by inserting disk 1 in the A:\ drive and
running SETUP. Insert the other disks as required.
2. After installation, connect the software key (dongle) to any PC parallel port.
Start the MagLog program (via desktop shortcut or via menu). The program
will ask you to enter your company name and user name. You must answer
these questions in order to register your software. After you answer these
questions, the program will exit.
3. To use MagLog or MagLogLite, you must always have the software key
(dongle) connected to a parallel port of the PC on which the software is
installed (or you must have a digital key code from Geometrics, see below).
Start the program again and you will be operating as either MagLog or
MagLogLite, depending on which program you purchased.
4. You may install MagLog on as many computers as you wish, but only the
computer with the software key connected will be able to acquire data. If you
have installed with a software key, you may ignore steps 5, 6 and 7.
5. If you do not have a software key or have lost it, when you start MagLog it will
be running as a demo version of MagLog. This means that you cannot read
data from the serial ports, only playback surveys from files. To enable the
software for logging use, you must contact Geometrics, Inc. to obtain a
THIS PROCEDURE: First, click on Help/About and write down your User
Code. Then, contact Geometrics, Inc. via either e-mail, telephone or fax and
inform us of your User Code. In response, Geometrics will provide to you
your Registration Number. Write this number on the blank Registration
Disk. To learn more about software registration, see “Software registration.”.
Geometrics, Inc.
Tel: 408-954-0522
Fax: 408-954-0902
E-mail: [email protected]
6. With your Registration Number at hand, start MagLog again and go to
Help/Register . . . Insert the blank Registration Disk into drive A: and then
enter your Registration Number. Press Ok to create your Registration Disk.
After the message Operation completed is observed, you have registered
MagLog or MagLogLite.
7. Geometrics licenses this software for installation on one PC only. You will
have to repeat these steps every time that you install MagLog on a new PC.
The registration number is unique for each installation, even if you reinstall on
the same PC. However, if you created the Registration Disk you may use it
to re-install on the same PC without contacting Geometrics. To do so, press
Have Registration Floppy instead entering the company name and user
Completion of the above procedure enables full operation of the version of
software you purchased, either MagLog or MagLogLite.
Quick Start Survey Configuration
Connect the GPS and Magnetometer or Gradiometer (2 concatenated
magnetometers) to the communication port on the computer. Start MagLog. To
begin configuration, click on File in the menu bar and then on Survey Wizard. The
program will ask some basic questions about the marine system you are using
(type of magnetometer), GPS antenna to tow point offsets, tow cable lengths and
give an explanation of the setup procedure. When you have completed the
wizard, the software will begin displaying the data in analog chart format on the
computer screen. Begin logging by clicking on File and then Start Logging.
This manual is for both MagLog™ and MagLogLite. MagLog™ and
MagLogLite™ are essentially the same program except that the full featured
MagLog™ is used primarily in multi-sensor array, multi-instrument geophysical
survey applications (airborne, land or marine). The MagLog™ program supports
various external third party instruments. MagLogLite™ is designed primarily for
the small marine magnetometer/gradiometer data logging market and can be
used for land/ marine dual sensor arrays in archeological or UXO type surveys.
Almost all sections pertain to MagLogLite except those that refer to logging such
devices as Gamma Ray Spectrometer, Gyro, ORE Trackpoint II, cable payout
indicators, etc. However, MagLogLite does include the ability to log other
devices using the generic serial device logging option under Configure and Input
Recorded data may be processed using MagMap-2000. Check Geometrics
website ( for the latest version of MagMap2000.
Data Logger User's Guide
INTRODUCTION ....................................................................................................... 1
FIRST TIME START-UP OF MAGLOG................................................................. 2
SOFTWARE REGISTRATION ....................................................................................... 5
GETTING STARTED................................................................................................. 6
STARTING A NEW SURVEY ........................................................................................ 7
CONTINUING AN EXISTING SURVEY ......................................................................... 9
WIZARD ........................................................................................................................... 10
STARTING MAGLOG WIZARD ................................................................................ 10
CONFIGURING GPS AND ITS DISPLAY..................................................................... 12
CONFIGURING MAGNETOMETER OR EM (PULSE 12) HARDWARE............................ 15
MAGNETOMETER CALIBRATION ............................................................................. 18
REAL TIME LAY BACK CALCULATIONS. .................................................................. 19
DATA DISPLAY CONFIGURATION ............................................................................ 22
SEE NEXT SECTION). ......................................................................................................... 24
4.8 CONFIGURING SYSTEM-WIDE WINDOWS™ PRINTER. ............................................. 25
4.9 FINISHING SETUP .................................................................................................... 26
MANUAL CONFIGURATION OF INPUT DEVICES......................................... 27
5.3 CONFIGURING THE G-880 MAGNETOMETER ........................................................... 34
5.3.1 Configuring the magnetometer....................................................................... 34
5.3.2 Configuring MagLog or MagLogLite to recognize incoming data................ 38
5.4 CONFIGURING THE GPS ......................................................................................... 41
5.5 CONFIGURING SERIAL EVENT DEVICE .................................................................... 42
5.8 CONFIGURING A GENERIC SERIAL DEVICE .............................................................. 45
5.9 CONFIGURING THE RMS AADC AIRCRAFT COMPENSATOR.................................. 47
CONFIGURING G-886 / G-877 PROTON MAGNETOMETERS .................................. 48
G-877 depth calibration.............................................................................. 53
G-877 Terminal Calibration Log................................................................ 58
CONFIGURING G-822A SUPER COUNTER DEVICE ............................................... 61
CONFIGURING EM61 DEVICE.............................................................................. 61
CONFIGURING EM61 MARK II DEVICE ............................................................... 62
CONFIGURING GYRO COMPASS DEVICE .............................................................. 63
CONFIGURE CABLE PAYOUT INDICATOR ............................................................. 64
CONFIGURING THE G-858 MAGNETOMETER ....................................................... 64
CONFIGURING PULSE 12 EM DEVICE ............................................................... 65
CONFIGURE ECHO SOUNDER DEVICE. ................................................................. 66
TTL PULSE DEVICES IN MAGLOG ....................................................................... 67
Configuring TTL event Mark device.......................................................... 68
Configuring PPS GPS device...................................................................... 70
Configuring a Trigger device...................................................................... 71
Configuring Speedometer device (wheel tick) ............................................ 72
GENERIC SERIAL TRIGGERED DEVICES................................................................ 73
ASCII trigger, ASCII output. (DGH1141) .................................................. 73
Binary (hexadecimal) trigger string, binary fixed length data (3DM-GX1).
Honeywell PPT (Precision Pressure Transducer) device........................... 80
CONFIGURING INPUT DEVICES FOR DISPLAY............................................ 81
6.1 THE DISPLAY ......................................................................................................... 82
6.1.1 Configuring a Slot .......................................................................................... 84
6.1.2 Configuring a Trace ....................................................................................... 87
6.1.3 Editing the Display......................................................................................... 91
6.1.4 Horizontal Slots and Slot Legend................................................................... 95
6.1.5 Slot context menu............................................................................................ 95
6.1.6 Slot size adjustment ........................................................................................ 96
6.2 CONFIGURING THE GPS DISPLAY .......................................................................... 96
6.2.1 GPS display context menu and mouse functions .......................................... 101
6.3 PREPARING A SURVEY PLAN FILE ......................................................................... 102
6.4 USING ATLAS BOUNDARY (BNA) AS MAGLOG MAP FILE ................................... 109
6.5 USING ONTRACK PLOTS ....................................................................................... 110
MINI-WINDOWS.................................................................................................... 114
USING FLAGS ........................................................................................................ 115
DIGITAL DISPLAY MINI-WINDOW.......................................................................... 115
ADDING FLAGS FROM DISPLAY SLOTS. ................................................................. 120
ADDING FLAGS FROM GPS DISPLAY .................................................................... 120
ADDING FLAGS USING HOT KEYS ......................................................................... 121
USING COMMENTS TO FLAG POSITIONS................................................................. 122
USING WINDOWS™ PRINTERS AND PRINT DRIVERS.............................. 122
9.1 GENERAL CONSIDERATIONS ................................................................................. 122
9.2 MAGLOG PAGE EXAMPLE ..................................................................................... 124
9.3 CONFIGURING MAGLOG PAGE LAYOUT ............................................................... 127
9.3.1 Setting up printer and page .......................................................................... 127
9.3.2 Setting up slots to draw the data automatically. .......................................... 129
9.3.3 Setting up slots to draw the data manually. ................................................. 130
9.3.4 Populating slots with data............................................................................ 131
PRINTING MAGLOG PAGES IN REAL TIME SURVEY ............................................... 141
PRINTING MAGLOG PAGES IN PLAYBACK MODE................................................... 142
CONFIGURING OTHER DEVICES ................................................................ 144
CONFIGURING SLOTS/TRACES FOR PRINTER ..................................................... 147
CONFIGURING OUTPUT DEVICES ...................................................................... 150
Configuring the Video Titler (Airborne Applications): ............................ 150
Configuring Direct Printer (Printrex and Dot Matrix printers)............... 151
CHANGING LINE NUMBER DURING SURVEY....................................................... 155
THE SURVEY ...................................................................................................... 156
READY TO START LOGGING DATA............................................................ 159
THE MAIN SCREEN ........................................................................................... 156
THE MENUS ...................................................................................................... 158
AUTO LOGGING FEATURE .................................................................................. 159
SURVEY UNITS .................................................................................................. 161
OUTPUT FILES................................................................................................... 162
DEPTH/ANALOG CHANNEL CALIBRATION............................................. 163
CALIBRATION PROCEDURE: .............................................................................. 163
AUTOMATIC DEPTH/ANALOG CHANNEL CALIBRATION:................................... 164
MANUAL CALIBRATION:................................................................................... 166
EFFECTS OF DEPTH CALIBRATION ..................................................................... 167
WHY SHOULD WE CALIBRATE? ......................................................................... 167
THE INTERPOLATOR ...................................................................................... 169
OVERVIEW ........................................................................................................ 169
Uses of the Interpolator ............................................................................ 169
Output Capabilities ................................................................................... 170
MENU-ORIENTED INTERPOLATOR SETUP ........................................................... 170
“Mags” Dialog ......................................................................................... 171
“TRK” Dialog........................................................................................... 174
“UTM” Dialog.......................................................................................... 175
“GRAD” Dialog ....................................................................................... 178
“Positions” Dialog ................................................................................... 180
“Net” Dialog............................................................................................. 183
INTERPOLATOR OUTPUT ................................................................................... 185
INTERPOLATOR EXAMPLES ............................................................................... 190
GYRO, GPS, and Cable length using transverse horizontal gradiometer.190
ORE Trackpoint II, GYRO, and three sensors:......................................... 195
INTERPOLATOR DIAGNOSTIC MESSAGES .......................................................... 201
LEGACY SOLUTION: WINDOWS NT ONLY ......................................................... 203
THE MODERN SOLUTION: REAL-TIME SERIAL DRIVER. .................................... 205
Accurate time stamping with COMM/DRV driver.................................... 205
Installing run-time COMM/DRV environment. ........................................ 206
Using COMM/DRV within MagLog software........................................... 209
Using GPSPCI card to synchronize MagLog time with UTC................... 213
VIEWING DATA WITH PLAYBACK ...................................................................... 215
SURVEY QC CHECKS....................................................................................... 222
ACQUISITION SYSTEMS .................................................................................................. 224
Hardware you will need:........................................................................... 224
Assembly.................................................................................................... 224
Operation .................................................................................................. 225
Analysis ..................................................................................................... 226
OTHER TOPICS.................................................................................................. 228
PASSWORD PROTECTION ................................................................................... 228
OUTPUTTING STATUS INFORMATION FOR QC PURPOSES ................................... 231
SETTING OPTIONS THROUGH “MAGLOG.INI”..................................................... 234
MAGLOG PRINTER LAYOUT FILES. .................................................................... 236
PROGRAM ....................................................................................................................... 237
HARDWARE CONFIGURATION.................................................................... 238
WINDOWS NT INSTALLATION: ......................................................................... 238
INSTALLATION OF DIGI ADAPTER (OPTIONAL) ................................................. 242
INSTALLATION OF MAGLOG ............................................................................. 243
INSTALLATION OF PRINTREX PRINTER (OPTIONAL) .......................................... 243
PULSE DRIVERS IN MAGLOG DISTRIBUTION ...................................................... 243
Windows NT .............................................................................................. 243
Windows 95/98.......................................................................................... 247
INDEX ................................................................................................................... 248
1 Introduction
This section describes general MagLog operating principles and will be useful for
understanding the overall software and hardware architecture.
MagLog™ and MagLogLite™ are essentially the same program except that the full
featured MagLog™ is used primarily in multi-sensor array, multi-instrument geophysical
survey applications (airborne, land or marine). MagLog™ supports various external third
party instruments. MagLogLite™ is designed primarily for the small marine
magnetometer/gradiometer data logging market and can be used for land/marine single or
dual sensor arrays used in wide mag, archeological or UXO type surveys.
MagLog is a general-purpose data logger that provides logging to disk and display of the
following types of information:
• Serial data streams which comply with RS-232 specifications. MagLog assumes
that there are 8 bits of information, no parity, 1 stop bit and no hardware flow
control. ASCII data is preferable, but binary data also is accepted. Not all serial to
USB or PCMCIA converters will work with all geophysical equipment. Contact
the factory for names of models known to work.
• Hardware generated pulses. Typically this is a TTL (5 volt) pulse arriving at the
computer parallel port from an external device. MagLog fixes the time of the
pulse arrival and writes this time into the log file. Examples of such hardware
pulse devices are various event markers, GPS PPS (pulse per second) output and
trigger pulses used to start other devices (e.g., air guns). The recommended width
of such a pulse should be greater than 1 ms.
• Analog inputs. This requires a special A/D converter card installed into the
computer. Geometrics can recommend the model and performance
• Trigger output. The pulse generated is similar to an event mark, however this
feature requires the installation of a special multi-function card. The card works as
a pulse generator and MagLog can provide a logged pulse time stamp for each
output pulse generated.
The figure below explains how MagLog handles data streams:
Input streams
PC running
Output files
Log file
GPS serial ASCII data
Magnetometer data
Generic serial data
Pulse data
Analog data
Pulse In/Out
Magnetometer real time
position computation
Log file for COM2
Log file for COM1
Log file for COM3
Data display
and QC
A/D converter
Log file for pulse data
Log file for analog data
Log file for trigger
Each output file contains
unaltered original strings and
their arrival times
Most common data sources are logged via serial ports that may not require any additional
MagLog handles incoming data in the following manner:
• Records PC clock time when the string becomes available to the program.
• Logs the string into a log file, if logging is switched ON. The string is logged with
its arrival date and time.
• Parses string (converts ASCII text into digits) to display its content. However the
parsing result is not saved and is only used temporarily for display purposes.
• Display the string content as digits or graphs as defined in setup.
MagLog also performs real-time QC monitoring of the data. For instance, if the value of
the incoming data is outside of a preset range assigned by the user during setup, the green
running light for that device (upper left hand corner) turns yellow and an alarm may be
generated which could include audio warnings (verbal alert of cause of alarm) and pop-up
dialog boxes showing the cause of the condition. Should the data transmission from a
device stop all together the running light turns red and additional verbal and visual alarms
are initiated.
In simple terms, MagLog logs data with date and time of arrival and then displays the data
while performing real time Quality Control functions.
2 First Time Start-up of MagLog
After installation is compete two new icons will be present on the computer desktop:
to launch MagLog program and
to launch CM201CFG configuration program (used to re-configure 880/882
Click on the Windows Start Button and select “Programs”, and then “Geometrics”. You
will be able to select “MagLog”. Or, double click on the MagLog icon located on the
desktop. MagLog starts and displays the following dialog box:
Please enter your company and user name, and then press the “Ok” button. If you have
purchased MagLog make sure that dongle is connected to the parallel port. If you have reinstalled MagLog on the same computer where it was running before with a software key,
insert a previously created registration floppy in the “A:” drive and press “Have
registration floppy” button.
It is good practice to keep your future files separate from MagLog system files. To assist
in this task, MagLog suggests creating of a new folder for these files. By default this
folder is located at “C:\MagLogData” however the user is free to change its location. The
following “Browse For Folder” dialog is displayed:
The user can navigate and select the appropriate folder for survey file storage or use
“Make New Folder” button to create new folder with a custom name.
Note: On older systems (Windows 95 or Windows NT) this feature may not be fully
After the “Ok” button is pressed MagLog updates its security files and exits with the
following dialog:
If you downloaded MagLog from the web or installed it from the Magnetometer CD for
limited testing period please write down your user code from the above dialog and contact
Geometrics customer service to obtain a temporary license code (the User code can be
obtained later by selecting “Help / Register” menu).
After “Ok” button is pressed MagLog exits. It is normal program behavior. Please start
MagLog again to proceed with your survey.
Software registration
MagLog is protected by the software or hardware key (dongle). The software is not fully
functional if a dongle is not plugged into the parallel port or if software registration has
not been completed. In this case word <UNREGISTERED> is displayed in the main
window title bar.
MagLog software may be downloaded from the web for a limited trial period and will be
enabled free of charge. Here is how to register your software after installation:
Go to “Help / Register” dialog. Write down “Your user code” from the dialog
below (example):
Contact “Geometrics” by phone or e-mail and obtain your “Registration
number”. Type your registration number in the above dialog. Press the “Ok”
In the event that the error message “Registration failed” is posted on the screen,
double check your user code and contact “Geometrics” again. When the correct
registration code is typed in, the following dialog is displayed:
This gives you an opportunity to save current registration file to a floppy
disk. If program is later re-installed on the same computer you can use your
registration floppy to enable software without repeating the registration
procedure. The floppy is valid only for particular computer and cannot be
used for others. Insert a blank floppy disk in the A: drive and press the “Ok”
button. To skip writing the registration floppy press “Cancel”. Your program
will still be registered but you lose the option of quick registration if you
need to re-install the software for any reason.
Now exit the program and start it again. You can see that word
<UNREGITERED> is gone.
3 Getting Started
Click on the Windows Start Button to start the program. Select “Programs”, and then
“Geometrics”. You will see and be able to select “MagLog.
Or, click on the MagLog icon located on the Desktop:
You should immediately see the main MagLog screen:
You are ready to begin initializing your survey.
Starting a new survey
You can begin a new survey by selecting “Start New Survey” from the file menu.
Then enter the name of your survey in the field “File name:” of the “Save As” dialog box.
Navigate to your data folder and click on the “Save” button.
Next, you will see the following survey information dialog box:∗
The information in this dialog box must be filled out before you may proceed.
It is primarily used for bookkeeping or record annotation. These fields are not actual
configuration settings – they are notes about the survey for future reference. It is not
necessary to fill in every field and the contents will not affect future performance. Click
“OK” to proceed.
This dialog box can be switched off if field Info Dialog is set to 0 in Maglog.ini file (see
Next, you will be presented with the following choices:
You may base the new survey on any of the following settings:
• Same hardware setting as last survey: This will copy the hardware settings from the
most recent survey that you have run. This would be the option to choose if you wish
to start a new survey with the same hardware settings as previously used.
• Hardware setting of another survey.
This will copy the settings of a different survey than the last one used. If you choose
this, you will get a dialog box allowing you to specify the name of the survey from
which to copy the hardware settings.
• No pre-configured hardware.
Use this option if you want to start the hardware configuration from scratch, or if there
is no previous survey. Also, use this choice if you have updated the version of
MagLog, and the new version is not compatible with previously generated Survey
Since this is a new survey, and there should be no previous surveys, choose: “No
Preconfigured Hardware”.
Continuing an Existing Survey
If you don’t wish to start a new survey, you can continue an existing survey by selecting
“Continue Existing Survey” from the menu above. This will then allow you to load your
current survey file.
Note: Once you have specified a password on a survey file, this will remain for the
life of the file. Remember your passwords for your surveys because you will be
prompted for them each time you make configuration changes. Passwords are not
required but can assist in maintaining quality control.
4 Configuring Input Devices and Displays with MagLog wizard
To work with a particular hardware configuration MagLogLite™ or MagLog™ should be
configured accordingly. MagLog is a highly customizable program that allows a variety of
different data presentations. However, flexibility always comes at the cost of complexity
and therefore we have endeavored to minimize configuration difficulties by employing a
MagLog Configuration Wizard. It should be pointed out that the wizard covers only a
limited number of hardware configurations (many others are possible) and that these
GPS device sending NMEA $XXGGA strings to one of PC’s serial ports. Here
“XX” are any characters. For example, for GPS receiver sends $GPGGA messages
(GP stands from GPS). Later in this manual the GPS string is also referred to as
Geometrics magnetometers connected to a second serial port. The models
supported are:
o G-880/881/882 cesium vapor magnetometers with up to two magnetic
sensors and optional pressure transducers and altimeters.
o G-886 / G-877 marine magnetometer proton precession family
o Pulse 12 EM (JW Fisher)
o G-823A or B airborne systems (same setup configuration as G-880/881)
Other devices for logging and display may be configured manually (see below). It is
possible to configure basic devices (such as the GPS and magnetometer) with the wizard
and then append more devices manually at a later time.
Starting MagLog Wizard
To start the configuration wizard, select Survey Wizard from file menu:
It is recommended that you have your hardware (magnetometer and GPS) connected to the
computer and running at this time. The GPS should be outputting real positions, and the
magnetometer should also be running although it need not be producing real
measurements (for instance, it can be lying on the ship’s deck near large steel objects). If
these requirements are not met you still can proceed with the Wizard, but there is some
chance that you may encounter configuration problems in the future and have to
reconfigure the system when real data is present.
The next screen is the wizard Welcome screen:
All Wizard screens have a short help file associated with them (duplicated in this
Next you must specify a survey file name. It is recommended that you press the Browse
button and select an appropriate folder and name (don’t place your survey files in the same
folder where maglog.exe executable files reside but in another folder such as
C:\DATA\SURVEY1). Please note that the program requires a unique and new file name
for the survey file. MagLog will not allow you to overwrite previous survey files.
The survey file is a binary file that stores all of the settings of your survey - devices, ports,
display configurations, etc. As soon as it is created, it can be used to continue a survey or
create a new one with the same settings.
It is possible at this time to specify distance units to be used in the survey. “Meters” or
“feet” are currently available. Select the appropriate units under “Survey units” drop box.
Units can be changed any time during the survey using “Configure / Units for this survey”
menu item.
4.2 Configuring GPS and its display
The next screen will allow you to configure the GPS. It will work best if the GPS is
connected to one of your serial ports during setup. This is because MagLog automatically
computes the central meridian for your area from the GPS position. The central meridian
is used for conversion to UTM coordinates (meters) when real time interpolation is
employed (computation of actual sensor position for each reading, see below). If the GPS
is connected, press "Auto set communication parameters" and MagLog will scan your
serial ports to find the GPS port and its baud rate. It may take a few minutes; therefore if
you know (or you think you know) these com port parameters, set them in the dialog box
and press "Auto set Communication Parameter" to check if they are correct.
MagLog can generate a warning if the GPS signal deteriorates during survey. To enable
this feature, you should check "Differential GPS fix required" and set the minimum
number of satellites. If one of these conditions is not met, an Alarm Window with a
warning appears on the screen and a verbal alarm is voiced (requires a sound card and
A note on real-time layback calculations: MagLog provides a feature that calculates
where the sensor (fish, bird, land system offsets) is at all times. It does this by noting the
position of the GPS antenna and then taking input from you regarding the antenna position
relative to the tow point on the back of the ship (or other tow platform) and the amount of
cable deployed. If you plan to use real time layback calculations you will need the central
UTM meridian of your location. If you are located at the same area where you plan to
make a survey (or at least in vicinity of few hundreds of kilometers) and your GPS is
getting real positions, the Wizard will analyze the GPS messages, find the corresponding
central meridian and enter them automatically into the proper part of the program. This
makes it very easy to configure MagLog Interpolator as shown in the next few screens and
why we recommend that you have a good GPS data transmission available as you set up
the survey.
The GPS display can be configured with user selectable background colors and annotation
fonts. Also, MagLog has the capability to import ArcInfo shape file maps (more on this in
the section “Preparing a Survey plan file”.). If there is a map available (presented in
ArcInfo Shape file format) it is possible to combine the GPS display with that map. The
screen below shows a typical view of the MagLog GPS screen and allows the user to set
parameters such as:
• Press here to set annotation font and user-supplied map. An additional dialog
appears which allows user to set all these parameters. It is assumed that user map
(if any) is presented in MagLog format already and user can simply import it. If
the map has not yet been transformed into MagLog format, use the next button:
Map Import. This allows the user to select a set of ArcInfo shape files (both .shp
and .shx set of files must be available) to be converted into MagLog format.
During conversion, geometry information can be clipped into a rectangular region
and user marks and user lines can be added to the view. (This is a separate feature
from that portion of the program under File that provides “Create Survey Plan”
ability to create survey lines in the GPS map area). Note that ArcInfo shape files
are available for most regions of the world on several Internet sights at no charge.
Only linear features (such as coastlines, roads, etc) are taken from shape files. Point
features as well as names in any associated .dbf file are ignored. The user should take
care in employing this MagLog feature as large numbers of shape file elements can
slow down the program performance.
San Francisco Bay Arcinfo Shape file map
4.3 Configuring magnetometer or EM (pulse 12) hardware
The Wizard next takes us to the magnetometer configuration section. It is recommended
that the magnetometer be connected to one of the computer serial ports and sending data
during this procedure. If you know the port and baud rate, set it and press Autoset
communication parameters. MagLog scans all available ports and baud rates trying to find
the magnetometer data. It starts the search with the parameters you have set; therefore if
the port and baud rate are set correctly, the magnetometer will be found very quickly.
Next set Hardware Type. The following configurations are available:
1. 1 G-88x/823 mag system. This system consists of one magnetic sensor with its
signal strength channel. It outputs two numbers per reading – total field and signal
2. 1 G-88x/823 mag with depth sensor. The same as above, but with pressure
transducer. It outputs 3 numbers per reading: total field, signal and a depth reading
that needs to be calibrated.
3. 1 G-88x/823 mag with depth & altimeter. The same as (2) but altimeter data has
been added. The system outputs 4 numbers: total field, signal, depth and altitude.
Depth and altitude data both need to be calibrated (see calibration section).
4. 2 G-88x/823 mag system. Same as (1) but two magnetic sensors connected into a
gradiometer chain (Note: See manual setup for configuration of multiple sensor
arrays). Now the system outputs 4 numbers: Total field for first sensor, its signal
level, total field for second sensor and its signal level.
5. 2 G-88x/823 mag with depth sensors Identical to (2) but has two magnetic
sensors connected into the concatenation chain. Outputs 6 numbers: total field for
1st sensor, its signal, depth, and then repeated for the second sensor.
6. 2 G-88x/823 mag with depth & altimeter. Identical to (3) but has two magnetic
sensors connected into the chain, each with its own depth transducer and its own
altimeter. The system outputs 8 numbers that are total field, signal, depth, altitude
and then repeated for the second sensor. Depth and attitude sensors have to be
7. G-877 / 886 Proton Magnetometer. This device may have additional channels
(depth) but they are normally factory pre-configured. Magnetometers need to be
tuned for the region you are surveying.
8. Pulse 12 1 coil system. For Pulse 12 EM device with one coil (Fish) use this
selection. Please connect coil to the first slot.
9. Pulse 12 2 coil system. For Pulse 12 EM device with two coils use this selection.
Connect coils to slots #1 and #2.
10. Pulse 12 3 coil system. For pulse 12 EM device with three coils. Note that even if
there is only one coil available but is connected to slot #3, you should select
system as “3 coils” after wizard finishes, remove slots for coils #1 and #2.
If your hardware configuration does not match exactly one of these 7 pre-defined sets,
adjustments are easy to make. For example if you have 2 each G-880 magnetometers with
depth sensor and altimeter on one of them; then you can use configuration (6). In this case
the depth transducer and altimeter for the second magnetic sensor will output zero values
and that is ok for most data processing programs. However if your hardware consists of 3
magnetic sensors in a gradiometer array, you will not be able to use the Wizard to set up
the (multi-sensor) array and will have to configure the logging and display manually.(see
sections “Configuring the G-880 magnetometer:” and “Configuring Input Devices for
On the Wizard screen you should now set the desired cycle rate for magnetometer. Typical
values for the 880 family would be 0.1 seconds (10 HZ) and typical value for the marine
proton magnetometer is 1.0 seconds (1.0 Hz) or 2.0 seconds (0.5 Hz).
After all parameters are set and the auto detection sequence has been completed, press the
Next button. Before going to the next Wizard screen, the program will attempt to
communicate with the magnetometer configure the data transmission format and cycle rate
accordingly. If the magnetometer is not connected, the program will fail to converse with
the mag and you must press the Cancel button. After canceling you can still proceed to
the next dialog box but in general we recommend that you use the Wizard only when all
devices to be logged are connected and sending data to minimize possible mislabeling of
input devices.
The communication program may fail for other reasons as well, such as a wrong number
of magnetic sensors entered into the dialog box, for example, if your system has only one
sensor and you are trying to configure it as a 2-sensor system. The solution is to simply
go back to the start and set up a new survey with the proper configuration information.
Magnetometer calibration
This section is not available for the proton G-877/866 magnetometers or for the EM Pulse
12 (G-877 has its depth sensor internally calibrated and EM Pulse 12 does not have a
depth sensor). If you have one of these devices you can skip to the next section.
If your hardware includes depth or altimeter sensors, they need to be calibrated. The
Wizard does not provide full calibration capabilities (see below “Depth/Analog channel
calibration” how to do complete depth/altimeter calibration) however it does allow
entering of the calibration coefficients if you know them. These values might be obtained
from the factory (check marine sensor fin assembly for sticker with coefficients) or as the
result of previous calibration procedures. .
If depth is to be used during real-time layback calculations (see below) check box “Use
depth for layback” This makes MagLog to use depth and cable length to compute distance
from the boat to the fish.
You can check the Do not enter calibration coefficients now button and the scale will be
set as 1 and bias as 0. Do this if you don’t know the calibration coefficients at this time.
Note that this screen will not appear if you do not have depth or altimeter sensors in your
Real time lay back calculations.
MagLog has a feature called "Interpolator" which allows you to calculate the real time
position of the magnetic sensor based on the GPS position and the system geometry. This
function saves time and effort because the final data will be logged in a format ready to be
loaded into many popular programs (like Surfer or Geosoft Oasis for example) with the
position of the Fish (not the GPS antenna on the boat) in the file. In order to use this
feature, you will need to know the geometry of the magnetometer array (boat size, GPS
antenna, tow winch location, tow cable length) as well as the geographical position of the
survey area. Be ready to enter all these values and the central UTM meridian if you want
to enable this feature.
Note: If your GPS is connected, transmitting correct positions and you "auto detected" it
during the GPS configuration step, the central meridian will be computed and entered
To enable the “Interpolator” function, just click “Yes, I want real time layback
calculation” and fill in the subsequent information. If you answer “No”, then the set of
subsequent screens are skipped and this feature is disabled. If you answer “Yes”, be
prepared to answer questions about your boat and cable geometry.
The Wizard does not cover all possible aspects or subcomponents of the Interpolator
configuration such as the use of a GYRO compass or ORE TrackPoint II underwater
positioning system. When you are using such systems you should configure the
Interpolator manually (see below).
The next screen allows you to choose between two basic single sensor or gradiometer
sensor array configurations (for multiple sensors). Note the gradiometer applications are
many and varied, primarily associated with wider swath of coverage (transverse
horizontal) or removal of the diurnal field variations (longitudinal) or enhancement of
nearby point objects as in UXO surveys (vertical). Contact Geometrics for more details.
Select the picture that best fits your actual geometry. Enter the values of A, B, C, D, C1
and C2 on the next screen shown below. Even if you have only one magnetic sensor,
MagLog always calculates two positions; in this case simply ignore the second sensor
position data. On the next screen, enter these values (all distances are in meters or feet
depending on units selected; the central meridian is in degrees). If your survey
configuration is completely different from these, you will need to manually configure the
Interpolator. Please see the section on manual Interpolator configuration later in this
On the previous screen you chose which mode (longitudinal or transverse) fits your actual
geometry best. The next screen presents the selected mode dialog box:
Note that Central meridian field will be filled in automatically if you auto-detected the
GPS. Other values have to be physically measured on the vessel and entered.
The final Interpolator Configuration screen presents the layout of the Interpolator log file.
This file consists of many columns and includes magnetic field, signal, depth and altimeter
readings as well as the GPS antenna and magnetometer Fish positions. The file can be
loaded directly into popular programs like Golden Software’s SURFER or Geometrics
MagMap2000. It is recommended that you note which data are in which columns for
future reference during the analysis and interpretation phase of the data reduction and map
making. You can save the information by clicking on the “Save this information into file”
Data Display configuration
MagLog has several different options for displaying incoming data. Primarily, the data is
presented in the form of analog strip chart traces or profiles. There can be multiple analog
charts on the screen (slots) with multiple pens (profiles) per slot and they can be oriented
in either horizontal or vertical mode. Also, each chart (slot) can be set with individual
rates of speed and full-scale values. The Wizard covers only a subset of the possible
display configurations. The user can choose from the following display configurations:
Horizontal (landscape) or vertical (portrait) graph orientation
Trace color.
Coordinate grid color.
Annotation text font and color.
Window background color.
We recommend the horizontal graph orientation for better overall presentation.
Depending on the configuration, MagLog will display one or more traces in each display
slot. For example, if there is only one magnetic sensor, its field is displayed with color 1.
If there are two magnetometers, then color 1 used for first sensor and color 2 used for the
second sensor, and both fields are displayed in the same slot. All these parameters can be
changed later manually after the survey is configured.
Here is a typical wizard graphics configuration screen:
The next screen allows you to set the scale and grid parameters for the slots, as well as the
slot type. MagLog produces an automatic display layout based on your configuration and
the following rules:
• Magnetic field is always displayed in the wrapped mode. This means that when the
graph reaches the slot’s border, it reappears from other side of the slot.
• Signal strength can be displayed as in wrapped mode or in fixed mode. In fixed
mode, slot borders have fixed values; if value to be plotted is out of this range, the
profile simply disappears from the screen.
• Depth can be plotted in either mode.
• If there are depth and altimeter sensors, MagLog makes a “Flying Fish” plot. This
includes plotting of sum of depth+altitude to show bottom profile and depth
plotting in the same slot to show the Fish’s actual vertical position in the water
column. This kind of plot has a fixed range with the positive axis pointing down
(in landscape mode) or left (in portrait mode).
In the dialog box below, the user can set ranges and scales for all the above slots, as well
as total a slot’s duration in seconds (speed of trace control).
Configuring dot matrix or Printrex printers (For other printer models
see next section).
MagLog allows you to produce hardcopy output during data acquisition. This option
works with Printrex 8” or 11.5” thermal printers or with standard Epson type dot matrix 8
or 24 pin printers that are ESC/P compatible. Most dot matrix and some ink-jet printers
are compatible with these specifications; however consult your printer manual regarding
your specific printer.
Connect the printer to LPT1 (or to the back of the software key or dongle) and check the
Use parallel printer box to enable printing. Then select the correct printer type. Note that
if the printer type is incorrectly selected, unrecognizable characters will be printed.
You also can configure the following printer options:
• Select chart speed.
• If layback calculation is enabled, print GPS position in decimal formal or layback
calculated position (actual sensor position in Lat Long).
• Select the position on the chart where text is to be printed.
MagLog creates an automatic printer layout based on your hardware configuration. This
layout can be altered later manually if you wish. At the beginning of the chart MagLog
prints a short legend wherein it explains the printer layout.
Printer setup dialog:
4.8 Configuring system-wide Windows™ printer.
While dot matrix printers offer continuous printing they are also noisy and in general
becoming obsolete. For that reason, MagLog provides the option to use printers supported
by the Microsoft Windows™ operating system. MagLog can use any printer installed with
a Windows™ driver, including network or virtual printers (for instance Adobe Acrobat
writer software or FreePDF software to create PDF files on the fly). The main difference
between dot matrix or the Printrex brand thermal printer is that output is created page by
page, not as a continuous paper tape. Windows™ printer output is highly configurable
with a preview option available during the survey. For more information, please see
“Using Windows™ printers and print drivers”.
MagLog ships with set of pre-defined printer layouts for different configurations created
by the MagLog printer wizard. Based on settings selected on the previous screens,
MagLog displays the appropriate layouts for the survey. Below is the typical wizard
screen for Windows™ printers:
Typically one or more layouts are available. To use this feature check “Use windows
printer” box and select the appropriate layout. Then press “Configure printer…” button.
This displays a standard printer selection dialog box. Select one of the printers available
for your system and hit “Ok” button.
4.9 Finishing setup
After the Finish button on the final screen is clicked (not shown here), MagLog will
attempt to set up the survey as it was configured. You should have your GPS and
magnetometer connected and transmitting data at this time. If you don’t have real inputs
coming into the serial ports, MagLog will still create a survey, but you won’t be able to
run it. If you are running an unregistered version of the program or do not have a
registration Dongle Key (which plugs into the printer port to enable full access to
program), MagLog will switch data inputs from serial port input to data file input (demo
MagLog creates two windows (a magnetometer display window and a GPS view window)
and tiles them on the screen. The GPS window initially has the minimum possible
magnification so you are able to see whole earth globe. Make this window active with the
mouse (by clicking once on it) and then use “+” and “-“ keys to set desirable
magnification (zoom to your area). You may need to activate the NumLock key to access
the “+” and “-“ keys on some computer keyboards. Use the arrow keys to shift or
translate the location map horizontally or vertically.
The Magnetometer profile display window begins with a default layout. It can be altered
manually if desired (see manual configuration section below). Make this window active
with a mouse click and then use the arrow keys to navigate between the slots and change
the data FULL SCALE values inside each slot.
5 Manual Configuration of Input Devices
The following procedures will show you how to manually configure input devices. This
includes magnetometers, global positioning systems, gyro’s, tracking systems and others.
For each device that you want to configure, you need to have a unique communications
port assigned to that device. This can be physical serial port or TCP/IP port. MagLog
supports logging and data export transmission over these communication links.
If your current survey is based on hardware settings from a previous survey, or you
opened an existing survey, you will not need to start the hardware configuration procedure
from the beginning. You will simply need to edit or revise the existing settings. The
following section assumes you are initializing a new hardware configuration.
Select “Configure / Input Devices” from the menu:
You will then see the following dialog box:
This is the Input Devices Configuration dialog box. It is the central dialog box for adding
or changing those devices to be logged.
From this dialog, add devices of your choice. After adding the devices, you will then
specify how each data source is to be plotted on the screen or dot matrix printer using the
“Input devices / Configure displays” menu:
The following dialog box will be displayed:
In this dialog, a list of all connected devices is displayed (only one in this particular screen
shot). To configure a device display, select the device from the list and press “Slot/Traces
for display button”. To configure a dot matrix printer output (not for the Windows printer)
press “Slot/Traces for Printer” button.
Note: In MagLog versions prior to 2.84 it was possible to configure devices and
their displays in the same dialog. However this was perceived to be confusing; and it
caused MagLog to re-initialize devices even if only a minor display change was
needed. For clarity, the program has been revised to separate these functions.
Configuring serial port or TCP/IP connection parameters
One dialog box is used to configure both serial and TCP/IP communication parameters.
All serial devices supported by MagLog have a common menu in their configuration of
serial port parameters. MagLog assumes that every serial connection has the following
fixed parameters:
• 8 information bits.
• No parity.
• 1 stop bit.
• No hardware flow control.
These parameters cannot be changed within MagLog and therefore devices must be
configured in such a way as to meet these requirements.
This is the serial and TCP/IP parameters dialog box:
It has the following parameters (for each device individually):
Data Source: from serial port or data file. Once a device is created, you cannot
alter this choice without reinitializing the survey setup.
Serial port number (COM1, COM2 … TCP/IP) ─ the last selection in the list is
TCP/IP. This allows MagLog to connect to the server which supports point-topoint TCP/IP connections.
Baud rate ─ if a serial port is selected, or a host name and port number if TCP/IP is
selected. In the latter case the “Host” is the name or IP address of the data source
(examples: “” or “” or “localhost”) “Port” is
defined as the TCP port for the data source (for example: “14001” for Lantronix™
serial data to TCP converter). Please consult your device manual for proper host
and port values.
Data sampling rate ─ if data is being read from a file, in milliseconds. Note that
MagLog may not keep up with this rate precisely: this depends on system load and
other factors. If you are using this feature to playback your data, there might be
slight discrepancies introduced between GPS positions and magnetometer
File name ─ to retrieve and from which to read data
Sample Rate ─ There is an option that allows the program to compute the sample
rate from the data in the file. In this case the file must have date/time stamps (the
typical case when data is logged with MagLog).
Serial filter ─ This is list of prefixes to filter out unwanted serial strings. When
MagLog sees a string that starts with one of these prefixes, it filters it out (no
logging, no parsing). One of the possible applications for this is to connect one
physical device with multi-string output to two serial ports (thus creating two
MagLog logical devices) and set proper filters for both of them such that one string
is received in each port.
Change “port <-> file” next start ─ If the user wants to change the input data
source from serial port to data file or vise versa, this box should be checked. It
signals MagLog to switch the data source from serial port to data file (or the
reverse) the next time the survey is started. For example, the user has acquired
some data and now he or she wishes to use these files for training purposes. To
“reconnect” MagLog from the serial port to the file, check this box and terminate
the survey. Then restart the survey. MagLog will try to read data from the files,
and there will be an opportunity to enter the file name. Another case is when the
user is preparing for a field trip. He or she can create a survey to be used later for
the actual acquisition. The created survey includes all the devices with their
display configurations, etc., and it works with all files. To use this survey as a real
survey, check this box for all serial devices and terminate survey. Then restart it. If
the serial port information is not correct (port and baud rate) adjust it.
Note: Care must be taken during actual survey procedures not to begin logging
a pre-captured or pre-logged data file as actual survey data. Always refer to the
header on each of the slot windows for information as to the source of the
displayed data to ensure that you are logging from the correct port during actual
For data streams with multiple message types (or for data streams where messages from
different physical devices are combined) MagLog allows simple message filtering based
on a message prefix. This may be required to allow part of the data stream to be logged
while rejecting other parts of the stream. For instance the GPS stream can typically have
not only $GPGGA messages but other types of $GP… messages as well. To filter out all
messages except $GPGGA the user can use a prefix filter mechanism as3 described
Serial filter prefix dialog box appears as:
To add prefixes, type the new string into the Prefix: field and press Add. The string will
be added to the prefix list for the particular device. You can remove a filter string from the
list by selecting it and pressing the Remove button, or by pressing Remove All to clear
the list.
Depending on the Policy settings, MagLog will accept or reject strings with prefixes in the
list. If the policy is set to Reject only, then all strings with the listed prefixes are rejected.
If the policy is Accept only then only strings identified in the list are accepted, the rest are
rejected. This latter condition may be useful when some string formats are unknown.
Important Note: A Serial filter can be applied to MagLog displays without being applied
to the recorded data. If “Do not apply filter to the logged data” is checked, then MagLog
uses filters inside the program to filter serial data for display purposes but all data
transmissions from the serial device are logged. If this box is not checked, the filter is
applied to the logged data also, which then reduces the amount of logged information and
the data file size.
For example, a Gyrocompass outputs two messages:
$HEHDT,183.1,T*24 06/22/01 10:22:55.737
$HEROT,13.5,A*1C 06/22/01 10:22:55.754
The first message, $HEHDT reports true ship heading and is used by MagLog. To accept
this message add $HEHDT in the list and select the “Accept only” policy. If “Do not
apply filter to the logged data” box is not checked then only $HEHDT messages are
logged. However if box is checked both $HEHDT and $HEROT messages are logged.
Now if there is a $HEHDT prefix in the list and the “Reject only” policy is selected,
MagLog filters out all data strings (and therefore the gyro compass light stays red). If at
the same time “Do not apply filter to the logged data” box is checked, the data is still
saved to disk. (Light stays red, but file size numbers show increasing size of the log file).
Note: For a new list to take affect, you must restart your survey.
Note: If you don’t want any filter, select “Reject only” policy and leave the prefix
list blank (this is the default condition).
Using one serial or TCP/IP port to record multiple devices.
It is possible to attach more than one logical serial device to one physical serial port or
TCP/IP port. The primary purpose of this feature is to allow mixed mode data streams
(data streams with multiple information sources included) to have display for each of the
included data sources. For instance, if the GPS and magnetometer data are mixed in the
same data stream, the MagLog GPS device and the MagLog 880 logical device can share
the same physical port. The software can open the data stream twice to log each part of the
serial stream as a separate input, thus allowing each “device” to have its own display
window. Proper prefix filtering in this case could be used to separate 880 and GPS data
inside MagLog.
To share a serial port among multiple devices the following conditions must be met:
• Each device must have exactly the same baud rate.
• Each device must transmit in ASCII mode and use same string terminator.
Only one device is allowed to provide “handshake” or to talk back to the program.
For example, for 88x/823 magnetometers, MagLog sends commands down the line
to configure the magnetometer. This means that two 880 logical devices cannot
share the same port inside MagLog because the program will attempt to
communicate to both physical devices over the same transmit line and this is not
allowed. However two Generic Serial Devices can be assigned the same port in
MagLog, where a mixed data source string is being logged, and each logical device
assigned a separate display window and logged data file.
When the user sets up another serial device using the same port the following
message appears:
Here is “MAG” name of the device that is using this port already.
Note: If there are no serial filters used (see Configuring serial port parameters.) log
files for each serial device sharing the same port hold the same information.
Configuring the G-880 magnetometer
In order to configure your magnetometer correctly, you need to know
1) How many magnetometers you have.
2) How many analog channels are required for each magnetometer.
In this manual, we will refer to channels as analog to digital converted data
transmissions such as the signal strength, depth sensor, and altimeter that your
magnetometer outputs. We also assume that every magnetometer outputs a
magnetic field by default.
The magnetometer configuration is accomplished in two steps discussed in this section:
1) Configure the hardware (tell the magnetometer what to output)
2) Configure MagLog (tell the software what is coming).
5.3.1 Configuring the magnetometer
The hardware configuration is achieved through a screen labeled “G-880 Configuration”.
You access this screen by selecting “Mag880” on the left pane of the Input Devices dialog
box and then clicking on the “ADD” button. This is the screen that allows you to setup
and communicate with the magnetometer hardware (denoted as Counter 1, 2, 3 etc below.
Each Larmor counter is associated with one magnetometer in the concatenated data string.
Example below has 5 magnetometers listed, 1 to 5 with one analog channel selected for
each. Channel 1 refers to the signal strength). If you have used a terminal emulation
program such as Windows™ Hyperterminal, you will find it quite similar in that you can
use this screen to see the data coming in on a given port, adjust the baud rate, and enable
channels through device-specific commands.
The program will attempt to communicate with the magnetometer using the default
communications port. If you get a message such as the one seen above: “Could not open
COM11!” this means that MagLog is unable to read any data coming in on the specified
communications port. The following steps should allow you to systematically correct the
error and get your device working:
1) Set the communications port and baud rate. Complete the entries in the boxes
labeled “Port” and “New Baud Rate”. After you have specified these, you should
then press “Send Configuration”. (Default baud rate for the CM-201 counter in G880/881/823 is 9600. Port refers to the computer serial port to which you have
connected the device). You should then see a series of numbers (magnetometer data
strings) scrolling up on the large empty box. This confirms that the communications
port is receiving data. MagLog can also use a TCP/IP connection to talk to the
magnetometer (for example, the magnetometer can be connected to serial-to-TCP/IP
converter and the converter connected to the network). To use TCP/IP select “TCP/IP”
from “Port” list (the last selection in the list). Then enter a “Host” name or IP address
and a “Port” number and press the “Connect” button to initiate the connection.
2) Enable analog channels: This is accomplished by making entries in the section
labeled “Analog Channels On”. “Counter” refers to the CM-201 counter board that is
installed in each magnetometer, so we are effectively setting up the analog output
channels in each magnetometer sensor electronics assembly. To enable a channel from
a counter, enter a channel number as shown above. Multiple channels should be
separated by a space. For instance, if you have two magnetometers, one with field,
signal, depth, and altimeter and the second with field and signal, you will enter the
Counter 1: 1 2 3
Note: Channel 1 default is Signal Strength
Counter 2: 1
Channel 2 default is Depth Transducer
Channel 3 default is Echo Sounder Altimeter
In this case, “0” always refers to the digital magnetic field value that is always on, and 1,
2, and 3 refer to the auxiliary analog channels that the program will enable. It is not
necessary to enter “0” in the dialog box because the magnetic field is always enabled. If
the analog channel is not valid, you will probably get some nonsensical “dummy” strings,
i.e., the counter will try to output a number even if there is no reading. If you accidentally
enable a channel that is not valid, you can correct the setup and then re-send it to the CM201 counter in the magnetometer using the “Send Configuration” button.
3) Check for correct data: After entering all channel information, you can check to see if
you are getting correct data by counting the number of transmitted data fields separated by
commas. For instance, in the above example, one would expect to see strings such as:
40001.24, 0243, 2001, 1209, 40291.35, 0543
From this, you could easily tell if there was a missing a channel by counting the fields. In
this case, you specified six channels and received six strings, the correct result. To
examine the data you can check “Stop window update” check box. This stops updating the
screen scrolling which enables one to examine the data.
Field “Estimated data rate, Hz” shows approximate sample rate as the CM201CFG
program estimates it. This is approximate value in Hz for the QC purposes.
4) Specify Cycle Time: You may also specify the cycle time – the time between
sequential magnetometer readings. Cycle time is specified in units of 0.01 seconds (total
time between readings = cycle time times .01 seconds), so if you want ten magnetometer
readings per second, you will specify 10, or if you wanted five magnetometer readings per
second, you will specify 20. Note that for the CM-201 the practical limit on cycle time is
approximately 20Hz. The system can be run at 40Hz or higher but there will be
significant degradation of the signal quality.
Remember that you have to press “Send Configuration” to make any changes to the
above configuration. If you want to reset the magnetometer to its original powered on
state, press “Reset Configuration”.
Note: After you have specified these settings once, setup will default to these same
settings until you change them.
In 2002, Geometrics began shipping G-881 and G-882 marine magnetometers with the
CM-221 counter hardware. This counter allows storage of default startup parameters in
the processor memory. A button labeled “Store configuration” is available for those
sytems employing the CM-221 counter hardware (check your firmware version to see if
your magnetometer has this feature). After powering down the magnetometer and
powering it back up again, the magnetometer starts up with the same settings (number of
analog channels, baud rate, sample rate, etc.) as it had when the configuration was stored.
Solutions to Possible Communications Setup Problems
a) No magnetometer data on the screen: This could mean that you have set up an
invalid communications port, your magnetometer is not powered up, or your
magnetometer is not properly connected. If you are not getting a message like the one
described above: “Could not open COM11”, you should check to see if your
magnetometer is on. If it is, test the communications port by using another source of
external data (e.g. you could try a simulator that outputs RS232 serial data streams, or
you could hook up a GPS or Personal Digital Assistant to that port to check
If you are unable to open the communications port, make sure that you don’t have any
other devices using the same port. To check, right click on My Computer, then left
click on Properties, left click on Device Manager and then scroll down to Ports (Com
& LPT). Expand this section by clicking on the + box next to Ports and identify that
the Com port you are setting up exists and that it is not conflicting with any other
device (IRQ conflict). Also, some “listening” programs such as Hyperterminal, PDA
Palm HotSync, Modems or Fax software will keep the communications port busy until
you exit the program (check the Windows task bar at the far right for running
programs). If you still have trouble, it sometimes helps to completely shut off the
system, and reboot. This will reset all the computer hardware.
You must resolve any problems in the setup of communications ports at this time. If
you are not getting good transmission from the magnetometer or GPS please detail all
information about the setup and hardware configuration in an email to
[email protected] We will do our best to quickly troubleshoot your hardware
b) Data is scrolling up the screen, but it is not recognizable: Check the baud rate.
Often, if you are using the correct communications port, but the baud rate is incorrect,
you will get gibberish (strange characters) on the screen.
c) MagLog cannot communicate with the magnetometer. In some systems with long
tow cables, the PC serial port does not have enough power to propagate serial data
from the computer to the magnetometer. This results in an inability to interrogate and
command the magnetometer. There is a solution for magnetometers that have flash
memory (CM-221 counter): connect the magnetometer to the computer using a short
jumper cable, configure it using CM201CFG program (available on your desktop after
MagLog is installed), store configuration and then disconnect the magnetometer. Then
change “DO NOT CONFIGURE 880=1” in maglog.ini file stored in the windows
system directory. This prevents MagLog from attempting to re-configure the
magnetometer each time a survey is started. For additional information regarding
switches in MagLog.ini file see “Setting options through “Maglog.ini”.
After you are done, press “OK” and you should see the following screen:
5.3.2 Configuring MagLog or MagLogLite to recognize incoming data
We previously used MagLog to inform the Magnetometer what data we wanted sent to the
surface. Now we can make selections about how MagLog will interpret the incoming data
flow. First, specify the number of channels you expect to see as per the previous
magnetometer setup, and label the device name for in-survey reference. You can also set
pre-set limits on the values of the analog and digital channels that will generate warning
messages (visual and verbal or auditory, external speakers recommended) if values go out
of range. This is very useful in a noisy environment where you cannot watch the screen at
all times. Types of errors which generate verbal and visual warning flags might be a loss
of data transmission, a bad GPS fix, sensor going too deep or sensor too close to the
To specify an alias for your device (the name that will appear on all windows associated
with your magnetometer), you can type a name under “Alias Device Name”. Here, we
have selected “G-880”.
The sensor setup is also very important. Typically the number of magnetometer sensors
and channels is set automatically. However in certain cases (when the magnetometer
cannot be interrogated or configured due to downlink communication difficulties) you
may need to carefully count how many strings are coming in your communications port.
Above, a sample string for two magnetometers was given as:
40001.24, 0243, 2001, 1209, 40291.35, 0543
The incoming string is shown above. The MagLog program needs to know
1) The number of concatenated magnetometers you have coming into a single
serial port – you can select up to eight by checking the sensor boxes as shown
(note that cable length and bandwidth considerations may limit the number of
concatenated magnetometers one can employ).
2) The number of additional analog channels for each magnetometer. The
magnetic field value is not assumed to be a channel.
If we apply these two rules to the string above, we notice that we have two
magnetometers, one with three analog channels, and the second with one analog channel.
Enabling the proper number of channels and sensors is very important.
You will have another opportunity to change port settings by selecting the “Port Settings”
button and entering information into the following dialog box. If the “G-880
Configurations” screen exited successfully, you will see the dialog box that reflects the
port settings you previously selected. Otherwise, port settings will default to COM1.
You also have the option to set various quality control values that will generate useful
warning messages during survey operations:
The quality control options are:
a) Signal: Set the minimum signal value you would like to allow during the
survey. Good data is characterized by a strong signal, and data with signals
lower than 500 are suspect. A good range for this value is probably
somewhere between 600 and 1200. If the signal drops below the set value
during the survey, you will get a warning message.
b) 8th RMS: This is the magnetic field quality control value that gives a measure
of how much the field is varying. The 8th RMS value is generated by
computing successive differences of 10 readings. A higher RMS is indicative
of a noisy field, and you should specify the highest value you will tolerate, e.g.
c) Min and Max Field: This will allow you to specify minimum and maximum
fields you expect to occur during normal survey. This could be set so that you
will be alerted to the existence of a large anomaly. Note that under trace
properties, you can set up an anomaly detection parameter (rate of change of
field) that is separate from this min-max value.
“Analog channel calibration setup” control group is disabled if device has just been added.
To access this group you need to have the magnetometer running. Complete the
magnetometer setup and then return to its properties box using “Configure / Input devices
dialog. You will have the ability to set quality control values for your analog channels
(e.g. depth and altimeter) by selecting the sensor number, channel number, and pressing
“QC Range…”. This will bring up a dialog box that you can fill out to set quality control
values. A sample is shown below:
Here, we have selected Sensor 1, and selected the analog channel, “depth”. The option
labeled “Do not apply QC range for this channel” is usually checked, which would result
in no quality control factors being used for this channel. However, we have unchecked it
and set a minimum value of 10, and a maximum of 1000. If a depth value is not within
the range we have specified, we will get a warning message.
Note: The signal quality control should only be enabled from the main screen. If you
enable quality control through the button, “QC Range”, but do not specify any values
under “QC” on the main screen, the program will not generate any warning
You also have the option of setting quality control values for the three unnamed
analog channels, 4, 5 and 6. (Channels 1 to 3 are for signal, depth and altimeter.
Additional analog channels are available in the 880 internal counter modules [CM201 or CM-221] for special purposes like yaw, pitch and roll sensors or radar
altimeter for small airborne systems using analog altitude output).
The calibration of analog channels will be discussed later in this manual. (see
Depth/Analog channel calibration)
When you are done, press “OK” to continue on with your setup, or “Cancel” to cancel any
changes you made.
Note: Once this screen has been exited, the only way to change the port settings is to
delete the magnetometer setup and start over.
Configuring the GPS
The GPS can be configured by highlighting the selection “GPS” located in the left
window of the Input Devices Configuration dialog box.
The following dialog box will appear:
This dialog box allows you to select a device name, configure the port settings (much like
that done with the magnetometer) and set quality control factors.
Click on "Port Settings" to specify the communications port selection.
The quality control factors available are:
a) Differential GPS fix required: This will give a warning message if there is no
differential fix available.
b) Number of Satellites: If the number of satellites is not at least as many as you
specify, you will get a warning message each time a new GPS reading comes
in (e.g. in the above example, you will never get a warning message because
there are always at least 0 satellites). This can get rather annoying if you don’t
have enough satellites, but it is a good indicator of the accuracy of the GPS
coordinates. It is commonly understood that 6 or more satellites are necessary
to get the best position data.
Configuring Serial Event device
Serial Event Mark device is useful if some event is used as an index for all data streams,
and the user wanted to include an “event number” in every log file and print it. Let’s
assume that some device generates strings like:
1241, 21-Feb-01 17:24:30,351783.12,146676.69,01°19'36.000"N,103°40'04.002"E
Here is first number, “1241” is a fix (or shot event) number. To include this “fix” value
into every log file and print it, the user has to configure a Serial Event Mark device. Note
that the “fix” number is always an integer.
Go to Configure / Input devices and select Serial Event Mark from the list of available
devices on the left side of the dialog box. Press Add and the following configuration
dialog box will appear:
Alias device name: User enters the device name.
Max string length: Set buffer size to accommodate any possible string coming out of
your device. In many cases 2000 will work just fine, but you should change this value if
your device generates particularly long strings.
Fix field position: Numerical field number where “fix” is located. In the above example
it would be 1, because the “fix” is the first number in the string. Here is how MagLog
parses an ASCII string:
We have used a symbolic format for clarity, here “11111 …. 66666” represents numerical
fields and “s” represents a separator that can be any character that is not in the following
numerical valid character string: (Ee and De refer to exponential notation)
To display a value “11111” as a fix you should refer to it as “1” and to display value
“66666”, refer to it as “6”. (Count numerical fields from left to right using separators)
Termination char This is the last character of the string. In the case of ASCII strings it is
normally ASCII 10 (LF or Line Feed).
If a Serial Event Mark device is present, it will be inserted in the log files of other devices.
MagLog records the current fix value before recording the date and time stamps.
5.6 Configuring the ORE Trackpoint II Sonar Tracking Device
ORE Trackpoint II should be outputting EC-3 format to be compatible with MagLog.
Please see ORE manual how to configure Trackpoint II.
To ass ORE to MagLog survey select ORE Trackpoint and click on the “ADD” button.
You should see the screen below:
Here, you can set the device name (specified as ORE in this example) and the
communications port and baud rate (through the “Port Settings” button).
After you have pressed “OK”, you will then see the following display in the Input Devices
dialog box:
This confirms and summarizes the hardware that has been configured.
5.7 Configuring the GR-800 Gamma Ray Spectrometer (airborne):
Select GR-800 and click on the “ADD” button.
The GR-800 Settings dialog box will appear on the screen:
The “Number of predefined Accumulators” is varies in some GR-800’s. Some people may
have custom firmware with more or less than 12 accumulators. This number represents the
number of custom channels (like K- potassium40).
Configuring the DAS1700 analog to digital converter card:
Note: This device is primarily used in specific applications where multiple analog voltages
are being logged. In the digital world, this option is less frequently required.
Select DAS-1700 and click on the “ADD” button.
The DAS-1700 Settings dialog box will appear on the screen:
The DAS-1700 card is shipped with Driverlinx software where you can configure the card
(Interrupt, DMA, single ended or differential mode, and device number).
You can have up to 4 analog cards in your computer. However only one card can be used
at a time and it will be enabled by selecting the corresponding device number.
Select the card you want to use by entering a number between 0 and 3 for the device
The sampling time is entered in seconds. All the analog channels will be sampled at that
rate at approximately the same time (10 microsecond delay between each channel).
Refer to the Driverlinx manual for more information. Note that if you change any
parameters using the Driverlinx driver (including switching from 8 channels differential to
16 channel single ended), you must reboot your computer.
If no card is plugged in your computer or an invalid IRQ and DMA have been set you will
get the following error:
Configuring a Generic serial device
To log and display customer supplied serial devices, MagLog provides a Generic Serial
Device interface. Devices that can be logged with this interface must comply with the
following specifications:
• Device output’s one string of characters per reading. The string should have a
unique termination character. The user is asked to provide the decimal value of the
string termination character.
• ASCII strings are preferred but binary data also can be recorded with some
• To be displayed by the MagLog program, the string should have a fixed number of
numerical fields separated with non-numerical characters. The number of fields
should not vary between readings.
To use the Generic Serial Device go to Configure / Input devices and select Generic Serial
Device from the list of available devices on the left side of the dialog box. Press Add and
the following configuration dialog box will appear:
The user must enter:
Alias Device Name: Enter a device name as you wish it to appear in MagLog.
Max string length: Set buffer size to accommodate any possible string coming out of
your device. In many cases 2000 will work just fine, but you should change this value if
your device generates particularly long strings.
Max number of field to parse In this example, MagLog will try to parse first 5 numerical
fields of your string. If the actual number of numerical fields in your string is more then 5
then you won’t be able to display the rest of the values unless you change this number to a
larger value. If total number of fields is less then 5, then zero values are displayed for
those fields where there is no data. However, the string will always be logged in its
entirety regardless how many fields are set to parse for display purposes.
Termination char This is the last character of the string. In the case of ASCII strings it is
normally ASCII 10 (LF or Line Feed).
Binary or BCD data If you device produces binary output, MagLog logs this data as
mixture of binary bytes and program added ASCII strings (time and date). If you check
this box MagLog will convert and log the data in hexadecimal format. This allows one to
create and log a file that consists of ASCII characters only (hexadecimal code is in ASCII
Note: Although binary data is logged to disk, there is no display for binary data in
MagLog and presently MagMap2000 processing software also will not accept this
type of data file.
Here is an example how MagLog parses an ASCII string. We have used a symbolic format
for clarity:
Here “11111 …. 66666” represents numerical fields and “s” represents a separator that can
be any character which is not in the string: “-0123456789.EeDe+” To display a value
“11111” in MagLog you should refer to it as “channel 1” and to display value “66666”,
refer to it as “channel 6”.
Configuring the RMS AADC Aircraft Compensator
Go to Configure / Input devices and select AADC magnetometer from list of available
devices on the left side of the dialog. Press Add and this configuration dialog appears:
Alias device name: MagLog automatically knows the device name
Number of Sensors: Total number of magnetic sensors. MagLog supports AADC
systems with one to four sensors.
Maximum / Minimum magnetic field: If recorded magnetic field does not fall into the
preset range, a QC Alarm is generated and the QC device light is turned from green to
8th difference limit: If the magnetic field RMS 8th difference value is being calculated and
it exceeds the preset limit, a QC Alarm is generated and the device light is turned from
green to yellow.
For the RMS AADC to be used with MagLog, it must be configured (on the front panel)
so that it outputs the following information:
1.) Start char: symbol '#'
2.) Scan number: integer value (7 digits max)
3.) X-component (Fluxgate)[nT]: real number
4.) Y-component (Fluxgate)[nT]: real number
5.) Z-component (Fluxgate)[nT]: real number
6.) Uncompensated mag1 [nT]: real number
7.) Uncompensated magN [nT]: real number
8.) Compensated mag1 [nT]: real number
9.) Compensated magN [nT]: real number
10.) Error code: integer
Here N cannot be more then 4 and the user must configure the settings appropriately.
MagLog does not parse (1) and (2), so the logical channels start with (3) (X fluxgate).
5.10 Configuring G-886 / G-877 proton magnetometers
Like the Geometrics cesium vapor magnetometers, our proton precession magnetometers
require MagLog to query the device to determine the hardware configuration and to set up
the system. To set up the G-886 or G-877 magnetometer, go to Configure / Input devices
and select 886 Magnetometer (used with both 886 and 877) from the list of available
devices on the left side of the dialog box. Press Add and this configuration dialog box
will appear:
Alias device name: MagLog will use the device name you enter.
Cycle rate, s Sample rate in seconds (cycle time) for the magnetometer. The minimum
allowable value is 0.5s (two readings per second). MagLog will configure the G-886/G877 hardware to cycle at this rate.
Tuning, nT: Expected background magnetic field value for magnetometer hardware
tuning. MagLog will configure the magnetometer hardware to this tuning value.
Where to get tuning: Depending on your selection the program can obtain G-877 tuning
values from different sources. There are four options:
• Have user enter appropriate tuning value in the field above.
• Select auto-tuning mode for the 877 magnetometer. This is not recommended in
most cases (see explanation below).
• Have user enter his approximate position on Earth (latitude and longitude) and use
the internal IGRF model to calculate Earth’s magnetic field at that point. (For more
information about the IGRF model see, for instance IAGA Working Group V-8
(1995). International Geomagnetic Reference Field, 1995 revision. Submitted to
EOS Trans. Am. Geophys. Un., Geophysics, geophys. J. Int., J. Geomag.
Geoelectr., Phys. Earth Planet.Int., and others. You also can check out
• Have MagLog take the current position from the attached GPS device (if GPS is
available) and calculate the tuning value using IGRF model (recommended when
GPS is connected)
For best operation, the tuning value should be within the range of ± 500 nT of the average
field in the survey area. The IGRF model suits this criterion perfectly and is a good
solution for quickly tuning the magnetometer, even considering annual drift.
The program updates the tuning value when one of the IGRF options is selected. For
example, if the user knows his approximate lat/long position, he may select “IGRF – enter
your position” in the drop list. The following dialog appears:
Enter the approximate position of the survey area in decimal degrees and the program
calculates Earth’s magnetic field at this point and uses the value to tune the G-877 or
G-886. To enter another position, just re-select the same string in the drop list.
When user selects “IGRF – take position from GPS”, the program will try to obtain the
position from the last GPS reading. If the GPS data is available, the following message
Check the reported position to ensure proper calculation of the reference field.
Port settings. Set serial port communication settings.
Maximum / Minimum magnetic field: If recorded magnetic field does not fall into the
preset range, a QC warning is generated and the device light is turned from green to
8th difference limit If the calculated RMS 8th difference is greater than this value, a QC
warning is generated and device light is turned from green to yellow.
Signal strength. If proton magnetometer signal level is less then this value, a QC warning
is generated and the device light is turned from green to yellow.
Use depth sensor to interpolate position. If this box is checked and real time position
interpolation is enabled during the survey (see “The Interpolator”) then the depth sensor
reading can be used to mathematically reduce layback distance (x) relative to the cable
length (hypotenuse) Note that proper depth sensor calibration is required for this feature to
work properly.
Upon completion of this dialog box and the following serial parameters dialog box,
MagLog will communicate with the magnetometer hardware to ascertain its configuration.
This may take as a few seconds up to as long as a few minutes depending on baud rate and
other parameters..
The program waits for incoming data strings and then sends a command to turn the
magnetometer into a terminal (command) mode. Once in terminal mode the program
issues a command to dump all hardware setting and proceeds to parse magnetometer’s
output. Upon completion, the program turns the magnetometer back into command mode.
The user can see this process in the following window:
Note that at this stage MagLog simply reads the device configuration but does not set the
cycle rate and tuning value. This occurs after you close Input Device Configuration dialog
box and again this may take a minute (it also happens every time when you change cycle
rate and tuning for an already configured device). MagLog displays a dialog box with the
magnetometer messages as below:
Note: The AutoTuning feature is not recommended if you know the field range.
Read below for additional explanation.
The G-877 magnetometer employs an AutoTuning function to automatically tune the
magnetometer to the actual field value. This can maximize signal-to-noise ratio when the
field values are expected to vary as much as 3,000 nT or more over a short amount of
time. The situation where this might be encountered would be in high gradient areas
associated with volcanic geology or in harbor areas where there are large gradients due to
steel objects. However, because the width of the G-877 tuning is broad (about plus-minus
2,000 nT before any noticeable degradation in signal strength is visible) and because
under some low signal-to-noise conditions (in a low field area such as off the
coast of Brazil or Peru, going east-west) the magnetometer may lose "lock" on one
reading. In this case, the magnetometer will engage a signal search mode and therefore in
general, it is not recommended that the AutoTuning function be used under all conditions.
When the AutoTuning function is informed that the magnetometer has lost "lock" of the
field, it begins a search starting at the field value default which is set into the G-877
magnetometer (not the last known good reading for instance) and begins sequentially
retuning to values at approximately 5,000nT above and then below the preset value in
larger and larger jumps until it acquires signal or starts the process over. This can take
several minutes if the default field value is not set to the background field value of the area
you are surveying. Normally, one would not expect to encounter variations exceeding
2,000 to 3,000nT even over targets such as anchors. However, this might occur over large
steel vessel at distances less than 500 ft., but under those conditions losing "lock" due to
mistuning is a valid indication of a huge magnetic anomaly.
5.10.1 G-877 depth calibration
Geometrics G-877 magnetometer comes with a depth transducer calibrated at the factory
and normally needs no calibration. However if the user has altered the factory settings or
simply wants to provide more accurate depth estimation, the MagLog calibration
procedure can be used.
NOTE: Regardless of units selected for the survey (feet or meters) depth is always
calibrated in meters.
The G-877 device stores all settings inside the magnetometer non-volatile memory and the
user can permanently save calibration settings in this flash memory. The values are
permanent and will not be lost after power is removed.
The G-877 has a sophisticated user interface accessible via a terminal program (such as
MS Windows Hyper Terminal). This allows the user to make G-877 software changes
employing standard Windows software. However, an inexperienced computer user may
find using the terminal emulation mode difficult and therefore MagLog includes an easy to
use interactive menu dialog to compute and store depth calibration parameters.
Here are general steps performed by MagLog to calibrate the G-877 depth sensor.
Find depth channel in G-877 data stream, or enable it if it is not enabled.
Set format appropriate for calibration.
Reset internal G-877 depth scaling and bias to their initial values (scale 1, bias 0).
Start magnetometer. Have user deploy and level the G-877 at different depths and
take readings.
Calculate calibration coefficients based on several data points collected by the
Transform calculated scale and bias in the format appropriate for G-877 and write
values into G-877 memory.
Set new format for the depth reading.
Save settings permanently in the G-877 device’s flash memory.
If depth transducer calibration is accomplished using MagLog by itself, step (4) requires
some user intervention. If the calibration is done via a terminal program, the user will be
required to implement all 8 of the above steps using coded key commands.
Note: Due to possible low baud rate communication rates, steps 1-3 and 5-8 can take
several minutes. Please be patient during the calibration process.
The Calibration option is only available during the device setup which means that if you
want to reset the calibration parameters that are stored in the G-877 electronics, you must
setup a new survey and add the G-877 device. The G-877 can be the only device in the
survey and you need not actually collect any data for that survey. After you press the
“Add” button in “Configure / Input devices” dialog, the following screen appears:
Here “Perform depth calibration as part of setup” is unchecked by default. Check it if you
want to calibrate G-877 now.
After MagLog puts the G-877 into terminal mode, it confirms desire to calibrate:
If you answer “Yes”, MagLog starts with item (1) from the list above. The user can
observe communication messages between the program and the G-877 on the screen. As
soon as steps (1) to (4) are complete, MagLog launches the calibration dialog box:
Please read the “Directions” section of the dialog box and follow the instructions. Use the
following procedure to calibrate the magnetometer:
• Place the G-877 fish at depth 0 (for instance, on deck or floating at surface). Enter
Value equal to 0 and press Reset av. button. Wait about a minute to allow device to
acquire some data. Then press Add to the list. Note that new string appears in the
list at the bottom of the dialog box.
• Lower the magnetometer down the water column to a predetermined depth by
marking the cable beforehand. Make sure that the Current value is changing (if
current value is not changing, it may mean that your G-877 does not have the
depth transducer installed or that the sensor or associated electronics is
malfunctioning…contact Customer Service immediately). Measure the actual
depth by pre-marking the cable or using a rope. Enter the actual depth in the Value
field. Press button Reset av. and wait for about a minute to allow device to acquire
new data. Then press Add to the list. Now the program has two depth points and
can calculate depth and bias parameters for initial calibration.
• Lower magnetometer to another depth and repeat. Compare “predicted” and
measured values in the list to make sure that they are consistent. If maximum depth
in the list is less than 20 meters, the results may not be optimal and a deeper
calibration point should be used.
You can delete a point in the list by right clicking on it and selecting “delete”.
Press OK (accept calibration) if you are satisfied with the results. MagLog will prompt
you to save the calibration data into a file. This file is for your reference only and is
not used by MagLog (remember the parameters are actually stored in the G-877 fish
electronics). Here is an example:
877 depth calibration
# Reading Value
1 2340.36 0.00
2 4095.00 40.00
Results scale: 0.022797
bias: -53.352331
G-877 setup values:
depth scale factor : 5083
depth bias sign (0 = add, 1=subtract) :1
depth bias : 868
depth decimals : 5
The last four strings represent values that are suitable for G-877 calibration in terminal
mode. These are provided in case you need to reenter them into the G-877 using terminal
Now the program will set the new values into the G-877 magnetometer, by converting the
depth output format and saving the results into the flash memory. When all these steps are
complete, the following message will appear:
At this point, MagLog proceeds with the normal G-877 setup process. If you are not
going to use this survey for actual data acquisition, you may terminate it at this time.
5.10.2 G-877 Terminal Calibration Log
I n this section we show an example of the G-877 depth calibration process using the
Windows HyperTerminal program. This log corresponds to MagLog depth calibration
described above. Characters that are sent by MagLog (or typed by the user if
HyperTerminal is used) are printed with bold font. The fields that are being altered by
MagLog or by the user are marked with an asterisk (*).
G877 Version 1.13
Abandon changes
Cycle time
Every thing
cable and sensor
Next (multi systems)
Save parameters
Baud rate
Display all parameters
Format of output
Mode of operation
Run magnetometer
-> F
Preamble :=
field display position(1=1st, 2=2nd, .. etc) : 1
field display format :######.##
time display position(0=none,1=1st, 2=2nd, .. etc) : 0
time display format :#####.#
fid display position(0=none,1=1st, 2=2nd, .. etc) : 0
fid display format :#####
signal display position(0=none,1=1st, 2=2nd, .. etc) : 2
signal display format :####
* depth display position(0=none,1=1st, 2=2nd, .. etc) : 3
* depth display format :####
input voltage display position(0=none,1=1st, 2=2nd, .. etc) : 0
input voltage display format :####
temperature display position(0=none,1=1st, 2=2nd, .. etc) : 0
temperature display format :####
polarize voltage display position(0=none,1=1st, 2=2nd, .. etc) : 0
polarize voltage display format :####
tuning display position(0=none,1=1st, 2=2nd, .. etc) : 0
tuning display format :###.#
Status display position(0=none,1=1st, 2=2nd, .. etc) : 0
Status display format :##
Postamble :\N
-> P
Password :VERADDA
signal scale factor :
signal bias sign (0 = add, 1=subtract) :0
signal bias :
signal decimals :0
depth scale factor :1
depth bias sign (0 = add, 1=subtract) :0
depth bias :0
depth decimals :0
input voltage scale factor :
input voltage bias sign (0 = add, 1=subtract) :0
input voltage bias :
input voltage decimals :0
temperature scale factor :
temperature bias sign (0 = add, 1=subtract) :0
temperature bias :
temperature decimals :0
polarize voltage scale factor :
polarize voltage bias sign (0 = add, 1=subtract) :0
polarize voltage bias :
polarize voltage decimals :0
-> R
---------- Running magnetometer software
Setting Baud rate
20131.84 4095 4095
20131.84 4095 4095
< Here is magnetometer put at different depths >
G877 Version 1.13
Abandon changes
B Baud rate
Cycle time
D Display all parameters
Every thing
F Format of output
cable and sensor
M Mode of operation
Next (multi systems) R Run magnetometer
Save parameters
T Tuning
-> P
Password :VERADDA
signal scale factor :
signal bias sign (0 = add, 1=subtract) :0
signal bias :
signal decimals :0
depth scale factor :83
depth bias sign (0 = add, 1=subtract) :1
depth bias :
depth decimals :4
input voltage scale factor :
input voltage bias sign (0 = add, 1=subtract) :0
input voltage bias :
input voltage decimals :0
temperature scale factor :
temperature bias sign (0 = add, 1=subtract) :0
temperature bias :
temperature decimals :0
polarize voltage scale factor :
polarize voltage bias sign (0 = add, 1=subtract) :0
polarize voltage bias :
polarize voltage decimals :0
-> F
Preamble :=
field display position(1=1st, 2=2nd, .. etc) : 1
field display format :######.##
time display position(0=none,1=1st, 2=2nd, .. etc) : 0
time display format :#####.#
fid display position(0=none,1=1st, 2=2nd, .. etc) : 0
fid display format :#####
signal display position(0=none,1=1st, 2=2nd, .. etc) : 2
signal display format :####
depth display position(0=none,1=1st, 2=2nd, .. etc) : 3
depth display format :###.##
input voltage display position(0=none,1=1st, 2=2nd, .. etc) : 0
input voltage display format :####
temperature display position(0=none,1=1st, 2=2nd, .. etc) : 0
temperature display format :####
polarize voltage display position(0=none,1=1st, 2=2nd, .. etc) : 0
polarize voltage display format :####
tuning display position(0=none,1=1st, 2=2nd, .. etc) : 0
tuning display format :###.#
Status display position(0=none,1=1st, 2=2nd, .. etc) : 0
Status display format :##
Postamble :\N
-> S
Press "Y" to save to FLASH any other key to abort:Y
At this point MagLog notifies the user that the calibration procedure is complete.
5.11 Configuring G-822A Super Counter device
MagLog is specifically designed to log data from Geometrics airborne G-822A Super
Counter. Go to Configure / Input devices and select Mag 822A from the list of available
devices on the left side of the dialog box. Press Add and the next configuration dialog box
will appear:
Alias device name: Assign alias device name here
Number of Sensors: Total number of magnetic sensors. Maximum number is 4.
BCD format. Check this box if the magnetometer counter is set up to output in BCD
mode, XS3 (very high speed up to 100Hz sample rate). In this case the program logs a
hexadecimal dump of magnetometer output.
5.12 Configuring EM61 device
This feature provides a logging interface for the EM61. Note that this device needs to be
triggered from the MagLog program by sending a command via the serial line. Therefore
it should have both Tx (transmit) and Rx (receive) lines wired in the interconnecting cable.
Note: If you have multiple EM61 devices and you want to trigger them all at the
same time, you can use one Tx line from one serial port (on the PC). Connect this
line to all Rx pins on all the EM61’s, i.e., do not connect the other PC Tx wires from
the other PC serial ports.
Go to Configure / Input devices and select EM61 from list of available devices on the left
side of the dialog box. Press Add and this configuration dialog box will appear:
Alias device name: Assign alias device name here
Number of Sensors: Total number of electromagnetic sensors. .
Sampling Time (s): Trigger interval, in seconds.
Battery Warning (V): Voltage level to generate “low battery” warning.
5.13 Configuring EM61 Mark II device
This device provides an interface to the newer EM61 Mark II system. It has a similar setup
to the EM61 but there are some significant differences in data acquisition. Like the EM61,
this device needs to be triggered with a serial character; therefore both the transmit and
receive wires of the serial port must be wired. The original MagLog interface design
attempted to match the time when a trigger character was sent with the time of the data
arrival. However at high cycle rates (around 100 ms per sample) the device cannot
respond within the sample interval period. This means that if one trigger character was
sent at 0 ms and the next at 100 ms, then at 200 ms, etc. data from the 0 ms trigger can
arrive during 0-100 ms interval or 100-200ms interval or even in 200-300 ms. If for some
reason the EM61 Mark II does not respond to the trigger character (for instance, if the
trigger character was lost due to disconnection of the device) the trigger-data sequence is
distorted which appears as additional latency (e.g., time stamp assigned to the data related
to previous data, not the current data).
One of the techniques employed by MagLog is to count the number of triggers in the
trigger buffer that did not produce data. For example if 10 trigger pulses were sent without
getting data back the program knows that on the next data arrival the trigger and data
buffers should be flushed because it is likely that there was data loss or a cable
Another method used to address this potential problem is to record the time of the data
arrival. MagLog records this time as a time difference in ms between the arrival and
trigger event times. Thus the arrival time can always be calculated (that is to say with
Geometrics MagMap2000 program, which knows about this feature and computes the
absolute arrival time on the data input load).
The following is the configuration dialog for the EM61 Mark II device:
This is almost identical to EM61 except for the field “Max. allowed number of missing
triggers” discussed above.
Note: To ensure proper operation and estimate overall latency of the system
Geometrics recommends a latency test before surveying. The test need only be made
only once for particular equipment set (including PC, EM61MII and GPS). If any of
these parts are replaced or new software installed, a new latency test should be made.
5.14 Configuring Gyro Compass device
MagLog can handle data from NMEA compliant Gyrocompass device connected to one of
RS-232 ports (if your Gyro works with RS-422 use special wiring or RS422 to RS-232
converter). The Gyro hardware should output strings with the format:
Here is $HEHDT message prefix, 360.0 is heading (in degrees), “T” indicates that this is
true heading (not magnetic) and “2” after “*” is a checksum
If the Gyro outputs other strings they are ignored my MagLog. Go to Configure / Input
devices and select GYRO from list of available devices on the left side of the dialog. Press
Add and this configuration dialog box will appear:
In this case there is only one field to be set – the alias name.
5.15 Configure Cable payout indicator
Some marine systems can have devices that measure cable length automatically and
transmit the results via a serial port ASCII strings. Go to Configure / Input devices and
select Cable from list of available devices on the left side of the dialog box. Press Add and
the following configuration dialog box will appear:
Alias device name: Assign alias device name here
Units: Units are as per the setup of the indicator device. They can be meters, feet or
fathoms. This selection does not affect log file but should be set properly for use by
MagLog real-time layback Interpolator.
Cable length channel: Specifies device channel for cable length. Parsing rules are the
same as for Generic Serial Device.
Termination char: Decimal value for string termination character.
5.16 Configuring the G-858 magnetometer
The Geometrics G-858 MagMapper is a hand-held device used primarily for land
magnetic surveys. It has an option to output magnetometer data via its serial port and can
be used in conjunction with MagLog acquisition software.
• Set up for the G-858 console. Start a new survey as a Base station. Choose Store
mode as Transfer to PC only or Store & Transfer to PC. In the first case, data will
not be stored by the G-858 internally, but only by the PC. In the second case data
will be stored both in the 858 and externally you can download the data set and
process it in the Magmap2000 program. Of course you can also bring in MagLog
and MagLogLite Survey files into MagLog2000 as well.
Set up MagLog. Go to Configure / Input devices and select G-858 from the list of
available devices on the left side of the dialog box. Press Add and the next
configuration dialog box will appear:
Alias device name: Assign alias device name here
Number of Sensors: G-858 magnetometer can have one or two sensors connected.
BCD format: Always disabled for this device.
5.17 Configuring PULSE 12 EM device
JW Fisher’s Pulse 12 EM device may include up to 3 coils connected to three hardware
ports. Regardless of the real number of coils available, the device always outputs voltage
for these three slots – if there is no coil present, it will just output a constant value.
Therefore if the user has just only one coil and accidentally connects it to slot #3, he
should treat the device as a 3 coil system and neglect data for coils #1 and #2.
Next following dialog box appears to configure the Pulse 12 device:
As usual, user has to assign the alias name. Port settings are standard for any MagLog
serial device.
Note: It is necessary to eliminate the coordinate strings in the Pulse 12 data string
(starting with symbol “@”). MagLog automatically sets the filter reject prefix as “@”
to remove those strings, which are therefore not recorded.
5.18 Configure Echo Sounder device.
MagLog software provides a simple interface to marine echo sounder devices compatible
with the NMEA standard transmission protocol. The echo sounder option is available in
both (full and light) versions of MagLog software. The device should be able to output
via serial link a DBT message (water depth referenced to the transducer) in the following
Go to Configure / Input devices in the MagLog toolbar menu and select Echo Sounder
(NMEA) from list of available devices on the left side of the dialog box. Press Add and
the following configuration dialog box will appear:
Alias device name: Assign alias device name here
Port Settings: Standard serial connection parameters dialog.
An echo sounder device has the following channels: depth (feet), depth (meters) and depth
(fathoms). By default it only accepts strings with the prefix $SDDBT. All other strings are
rejected and are neither logged nor parsed. If for some reason your echo sounder has
different “talker ID” (Note: talker ID refers to the first two letter pair in the Prefix, i.e.,
other than “SD” in the example prefix) you can replace it by pressing “Serial filter…”
button in the Serial parameters dialog. The following window will be displayed:
To replace a device talker ID, press “Remove all” button, then type new prefix in “Prefix”
field and press “Add”. Note that the new prefix can only be in the form $xxDBT, where
“xx” is your talker ID. Then press Ok, close Serial Setup and device dialog boxes, and
restart the survey for the new setting to take effect.
5.19 TTL Pulse devices in MagLog
“Pulse devices” refers to external time tags or event marks. Please do not confuse this type
of device with the previous PULSE 12 EM device.
MagLog has ability to log the time of TTL pulse arrival that come to pin 10 of the printer
parallel port. The recommended voltage is 5 volts with a duration of not less then 1 Ms.
This pulse generates a parallel port interrupt and MagLog will then obtain the time of the
interrupt event.
Interrupt pulses can be treated with Geometrics parallel port custom drivers (under
Windows NT only) or with general purposes driver DRVX28 (under Windows NT and
WIN9x). The Geometrics parallel port driver has an advantage over DRVX28 because it
provides high accuracy time stamps (1ms or less). However, as noted its usage is limited
to the NT platform only. The Win9x DRVX28 driver gives less accuracy, in the 20 ms
range. This is no doubt sufficient for slow moving surveys but perhaps not for airborne
type surveys.
At present, the following devices are supported by one or the other of these drivers:
PPS (pulse per second) GPS device. Some (usually expensive) GPS receivers can
output 1 ms pulses synchronized with beginning of the UTC second. PC time
tagging of these pulses can be logged with MagLog PPS device. At the same time
GPS outputs UTC string which can be logged with MagLog Generic Serial
Device. Having logged both these data streams it is possible to recalculate PC time
into UTC and vise versa for increased accuracy of timing and positioning.
TTL Event Mark device is similar to PPS, but has some additional features: user
can set pulse counter starting value and increment. Often this is used as a shot
counter in seismic type surveys where the shot point must be reference to the
magnetometer reading.
Trigger. This device is based on Keithley CTM-10 / CTM-05/A internal
multifunction card that must be installed in the computer. This device works as an
internal pulse generator driven my MagLog. It is used to trigger the G-822A Super
Counter in high precision land and airborne MTADS type magnetic survey
systems. The device also allows the user to log the time of the trigger pulses with
accuracy to about 1 ms. It is available under the NT platform only.
Speedometer. Also based on Keithley CTM-10 / CTM-05/A multifunction card
and uses internal hardware counters to count pulses (without generating an IRQ to
the CPU). It is used to count wheel ticks in specially equipped land vehicles
(carts). It is available under NT only.
All these devices require a specialized driver and hardware installation. Please see details
under Hardware configuration section. In the section below we assume that the drivers
are properly configured and running.
5.19.1 Configuring TTL event Mark device
Go to Configure / Input devices and select TTL Event Mark from the list of available
devices on the left side of the dialog box. Press Add and the following configuration
dialog box will appear:
Alias device name: User enters device name.
Reset counter to starting value. This is effective when you edit the configuration of an
already running device. For example if the counter has counted: 1, 2 …50, and at 50 you
opened the configuration dialog box and changed the increment to 2 to get numbers 52,
54, 56… If “Reset counter number” is checked and “Start count number” is set to “0”,
then the result would be 0, 2, 4, etc.
If the box is not checked, then you would get 52, 54… regardless of the “Starting counter”
Starting count number: Initial counter value (integer).
Counter increment: Step to increase / decrease counter value. Negative value will
decrease counter, positive increase it. This is an integer value only.
Hold-off time: After program has received a pulse, it will not react to any additional
pulses during this hold-off time interval. This provides protection from switch contact
bounce or “ringing” in the wire that could produce false interrupts.
The Next group of parameters is effective only if device is powered by the DRVX28
driver (Win9x). If the device is based on Geometrics custom parallel port driver (NT
operating system only) these parameters need to be set directly in the Windows Registry.
Contact the factory for more information regarding our customer parallel port driver set up
for Windows NT.
Parallel port. Port where TTL pulse is connected. Note that you still can use this port for
the dongle key and for printing; however you will need a special adaptor to disconnect pin
10 from printer side and connect it to TTL pulse source. Contact Geometrics for more
information if you want to use this event mark or pulse counting feature.
IRQ. Interrupt line for printer port interrupt. Usually it is 7 for LPT1 and 5 for LPT2.
However this value can be changed in the BIOS setup (for the on-board parallel port) or
by switches (for ISA parallel port extension card). Consult your computer or extension
card manual.
Address: Parallel port base address. Similar to IRQ, this value can be altered by BIOS
setup or by switches. Consult your manuals.
Note: MagLog will not work with PCI parallel port extension cards.
It is recommended that you use the Digital Display mode for the TTL event mark device
If a TTL Mark device is present, it will change the log files of other devices: MagLog
records the current value of the event counter(s) before recording the date and time
5.19.2 Configuring PPS GPS device
Go to Configure / Input devices and select GPS PPS pulse from list of available devices
on the left side of the dialog. Press Add and next configuration dialog appears:
Alias Device Name: User inputs name of device.
Real time interval correction. One of the problems with the original PPS pulse design
was due to its short duration (1 ms). This kind of signal may or may not produce a PC
interrupt. Thus without special treatment (hardware or software) half of the pulses will be
lost. To solve this problem MagLog uses real time interval correction. Let’s assume the
program gets a pulse at a 1000 ms relative time interval. If the expected interval is 1000
ms and the tolerance is set to 5 ms, the program will be looking for the next pulse between
1995 and 2005 ms. If the pulse arrives during this interval, the program accepts it. If there
is no pulse between 1995 and 2005, the program artificially creates a pulse at 2000 ms, as
it would be as if it had arrived. The program does this in order to maintain data
synchronicity with external “pulse per second timing chains”, used for removal of GPS
and operating system latencies. If the pulse arrives at say 1500 ms, the program
disregards it assuming that this is just noise.
The Log file for this device has a keyword “PPS” and the program records the arrival time
in every string. There is no visual display for the PPS GPS device.
Note: After real time interval correction is selected you MUST restart the
survey for the option to take effect.
5.19.3 Configuring a Trigger device
This device requires a CTM-10 (or CTM-05/A) multifunction card to be installed in the
computer. Consult the “Hardware configuration” section and card manual how to install
the board. The device is available under Windows NT only, and the key.sys driver
must be properly loaded and running. If these conditions are met you can go to Configure /
Input devices and select Trigger from list of available devices on the left side of the dialog
box. Press Add and the following configuration dialog box will appear:
Alias Device Name: User enters the name of the device.
Counter: CTM-10 card has 5 counters that can be used to generate rectangular pulses.
Select the number of required pulse generators between 1 and 5. Note that the counter
selection will determine which pins of CTM-10 main I/O connector should be wired.
Period, ms: Period in milliseconds for generated pulses.
Duration, ms: Width of each pulse in milliseconds. If the signal is used to trigger the G822A Super Counter the duration should be 2 ms. (1 ms may be too short).
Real time interval correction. CTM-10 card has evidenced a problem with internal
interrupts, perhaps due to card design. This problem appears as false interrupt generation.
For example, if the period is set to 100 ms., the expected interrupts times are 100, 200,
300, … 1000 ms. However in a few cases the card may produce interrupts at 100, 200,
202, 300, … 1000. Here is 202 is a false interrupt and must be discarded. In this case, real
time interval correction should be used.
Let us assume that the first pulse arrived at 100 ms and that the period is 100 ms and
tolerance is set to 2 ms. Then all pulses that appear between 100 and 198 ms will be
discarded. OF the pulses arriving between 198 and 202 ms, only first one is counted. If
there were no pulses between 198 and 202 ms an artificial pulse at 200 ms is inserted. The
next period is counted from this artificial pulse (if there were no real pulses) or from real
pulse. Thus if a pulse came at 199 ms, the next check period would be between 297 and
301 ms.
Note: You should use this feature for proper operation unless tests show that there
are no false interrupts being generated. This could be a case when another parallel
port is used to log trigger pulse time.
Synchronize logging with trigger. If a trigger is used with 822A Super Counters and the
data is logged via serial ports, it is desirable that the trigger and serial log files match on a
per string basis. This means that the first trigger string should match the first serial string.
To ensure this, Synchronize logging with trigger box should be checked.
There is no display for Trigger device. The Log file has the keyword “TRIG” in each
string and time stamp.
Note: IF real time interval correction and synchronize logging with trigger
options are set you MUST restart the survey for these options to take effect.
5.19.4 Configuring Speedometer device (wheel tick)
This device requires the CTM-10 (or CTM-05/A) multifunction card to be installed into
computer. Consult the “Hardware configuration” section and card manual on installation
procedures. The device is available under Windows NT only, and key.sys driver must
be properly loaded and running. If these conditions are met you can go to Configure /
Input devices and select Trigger from list of available devices on the left side of the dialog
box. Press Add and the following configuration dialog box will appear:
The CTM-10 has 5 internal counters that can be used to count external pulses. Normally
these pulses come from vehicle’s wheels or odometer/speedometer. Counting does not
involve the main CPU unit and does not produce an additional IRQ overhead. During each
polling interval, MagLog reads the current counter’s value and writes the counter value
and ratio [time interval]/[number of events] into the log file. This last value can be
transformed into speed if the proper scale factor is used.
It is not recommended to use the polling interval with less then on pulse every 100 ms
because this can produce an additional load on the CPU, slowing graphics and logging
5.20 Generic Serial triggered devices.
Full version of MagLog program can handle devices, which require trigger to produce
serial output. Some of these devices need ASCII trigger string and produce ASCII output,
some require binary trigger string and produce binary output. Mixed cases are also can be
handled. All types of these devices are handled by Generic Serial Triggered device
Here we show how to use Generic Serial Triggered device using A/D converter from
DGH corporation ( DGH1141 and direction sensor from
MicroStrain ( 3DM-GX1 as examples.
Both devices must be configured prior to 8 bit, no parity, 1 stop bit prior to connection to
PC. Please see product manuals for configuration procedures.
This type of device has limitation similar to other MagLog devices: it can not handle multi
telegram messages. In addition, you also can not share port used for triggered device.
5.20.1 ASCII trigger, ASCII output. (DGH1141)
This device defers from Generic Serial Device only by the trigger. It needs trigger to be
issued by host computer to produce reading. The simplest trigger format is $1RD with
following cartridge return (decimal code 13). Program will run timer at user-selectable
interval and issue the triggers. Device produces ASCII strings terminated with cartridge
return symbol (decimal 13).
To use this device, go to Configure / Input Devices select Generic Serial Triggered device
on the left side and press Add button. The following dialog appears:
Here the following parameters have to be filled in:
Alias device name: Assign alias device name here. You cannot change this name after
device starts.
Data type: Possible choices are “ASCII TEXT” or “BINARY”. DGH1141 produces just
ASCII strings, so select ASCII TEXT.
Trigger type: Choices are “ASCII TEXT” or “HEX CODES”. Select “ASCII TEXT”
Trigger string: Type trigger string as it is required by the device (see device manual for
details). For DGH1141 it is just “$1RD” to acquire simple reading (other trigger strings
are also possible).
Trigger termination character, decimal: In most cases it would be or Line Feed (10) or
Cartridge Return (13). DGH1141 uses cartridge return.
Trigger sample interval, ms: This sets time interval for triggers.
Trigger sync mode: To prevent jamming the device, you could require that no trigger
could be issued if PC in the reception of the data from the device. This only could be a
case if high sample rate is used.
Data string length: This is buffer size to be used to accommodate one string of device
data. In fact, in case of ASCII data any number big enough (like 1000) would be
sufficient. This would be however critical parameter in case of binary data (see below).
Data termination character: In most cases, it’s 10 or 13. DGH 1141 requires 13. Note
that if you change it for existing device you need to re-start survey for changes to take
Max number of fields to parse: How many channels you might have in the data string.
The parsing rules are exactly the same as for Generic Serial Device device: any nonnumeric character is considered as field terminator.
Load and Save buttons: These are useful when you deal with binary devices and enter
your own parsing table (see below).
After you are done with the dialog press Ok button and standard Serial Port Setup dialog
appears. Set appropriate port and baud rate. Note that this type of device also can be used
with TCP/IP (but not UDP) and real time serial port connections.
New device appears in the right side of Input device configuration dialog:
If parameters are correct, green light appears on device bar. You can configure now device
display as usual using Configure / Displays configuration menu.
5.20.2 Binary (hexadecimal) trigger string, binary fixed length data (3DM-GX1).
Here we create device to handle binary data of fixed length. In some cases these data can
only be logged, and not parsed by MagLog. However MagLog provides basic parsing
capabilities for binary data assuming that they have standard format (such as 1, 2, or 4
bytes integer or floating values). Maglog cannot parse individual bit fields.
As an example here we use MicroStrain orientation sensor. This sensor can send out
different data; we will assume that we need Gyro-Stabilized Euler Angles. The command
to produce these values is “0E00” (in hexadecimal format). The response of the device is
11 bytes long and has the following format:
Byte 1
Byte 2
Byte 3
Byte 4
Byte 5
Byte 6
Byte 7
Byte 8
Byte 9
Byte 10
Byte 11
Header byte = 0x0E
Roll MSB
Roll LSB
Pitch MSB
Pitch LSB
TimerTicks MSB
TimerTicks LSB
Checksum MSB
Checksum LSB
In addition to these data, MagLog adds 4 bytes integer value in little endian format which
holds time delay between issuing the trigger and data arrival. Here we will parse all these
data, display and log them.
Again, to use this device, go to Configure / Input Devices select Generic Serial Triggered
device on the left side and press Add button. Fill in dialog values as it is shown below:
Alias device name: Assign alias device name here. You cannot change this name after
device starts.
Data type: Possible choices are “ASCII TEXT” or “BINARY”. 3DM-GX1 produces
binary data, so select “BINARY”.
Trigger type: Choices are “ASCII TEXT” or “HEX CODES”. Select “HEX CODES”
because trigger string is binary as well.
Trigger string: Type trigger string as it is required by the device (see device manual for
details). 3DM-GX1 requires two-character trigger. Type hexadecimal codes (do not use
prefix “0x” or “x”). You must type 4 characters. In this case these are “0E00”.
Trigger termination character, decimal: Leave it black.
Trigger sample interval, ms: This sets time interval for triggers.
Max. allowed number of missing triggers: This controls how device handles
disconnection. If there are more triggers issued than data received, device flashes its data
and triggers buffers and starts over.
Trigger sync mode: To prevent jamming the device, you could require that no trigger
could be issued if PC in the reception of the data from the device. This only could be a
case if high sample rate is used. 3DM-GX has internal buffer to accommodate up to 16
commands, so you don’t need to use sync mode.
Data string length: This is crucial here. Wrong length will not allow MagLog to receive
and parse data. Enter “11” as it appeared from the table above.
Data termination character: Not applicable for binary devices.
Max number of fields to parse: Not applicable for binary devices. Use Binary parser
Load and Save buttons: Saves entire device configuration (including parsing table). Does
not save however port and baud rate. You need this file to use in different survey as well
as to convert into ASCII representation using MagMap2000 software.
Binary Parser: By pressing this button user can configure how to parse data. It also
allows enabling checksum computation. The parser dialog is shown here:
By default, it is blank. Use Add channel button to add new channels to the device. Then
click directly on the table to modify name, start byte, type, endiannes, scale and bias. You
can also modify number of decimal places, but it only used in MagMap2000. It is
recommended if you use checksum (presently only no checksum or 3DM-GX1
computations is supported).
After your complete the channel table, press Ok and Save to store all information into text
file. It is saved into survey file anyway, so text file is not needed to run the survey. Text
file is needed to re-parse data in the MagMap2000.
If you modify parsing table for running device, you might want to remove display for this
device first. You also might need to re-start the survey.
After device dialog is completed, press Ok and program brings you into Serial Port Setup
dialog. Select appropriate baud rate and port number here. Note that this type of device
also can be used with TCP/IP (but not UDP) and real time serial port connections. Serial
port cannot be shared with other devices.
Below is an example of data logged for 3DM-GX1:
Note that each record consit of 11 data bytes, 4 delay bytes and 22 byets of ASCII time stamp. Note that
time stamp represent trigger time, not time of the data arrival.
5.20.3 Honeywell PPT (Precision Pressure Transducer) device.
Setup for the Honeywell PPT device can be accomplished using the Generic Serial
Trigger, which is available in versions 3.01b and later. Typical settings for the Honeywell
PPT to output pressure at 10 Hz rate is shown below:
Note that only channel 2 has information which needs to be displayed, because the data
message contains two fields as shown below:
where "01" represents the device address #1, “CP” represents the type of data, and
"1012.4" represents the value of the measurement, which is decoded by MagLog as
channel 2.
Also please note that a trigger device uses Windows multimedia timer. This means
a) You cannot have too many of these devices (about 10).
b) It affects your ability to use mini-windows.
There is a possibility to use a single Honeywell device for both
pressure and temperature. To accomplish this, follow this procedure:
1. Connect the Honeywell device to two serial ports.
2. Setup a Binary trigger device on port #1. Use a hexadecimal trigger string as:
This includes both triggers for pressure and temperature, along with cartridge returns.
3. Set up a filter on port #1 as "?01CP=". Uncheck the box so the filter is applied to the
logged data as well.
4. Set up a generic serial device (not trigger) on port #2. Setup a serial filter as ?01CT=".
Uncheck the box so the filter is applied to the logged data as well.
Now the two data streams are clearly separated and one log file holds only pressure and
other only temperature.
At present it is not possible to share a serial port used by the binary trigger. This is why
two physical serial ports are required.
6 Configuring Input Devices for Display
Once devices have been selected for input, you must now specify how you wish the
information to be displayed on the screen. MagLog creates one window for each device.
You can then add slots and traces to the windows to graph details that you want to see.
Window: An independent, sizeable object that you can use to display information
about your device. Only one is allowed per device
Slot: A subdivision of a window. You can have as many slots as you want, and can
use each slot to have as many traces as you want.
Trace: A graph of one variable.
This section will show how to configure the most commonly used displays, and will give
some generic features common to all displays.
To configure the display for a device use “Configure / Displays configuration” menu. You
need to select the device from the list of “Connected Input Devices”. Then click on
“Slots/Traces for display”.
The Display
Following is a description how to configure a device display. The G-880 magnetometer is
used as an example but the methods can be applied to all other devices with the exception
of the GPS and devices that have no visual display (e.g., trigger pulses).
To configure the G-880 display, you need to select the G-880 magnetometer and click on
“Slots/Traces for Display”.
You will get the following dialog box:
This window allows you to see the slots you have defined. In this screen, you have not
specified any slots so it appears empty. The options available allow you to add, delete, and
edit existing slots. Discussion in more detail follows:
Auto Add Slot: This button allows you to create one slot and one trace for each value
MagLog receives. In the case of the sample input string:
40001.24, 0243, 2001, 1209, 40291.35, 0543
MagLog will create a window split into seven parts (slots). Each slot will have one
graph (trace) that will correspond to a changing value in the above string. The slots
will be given default names such as “Slot 1” (corresponding to the changing value of
40001.24), “Slot 2” (corresponding to the changing value of 0243), etc. This option is
convenient for quickly getting a graph of all your data without having to customize
each individual slot and trace.
Add Slot: This button allows you to add a new slot.
Remove Slot: This will remove a selected slot and remove all traces inside the slot.
Properties: This will allow you to edit the properties of an individual slot once it has been
Finish: Exits the window.
Window setup: This controls window orientation, background color and font used for
annotation. It brings the next dialog box:
The following options are available:
Orientation: Set Portrait for vertical slots or Landscape for horizontal. Note in
general we find horizontal plotting easier to understand as a vertical “slice” down
through the data plots allows one to see all data at the same “time”.
Background color: set background for slot.
Slot border color: Set border color for the slot.
Auto center time, minutes. Set this time to auto center wrapped slots after certain
time. Use 0 to disable this feature.
Annotation font. Set annotation font for the slot header.
Use the same time scale for all slots. If this box is checked, then a change in the
time scale for one slot will cause an automatic change in the time scale for all slots
in the window. This makes it easy to keep all data slots synchronized.
6.1.1 Configuring a Slot
This dialog box appears when you have selected “Add Trace” or “Properties” from the
previous dialog box. It allows you to edit, add, and remove traces, as well as customize
individual features of the selected slot.
A slot is a rectangular region where traces (corresponding to a sensor or channel) will be
plotted. Slots are common to most MagLog windows, and will be used in the majority of
your displays.
A slot can have unlimited traces. All traces will inherit the slot properties such as vertical
scaling, and sizes of the traces.
You can fill in details of the current slot as follows:
Slot Name: This is the name you wish to give to the slot. It will be printed on top of the
Time Scaling: This is the total duration of the slot in seconds. If the duration of the slot
exceeds the total size of a device internal buffer, MagLog will not be able to re-draw the
complete slot. For instance, if the slot duration is large (say 600 seconds) MagLog will
display the data normally, scrolling down the slot. However when the user changes the
vertical scale, the beginning of the slot may not be plotted with data. The maximum slot
duration can be calculated as MagLog device buffer length multiplied by actual device
sample rate (see Setting options in “Maglog.ini” file)
Data Scaling: This is the width of the slot in data units. It corresponds to a variation of the
Pen width This how wide in pixels (1-5 pixels) the traces should be plotted. Higher
values will make the graph appear to have a fatter pen.
Grid Lines: This will allow you to put grid lines on your slot. They are by default turned
off, but you can turn them on and customize the color and frequency of the grid lines by
pressing “Grid Lines”.
The gridlines dialog box allows you to select time and data grid lines. You can also
specify the number of grid lines you want by adjusting the interval (in seconds). For
instance, using default settings in the “Slot Configurations” dialog box, you would get 10
horizontal grid lines if you enabled them by checking the “time” box.
You can select the color you want by selecting “Grid Color”.
Fixed scale: This allows user to set a fixed data scale for the When you press this button
next dialog appears:
To use wrapped scale (suitable for magnetic field display) uncheck Use fixed range for a
slot. All other fields in the dialog become grayed. Press Ok.
To use fixed scale, check this box and fill in other fields.
Min and Max values represents limits of the slot in data units. If data is not in these limits
nothing is plotted.
Positive axis left or down shows where maximum value is. For example if you plot depth
inside horizontal slot it makes sense to check this box.
Scaling method has next choices: Both, Min. Value, Max. Value. It defines how to scale
fixed range slot with arrow keys. It Both is set, then scaling changes both limits of the slot.
When Min. Value is set, only minimum limit is changed, the same with maximum. For
example to plot altimeter readings it makes sense to set fixed scale range, minimum value
as 0, maximum value as 100, positive axis down and scaling method as maximum value.
Then originally slot will represent depth in range 0 – 100 m. After you scale it with arrow
key it may represent 0 – 200 m range or 0 – 50 m range depends on the scale direction.
Use Digital Display Only: This option allows you to use the slot to output a numerical
rather than a graphed value. You can select either “vertical” or “horizontal” to show
whether you would like to output the values in a vertical column or a horizontal row when
you want to display numerical values for two or more traces.
Digits after Dot: This controls format of digital display.
You can also manipulate individual traces in the slot by using the following buttons:
Auto Add Trace: This works similarly to the previous option, “Auto Add Slot”. In this
case, a trace is generated for every data value, but all of them are confined to one slot. In
the case of the sample string,
40001.24, 0243, 2001, 1209, 40291.35, 0543,
selecting this option would yield seven graphs, all within the same slot. (See the
below discussion of traces for further description on how to identify them). The seventh
trace corresponds to the gradient. This gradient value is automatically calculated anytime
there is more than one magnetometer.
Add Trace: This option allows you to add and customize a trace.
Remove Trace: This removes the currently selected trace from the slot. It will no longer
be displayed.
Properties: This allows you to edit the properties of the currently selected trace.
In the screen above, no traces have been defined. To add a trace, click on “Add Trace”.
6.1.2 Configuring a Trace
Traces, which represent profile plots of the data, are also common to most displays.
The following dialog box allows you to choose what you would like to plot and how you
would like to plot it.
The available options are:
Trace type: MagLog can display single channels or combinations of channels. If you
want to plot just a single channel check Single channel. If you want to plot a combination
(such as gradient or depth + altimeter) check Linear combination.
Units (for digital display). This is the suffix to be added to the digital display allowing
easy recognition of the data source on the screen.
Sensor/Channel number: This represents which sensor (magnetometer) or which channel
(analog device such as depth transducer) or which predefined accumulators ( GR-800 or
GR-820 gamma ray spectrometers – used in airborne survey) you want to plot. In the case
of the earlier sample magnetometer string example:
40001.24, 0243, 2001, 1209, 40291.35, 0543
we plotted valid channels ranging from 1 – 7.
correspond to:
1 = Counter 1, Field
2 = Counter 1, Signal
In this case, the numbers would
3 = Counter 1, Depth
4 = Counter 1, Altimeter
5 = Counter 2, Field
6 = Counter 2, Signal
7 = Gradient (available only for 2 or more sensor systems)
Note: The gradient will always be included anytime there is more than one sensor.
(i.e., compatible with concatenated 880/881/823 only) To get the channel number of
the gradient, take the total number of channels specified for the magnetometer (in the
above example, six), and add one.
Horizontal Scaling Ratio: This is a full-scale multiplicative coefficient that will be
applied to the slot horizontal scale factor. This allows the user to plot the same channel at
different horizontal scale factors in the same slot. The total width of the trace is found by
multiplying the horizontal scale factor for the slot by the horizontal scale factor for the
trace. In the case of this example, if we specified a horizontal scale factor of 2, and
horizontal scaling (specified in the slot configuration screen) to be 128, the data would
span a range of 256. If you had one trace with a scale factor of 1, and the second with a
scale factor of 2, the second trace would appear to be one half the size of the first.
Linear combination formula: This can be used to display values like gradients and total
depth of the water column in marine surveys. For gradient display the user has to
determine the channel numbers for both magnetometers. For example, for a dual G-880
magnetometer system it might be 1 and 4. Then linear combination formula for pseudo
gradient will then be:
[4] - [1]
If user wants to display the sea floor bottom topography for G-880 system with a depth
sensor and an altimeter then the formula reads:
Here [3] is the depth sensor channel number and [4] is the altimeter channel number.
0.001 is the calibration coefficient for the depth sensor and 0.01 the coefficient for the
altimeter. (These values will vary in each customer's system).
If depth and altimeter have non-zero bias (offset) in their calibration formulas then the
complete formula will look like this:
Where bias = bias3+bias4
For the G-880/881 magnetometers, depth/altitude calibration coefficients can be assigned
to the corresponding MagLog device. Therefore there is no need to enter them in the trace
configuration dialog. In the case of the G-877 magnetometer, the calibration coefficients
are stored in the magnetometer internal memory. However the “Linear combination”
feature will still useful if customer wants to display values in units other than those
specified by the calibration units. The depth sensor is typically calibrated in meters; to
display its reading in feet use the following formula:
and type “ft” as units for digital display.
Note that Linear combination trace" can be represented with a constant like:
This means that the program will display and print a horizontal line.
Trace Color: This represents the color of the trace. Each trace can have its own color. To
change the color of a trace click on “Change Color”.
The following dialog box shown below allows you to select the color.
Once you have defined your trace color click “OK”.
Min/Max Auto Detection. MagLog has the ability to automatically detect the minimum
and maximum values in the data as excursions occur during survey. As soon as min/max
point has been detected, the program sets a user flag on the GPS map and saves the
position in the user flag list. (See Using flags below).
Any trace can be used for setting flags; however the user should not overuse this feature as
a crowded map will result. The following parameters are used for automatic flagging:
Enable. This enables flagging for the trace.
Label prefix. This is the prefix used in the flag ID.
Data step, in trace units. Only amplitudes equal to or greater than this threshold
will be flagged. This provides a method for removing noise. It is recommended to
set this value be set well above the device noise level.
• Time step. Points are marked only if time gradient exceeds a “data step/time step”
value. It allows filtering out relatively flat minimum and maximum points that are
of no interest. For example, if the survey vessel speed is 4 knots (which is
approximately 2 meters/second) and the water depth is approximately 20 meters,
then anomalies from the sources on the sea floor have half width of about 10
meters. Therefore, a suitable time step will be 10m / 2m/s which equals 5 seconds.
If the time step is set to zero then the program marks all anomalies (even if they
are very flat).
• Mark GPS/ Mark fish position. This controls where flags are placed on the map.
To use this feature, the fish position Interpolator feature must be configured
Flags are gathered in the user flags dialog list. The user can inspect, save or remove flags
any time.
6.1.3 Editing the Display
The examples above illustrated how to add a single trace to a single slot. However, often
you will want to add many more traces or slots to further customize your window.
This section explains how you can edit existing traces and slots and add new ones.
Configuring the traces and slots can be done from the “Input Devices Configuration”
screen or from the “Configure / Display (slots)” menu item or from the context menu
(right click and “Display: All slots” item will appear). The latter two methods are
recommended because MagLog does not re-initialize the device if the “Input Devices
Configuration” dialog is not called. At this point in time, after adding a single trace, you
should see your main configuration screen appear as:
This window gives you a lot of useful information. By looking at the list of connected
input devices, it allows you to see how many windows and slots you have for each device.
You can also see there is currently no display set up for the GPS -- “0 Windows”. This
will be discussed later.
To edit the display for the G-880, press “Slots/Traces for Display” (the same dialog is
accessible from “Configure / Display (slots)” main menu item or from context menu item
“Display: All slots”). This will again bring you into the window that shows the slots you
have defined.
This window shows one slot with one trace. You can further edit this slot by pressing
“Properties”, or you can add a new slot by pressing “Add Slot”. This will discuss how to
add an additional slot with two traces, and will show the resulting window. To add an
additional slot, press “Add Slot”. In this example, we will name the new slot “Two
Fields”, and we will press “Add Trace” twice. We will use the first trace to plot channel
1, and the second trace to plot channel 5. The final window should appear similar to the
screen below:
The resulting Display Configuration screen (seen when exiting the slot configuration
window) should appear similar to the screen shown below:
When you press “Finish”, and exit out of the configuration screens, the final window
generated for the G-880 display should appear similar to the screen below.
Note: Here, we have manipulated the scale factors to fit the data input. In this case,
the first slot (Field) has a horizontal scale of 32, and the second slot (Two Fields) has
a horizontal scale of 64. You can also see that channel one is graphed on both slots,
but the second channel has an additional plot (channel 5) present.
To change the slot orientation you can press the “Window setup” button. It displays the
following dialog:
Here is you can define the graphical parameters such as slot orientation, background and
border colors and annotation font. Here you can also define:
• “Auto center time.” Because the magnetic field is wrapped when it is plotted it is
possible that much of the graph will be plotted near the slot borders or
continuously wrapping and unwrapping. In other words, the central field value
(value assigned to the center of the slot) may not match to the actual field valut.
To avoid this the program can re-adjust the central field value every so many
minutes as selected by the user. Enter this time interval here. Note that when this
feature is used the field graph can “jump” from time to time when the central field
value is adjusted.
• “Use same time scale for all slots” From time to time you may need to change the
slot duration. For instance if original slot duration was 60 seconds and you want to
increase it to 120 seconds, you need to do this for all defined slots which could be
laborious if many slots are defined. Checking this button means that if the duration
of any slot is changed then the durations of all other slots are adjusted
automatically to match new time interval.
• Equalize slots button allows you to assign all slots equal sizes. You may use this
button if some slots are lost as result of interactive slot manipulation (see “Slot size
adjustment.” below).
Note: An easy way to change slot display parameters is by right clicking on the screen to
call up the contextual menu. Then select Display… item. It will bring you immediately
into the slot configuration dialog box.
You can configure the display in the same way for other devices.
6.1.4 Horizontal Slots and Slot Legend
The graphic below is an example of horizontal slots mode often preferred to maximize the
use of available screen area:
The labels “mags” and “sigs” are names of the slots. The total duration of the slot (50s) is
computed in the following manner: Values in [] are current limits for green and blue
traces. When the trace wraps, its limits are altered automatically to show the current slot
scale. On the far right side is slot’s vertical scale. If slot has a fixed scale, the key word
“fix” is present. This means that the traces for this slot cannot wrap.
Vertical slots have the same legend if space permits. If not, only the slot’s name is
6.1.5 Slot context menu
When the user right clicks on the slot window the context menu shown below will appear:
Set GPS Flag and Set FISH flag allow the user to set flags on the anomalies at
GPS or magnetic fish position accordingly (see “Adding flags from display slots.”
for more information.
List flags… retrieves a dialog box with all existing flags listed allowing the user to
save, load and modify flag information.
Display (All slots) brings a dialog box that controls the appearance of the entire
slots window.
Slot: MAG (“MAG” is substituted with actual name of the slot selected by the
user) retrieves a dialog box that controls the appearance of a particular slot.
Zoom In and Zoom Out zooms the data axis in the slot (not the time axis). The
same functions have can be accessed via cursor keys on the keyboard.
6.1.6 Slot size adjustment
Slot sizes can now be adjusted interactively using mouse. Move your mouse cursor to the
slot border (right border for vertical orientation and bottom border for horizontal). The
mouse cursor will change its shape to indicate that the border can be moved (you may
need to try few times to catch right mouse position – move mouse slowly near slot
border). Click and hold left button and drag slot border into new position, then release the
button. You can see slot size changes permanently.
It is also possible to change slot order directly on the screen using the mouse function. For
instance to interchange the first and second slots do the following: move the mouse cursor
into the second slot, press and hold left button. You can see that the mouse cursor changes.
Now move the cursor into first slot area and release the button. Slots will interchange their
6.2 Configuring the GPS Display
The GPS display configuration is different from the magnetometer display configuration
because it displays spatial position information, not time series information. To show any
point on the Earth on paper or computer screen some kind of geographical projection
must be employed. To show GPS position, the map and flags MagLog uses orthographic
projection based on sphere with the central latitude and longitude in the middle of the
screen. This allows us to combine speed of calculation with reasonable accuracy. To
read Latitude and Longitude at the mouse location, MagLog uses inverse orthographic
projection. This cancels distortions introduced by the projection calculation process.
You can configure the GPS display by entering the “Configure / Configure displays”
menu and selecting GPS.
From here, you can press “Configure GPS Display” to add a new window and configure
the display. At this point there is no window present for the GPS. To remove display if
there is one delete the GPS input device, and then re-configure it without enabling the
display. Use the “Properties” dialog box if you want to modify your GPS settings (e.g.
communications port number, quality control values…).
If you press the option “Configure GPS Display”, you will see the dialog box:
This dialog box allows you to specify horizontal and vertical scale factors for the
portion of the GPS graph you will be observing. Because of the projection
distortion and aspect ratio of the window, the “input values” are used by MagLog
as a “recommendation” only. The actual spatial extents are plotted in the window.
Plot real time Fish position. This option is only available if the MagLog
Interpolator is running (see below). MagLog will show the position of the vessel
(GPS) and the calculated position of the magnetometer Fish, using an internal
dragging algorithm. However, if the screen distance between the boat and Fish is
less than the size of the GPS mark, the Fish position is not plotted.
Keep aspect ratio. To have uniform scaling along both axes, check this box. This
may misrepresent the trackplot x and y distances; however, it will have no effect
on the logged data.
Plot coordinate grid. If the extent of the area is less then 100 km, MagLog can
plot a coordinate grid for easy distance estimates. The grid step value is chosen
automatically, based on area extent. The Grid color is the same as the border color.
Plot real time Fish position. If the Interpolator device is configured, MagLog can
also plot the Fish position (marine surveys). Note that the Fish mark will
disappear if it is too close to the GPS mark.
Plot gradient. With marine transverse gradiometer systems, MagLog can calculate
and plot the full horizontal gradient. The Interpolator device must be configured to
utilize this feature.
Gradient plot scale. If the above feature is enabled, enter the Gradient Plot Scale
GPS marker icon. Select a GPS marker (vehicle icon) to be plotted on the screen.
Currently four types of markers are available: default (compass), boat, plane and
truck. Boat, plane and truck are vector icons which will show the actual heading of
the vehicle. The default marker is a bitmap icon and shows only North, South,
West and East directions. All icons are shown below:
Note: Direction is shown only if GPS outputs NMEA VTG messages such as
$GPVTG messages, or a Gyro compass is used during the survey (if both Gyro
compass and VTG messages are available, the Gyro compass is assumed to be
more accurate and will be used to show the direction).
Marker color Select color for boat, plane or truck icons. Color for default icon is
Position…. Sets the color for the dots that make up the GPS track plot.
Logged pos.. Sets the color for the dots that make up the GPS track plot when the
software was logging to disk.
Background… Sets the background color for the GPS window.
Border …. Sets the color of the border around the plot.
User Map… Sets the color of the imported User Map, if applicable.
Gradient… . Sets the color of the plotted gradient lines (see “GRAD” Dialog in
the INTERPOLATOR setup). An example of real time gradient plot is
shown below:
Typical real time gradient plot.
Survey area. Color of the defined survey area (if defined). The survey area will be
plotted as a filled polygon. A light color (for example, gray) is recommended.
Note: If Automatic Logging is enabled, logging will commence when boat OR
when magnetometer fish enters the survey area (user selectable).
Load User Map from File. Click this box if you want to load a User Map.
NOTE: If you select this option, you must also specify the User Map file
(including full path) in the provided entry field.
Annotation font. Font to be used to plot border annotations on the GPS map. Note
that flag annotations are always plotted with system font.
Note: Normally MagLog expects GPS input to be in geographical (latitude and
longitude) coordinates. It will do an automatic conversion to meters (UTM) on the
screen, and the scale factor that you choose will be roughly equal to the size of the
area you would like to look at.
After making any adjustments to the GPS map parameters, you can enable the GPS
display by pressing “OK”. You should then see a GPS window appear in your MagLog
After the GPS display is established the first time you can right click on it to call a
contextual menu. Option Display…calls a dialog box to re-configure display (the same as
You also can read the Latitude and Longitude of the mouse position on the program status
bar. The format can be set as decimal degrees, degrees and minutes or degrees, minutes
and seconds.
6.2.1 GPS display context menu and mouse functions
Using a right mouse click on the GPS Track Plot window will bring the following menu:
Set MAP flag. Sets a flag in the current mouse position. Flags set with this
function have names such as “MAP_#” where “#” is the flag number. These flags
are useful because they mark positions that can be converted into survey plan
elements. (see below)
List Flags… Brings a dialog box with a list of all flags set so far. It provides for
saving or loading flags from the file, editing flag’s position and associated text.
Display… Bring the GPS display configuration dialog box (see Configuring the
GPS Display.)
Clear GPS track. In certain cases you may want to hide a previous GPS track.
The typical example is when a boat cruised the survey area with MagLog running
prior to the start of actual survey. In this case the GPS display is “contaminated”
with a previous track that is not related to the actual survey. “Hide old GPS track”
hides all GPS position prior to the current time. “Show all GPS tack” restores all
GPS positions on the screen.
Add plan elements… Allows converting flags into survey plan elements and
saving the survey plan in a file. For instance two flags can be used to generate a set
of parallel lines to be displayed as a background navigation map in the GPS
window. Note that user map (survey plan) has to be re-loaded after new elements
are added.
Auto scroll… When checked this keeps the GPS location in view and scrolls the
window automatically. In this way the GPS location is always visible.
Zoom In… Zooms in GPS window. The same function can be accessed via the
“+” key on the computer’s numeric keyboard (on many laptops press function key
to access numeric “+” – typically marked in blue on the keyboard).
Zoom Out… Zooms GPS window out. The same function can be accessed via the
“-” key on the computer’s numeric keyboard (on many laptops press function key
to access numeric “-” – typically marked in blue on the keyboard).
Pan East, West, North and South Pans GPS view in coordinal directions. Note
that this might interfere with automatic scrolling if the latter is enabled (GPS
position is never scrolled out of view if auto scrolling is on)
A simple click in the middle of the GPS window will center it at that point (auto scroll
should be off to make this feature function properly) When mouse cursor is moved to
borders of the GPS display, it will change its shape to
South border,
at the West border and
at the East border,
at the
at the North border. When the cursor in
moved in the corners of GPS display it changes its shape to
. If
the cursor has changed its shape, using a mouse click causes panning in the direction
shown. NB: This could interfere with the auto-scrolling feature.
6.3 Preparing a Survey plan file
MagLog allows you to overlay GPS information on a map that consists of polylines and
(optionally) of the survey area polygon. Each string has pair of numbers: latitude and
longitude of the segment’s node. An empty string indicates the end of the polyline
segment; the next string shows the start of the next line. Here is an example:
37.778928000 -122.245980000 Label text
37.779128000 -122.247780000
37.785328000 -122.254680000
37.463138000 -121.968370000
37.461839000 -121.973271000
Here first polyline has 2 linear segments and second polyline has just one. Latitude and
longitude are given in decimal degrees, and “-“ indicates Western longitude or Southern
Optional label text can be added after the longitude to be plotted on the screen. Text size is
not scaled with the map that makes it easy to recognize at any map magnification.
Survey area polygon can be added to the plan file in the following manner:
-87.250981170 30.327092640
-87.250981190 30.328732130
-87.248135360 30.328732130
-87.248135390 30.327086180
The keywords “SurveyAreaStart” and “SurveyAreaEnd” mark the beginning and end of
the survey area polygon. If multiple areas are included in the file, only the last one is
The survey area is displayed in the GPS window as a shaded polygon. The polygon color
is user-selectable from within MagLog, usually a light color. It is suggested to use a light
color to avoid obscuring of other plan features and the GPS track (for instance, light grey
or green).
A most important feature of the survey area map is that data logging can be started
automatically when boat or fish enters area (see “Auto logging feature”) and automatically
stopped when the boat or fish leaves the survey area!
While the user could prepare the survey area polygon coordinate file with a text editor, to
facilitate the creation of the survey area plan, we have provided a special tool to convert
GPS flags into the following plan elements: scaled marks, lines and line sets. GIS ArcInfo
“shape” files can be converted into this format also but cannot be used to define the survey
area. This option is available from the main MagLog menu and should be used before
starting any survey.
Select Create survey plan option under File menu. This will bring MagLog into the survey
plan preparation mode. In this mode a maximized GPS window is displayed; however
program cannot accept GPS information at this time. The user should insert flags on this
map in the appropriate places using the GPS display context menu. Prepare a set of
ArcInfo “shape” files if this information is available. After all information is ready select
“Add plan elements” as it is shown below (you can call this dialog as many times as you
Note: All features described in this article are also available when the actual survey
is running. However in this case, to update GPS display map, the file must be reloaded using “GPS PLOT CONFIGURATION” dialog.
The dialog box “Create or import map data” allows you to specify the following
geometrical features:
User marks. These are simple scalable crosses. Press Add user mark button to
enter latitude and longitude of the center point and span (in meters) of the cross.
To avoid typing latitude and longitude for the point, press “Add from flags” button
and select the appropriate flag. The flag’s position will be used as coordinates for
the point. Note that you can still edit this position if you need to (in Add mark
dialog or in User flags dialog.) Enter optional label text (recommended) for easy
mark recognition on the screen (default is just the flag’s name) Use this feature to
mark known anomalies or other landmarks or hazards etc.
User lines. These are simple line segments that can be used to set up a survey line
grid for the survey process. Press Add user line and enter the end points (longitude
and latitude). You can use “Add from flags” buttons to get end-line positions as
well. To setup multiple parallel lines check “Create multiple lines parallel to the
base line” box. This will use the line you entered as a base line and will create
additional lines parallel to the reference line at your desired lane spacing. Enter the
number of lines, line interval and which side of the base line you wish to create the
lines. The choices are “Right” “Left” and “Both” MagLog creates lines on either
side of the base line looking from start point to end point. If N additional lines are
requested program creates N+1 lines for “Right” or “Left” options and N+1 line
for “Both” option (including base line)
Enter optional text annotation (recommended) for easy line recognition on the
screen. Annotation is used as a prefix to the line names which are #1, #2 etc
starting from left to right (looking from start point of the line to the end point) In
this manner a preconfigured grid pattern for the survey can be established prior to
acquiring data. This can help the vessel stay on course, but it is recommended that
such features present in the GPS itself be used to actually steer the vessel.
Add Survey area. Use this button to define a survey area. Below is the procedure
to define an area:
1. Write down Longitude / Latitude pairs for the boundary of the survey area
in clockwise order. Alternatively put map flags on the survey plan screen
and write their Ids (identification names listed on screen or under Flag in
Flag dialog box) in clockwise order (note that flags should be set before
calling “Add plan elements…” menu). Note: Check “Plot Flag ID” box in
User Flags dialog box to see the flags on the survey plan.
2. Press Add survey area button. The following dialog is displayed:
Populate this dialog by pressing the “Add” button and entering the coordinate
pairs as shown here:
Note that you can type a position directly (using decimal degrees, degrees
and minutes or degrees minutes and seconds – as selected in the “Format”
field of the “Define survey area” dialog”) or press the “Add from flags…”
button and add positions of the existing flag
3. Inspect your entered positions. You can remove or edit area points by using
the appropriate buttons. However keep the survey area corners in the right
4. Press “Ok” to accept the survey area. Note that the “Survey map elements”
list will not show the survey area boundary coordinates. However upon
pressing the “Add survey area” button a second time you will see defined
area boundary coordinate list.
Button “Add ArcInfo™ shape file allows the user to include shape files in the
survey plan. Both .shp and .shx file type must be available for the program to
import the boundary maps successfully. Shape files are available from the ESRI
website shown below (ESRI requires that you register to download the data). We
suggest using the demographic Tiger database located at: Please note
that shape files should use the same geodetic datum as GPS you are using, for
example WGS-84. Contact your GPS manufacturer or us if you are unclear on this
Buttons “Remove element” and “Remove all” allows you to remove a selected
element or all elements from the table “Survey map elements”
Button “Edit element” modifies parameters of a mark or individual line. It does
not allow you to change parameters in the shape file.
“Save table” and “Load table” buttons allow you to save or modify the “Survey
map elements” table for future reference. Note that it is a simple ASCII file which
cannot be used as MagLog map.
Clip Area. All survey plan information can be clipped into a rectangular region if
needed. To clip, uncheck “Don’t clip” box and specify West and East and North
and South limits. Note that GPS flags can be used to enter limits of the clipping
area using “North – East flags“ and “South - West flags” buttons Clipping is
highly recommended if shape files are used because they can cover a considerable
area (like the entire coastline of the US) while just a small area may be needed
during a survey or survey playback. Clipping also reduces the program overhead –
the map file should be as small as possible and still cover the area of interest.
Output file. Set output ASCII file used by MagLog. If Append data to file box is
not checked then file is overwritten if it exists. If the append box is checked the
program appends lines to the end of the existing file allowing sequential build of
MagLog maps for the area
“Create MagLog map file…” button produces an actual file loadable as a survey
plan. The user must press this button to create a map before leaving the dialog box
if he or she wants to generate a map. After the Create MagLog map file button is
pressed, the program will process all elements (shape files, user marks and lines) in
the list. This may take a while. The result is a file that can be used as a MagLog
Survey plan file∗.
Append data to the file. If this box is checked, new map elements are added to
the existing file without erasing the file. This allows you to keep previous a
MagLog survey plan as part of the new plan.
Note: Be careful while using this feature. The map file MUST BE IN THE SAME
DATUM AS INCOMING GPS DATA. For example if the GPS is transmitting WGS84 coordinates and you are using a national map to create the map file, chances are
that map positions differ from GPS by few hundreds of meters (unless you are
operating in the US and map is based on NAD-83).
If the concepts “DATUM” or “WGS-84” are unfamiliar to you see your GPS manual
or seek assistance from navigation professional.
This feature is not accurate enough to be used as a navigation aid for boat or
vehicle steering. “Geometrics” accepts no liability nor offers any warranty for the
misuse of this feature.
6.4 Using Atlas Boundary (BNA) as MagLog Map file
The Atlas BNA format is a simple vector format supported by SURFER software.
MagLog is capable of using this format instead of the internal map format described
above. To take advantage of this feature, follow these steps:
• Prepare the map with SURFER. The map must only include lines. Text will not
be converted into the BNA format. It is possible to convert text into lines by
exporting the map from SURFER in the AutoCAD DXF format and then
importing it back into SURFER. This will convert text into graphical outlines.
The map must be based on geodetic coordinates (latitude and longitude) or UTM
coordinates, based on the datum that the GPS is using.
• Export the map in BNA format.
• In MagLog, follow the same steps described for importing a User Map above to
load this base map.
Note: If the BNA file consists of UTM coordinates, the UTM setup parameters in
MagLog Interpolator must match the map parameters. However, if the BNA file
format is used, you cannot employ the MagLog survey area polygon feature.
Some data for the US and other parts of the world are available at no charge at
6.5 Using Ontrack Plots
MagLog allows plotting information from other devices (typically magnetometers) as an
overlay of the GPS plot for easy display. Data from different sources can be combined
into single values to be displayed in the following ways:
Real time stack profile.
Real time longitudinal gradient plot. If the gradient along the line exceeds some
user-defined value, colored triangles are plotted on the track. Triangles are scaled
to the distance between adjacent GPS positions.
Real time amplitude plot. If either the relative or absolute amplitude exceeds
certain limits, colored circles are plotted on the track plot. These circles are not
scaled if the scale of the map changes.
Real time value plot. Readings (or combination of readings) from different
devices can be plotted on GPS map equidistantly, or when the difference from a
previously plotted value exceeds some limit. For example, “total depth” (for
Systems with altimeter and depth-sensors) can be plotted each 100 m, or for a
change of more then 2 meters. Another application of this feature is plotting of
Event Marks on the GPS map.
PRECAUTION! Use caution when activating these features, as the data could obscure
important data if survey line spacing is small.
To activate this feature, select the GPS display window and select Configure / On track
plots. The following dialog box will appear:
All four possible On Track plots are listed under Plot Types. Initially, no data is selected
for plotting. To enable a particular plot type, check its box, and then click Modify to
assemble the formula. For example, to use a real time magnetometer stack plot, check
Stack Plot and then click Modify. The following dialog box will be displayed:
There are two ways to enter the formula:
Type it into the entry field. The Formula must use the following syntax:
multiplier1*[device-alias1#device-channel1]+multiplier2*[device-alias2#devicechannel2] …+ bias. Multipliers must precede devices. “Device-alias” is the
device alias assigned during creation of that device, and displayed on the light bar.
Device-channel is the number of the channel to be used. Signs [] # * + (or -) are
mandatory. No spaces are allowed inside []. You can mix different devices in one
formula. Bias is a constant to be added to the final formula.
Use the lower area of the dialog box to create a new term for the formula. For
example, to plot magnetic field select “mag” in the Device field, “1” Channel field
and then click Add new term. This Formula becomes [mag#1]. ”Add new term”
can be used as many times as needed. For example, to display total water depth
(assuming that there is a depth sensor as magnetometer channel 3 and an altimeter
as magnetometer channel 4), assemble the following formula: [mag#3]+[mag#4].
If you need to scale the data channel, enter “scale” before pressing add new term.
If there is any bias to be used in the final formula, append it.
Real time plots can be tied to the GPS position or the Fish position (the latter is only
possible if the INTERPOLATOR device is used).
After enabling all the desired information, the GPS on track plots dialog may look like:
There are important parameters to be used for on-track plots. They are listed in the bottom
part of the dialog box. Typically, each type of plot needs its parameters to be entered.
Below is the list of plot types with their corresponding parameters.
1. Stack plot. The following values affect the Stack Plot:
o Average window, in meters. To find the “middle line” for a Stack Plot, the
program uses a low-pass Bartlett filter. You must enter the length of the
filter. The typically filter should be longer than expected anomalies, but not
too much longer. For example, for marine UXO survey at 40 feet total
water depth, a value 100 meters for the filter would be logical.
o Stack scale, meters per unit. This is the scale to convert field units (nT) into
distance units (meters) to be plotted on the map.
o Stack gravity azimuth. This is the direction where positive anomalies would
“gravitate”. For example, if the survey consists of lines going South –
North and this value is 90 degrees, then positive anomalies would be
plotted to the East regardless of the direction of the survey line.
o Positive and negative colors. Positive areas of the Stack Plot are plotted
with the “positive” color; negative areas are plotted with the “negative"
2. Longitudinal gradient (L. grad). The only value required is L. gradient limit. If
the absolute value of the longitudinal gradient exceeds this limit, the program will
plot arrows using the “negative” color if the gradient is below zero, or with the
“positive” color if the gradient is above zero.
3. Amplitude plot. This plot cannot be used simultaneously with the Longitudinal
Gradient plot. . If either of these plot-types is active when the other is selected, the
former type will be de-selected. These parameters are required for the Amplitude
o Average window - this has the same meaning as in the Stack plot. The
program calculates the average and plots colored circles if the absolute
value of the difference between the current data and the average exceeds
max. amplitude. Note that if both Stack and Amplitude plot are used
simultaneously, they both share the same Average Window.
o Max. amplitude. If the “Use range for amplitude plot” checkbox is not
checked program starts plotting colored points if difference between
average and current value exceeds this limit.
o Use range for amplitude plot. There are two modes for an Amplitude plot:
The first mode utilizes the Average Window, and therefore does not require
absolute field values.
The second mode allows control of the plot by setting absolute limits. If
“Use range for amplitude plot” is checked, then “min” and “max” values
must be entered. If the reading is below the “min” value, the program plots
circles with the “negative” color. If the reading is above the “max” value
the program plots circle with the “positive” color.
o “Min” and “Max” values. These are the limits for an Amplitude plot in
absolute mode.
o “Positive” and “Negative” colors. Positive areas of the Amplitude Plot are
plotted with the “positive” color; negative areas are plotted with the
“negative" color.
4. Value plot. The following parameters are required for the Value plot:
o Data step to plot value. If the absolute difference between the last plotted
value and the current data value exceeds this limit, the new value is plotted
on the track.
o Distance to plot value. If the distance between the last point where a value
was plotted and the current point exceeds this limit, the current data value
is plotted. For example, if you want to plot a value each 100 m, enter
“100”, and enter an unrealistic step in “Data step to plot value”. This will
effectively disable plotting by value. Conversely, if you enter very large
value for “Distance to plot value” (for example - 100000m) and set the
“Data step to plot value” to 1, a value will be plotted each time the data
changes by more than 1 (the latter might be useful to place event marks on
the GPS track).
o Value digits after dots. This setting controls the Value Mark format.
o Font. This entry selects the font, and the color for the Value plot.
7 Mini-windows.
Starting with version 2.88 MagLog has a special feature called “mini-windows”. Miniwindows provide the ability to place different types of information (digital, analog, etc) in
small “child” windows (child means a sub-window) which are displayed independently in
parent windows. Each mini-window is created as a child of any of parent device display
window, including the GPS display window, and each has the following properties:
• While sitting inside its parent it is without a header. However in can be dragged
and resized using the mouse. A context menu is available using a right mouse
click. The mini-window hides the part of its parent behind it.
• A mini-window can be dragged out of its parent and even out of the main MagLog
application window. As soon as it is out of the parent, it appears with a header and
the normal menu and can be dragged anywhere on the screen. For instance if two
monitors are used (one for remote display at another location, see for remote display over network connection) it can be
dragged to the second monitor to show another person some essential information
such as depth.
• If dragged back into parent window, it is displayed without the header again.
Mini-windows is designed to be big or small and offer the ability to spread MagLog
display on multiple screens, possibly mounted in different places.
At present (version 2.88) only digital display mini-windows are available, but there is a
plan to develop different types in the future. Below is an example of such a window inside
and outside of its parent. The smaller window is inside the parent.:
Digital display mini-window.
The digital display mini-window is essentially a timer device that gets called at userdefined intervals. Once called, it can obtain the latest values of any device channel and
compute a linear combination of them. The result is displayed in a user-selectable format.
This feature can be useful when data of different devices are to be combined for the
purposes of display. A typical example is combining a boat fathometer reading with
magnetometer depth. The difference between these two indicates approximate fish
elevation above the sea floor and can supply crucial information to avoid collision with
the sea floor.
To create a digital mini-window use the following steps:
1. With any MagLog display window highlighted, select the Configure menu on the
top menu bar. Select Mini-window option. A new blank white rectangle window
will appear in the left top corner of the display window. Drag this window to
appropriate place and resize it as desired.1
2. Right click on the mini-window to bring up the context menu and select “Edit”.
The following dialog will appear:
To initialize the window you must construct a “formula” which can be as simple as
a single data field, i.e. depth.. Use fields “Bias”, “Scale”, “Channel” as appropriate
and then click the button “Add” to make a new formula. If you make a mistake
remove the formula using the “Clear” button. For example if you have boat
fathometer running as the first channel of the Generic Serial device with the name
“gen”, select the channel as “[gen][1]” and press “Add”. The new term will appear
in the “Data to display (formula)” field. Now to subtract the magnetometer depth,
set the “Scale” to “-1” and “Channel” to “[MAG][depth]” (device names can be
different in your survey). Press “Add” button again. Now you have a formula to
compute and display.
3. Fill in other fields as appropriate:
When you cross the border of the parent window you need to release the left mouse button and press it
again to gain control of the window positioning.
“Display update interval” is the interrogation interval in milliseconds. In
the above example the formula is computed 10 times per second.
“Check data in range” If this is checked the computed value is compared
with the data minimum and maximum interval. If value is not within the set
range an error is generated.
“Use audio alarm” If value is out of range an audio alarm will be generated.
“Annotation” Text that annotates the value. The text appears inside the
window or in the title bar.
“Units” Units to be displayed with the value.
“Digits before dot” and “digits after dot” control the value format. A format
example is displayed in the “Sample” field.
“Text color” / “Background color” / “Error color” Colors are used to print
the text and background. If value is out of range the background is painted
with “Error color”. Typically this error color would be red to enhance
“Format” controls how the value is formatted. The possible choices are
“Decimal”, “Degrees and minutes” and “Degrees, minutes and seconds”.
The latter two are useful for Latitude and Longitude display.
4. Advanced button is used for special settings. At the time of writing it brings the
following dialog:
This option limits the range of the displayed values. The display range is limited if the
box “Only display data in the range below” is checked. If data is not in the desired
range, the last available value is displayed. Note that the display can go blank after this
dialog is called and until the next acceptable value is received (at least one good value
should be received to activate the display).. A typical use of this feature is for spike
elimination. For instance, if the fish typically flies at 10 m elevation above the sea
floor and due to bottom conditions the altimeter frequently gives spikes to maximum
range (100 meters) it makes sense to limit display by values between 0 to 20 meters. In
this manner spikes are eliminated and if fish is 20 m or more above the floor, it is in a
safe condition. Note that “Check data in the range” setting above is still applied to the
original, non-despiked value. This flags conditions which arise when the device is not
working properly. The latest good value is still displayed, but the background color
changes. It is recommended to select neutral color for “Error color” value described
above, such as light yellow or gray. This keeps values clearly visible and the display
less annoying in the case of multiple spikes, yet the allows observation of device
errors. In any case we always recommend testing the altimeter if spiking continues to
determine if it is functioning correctly.
After you press the “OK” button the window begins showing the requested information. It
is updated at the selected time interval. Digits are resized when the window is resized in
much the same way as the digital slots are resized.
8 Using Flags
There is a common need to identify an anomaly on the chart plot with a position. MagLog
solves this problem by means of User Flags. Each flag is simply an identifier with its
Flag type and associated Latitude and Longitude. Flags are saved in an ASCII file and can
be edited with any ASCII editor or directly accessed via MagLog File menu under User
Flags. If you call this item the following window appears:
Flag names created by MagLog are abbreviated in the following manner:
• Depending on type of position requested by the user when he or she created this
flag, the first letter would be “G” for GPS position or “F” for the Fish position.
• If the flag was created on the GPS display at the mouse location, the first three
letters will be MAP.
• If flag was created from display slot, the device alias name is included.
Flags are numbered.
Each flag is tagged with MagLog (PC) time.
Flag type can have these values:
• FISH – user created flag from display slot and requested Fish position. This is
possible only if Interpolator is running. In this case position is position of the
• GPS - user created flag from display slot and requested GPS (boat) position
(always available).
• MAP – user created flag at mouse location on GPS display, not on the device slot.
User flags are plotted on the GPS display as crosses of constant size with associated
labels. Label names can be turned off for clarity when many anomalies have been
identified in a small area. If Plot flag ID is unchecked, no flag names are plotted on GPS
User can change flag’s name and position by selecting flag in the list and pressing Edit
button. The following dialog appears:
Name and position can be changed as desired.
All flags have the following attributes (scroll the flag list to the right to view all of them):
• Flag name.
• Flag type.
• Longitude. Can be displayed or exported as decimal degrees, degrees and minutes
or degrees, minutes and seconds.
• Latitude. Can be displayed or exported as decimal degrees, degrees and minutes or
degrees, minutes and seconds.
• Date and time. This is playback time, not the survey time for flags set in playback
• Line. Reflects logging status. Words “No line” indicate that flag was set when data
was not logged. Otherwise it gives the line number.
• CH1-CH4. First four device channels for the display where a flag was set.
Typically the devices would represent magnetic field, sensor signal strength, depth
and altitude if a flag was set using magnetometer display window. If flag was set
using GPS window all four channels are set to zero.
If Autosave on new map/field flag is checked then the program automatically saves the
flag list in the file each time a new flag is added.
This dialog box also allows merging flags from the different surveys. If Append to the list
is marked then the program does not clean flags when a new flag file is loaded. Instead it
increases the existing list. With this option the user can read a few files sequentially,
remove unnecessary flags and save the remaining flags into new file as complete list.
All flags are drawn with the same selectable color.
All flags can be exported into an ASCII text file, with positions formatted in the same way
as they are formatted in the above dialog, by pressing “Export flags” button. Export file
can be displayed in the Windows™ “Notepad” program and printed if required.
Adding flags from display slots.
Figure below illustrates how flags can be added from display slots:
Move mouse to the location where flag should be set.
Click and hold right mouse button to display context menu. Select appropriate flag
type (GPS or FISH) Note that FISH is not available if the Interpolator is not
Release mouse button to set a flag.
Flag is shown on all device slots and on the GPS display.
If you want to remove previous flag(s) go to List flags…
8.2 Adding flags from GPS Display
Here is how flags can be set on the GPS display:
Move the mouse cursor to the location where a flag should be set. You can see the
latitude and longitude of the mouse position on the bottom status bar.
Right Click mouse and hold it. A context menu appears.
Select Set GPS Flag and release mouse button.
Flag appears on the GPS display.
You can call the general flag dialog box by selecting List flags… option
Figure below illustrates this procedure
Adding Flags using hot keys
There are two hot keys that allow you to add flags instantly at the time when the key is
pressed. Both keys are enabled only if a GPS or magnetometer display is created.
• Key “F11” adds flag at current GPS location. When this key is pressed the
program takes the latest available GPS reading and creates a flag based on its time
and position. The user is prompted for a flag name. If no flag name is assigned
then default flag name is used.
• Key “F12” adds a flag at the current magnetometer location. This key is enabled
only if the Interpolator device is up and running. The latest GPS time is used as the
flag time and the corresponding fish position is taken as the flag position. The user
is prompted for the flag name. If no flag name is assigned the default flag name is
Note: In this case, Channel 1-4 values are taken from first device display (except the
GPS display). In the case where multiple devices are used (not only magnetometer and
GPS) these values may not represent magnetic field, signal, depth and altitude.
Using comments to flag positions
In addition to the “User flags” feature MagLog has another similar option called
“comments”. This feature can be called up via the “Configure / Comment” menu item.
When initialized you will see the following dialog box:
By clicking on “Browse…”, you can modify the file name that will hold your comment
Typed comments are logged exactly as entered, with a date and time stamp. Pressing
“Enter” will exit the screen and save the comment. To start a new comments line, press
MagLog does not display these comments. The comment file is intended for later
reference only.
9 Using Windows™ printers and print drivers
9.1 General considerations
Starting with version 2.8, MagLog software has a new feature that prints graphical plots of
data using standard Windows system printer(s), including network printers, PDF
converters and other types of printer-like devices in real-time or during post-processing.
Windows printers include lasers, ink jets and Epson style dot matrix or Printrex thermal
printers that have Windows drivers.
Windows printing is available under the “File / Windows print…” menu in either survey
or playback mode. If this menu item is grayed-out, it means that the printing library,
DevPrint.DLL, is not in the same folder as the maglog.exe file. Default location for
DevPrint.DLL file is in C:\Program Files\Geometrics.
Note: Windows printing option is completely independent from the earlier developed
continuous Printrex / Epson dot matrix print feature usually accessed through Configure,
Output Devices, Printer. The Windows system print feature prints discrete pages, not
continuous printing as offered under MagLog direct printing feature to continuous printers
such as Printrex and dot matrix devices. Also note that when the survey is running, there
are two Start Printing buttons listed under File dialog box: Start Direct Printing (Printrex/
Dot Matrix) and Windows Print (Windows system printers). Make sure you select the
proper start button.
The user should be aware of certain requirements before using the Windows print feature.
The Windows Printer driver prints in discrete pages even if dot matrix printer with
Windows driver is used. This means that the user needs to determine the proper
page duration before configuring the printout. Typical values range between 1
minute per page to 15 minutes and longer. Very short pages may eventually jam
the printer system queue depending on the computer system and printer
performance. The recommended value is 5 minutes per page.
There should be enough data in the program buffer(s) to fill in complete page.
Therefore buffer sizes need to be extended to accommodate enough data. If the
buffer size is not long enough only a part of the page will be covered with data. To
change the buffer size(s) start MagLog but do not start your survey and go to
“Configure / Device buffers”. Make sure buffer size (in device samples) has
sufficient size to cover the whole Printer page. For example, if you plan to print
10 minutes per page (600 seconds) and operate 880 magnetometer at 10Hz, you
need to set minimum buffer length as 600x10 = 6000 samples. Because of the
windows spooling time this buffer size needs to be increased by 20% therefore
total recommended size would be 7200 samples. Note that very big buffers
increase memory consumption and may slow overall system performance.
During actual survey, pages can be printed continuously (one discrete page after
another). For instance if the page duration is set to 10 minutes, a new page is
printed every 10 minutes. Your computer system should be powerful enough to
handle data acquisition and printing tasks at the same time. Most modern PCs can
do this with ease. However if an older PC and/or operating system are used (less
than 400MHz, older than Win98), this feature may fail. In this case the user can
print survey pages in playback mode to avoid overhead during the critical survey
If the user wants to re-configure the printer page layout, continuous printing will
be interrupted.
Print layout consists of a page model (page size, areas to print, data to print, how
to print etc.) and printer settings (printer name, properties etc.). Printer layouts are
kept in separate files and not in the general survey file. This makes it easy to have
multiple layouts for one survey and exchange layouts between different surveys.
Layouts are interchangeable between the surveys only if the same device alias
names are used in all surveys (for example, if customer has a 880 magnetometer
and it has the alias name “880” in all his or her surveys and not “880” in one
survey and “mag” in another survey).
Below is a description of the printer page and an example how a printer layout can be
configured. Note that MagLog has a set of pre-defined layouts that can be employed when
the survey is configured using the MagLog setup Wizard.
MagLog page example
Below is typical MagLog printout. This particular page was made for a simple magnetic
survey that included a cesium magnetometer and GPS devices. The magnetometer is
equipped with a depth sensor calibrated in meters.
The page has a legend area on the top and annotations on the bottom. Total duration of the
page in this example is 5 minutes. Time labels are printed on the right side of the page at a
user selectable interval (30 seconds in this example). Print Start and Stop times, logging
state, line number and survey file name are plotted on top of the page. The page number
automatically increases each time a page is printed.
The working space is divided into three slots. A slot is vertical slice of the page where
separate data can be plotted. In this particular example the user allocated one big slot to
plot magnetic field in two different scales (red and blue lines) and GPS positions in
degrees and decimal minutes. The magnetic field is plotted with a fullscale of 50 nT and
500 nT (red and blue) which allows the operator to see large and small magnetic
anomalies. The GPS positions are plotted every 2 cm or 29 seconds. The second slot is
used to plot depth readings in meters. The depth axis goes from right to left. The third and
smallest slot is used to plot the magnetometer signal strength. It has a fixed scale and the
signal axis goes from left to right. The fullscale range is chosen based on the acceptable
values for signal strength, 500 to 2500.
Data can be plotted in two different ways. One way is a simple time graph (“trace”),
which can wrap to the bottom of the chart when value goes out of range. The magnetic
field, depth and signal are usually plotted using this type of presentation. However for the
depth plot, a fixed range (no wrap) is preferred. Data also can be plotted numerically
(“marks”). In this example the user chose to plot the GPS position each 2 cm on slot #1
graph. These two types of plots are interchangeable, which means that the magnetic field
or depth can be plotted as a number each 1 cm as well as represented as an analog trace. In
fact, any MagLog data can be presented as traces or marks.
Start and stop times of the page,
was logging ON or OFF when page
was printed, line number.
MagLog version and
compilation date
Current page
Legend area
Survey file name
"Mark" type
plot (use for
GPS positions
and events)
data plot area
"Trace" type
Use for magnetic
field, depth,
field value
is plotted
when graph
User flag.
Flag name and
position are
slot #1
used to plot magnetic field in wrapped scale
slot #3
slot #2
plot depth in fixed scale plot signal in fixed
0 - 15 m, max. value on scale 500 - 2500,
max. vlaue on the right
the left
Maglog print page example
MagLog printer legends and annotations
Top area legends:
trace plot. Horizontal bar 1 cm length and
number above indicate scale (how many nT in 1 cm). Printed trace
name is assigned by the user.
Typical legend for mark plot (used for GPS, event marks, depth marks
etc). Icon on the left is plotted at the time when value is taken. "Lon" is
name of the mark, assigned by the user. "sep:29s" stands from
"separation 29 seconds" It means these marks are printed each 29
seconds (2 cm on the paper in this example).
Typical legend for flags. Flags are just special case of "mark" labels. Icon
on the left plotted at time when flag is set. "all" means all flags are
Bottom slot annotations
Bottom annotation for wrapped trace. "mag,nT" are trace name and
units (both are assigned by the user). "W" stands from "wrapped".
"5.00" is grid interval if grid is requested. "[50.00]" is total span on the
slot for this trace.
Bottom annotation for wrapped trace. "mag10,nT" are trace name
and units assigned by the user. User selected "mag10" to indicate
that scale of trace is 10 times of "mag" trace scale. "W" stands from
"wrapped". There is no grid requested therefore no grid interval. "[500]"
is total span of the slot for this trace.
Bottom annotation for trace with fixed scale, in this example used for
depth. "L" stands from "left". It means that maximum value (15
meters in this example) is on the left side of the slot. It also can be
seen in range indication: "[15.00:0.00]" Trace values out of this range
are not plotted.
Bottom annotation for trace with fixed scale, in this example used for
signal. "R" stands from "right". It means that maximum value (2500 in
this example) is on the right side of the slot. "[500.00:2500.00]" is
slot range. Trace values out of this range are not plotted (in this example
absence of the data would mean that magnetometer is out of operating
Flag example
Flag example. Horizontal line goes across the slot. Text above the
line is flag name, text below is position of the flag (in this case formatted
in degrees and decimal minutes).
Page legends and annotations
Configuring MagLog page layout
This section covers step-by-step layout configuration assuming a survey using a
magnetometer and a GPS.
Windows printing is available under the “File / Windows print…” menu in either survey
or playback mode. After “File / Windows print…” is selected from the configuration
menu, a Windows preview pane appears on the screen. This print preview shows the graph
as it will be printed on the paper. The window is resizable and allows you to define the
print layout interactively (dragging slot borders, etc.) Control of the window is
accomplished using control buttons and the context menu. The context menu is available
by right clicking the mouse when the cursor is inside the white page. By default each time
you choose “File / Windows print…” the program selects a print interval based on the
current time and page duration.
9.3.1 Setting up printer and page
Start your survey and go to “File / Windows print…”. Assuming that windows printer was
not enabled during the setup Wizard, a dialog with an empty page will appear on the
screen. The following buttons are available at the bottom of the page:
1. Print setup. This invokes the standard Windows printer selection and setup dialog. As
soon as printer is selected its settings are stored in the layout file. Printer settings can
be changed at any time.
2. Start printing. This button starts actual printing. It is described in details later in this
section. If no printer was selected using “Printer setup” button or the printer does not
exist, then this button is disabled.
3. “<<” and “>>” buttons. These buttons move the time interval one page forward or
backward. For instance if current page interval is 15:00:00 – 15:05:00 pressing “>>”
displays page between 15:05:00 – 15:10:00.
4. Save layout. The user is prompted for a file name where the layout can be saved. It is
recommended to save the layout from time to time during configuration. By default
the program creates a new layout file name by appending “.page” to the survey file
name. For instance if user is running survey “area1.Survey” then new layout name is
created as “”.
5. Load layout. The user is prompted for a filename to load another layout. Note that
layout loaded from the file replaces the currently configured layout.
6. Cancel. Cancel the setup without keeping any changes.
7. Ok. Stores changes and saves layout in the file. If no filename was selected in which
to store the layout, then a default file name is used.
Next press “Print setup” and select the appropriate printer along with the paper format and
orientation. Press the “Properties” button to select the appropriate paper. Note how the
Print Preview page on the screen changes when another paper or orientation is selected.
The next step is to set the page duration and attributes, such as time grid interval, margins,
line styles, etc. Right click on the white page and select “Configure page”.
The following dialog appears:
The most crucial settings listed are “Total page duration” in minutes and “Time grid
interval” in seconds. The other settings can be left with default values. A complete
description of all controls in this dialog box follows:
Stop print time and date. This is time of the bottom of the page and may be listed as
“End Page Time” in your dialog box. Because some “print layouts” will have stored an
earlier time or day in their setup, the program will attempt to synchronize the current time
with your print layout when you call “File / Windows print …” in MagLog menu.
Layout name. Optional string with layout name. This name is used when layout file is
installed as one of the default Wizard layouts.
Total page duration. Page duration, in minutes.
Time grid interval. Time grid interval, in seconds.
“Lines”, “At the start”, “At the end” controls. These controls are used mostly in
playback mode when user wants to position page at the beginning or at the end of the line.
Select appropriate line and then press “At the start” or “At the end” buttons to move to the
beginning or end of the page to the selected line. Do this and watch how “Start print time”
Color and styles. This group of controls allows changing page frame line colors and
styles. It also disables or enables drawing of “Geometrics” logo at the center of the page.
Margins. Sets page margins in centimeters. After dialog is closed with “Ok” button
program adjusts page look on the screen.
Min. slot width (cm). Controls minimum portion on the page which can be used as a slot
to draw the data. Minimum allowed value is 0.1 cm. The slot width can only be allocated
in multiples of the minimum width. For instance if minimum width is 1 cm then any slot
can have width of 1, 2, 3, etc cm but not 1.2 cm.
Line width is used to draw all page lines, including text, in device units. Value 0
corresponds to minimal line width for the printer. On high-resolution printers (600 dpi or
more) such a line is very thin. In this case increase the line width to 1 or 2 (or decrease
printer resolution in the printer setup).
Use uniform pen widths. For some high-resolution laser printers the default line width
could be too thin for visible output. Using this option allows increasing line widths for all
elements of the page layout at once.
Uniform line width, mm. Specify here a desirable line width. The recommended value is
0.1 or 0.2 mm. Note that this overwrites individual line widths for the traces (see below).
9.3.2 Setting up slots to draw the data automatically.
In the next section (see below) we describe how to configure the print layout manually.
Manual configuration gives the user full control over the page layout. However is can be
challenging for the inexperienced user. To assist in this task, an automatic configuration
feature is provided.
Automatic configuration is available from the print preview window via menu Page / Auto
configure. When this item is selected, the program erases the current page layout (if any)
and creates a new layout based on what is currently displayed on the MagLog display.
The automatically configured print layout does not recreate exactly what the user sees on
the MagLog screen. The program uses the following set of rules to convert the screen
layout to the paper layout:
Only waterfall slots are represented on the printed page. Their relative widths are
computed to be proportional to widths on the screen. Digital displays including
mini-window displays are not represented on the page layout.
Each display waterfall slot is translated into one printer slot.
If a display slot has a fixed scale, the corresponding paper slot also has a fixed
GPS position and Flags are printed using marks. If real time interpolation is used,
the position of the “shifted point” is also printed. Flags are plotted in the first slot,
GPS latitude and longitude on the second, and interpolated position on the third. If
there are less then three slots some information can be omitted. If slots are too
narrow information may not be readable.
The page duration is selected as double that of the maximum slot duration on the
In general the automatically generated page layout is a good starting point for refining the
layout. After the layout is initially generated the user may change slot widths, page
duration and other parameters (see the section below on how to configure the layout
manually). Then the layout can be saved and used in the subsequent surveys.
The software has an additional feature called “Keep Auto configuring”. It is available
from the “Page” menu as a “checkable” menu item. If checked, the program will
reconfigure the page layout using the screen each time a new page is to be printed. All
manual changes in the page layout are lost if the “Keep Auto configuring” menu is
checked. For example if the user has changed the screen layout (removed some slots;
changed scale on others, etc.) between the time when page #1 was printed and page #2 is
about to be printed, page #2 will not yet have the changes, they will appear on page #3..
9.3.3 Setting up slots to draw the data manually.
After page duration is set and required time grid is established, the user may allocate
“slots” or slices of the page space to draw the data. No data can be drawn outside the slot,
but any number of data lines can be drawn in any slot. The number of slots and their
widths depends on the number of devices the user wants to plot and is user defined. For a
typical simple magnetic survey with one magnetometer and one GPS device, a user might
want to print the following information:
Draw magnetic field as a linear graphs in different scales.
Draw depth as graph.
Draw magnetometer signal strength for QC purposes.
Plot GPS positions as degrees and minutes.
Plot user determined flags during the survey.
All this information could be drawn using only one slot; however logically it is better to
separate the data into different slots for clearer printout. The following slots are suggested:
Slot#1: Plot magnetic field and overlay it with GPS position plotted as decimal
degrees and minutes. Plot positions each 2 cm on paper. Use standard wrapped
display for the field. This slot should take most of the paper with about 70% of the
page width.
Slot#2: Plot sensor depth in range 0 – 15 meters. Overlay with flags when they
appear. This information is not as important as the magnetic field but still
important enough so allocate 20% of the paper width for display.
Slot#3: Plot signal strength. This information is not as important but still needed
for Quality Control. Acceptable range is about 500 – 2500 for the marine cesium
magnetometer so we will allocate the remaining 10% for this slot.
As soon as you decide how many slots are required, simply move the mouse to the
appropriate position and click the right button to access the context menu for space
Move the mouse approximately 70% from left paper border, right click and select “Add
slot”. A vertical line will be added which is the border on the new slot. Dragging it with
the mouse will move this line. Note that you cannot add a slot within a slot. Move the
mouse to the right into free space and repeat operation to add another slot, and then repeat
it again to add last slot. Drag the slot borders with the mouse into their appropriate
positions. Note that the slot borders can move in steps. By default this step is 1 cm on the
page. This value can be changed in the page setup dialog (min. slot width (cm).).
When the right mouse button is pressed a small yellow tool tip window appears to show
the mouse position in centimeters from the beginning of the page and beginning of the
slot. If the button is pressed out of the slot area then a text message “No slot” is displayed.
This information will be useful for putting textual data into appropriate places on the grid.
9.3.4 Populating slots with data
To add data to the slot, move your mouse cursor somewhere is the slot area and right click
to access the context menu. Select “Traces…” Alternatively you can just double click on
the slot. The following dialog box appears:
This dialog shows all graphic entities assigned to the slot. Presently there are none. The
most important buttons are “Add” and “Edit” which allows adding information to the slot.
There are two types of plots currently available: continuous waterfall graphs or “Traces”
(appropriate for magnetic field readings) and numerical value plots appropriate for GPS
positions and flags (called “Marks”).
Dialog buttons perform the following functions:
“Add…” Allows adding new graphic entity to the slot (“trace” or “marks”).
“Remove” Completely removes graphic entity previously selected in the list above.
“Edit” Allows user to adjust properties of the graphic entity selected in the list.
“Remove All…” Removes all graphics from the slot, makes it empty.
“Move to slot” Allows user to move the graphic entity from one slot to another when
multiple slots are used. For instance if the user wants to move flags originally plotted in
slot #2 (on top of the depth) to slot #1 to be plotted on top of the magnetic field, he or she
can do it by selecting the entity, then the “move to” slot and pressing the “Move” button.
“Duplicate” Duplicates currently selected graphical entity. A typical example would be
plotting the same data in two different scales. First configure one plot, and then duplicate
it. Then adjust scale and color for the copy trace.
Press “Add” button to add a new graphical entity. A small dialog “Add graph to the slot”
will appear. To add the magnetic field select “Trace”. This means that a waterfall graph is
being added to the slot. The next section describes in detail how to add a magnetic field
waterfall graph. Adding magnetic field plot to the slot.
Continue as in previous section, press “Add” button and select “Trace” Trace definition
dialog appears:
A complete description of the dialog controls:
Trace name. This is the trace name as it appears in the page legend. The name should be
unique. Appropriate names are “mag” “depth” etc.
Data units. Optional display of data units to be plotted in the legend and on the graph.
Trace type. There are two choices: “Single channel” or “Composite trace (formula).”
The first is used if a simple device reading will be plotted. The second provides the ability
to combine different channels into one waterfall plot. A typical example is plotting total
water depth for a magnetometer equipped with both altimeter and depth sensor. In this
case it is desirable to plot sum of these two values to track sea floor topography. A
“composite formula” can be used to linearly combine data from any devices regardless of
their sample rate. If the devices are sampling at different rates, the data is interpolated to
the same time interval before plotting the trace.
Device Alias. Lists all alias devices available in the program plus special devices “INT”
(for MagLog Interpolator, if used) and “Flags” for user’s flags. Select the appropriate
device to plot data.
Device channel. Select the device channel to plot. Popular devices like magnetometers or
GPS report their channel by names, while some of the devices report them by number.
Formula and Add. Type in a formula here if “composite formula” is selected above.
“Device alias”, “Device channel” and “Add” button can be used to create the formula
interactively. An example below considers the total water depth expressed in feet. The
following steps can be used to accomplish this:
1. Select device “MAG” and channel “depth” Press “Add” button. The new formula
reads as : 1.*[MAG][depth].
2. Keep device selection as “MAG”. Select channel “alt” and press “Add”. Formula
now reads as: 1.*[MAG][depth]+1.*[MAG][alt]
3. Because MagLog operates internally in meters we must modify the formula by hand
to express total depth in feet (3.28 is coefficient to convert meters into feet):
Interpolate formula to step. If “composite formula” is used then the data from multiple
asynchronous devices will need to be interpolated to the same sample interval. This field
allows the user to specify the interpolation interval. The other choice is to select “Use auto
step” and the program will select the interpolation interval automatically.
Scaling type. Controls how data is plotted in the slot. If “wrapped” is selected the data
graph wraps when slot border is reached. This is typical for magnetic field plots. It allows
seeing all the data but makes it more difficult to judge data value. “Fixed” implies fixed
scale for the whole slot. For instance it would be logical for depth data to plot it between 0
and 15 meters (assuming 15 meters is maximum fish depth). If the data is out of slot range
no graph will be plotted. There are two options for “fixed” type: “positive right” and
positive left”. Second is more appropriate for the depth graphs to see that at bigger depths
the curve goes down (when page is rotated counterclockwise).
Data scale. It is available for wrapped traces only. This is total span of the slot in data
Label wraps. It is available for wrapped traces only. If this is checked then the data value
is plotted when the trace wraps.
Lower limit and Upper limit. These are only enabled for fixed scale traces. For instance
for the depth it makes sense to set lower limit as “0” and upper limit as “15”.
Draw coordinate grid. Enables coordinate grid drawing for the trace. Note that if
multiple traces are plotted in one slot then each trace can have its own coordinate grid
plotted which will make the data display hard to read. Therefore user must select trace
scales and coordinate grid intervals carefully.
Grid interval. Coordinate grid interval. Example: the magnetic field is plotted with a of
scale “100” and a grid interval of “10”. Coordinate lines will divide the slot into10
Draw grid labels. This is available for traces with fixed scale only. In this case a
coordinate grid can be annotated. It is desirable to have coordinate lines marked for
example as 2m, 4m, 6m etc. Grid labels are enabled if this box is checked.
Grid label Y offset, mm. For grid labels this value controls where the labels appear on
the page. It is counted in millimeters from the top of the slot.
Label height, mm. Allows user to specify height of the grid label.
Grid label digits after dot. Selects grid label format.
Appearance. This group of controls allows selecting colors for the trace and its
coordinate grid as well as line styles and width. Width is specified in millimeters; however
the screen preview will be only updated for integer values like 0, 1, etc.
Minimum graph step, mm. To reduce printer overhead, the program will not try to plot
points separated by a distance (on paper) less than this value. For instance if the page
duration is 10 minutes and the magnetometer is sampling at 10 Hz, the program would
need to plot a line of 10*60*10 = 6000 points to fill the page. This number can be greatly
reduced if indistinguishable points are not plotted.
To finalize the setup assign a trace name (“mag”), set device and channel names, select
“single channel” type and appropriate scale and grid intervals. Adjust line styles as
needed. Press “Ok”. A new entity will appear in the “Data to draw for slot” dialog box.
Close the dialog with the “Ok” button. Note that annotation appears on the bottom of slot
#1. To see actual data you may need to move page forward with “>>” button.
Let’s plot the magnetometer data scaled by 10. Using the “duplicate” button can help.
Select the newly created trace in the “Data to draw’ dialog and press “Duplicate”. The
program creates the new trace with exactly the same parameters except the name (“mag1”
in this example). Select “mag1” and press “Edit” button. Adjust the parameters of the
trace: set name as “mag10”, scale as “1000” and disable grid drawing (grid for the
previous slot still can be used but with step “100” instead of “10”). Select a different trace
color to distinguish between traces. Press “Ok”. Note that there are two entities in the list
now. Press “Ok” one more time and check page preview. There should be two annotations
in different colors at the bottom of slot #1.
At this point you might save your work in a page layout file. Press the “Save layout”
button. A default file name is created as the survey file name plus a “.page” extension. Adding depth and signal graphs
Configuring the depth plot is very similar to configuring magnetic field plot. Slot#2 is
used in this example for a depth plot. Move the mouse cursor into slot#2 area and right
click to access context menu (alternatively you can just double click on the slot), then
select “Traces…” and follow the same was as for magnetic field till you get to “ Configure
trace” dialog. The following settings are specific for depth graph:
• Assign name “depth” and units “m” or “f”. If you like to plot depth in feet, see
• Select the trace type as “Single channel” if you are plotting depth in meters, or
“Composite formula” if you are plotting it in feet.
• Select the device alias as “MAG” and channel as “depth”.
• For display in feet, create a formula by pressing the “Add” button. The formula
should read as 1.*[MAG][depth]. Modify this by hand to 3.28*[MAG][depth]
(3.28 is the scale factor to convert meters into feet).
Select scaling type as “Fixed, positive left”, enter lower and upper limits as 0 and
15 (or whatever is appropriate).
To establish the depth grid check “Draw coordinate grid” and set appropriate grid
interval. Check “Draw labels”. Set “Y offset” as 100 mm (it would be
approximately in the middle of the page), label height as 2 mm and digits after dot
as 0 (if you are plotting the grid as whole meters or feet).
Specify line types and colors as you like.
Now press OK, note that new graphic entity appeared in the list, and press OK one more
type. Your depth graph is now configured.
Signal strength configuration is very similar. Use slot#3 to plot signal. Follow the same
steps as above. The trace name would be “signal” or “sig”, unit field can be left blank. In
this case you don’t need to express values in other units like feet therefore select “Single
channel” as trace type. Scale would be “fixed, positive right” and limits are 500 to 2500.
Appropriate grid interval is 500.
Save your layout after you finished. Adding GPS positions to the plot
To display boat and / or fish position, a “mark” type of graph is used. This allows plotting
data values equidistantly. Values can be formatted into decimals, degrees and minutes or
degrees, minutes and seconds.
Note that any type of data can be plotted in this way. For instance if the user wants to plot
depth on the paper each 2 centimeters it can be done using the “mark” plot for
magnetometer depth readings. The same can be done with the magnetic field.
It is also possible to print each data sample that arrives to the data logger. If the user has a
device that produces an output each 10 seconds (a typical example is an event mark) than
all of the events can be plotted.
Note that because data is plotted on a channel-by-channel basis the user needs to set up
two “marks” to plot both longitude and latitude numbers. It is the user’s responsibility to
input matching plot parameters so that the GPS position appears on the paper in a
consistent manner (it is possible for instance to plot longitude each 2 centimeters and
latitude each 1 centimeter – probably not what user wanted).
Below is an example how boat GPS position can be plotted.
Move mouse into slot#1 area and right click. Select “Traces…” and press “Add..”.
Alternatively you can just double click on the slot. In any case, select “Marks” type, not
“Trace” type. The following dialog appears:
For this particular example set all fields exactly as in this snapshot. Note that the first part
of the dialog box is the same as for “trace” plot. The definition of the fields is as follows:
Markers name. This name appears in the page legend. The name should be unique (not
used elsewhere). Appropriate names are “Lon” if longitude is plotted or “Lat” for latitude.
Data units. Data units (optional). Leave this blank for GPS positions.
Markers type. There are two choices: “Single channel” or “Composite trace
(formula).” The first is used if a simple device reading will be plotted. The second allows
combining different channels into one value. A typical example is plotting total water
depth for magnetometer equipped with altimeter and depth sensor. In this case it is
desirable to plot sum of these two values to track sea floor topography. The “Composite
formula” can be used to linearly combine data from any devices regardless their sample
rate. If devices are sampling at different rates, data is interpolated to the same time interval
before plotting values.
Device Alias. Lists all alias devices available in the program plus special devices “INT”
(for MagLog Interpolator, if used) and “Flags” (for user’s flags). Select the appropriate
device for data plot. In the case of a GPS it would be “GPS”
Device channel. Select device channel to plot. Popular devices like magnetometers or
GPS report their channel by names, some of the devices report them by number. Select
“Lon” for longitude.
Formula, Add, Interpolate formula to step, Use auto step. See discussion about adding
magnetic field plot. The meaning of these controls is the same as for “trace” plot.
Marker color. Select marker color. Marker is plotted to the left of the numerical value
text. The center of the marker corresponds to the time of the reading.
Horizontal position, mm. This is the distance from the left border of the slot to the
marker. You may need to adjust it to avoid overlap with other markers (as an example:
longitude is plotted at position 1 mm, and latitude is plotted at position 25 mm. If both are
plotted at position 0 mm they will overlap and are not readable).
Type. Select the type of the marker you wish to plot (or no marker at all). Available
selections include cross, star, circle, diamond, filled or not).
Size (mm). This is the marker size in millimeters. Value “1” normally looks good on the
Digits after dot. This controls number of decimal places for the value. For latitude and
longitude select the appropriate number (typically about 7). If “decimal degrees” is
selected as the format the “7” would be the number of decimal places in degrees; if
“degrees and minutes” is selected then the “7” is the number of decimal places in minutes;
if “degrees, minutes and seconds” is selected then “7” is the number of decimal places in
seconds. You probably need to reduce the number of decimal places if you are using
Text height (mm). This is the height of the printed text in millimeters. Increase this
number if the text is hard to see.
Text width (mm). This is width of the printed text in millimeters. Increase this number
for bigger text. Note that text is bounded by a “width x height” rectangle. The font size is
adjusted to fit exactly into this rectangle. For instance, if the height is 4 mm and the width
is 10 mm, the text appears compressed in the horizontal direction and is not readable. You
may need to adjust these values for clarity.
Minimum vertical separation between labels. This value controls how often data values
are printed. It is grayed out if “Print all data” (below) is selected. Note that if you print
longitude and latitude this value should be the same for both values for labels to align on
the paper.
Print all data (event mark mode). In this case the program will print all data. This makes
sense only if sample rate for the device is low (10 seconds or greater).
Print time. Time of the arrival is printed instead of data values if selected.
Marker format. Select appropriate format. For all devices except GPS or MagLog
Interpolator, the format is “Decimals”.
Next configure the latitude printout. It is logical to print it on the same line as longitude.
Go to “Data to draw” dialog and select just created “Lon” entity, and then press the
“Duplicate” button. A new entity named “Lon1” appears in the list. Select “Lon1” and
press the “Edit” button.
Presently “Lon1” has the same parameters as “Lon”. Some values have to be adjusted to
turn “Lon1” into latitude plot. Do the following:
• Change “marker name” from “Lon1” to “Lat”
• Change “device channel” to “Lat”
• Set marker type to no marker (marker already plotted for longitude)
Increase “Horizontal position” to 25 mm.
Now the latitude is plotted on the same line as longitude using the same text size, color
and format. Adding flags to the plot
Adding flags to the plot is very similar to adding GPS positions. MagLog creates an
internal device with alias “Flags”; adding this device to the “marks” plotter makes flags
appear. A flag is plotted as a horizontal line across the slot, with flag name plotted above
the line and flag position below the line. A flag icon is plotted on the line left of the text.
The printed position is the same as was selected when the flag was created. The user can
create flags at the GPS location (GPS antenna or boat location), magnetic fish location (if
MagLog Interpolator is configured) or on the map directly. The time the flag was created
can be plotted instead of the position if desired.
To add flags to slot#2, move the mouse into its area and double click (or go to context
menu “Traces…”). Press button “Add” and select “Marks” to add. Type “marker name”
as “flag” (or whatever) and leave the units blank. Select device alias as “Flags” and
channel name “flag”. Set appropriate sizes for the marker as well as text size. It is
important to check “print all data”. Otherwise the program will miss flags. Choose
correct position units. Close the dialog with the “Ok” button and close “Data to draw”
dialog with “Ok” button too. Now the flags will appear on the printout as soon as they are
Flags generated in playback mode are not printed. Service functions in preview mode
To give the user a sense for the actual dimensions of the survey data, the program displays
the mouse position when the left button is depressed. The program shows the distance
from the left page border, distance from left slot border (or “no slot” if pressed outside
allocated slot) and distance from the top of the plotting area. All distances are in
Some page parameters can be adjusted using right click and context menu. The following
functions are available:
• Add slot. Adds new slot if initiated in free area. Disabled in already defined slot.
• Delete slot. Removes current slot if pressed inside the slot. The rest of slots move
left to occupy freed up area. Disabled if clicked outside the slot.
• Traces… Calls dialog for trace and marker configuration if clicked inside the slot.
The same dialog is called if the user double-clicks inside the slot. Disabled if
called in slot free area.
Set Flag…This allows the user to set a flag in the current position of the page.
This menu item is grayed out if you attempt to set a flag outside of the defined slot.
This function is for use mainly in playback mode. It creates a user flag in
synchronization with survey time of the survey event, not at the current playback
time. These flags will appear correctly on the preview window and printer page.
Flags that are set on MagLog slots during playback have the time of the playback
and therefore do not appear on the print preview. The following dialog window is
displayed when “Set Flag…” is called:
Here “flag name” is a mandatory field to be filled in by the user. “Flag time” is the
time of the mouse click. The flag is assigned this time. “Flag type” allows
assigning different types and positions to the flag. Possible choices are “GPS”,
“FISH” and “MAP”. “FISH” type flags are available only if the MagLog
Interpolator device is running, computing fish position based on layback. Selecting
“GPS” or “FISH” reassigns “X-position” and “Y-position” fields to match GPS or
magnetometer fish positions. Selecting “MAP” simply changes the flag type
without re-assigning X and Y positions. In this case the user can assign any values
for X and Y positions by selecting “Device” and “Channel” manually for X and Y.
It is the user’s responsibility to assign proper flag positions under these conditions.
Channels values 1 to 4 are set to zero for flags set on the preview page
List Flags… This menu item calls up the user flag dialog box that lists all
available flags. Please see “Using Flags.” for details.
Configure page. Calls dialog for page configuration. The same dialog is called if
double clicked in a slot free area.
Center page. Moves center of the page to the mouse location adjusting page time
interval accordingly. This function is useful to center an anomaly of interest on the
page. Move the mouse cursor to the anomaly, right click and select “Center page”.
Anomaly is moved to the center.
Redraw. Redraws the page using the latest available data.
Zoom… This item has a submenu “Zoom twice…” and “Reset zoom. “Zoom
twice” increases page resolution by factor of 2 for easy detail recognition. Scroll
bars appear to let user scroll zoomed page. The maximum zoom factor is 8. “Reset
zoom” returns the page to its normal size.
Next page >> and <<Previous Page. Moves the page in time by page duration
interval (the same as “>>” and “<<” buttons).
Printing MagLog pages in real time survey
After the print page layout is configured you can save it as a template in a file. Pressing
the “Ok” button in the page preview dialog saves the layout immediately if the file name
was previously assigned. To start actual printing, call the preview dialog and press the
“Start printing” button (this button is disabled if printer was not configured; if this is the
case press “Print setup” to configure the printer). The following choice dialog appears:
Print choices.
This dialog box provides print selection options. The options are:
Current page only. Program prints the page currently being viewed on the screen.
Preview dialog is not closed and user can select another page using “>>” and “<<’
All available pages. Prints all pages that can have any data. Page duration and internal
program buffers define number of pages. Program does not close preview dialog.
Last pages. Program prints last N pages, where the user sets N. If “1” is set only current
page is printed. Program does not close preview dialog.
Continuous printout. This choice is available only in real time survey. Starting from the
present time the program starts printing pages continuously according to selected page
duration. (Note: Printer device could be Adobe Acrobat or other PDF maker such that the
printing is actually printing to file for later screen review). The program closes preview
dialog (warning is posted to the user). When continuous printing is running the page
cannot be re-configured. Calling “File / Windows print” function results in the warning
that continuous printout is running. If the user proceeds, the continuous printout function
is canceled and the preview dialog is displayed again. If the survey is closed while the
printout is running, the program prints the last page. This final page may not have a
complete data set.
Print on flag. This option initiates printing each time a flag is set (a flag can be set
manually by the user or automatically by the anomaly detection part of the MagLog
program). MagLog tries to center the flag on the page and therefore the user should not
expect printing to start immediately after a flag is set. For example if the page duration is
10 minutes and a flag set at present time, the program waits another 5 minutes to acquire
data for a complete page display. Flags received during these 5 minutes do not trigger
additional pages and will also be printed on the page. The preview dialog is closed and the
user cannot re-configure layout while the “print on flag” option is active. Calling “File /
windows print…” again cancels “print on flag” option.
The main window status bar field “Printing” indicates the windows printer system state at
each moment. It can have the following values:
"Printing OFF" No real time printout.
“Print in xx minutes” Continuous printout enabled and next page is going to be
printed in xx minutes.
"Print on Flag" the introduction of a flag (manual or automatic) can be used as a
trigger to start printing.
Printing MagLog pages in playback mode
Printing in playback mode is different from printing during real time survey because data
has already been acquired. Therefore there is no need to wait for each page to complete,
and all pages can be printed at once at the user’s request. The print preview window has
the ability to navigate to any part of the data easily. This can be accomplished by calling
the “Configure printer page” dialog box. In playback mode, this dialog has a list of all
acquired data lines. The buttons “At the start” and “At the end” move the beginning and
end of the page to the start or stop of the selected line. After the user closes “Configure
printer page dialog”, the preview window is adjusted accordingly. Below is an illustration
of the dialog in playback mode:
Use line selection box to navigate printout.
Select line of interest and press “At the start” or “At the end” button. Watch how the
program adjusts the “Stop print time” and “Date” to move to the selected place in the data.
When the “Start printing” button is pressed the following choices appear:
First three choices are the same as for real time surveys. For instance the user could
position the page to the place of interest and print only one page. He or she can adjust
page duration and scales for each anomaly.
The last choice “Print lines” enables selective line printing. When the last choice is
selected, the following dialog box is displayed before actual printing starts:
User should select desired lines to print. Multiple selections can be made.
The program starts printing immediately after the “Ok” button is pressed. All pages are
spooled into one print job (in real-time continuous or “on flag” printing each page is
spooled into separate print job).
10 Configuring Other Devices
10.1 Re-transmitting log information
Starting with v. 3.27 MagLog provides for re-transmission of the log file content in real
time. For each input device it is possible to send a raw unaltered device string and PC time
stamp, the precise content of the log file. Transmission can take place regardless of
whether MagLog is logging data or not. The following transmission channels are
Serial port (RS-232) communication.
TCP Point-to-Point connection, Server mode. Only one client at a time is allowed.
TCP Point-to-Point connection, Client mode.
UDP connection to the desired host. This mode could pass through a network
gateway and broadcasting to a host on another network.
UDP broadcast connection to any host on the local network.
The re-transmission device (transmitter) can interleave data from different MagLog input
devices into one data stream. However there is no guarantee that data time stamps would
be honored while sending data out.2
For instance, even if the data for device #1 arrived before data for device #2, it is possible that data for
device #2 would precede data #1 in the transmitter data stream.
To use this feature call up the Output Devices / Re-transmitters… menu:
The transmitters dialog is shown below:
This dialog initially has a blank list of configured transmitters. Press the “Add” button to
create a new transmitter device. To change the properties of the existing transmitter select
it in the list and press the “Properties” button. To remove a particular transmitter or all
transmitters use “Remove” or “Remove All” buttons. To disable a transmitter without
removing it from the survey, uncheck the checkbox located on the left of the transmitter
configuration string.
Selecting the “Add” or “Properties” buttons produce the following dialog:
The following controls are available:
TCP/UDP connections: Check this box to enable data transmission using TCP or
UDP protocols. If this box is not checked, all fields related to TCP or UDP below
are disabled.
Port number: TCP or UDP port number. Make sure port is available and not used
by some other application or another transmitter within MagLog. You may need to
try different port numbers. Your receiver application should use the same port
Mode: The following modes are available:
1. TCP Point-to-Point connection, Server mode. Only one client at a time is
2. TCP Point-to-Point connection, Client mode. You should type the server
IP or a symbolic name in the space provided.
3. UDP connection to the desired host. This mode allows passing through a
network gateway and broadcasting to the host of another network. The
name of the host or its IP address is required.
4. UDP broadcast connection to any host on the local network.
Server. Type the IP address in the form or a host name for those connection types
which require it (see above)
Second a group of the controls related to the RS-232 transmission:
Serial Output: Check this box to make serial output available. If the box is not
checked there would be no serial output from the program.
Port: Serial port number to be used for data re-transmission. Make sure the port is
available. The port cannot be shared with a different transmitter within MagLog.
Note special real time ports (handled by COMM/DRV by cannot
be used.
Baud rate: Transmission baud rate to be used by the transmitter. Your receiver
must use the same rate.
On the right side of the dialog there is a list of Devices available for re-transmission. To
include a particular device just set the appropriate check mark. You can also exclude
devices from re-transmission in this manner.
After the dialog is complete press the “OK” button to close. Transmission starts (or is
altered) when the transmitter list dialog is closed. The “Cancel” button keeps the existing
configuration intact.
10.2 Configuring Slots/Traces for Printer
You can control what the printer outputs by adding slots and traces to the printer. You
have the ability to control the types of traces outputted, and the width, size, and position of
each trace.
In order to configure the printer, you need to specify the traces you would like to output.
This is done from within the “Configure / Displays configuration” screen.
In the example below, we will configure the Printrex or dot matrix printer to output
several G-880 traces (for Windows™ printer configuration, see “Using Windows™
printers and print drivers.”)
From the “Input Devices Configuration” screen, select “Slots/Traces for Printer”.
You will see a summary of the traces your printer will output.
“Auto Add Slot” will generate one slot and one trace for each data field (similar to the
“Auto Add Slot” feature seen in chapter three).
To add a slot, press “Add Slot”. You should see the following dialog box:
From this screen you can specify the traces you would like to print, and where you would
like the traces to appear on the printed page.
Origin X (cm): This affects the trace origin on the page. For instance, most pages have a
width of 19 cm. If you want your slot to appear in the middle of the paper and be 2 cm
wide, you would use an origin setting of 9 and a width of 2.
Width (cm): This is the slot width in centimeters.
Note: The program will check to make sure that you don’t specify slots that could be
printed outside of the printed page.
Horizontal Scaling: This specifies the full-scale range of the slot.
Use fixed range: Like display slots, printer slots can be wrapped or have a fixed range. If
the trace is wrapped it always appears from the other side of the slot (wraps) if it is out of
scale. If the slot has a fixed range data is not plotted if its value does not fall into slot’s
range, it is “clipped”. This presentation can be useful for some types if data like depth and
altimeter information.
Min Max Maximum and Minimum data ranges for a fixed slot.
Positive axis left For some type of data (for example for bottom depth) it is natural to plot
them with the positive axis down (left when you are looking at paper coming out of the
printer). To enable this feature, check this box.
From this screen, traces can be added to the slots. Refer to chapter five for more
discussion on adding traces.
10.3 Configuring Output Devices
10.3.1 Configuring the Video Titler (Airborne Applications):
Select “Output devices / Video Titler” from the menu.
The following video titler configuration dialog box will appear:
If Video Titler ON/OFF check box is checked then GPS, line number and time
information will be sent to the video titler and will be recorded on the VCR. Otherwise no
information will be sent.
The default port is COM1 for the video titler.
10.3.2 Configuring Direct Printer (Printrex and Dot Matrix printers)
MagLog can support either the RMS GR33 printer/plotter OR the Printrex thermal printer
and ECS/P compatible 9 and 24 pin dot matrix printers. Printer support is hardwired into
the MagLog executable file. To find out if your version MagLog supports GR33 or
thermal and dot matrix printers, go to MagLog Help /About. If the dialog box says
“GR33” it means that the GR33 printing device is supported and this program will not
support either the Printrex or ESC/P (Epson dot matrix) printers. Very few MagLog
versions were released with GR33 compatibility.
Most copies of MagLog are designed with Printrex and ESC/P dot matrix support. If the
Help /About dialog box. says nothing about printer type or says “PRINTREX” you have
Printrex and dot matrix drivers.
Configuring the GR33A printer
Select “Output Devices / Printer” from main menu.
You should see the following dialog box:
This dialog box allows you to adjust the speed of the printer, and how often the GPS data
will be printed. The options given are:
Chart Speed: This is how fast the printer paper will go (in mm per second).
Print … - Here you are given a list of possible positions you can print.
GPS latitude and longitude: This will print the GPS coordinates in geographical
Layback geographical: This will print a calculated layback position in geographical
(latitude/longitude) coordinates.
Layback UTM: This will print the calculated layback position in UTM coordinates.
1st ORE target geographical: This will print the position of the ORE target in geographical
1st ORE target UTM: This will print the position of the ORE target in UTM coordinates.
At column (0-11): This specifies the column where the position will be printed.
At least every: This specifies how often the position will be printed (given in centimeters
of paper fed through the printer).
Configuring PRINTREX / DOT Matrix printer
Printrex configuration dialog differs from the GR33:
Chart Speed: This is how fast the printer paper will go (in mm per second).
Printer. There are 6 choices available under Printer selection box:
1. Printrex 8.5 “ Actual paper width for data plots is 19 cm.
2. Printrex 11.65” Actual paper width for data plots is 19 cm.
3. Epson generic 8 dot. Low quality matrix printer with actual paper width 17 cm for
data plots. Note that 24 pin printers normally can work in this mode.
4. Epson generic 24dot. High quality matrix printer with actual paper width 17 cm
for data plots. You must physically have a 24 pin printer to use this mode
5. Epson generic 8 dot wide. Low quality wide matrix printer with actual paper
width 29cm for data plots. Note that 24 pin printers normally also can work in this
mode. You need a wide printer to use this mode.
6. Epson generic 24 dot wide. High quality wide matrix printer with actual paper
width of 29cm for data plots . You need a wide printer to use this mode.
Parallel Port: specify the printer parallel port.
Address: Port address for the parallel port. 0x378 and 0x278 are defaults for LPT1 and
LPT2 respectively.
Consult your computer or parallel extension card manual for correct values.
Print … - Here you are given a list of possible positions you can print.
GPS latitude and longitude: This will print the GPS coordinates in geographical
Layback geographical: This will print a calculated layback position in geographical
(latitude/longitude) coordinates.
Layback UTM: This will print the calculated layback position in UTM coordinates.
1st ORE target geographical: This will print the position of the ORE target in geographical
1st ORE target UTM: This will print the position of the ORE target in UTM coordinates.
Print event (fix, shot) number only. This option is available if TTL or Serial event device
is available.
Print Lat/Lon as: Latitude and longitude can be printed as decimal degrees, degrees and
minutes or degrees, minutes and seconds.
If Interpolator is not running, only choices (1) and (6) are available.
At column (0-11): This specifies the column where the position and event number will
be printed.
At least every: This specifies how often the position will be printed (given in centimeters
of paper fed through the printer).
Print on event marks only: This option is available only if TTL or Serial event mark
device is present. If checked, MagLog prints GPS position and / or event number only
when event actually arrives. If not checked the same information is printed equidistantly
regardless of possible events.
Picture below shows typical MagLog printout. It consist of next elements:
• Header. Each trace has its name, scale, paper origin and size and value printed. It is
possible to print the same trace with different scale in different slots, or in the same
• Separators. For clear view, slots can be separated with solid lines.
• Print trace value on wrapping. When trace is wrapping, current trace value is
printed on the left side of the slot. To avoid overlapping next field value cannot be
printed at distance shorter then 3 cm (along the paper).
• Position Latitude and Longitude.
• Event numbers (fixes) are printed after position, if event device is available.
Alternatively, only event numbers can be printed (no position).
10.4 Changing line number during Survey
Select “Configure” from the menu then “Line Number”.
You should see the following dialog box that will allow you to change the line number.
The line number is used and recorded with the data while logging. It is automatically
incremented by one when you stop logging.
You can change the line number only when you are not logging data.
The line number is restricted to a range between 0 and 10000.
11 The Survey
This section describes a typical survey screen, the menus available, and many of the
operations you can do from within MagLog.
11.1 The Main Screen
Once you have defined all your hardware, display and printer settings you will have a
screen similar to the screen below:
Note: The screen above defines a system with a G-880 magnetometer, GPS,
compass and ORE TrackPoint II positioning system. The user also has enabled real
time position interpolation and has prepared a vector map of the survey area for
importation. The screen that you see may be considerably different depending upon
the exact display configuration you specify.
This screen has many informative features that help the user understand the data logging
process and maintain quality control.
Device Status Bar: This is located on the top of the screen when you start the program.
The Status Bar is useful to quickly inform you of the data status. The LED's come in three
Data is being received.
No data has been received within five seconds.
Device dependent sign that something is wrong with the data. In
the case of the G-880 magnetometer and GPS, this will turn yellow if one of the
conditions for good quality data (e.g., signal strength or data out of range) is not met.
Below the LED there is also a number that indicates the size in KB of data stored in the
individual file for each device. When you are logging, this value will increment.
Data bar: This is located below the menu and contains 16 black mini-windows that
indicate the last values of data received for the device corresponding to the current active
window i.e., what the mouse has selected. This is also useful to make sure that your data
is being parsed correctly. In the example of the sample magnetometer input string,
40001.24, 0243, 2001, 1209, 40291.35, 0543,
there should be seven windows with numbers. The first should correspond to 40001.24,
the second to 0243, and so forth. The seventh number is a gradient value that is only
available for two or more magnetometers.
The slot and trace window: This is where data will be plotted. In the example above,
there are four independent windows. Currently, the window titled 822A is the current
selected active window (indicated by blue title bar). When a window is selected, you can
use some short cut keys to make some changes to the window.
Left/Right Arrows: These will modify the scale factor for the selected slot.
Up/Down Arrows: These will allow you to navigate through the window and select the
For other operations please look at the “Display Setting” menu items.
The status bar: This is located at the bottom of the screen and displays Latitude and
Longitude of mouse pointer in mouse is inside GPS window. It also displays general
information like current line number, time and date, disk and memory free space.
11.2 The Menus
The menus that are available at a given time are dependent upon the active window you
have selected. This section will describe many of the standard menus always present, and
some of the device specific menus you will encounter.
File Menu: This menu allows you to start a new survey, terminate your existing survey,
and start or stop logging. The options available will depend on the state of the program,
e.g., if you don’t have any devices configured, it would not make sense to start logging so
that option will be grayed out
View: This menu allows you to enable or disable the status bar at the bottom of the
Configure: This is used any time you want to configure a device. After you have
successfully configured your devices, it is not necessary to make adjustments in this area.
Remember that you can reconfigure slot settings by right clicking on the pane and
selecting either Display for GPS or SLOT for slot parameters.
Note: Many of the options of this menu can be password protected. If you supplied a
password on entering the program, and later exited, you will need to supply a valid
password to have access to enter configuration parameters in this menu.
Display Settings:
This menu is device dependent. A few options are discussed below:
G-880 Display Settings: This menu has many options for changing the scale factor and
applying it to one or more slots. There are also shortcuts for centering the traces for a
specified slot, or all slots in a window.
GPS Display Settings: This menu has options for independently changing the scales of X
and Y, or changing them together. In addition, you can disable the “auto scroll” feature
that automatically shifts the grid coordinates of the map when the GPS North icon moves
off the current graph.
You can use this menu to arrange your current windows neatly within your
MagLog program. Some options that are available:
Cascade: This will overlap the windows. You can select a window by clicking on its title
Tile vertically/horizontally: This will show all display windows in MagLog
simultaneously. It will divide the desktop area by the number of windows and attempt to
arrange them appropriately.
There is also a list of most recently used windows kept here. If you select one, it will
become the active window.
Help: This displays the current version of MagLog.
12 Ready to start logging data
When you are ready to log data, select “Start Logging” from the file menu. Note that the
logging status indicator on the right side of the status bar changes its color from red to
to green:
In between survey lines, the turns, select “Stop Logging”, then “Start Logging” when you
are ready. This will increment the line number automatically.
Unless you specify a different survey name, all new data will be appended to the old data
You may set the line number when logging is stopped to any number in the Configure /
Line number menu.
12.1 Auto logging feature
If survey an area polygon is defined it is possible to start logging automatically when the
GPS or fish enters the survey area (please see “Preparing a Survey plan file.”). To use this
feature a GPS window should exist and be active. Select “Configure / Start auto
logging…” menu item as it shown on the screen shot below:
The following dialog is displayed:
In this dialog check “Start logging data after entering survey area” and select the
appropriate “Check for positions” (GPS or Fish) to enable auto logging feature. Position
selection allows the program to start logging if GPS or magnetometer fish enters the
survey area (if the INTERPOLATOR is not being used in the survey, only GPS position
can be selected for the autologging feature because the fish position is not calculated).
Upon entering of the survey area logging is started automatically. After leaving the survey
area logging is stopped and line number is automatically incremented by one.
Note that if survey area is not defined or there is an error in defining the area, logging may
never start. Make sure the survey area is visible on the screen as a shaded polygon. It is
highly recommended that the user ensure that logging actually started when the boat enters
the survey area for the first time.
Always keep in mind the GPS to fish separation if GPS position is used as a
reference for logging. For instance if the boat leaves an area and logging is stopped,
the area may not be fully covered because magnetometer sensor is a considerable
distance behind the boat. For this reason it is recommended to enlarge survey area by
the cable length in all directions when using GPS as the reference point.
13 Survey units
MagLog supports meters or feet as the primary distance units. The units can be easily
changed at any time by selecting “Configure / Units” menu item as it is shown below:
This will change all distance units in the current survey and can be implemented mid
survey. We of course do not recommend this action as it could be quite confusing!. For all
dialog boxes where distance units are used the notation [m] is replaced by [f] or vice
versa. The GPS window will change its grid units from meters and kilometers to feet and
miles. Magnetometer depth readings will also change units if channels are marked as
depth (for details, see “Manual Calibration:”).
14 Real time cable length adjustment
MagLog versions starting with 2.84 have the ability to adjust the magnetometer layback
input without interrupting the survey. This option is available via “Output devices /
Layback” menu. The short cut key is F2. Layback can be changed regardless of logging
status at any time. Layback values also are saved into Interpolator log file and Line
Number file In the latter case they can be used by the MagMap program to re-interpolate
the fish position in post-processing mode. It is assumed that cable length did not change
while acquiring the data (within the line), but may change when logging is stopped (in
between lines).
The purpose of this is to allow winch operators to vary the cable length in real time due to
varying depth conditions. Automated cable payout indicators can be used to accomplish
this also. See section on payout indicators for more information on this facility.
15 Output Files
MagLog writes several files during the logging process. All files are placed in the same
directory where the survey file was created:
Each file name starts with the Survey name, followed by ".Survey", then the type of
device, then the name given to the device in the configuration.
Data is logged to each file as it comes into the serial port. A time stamp is added to
provide positioning for all sensors with the GPS data. No processing is done to any files
unless the Interpolator is turned on. Thus, the GPS file will have GPGGA strings stored
(exactly as they were received from the GPS with the addition of a time stamp added by
MagLog), and the magnetometer file will have a series of magnetometer strings stored
(also with a time stamp).
In the screen above, the survey was named “Training”. It had several device files:
G-880 magnetometer – output file name: “training.Survey.880.mag”
GPS - output file name: “training.Survey.GPS.gps”
GYRO – output file name: “training.Survey.GyroCompass.gyro”
ORE – output file name: “training.Survey.ORE.ORE”
Cable length measuring device – output file: “training.Survey.Serial Device.cable”
These data files can be analyzed and plotted using MagMap2000, a free processing
program from Geometrics. Files can be reformatted for plotting in Surfer or other
graphics packages.
The above screen also has files used for annotation and document control:
Survey file- “training.Survey”. This survey file saves all device configuration settings
and slots/traces settings.
Log info file: “training.Survey.loginfo1.txt”. This file logs important events that
happen while the program is running. For instance, if you have an 880 magnetometer
configured, it will record the settings used to initialize the G-880 magnetometer and it
will state whether or not several of the operations involved in initializing the
magnetometer succeeded. This also records when a device is removed.
Line number file: “training.Survey.LineNumber”. This file records the starting and
stopping time of each line that you travel in your survey. This file will only be when
you select “Start Logging” and “Stop Logging” from the main “File” menu.
The Interpolator output file is discussed further in the “Interpolator output” section.
16 Depth/Analog channel calibration
In order to get an accurate depth sensor reading, the pressure transducer sensor must be
calibrated. This means that the depth sensor reading needs to be compared with a known
depth to account for the variations occurring due to air pressure variations and to
manufacturing variances. Bias and linearity adjustment can be made in the program to
empirically calibrate for depth. (You can read more about this method at the end of the
The depth reading from the magnetometer is an integer between 0 and 4095. This
represents the full-scale range of the depth transducer. There may also be a certain offset
that must be adjusted.
MagLog offers a few different ways to calibrate the depth.
Regardless of units selected for the survey (recording data in feet or meters) depth and
altimeter are always calibrated in meters.
Note: These methods also work for calibrating other analog channels.
16.1 Calibration Procedure:
The basic procedure for calibrating the depth sensor is as follows:
1) Place magnetometer in the water for at least 15 minutes at a known depth, say
3 meters. This will give the temperature of the sensor time to stabilize.
2) Write down the depth and reading that MagLog gives you.
3) Place magnetometer in the water at a DIFFERENT depth.
4) Write down the depth and reading that MagLog gives you.
5) Use either automatic calibration feature or manual calibration to apply results.
Note: If you use automatic depth/analog channel calibration, you can do this while
in the calibration screen.
16.2 Automatic Depth/Analog Channel Calibration:
1) From your configuration screen, you should select the magnetometer. This should
bring up the “Settings” screen that you originally used to input the number of sensors
and analog channels. (You can get to this screen by going into your main list of
devices, and then double clicking on the magnetometer description). You should see a
screen similar to the one below:
2) In the section labeled “Analog channel calibration setup” select the sensor and
channel number that you want to calibrate, e.g., to calibrate the depth of the first
sensor in the earlier example, select
Sensor #: 1
Channel #: Depth
3) Select “Auto calibration”. You should then see the following dialog box:
Note: At this time depth data is coming from the Fish that is being analyzed by the
program to compute the bias and scale factor. You must place the Fish on at least
two depths to get an accurate calculation. During Altimeter Calibration discussed
later, you must be over a hard bottom and the Fish must be held horizontally level.
You can add measured points to this menu and have it automatically calculate your scale
factor and bias. The depth sensor needs to be in the water for at least 15 minutes before
you take your first measurement. This allows the temperature of the electronics to
To add a new point, place Fish at known depth. Press Reset Average to discard current
average and wait for a few minutes to acquire a new one. Number after text Current
average: should stabilize. Then enter the depth that the device is at under “Value” and
press “Add to the list”. This will take the average measurement MagLog currently sees
for the depth, and it will add it to a list of calibration points.
It is important to remember to reset the average if you move the sensor. You can do this
by pressing “Reset Av.”.
You can also specify an acceptable range of points to be used by pressing “Acceptable
Range”. This will bring up a dialog box that will allow you to set a minimum and
maximum allowed value. This is particularly important when you calibrate your altimeter
because occasionally you might get a spiked reading (missed echo) that you don’t want
included in the calculation of your average.
After you have at least two points, MagLog will then try to calculate a scale factor and
bias. You need to make sure that you have at least two different depth points (e.g. it is
advised to have one point near the surface, and the second point as close to the bottom as
possible). Otherwise, the calibrations will not be accurate. It is advised to add more than
two points to get improved accuracy.
You should also select “Channel Represents Depth”. This option is important if you have
an ORE device.
If you are satisfied with the calibration, select “OK”.
4) You will then be given the opportunity to save your calibrations into a file. The file
will keep track of the scale and bias calculated, and the readings used to make the
calculation. It is advised to keep this for your records.
16.3 Manual Calibration:
Manual calibration gives you the opportunity to enter the scale and bias directly without
having MagLog calculate them for you. Typically these values are included along with the
marine magnetometers, often listed on a sticker found on the fin assembly.
If the depth channel is already properly calibrated, this dialog box also provides
instructions to MagLog to use the depth values in the real time position interpolation or
simply to inform Maglog that the channel represents depth or altitude.
In manual calibration you can either determine the scale and bias values yourself or enter
the bias and scale data supplied by Geometrics.
To use MagLog’s manual calibration feature, select “Manual Calibration” from your
device settings menu. (Make sure that you have the correct sensor and channel selected as
discussed in the section on “Auto Calibration”.)
You will see a dialog box:
Enter your scale and bias values, and check “Channel represents depth/alt.” if this is a
depth or altitude calibration. This informs MagLog that this channel has distance units
and is to be re-computed when user changes units for the survey (meters or feet). If the
user wants to use the depth reading in the real time position interpolation, then the button
“use for layback calculations” must be checked. If multiple depth channels are used
MagLog takes an average depth value to compute layback position. When the “880
settings” dialog box is closed MagLog reminds the user which channels are selected as
depth channels for position interpolation.
16.4 Effects of Depth calibration
After you have calibrated your depth sensor, you should see immediate changes in your
data. The graphs and displays will use the new calibrated values.
However, the device file will have the uncalibrated values logged in it (*.G-880).
If you need to store calibrated values, you should use the Interpolator device that will
write calculated depths and altitudes based on the entered or calculated scale and bias
values into the Interpolator file.
16.5 Why should we calibrate?
This is a brief discussion on how MagLog calculates scale and bias values and why this is
The depth sensor is a pressure transducer. This means that for a given pressure, it will
output a number proportional to the pressure measured. However, the number is
meaningless until we solve for a few factors.
Assume that the depth reading is related to the pressure reading by the following:
Depth = A×Pressure + b
In this case, the two parameters A and b are the scale and bias values that we need to find.
We can solve for these two values if we have at least two sets of measurements. If we
measure the following:
MagLog Reading (pressure)
I can then get two independent equations:
Y1 = A×X1 + b
Y2 = A×X2 + b
Solving for A and b, I get:
A = (Y1 − Y2) ⁄ (X1 − X2)
b = (Y2×X1 − Y1×X2) ⁄ (X1 − X2)
From here, we can now use these new values to calculate the correct depth, given only the
MagLog can then use these equations to automatically adjust all pressure readings to
accurately reflect the depth measured.
17 The Interpolator
MagLog is able to do real-time calculations of multiple sensor positions. The processed
data is then made available via either Ethernet (e.g., ship network with IP address) and or,
a serial connection and stored into a file.
The following chapter explains the capabilities of the Interpolator and the settings needed
to make it work.
17.1 Overview
17.1.1 Uses of the Interpolator
The Interpolator was made to solve the problem of computing and storing real-time
magnetometer positions. A typical survey has several different devices – some of which
give positional information and others that give measurement values only. The surveyor
usually wants to make a spatial map of the magnitude of the measurement and the position
where the measurement was taken. Since the device generating measurements usually
doesn’t output position information (e.g. G-880), we need a way of using the GPS
information to calculate the actual position of the magnetometer sensor. Additionally,
there are devices such as the ORE Trackpoint II and the GYRO compass that can be used
to obtain even more accurate positions of the magnetometer sensors. Usually the
calculations of the magnetometer positions are done after the survey is finished using
additional software such as MagMap2000. To provide a real-time solution, MagLog has
an Interpolator that is used for doing real-time calculations of the magnetometer position –
for each magnetometer reading, there will be a series of positions output.
MagLog is able to output several types of positions depending on available hardware:
1) Reference Point: This is a point (e.g., geodetic coordinate) that is assumed to
be on the ship. It is the starting point for most calculations and is present in all
files generated. The user is able to specify the type of reference point output:
a) GPS (raw antenna point) -- the actual reading from the GPS
b) Tow point -- another point, still assumed to be on the ship a fixed offset
away from the GPS. (More discussion is given at the end of this chapter).
2) Shifted Point: This is a point that is at a fixed, but not necessarily rigid offset
relative to the ship. The two types of shifted points available are:
a) Simple shifted point: This assumes a constant cable length (e.g., L) and it
uses the past movements of the ship to extrapolate the likely point a
distance L behind the ship.
b) Shifted point using variable cable length: This allows a variable cable
length and works similarly to a).
3) Acoustic Target Position: This is only available when the ORE Trackpoint is
used. The two types of position points that are output depend upon the type of
GYRO device used.
a) MagLog’s calculation of acoustic target position: This is used when the
ORE Trackpoint II does not have a GYRO connected. (Note that there
must always be a GYRO connected in order for the ORE to work
properly). It uses the ORE, GYRO and the GPS to calculate the position
of the acoustic target.
b) ORE’s calculation of acoustic target: This is used when the ORE has a
GYRO input available. This is a better position point because errors due to
GPS latency are minimized.
4) Sensor Positions: (may be set up for as many sensors as required)
a) Calculated as towed distance behind acoustic target: This uses the ORE
information and assumes that the magnetic sensor is a fixed distance behind
the acoustic target. It uses the same method as that used for the shifted
point to calculate the position behind the ship.
b) Difference in direction from GPS: This is useful with horizontal
gradiometers when there is a horizontal displacement between a line
parallel to the course of the boat, and the sensor.
c) Difference in direction from shifted point: This is almost the same as
above, except that a shifted point is used as a reference point instead.
All positions may be output in UTM or geographical (Lat/Long) coordinates but
geographical output is not recommended if the computer is underpowered or has a high
workload. Computers manufactured after 2002 should have no problem processing in
geographical data mode.
17.1.2 Output Capabilities
The Interpolator is able to output data into a file, through the serial port, or via Ethernet.
17.2 Menu-oriented Interpolator setup
This section explains how to set up the Interpolator using the normal sequence of the
menus. A few examples will be given later in this chapter to illustrate the concepts.
The Interpolator can be accessed through the configuration screen. No Interpolator
information will be available until a magnetometer and GPS are installed.
You can configure the Interpolator by selecting the “Configuration” menu, followed by
“Output Devices”, and then “Interpolator”.
This will allow you to access several tabbed dialog boxes (discussed below).
17.2.1 “Mags” Dialog
This dialog box allows you to set several attributes about the magnetometer.
Add/Remove Interpolator Device: This check box enables the Interpolator. There will
be no output or calculations if this is not checked. When this is checked, you should see a
circle with labeled “INT” at the top of the screen with the rest of your devices.
Magnetometer array offset: This is used in the calculation of a point behind the vessel.
It will mean different things for different configurations. A brief summary is given below
for a sample value of 100m that is input.
The ORE has no effect on any of the settings in the “MAGS” dialog. However, to
try to eliminate confusion, we have included the ORE in the list of “Devices
All distances and points are calculated from the GPS:
ORE, GYRO, Cable Length
Will calculate a shifted point equal to the
length of the cable measured + 100 meters
behind the boat with respect to GPS. ORE
is ignored.
Will calculate a shifted point equal to 100
meters behind the GPS.
GYRO, Cable Length
Will calculate a shifted point equal to the
length of the cable measured + 100 m
behind the boat. It is recommended to
specify a tow point and put 0 for this value.
If you don’t specify a tow point, but still
Cable Length
specify 0 for this value, you will a shifted
point that is calculated using a value equal
to the distance to the GPS minus the
distance to the point of attachment of the
cable length indicator.
Will calculate a shifted point equal to 100
meters behind the boat.
Will calculate shifted point equal to length
of cable measured + 100 meters behind the
Will calculate shifted point equal to 100
meters behind the boat.
See below for further discussion of what happens with this value if you specify a tow
point position.
Use Position of Tow Point Instead of GPS Offset: This enables position 1b (as
described earlier). To do this, you need to input two offsets from the GPS:
a) X offset – Distance from the GPS (in a direction parallel to a line going across
the boat from port to starboard). Starboard is considered to be positive. (More
discussion is given later in this chapter if needed).
b) Y offset – Distance from the GPS (in a direction parallel to a line going from
the back of the boat to the front of the boat.) The front of the boat is considered
the positive direction.
In order for this position to be calculated, you need to have a GYRO
Note: If this is checked, the tow point will be used in place of the GPS in all
further calculations.
The results stated above will change when the Use Tow Point box is checked:
All distances and points are calculated from the Tow Point:
ORE, GYRO, Cable Length
It is recommended to put 0 for this value.
Otherwise, it will calculate a shifted point
equal to the length of the cable measured +
100 meters behind the boat with respect to
the tow point. ORE is ignored.
Will calculate a shifted point equal to 100
meters behind the boat.
GYRO, Cable Length
It is recommended to put 0 for this value.
Otherwise, it will calculate a shifted point
Cable Length, no GYRO
equal to the cable length plus 100 meters
with respect to the tow winch.
Will calculate a shifted point equal to 100
meters behind the boat.
17.2.2 “TRK” Dialog
This dialog box sets up the ORE device.
Use ORE Trackpoint II: This enables the ORE device. If you don’t have a GYRO, this
should not be enabled (unless the GYRO is connected to the ORE II directly via an analog
input). However the Gyro compass can be used to enhance the computation of sensor
positions even if the ORE device is not available, particularly when there are cross
currents which can cause the direction of travel and the heading of the ship to be different.
Number of acoustic targets: Fill in the number of ORE targets you have. In most
configurations, one is used.
X/Y offset for hydrophone: This is used when the GYRO is not connected directly to
the ORE. If it is, these offsets will be input into the ORE, and the final position point that
is output will be correct with respect to the GPS or tow point. If the GYRO is not
connected, the computer needs to transform the position the ORE calculates, and take into
account the position of the ORE. The values you will want to input will be summarized
in the table below.
Use serial Gyro to calculate position: This should be enabled if the Gyro is connected to
MagLog (e.g., not connected to ORE).
Settings for above values given different configurations:
ORE, GYRO connected to
ORE, tow point specified
Enable Serial GYRO:
ORE, GYRO not connected
to ORE, tow point specified
ORE, GYRO connected to
ORE, GYRO is not
connected to ORE, but is
connected to PC
X/Y offsets:
X = 0, Y = 0. Offsets
should be specified
internally in ORE relative to
tow point.
X and Y offsets are given
with respect to tow point.
X = 0, Y = 0. Offsets
should be specified
internally in ORE.
X and Y offsets are given
with respect to GPS.
Positive X is assumed to point in the direction of the starboard side of the ship, Positive Y
points in direction of the bow or front of the ship.
Enable median filtering: This option enables a filter that will output the median value of
a history of ORE readings. The median value is found from taking a series of readings,
arranging them in numerical order, and then selecting the middle one. This is useful for
removing spikes.
Filter Size: This specifies the number of readings that are used when calculating the
17.2.3 “UTM” Dialog
This dialog allows you to set up parameters relating to the UTM coordinate
transformation. The only case in which you will not need this dialog is when the GPS
outputs UTM coordinates directly and you want your output in UTM coordinates. In all
other cases, it needs to be set up with the correct parameters.
Shown below:
The configurable options available are:
Use Internal UTM: This should be enabled if the GPS outputs latitude/longitude
(geographical) coordinates, and disabled if the GPS outputs UTM coordinates.
Geographical Output: This controls the format of the output position coordinates. It
should be checked for geographical output (latitude/longitude) and unchecked for UTM
output. If you want Lat/Long output, you must check both “Geographical Output”, and
“Use Internal UTM”. Geographical output is currently unavailable for GPS input given in
UTM coordinates.
Note: UTM to Geographical transform will apply to all positions output and stored.
Aside: This dialog is necessary because the program internally does all calculations
in UTM coordinates. These coordinates are more convenient and faster for doing
positional calculations. In order to do a conversion from geographical coordinates to
UTM coordinates, the Interpolator needs to approximate the earth as an ellipse with
specified parameters. Additionally, there are several other positional dependent
factors that you have to enter that are needed to get a correct UTM transformation.
These factors are also needed in the reverse transformation from UTM to
geographical coordinates.
The rest of these options are needed only when “Use Internal UTM” is checked, or
when both “Use Internal UTM” and “Geographical Coordinates” are checked.
Ellipsoid Parameters: These parameters allow you to choose a shape other than a sphere
to use when approximating the earth. This allows you to get better accuracy when doing
a transformation from spherical (latitude, longitude) to rectangular (UTM) coordinates.
These parameters must match those used by the GPS.
UTM Projection Parameters:
a) Central meridian: This value has a large impact on the UTM coordinates
generated due to the non-uniformity of an ellipse. It can be quickly estimated
as the value of the longitude, but you should look it up below for a better
calculation of your positions.
The Universal Transverse Mercator (UTM) Coordinate System uses zone codes
instead of specific projection parameters. The table that follows lists
UTM zone codes as used by GCTPc Projection Transformation Package.
Obtained from Software Documentation for GCTP General Cartographic
Transformation Package: National Mapping Program Technical
Instructions, U.S. Geological Survey, National Mapping Division, Oct 1990,
b) Scale factor:
Input 0.9996 for UTM coordinates.
c) Northing/Easting:
These are constant values that you would like to add
to your UTM coordinates. UTM coordinates are large numbers on the order of
a million meters but your survey may only be looking at thousands of meters.
This allows you to simplify your final numbers by adding or subtracting a large
offset. These values will not be used if you specify “Geographical Output”.
17.2.4 “GRAD” Dialog
If a Marine Transverse Gradiometer system is used, MagLog can calculate the total
horizontal gradient and plot it in real time. The difference between the two magnetic
sensors is used for the transverse part of the full gradient; and data history is used for
longitudinal part of the gradient, yielding the full horizontal gradient. This feature is
controlled in the “GRAD” tab:
All controls in this tab are disabled if a transverse gradient system is not available. The
following values must be entered:
Calculate full gradient - check to enable the feature.
Sensor 1 (and 2) - Enter sensors numbers for first and second sensor. They are
typically 1 and 2, but for multi-sensor system they may differ. For example, if
there are 4 sensor arrays and sensors 2 and 4 are used as parts of a transverse
gradiometer, enter the numbers 2 and 4.
Sensor separation - Enter the sensor separation distance in meters.
Distance lag, m -Enter the distance to calculate the longitudinal part of the
gradient. Typically, this should be the same order of magnitude as the separation
between sensors. Lag also controls how often gradient lines are plotted on the map.
For example, if Lag is 10 meters, each new line is plotted 10 meters from the
previous one.
The figure below illustrates how the full gradient is calculated:
Full horizontal gradient calculation
Sensor 2
longitudinal gradient based on lag distance
distance lag
Sensor 1
Transverse gradient at t2
Average transverse gradient
Sensor 2
Sensor 1
Transverse gradient at t1
17.2.5 “Positions” Dialog
This dialog box allows you to specify additional position points you would like calculated.
It will also allow you to specify what points of reference you want to use to calculate these
You can add a new position by pressing “Add”. You should then see the following dialog
Type: Specify the type of reference point you are using. The available options are:
a) GPS – position of the GPS
b) Shifted – Position that takes the cable length and other options specified in the
“Mag” screen. This is usually used for a horizontal gradiometer when you
magnetometers located horizontally away from the center of the boat.
c) Target – acoustic target calculated from the ORE.
Distance: Horizontal distance from reference point to desired position point.
Azimuth angle: Angle between direction of boat travel (or cable) and line connecting
GPS or Fish position (depending upon Type choice) to desired point. The positive
direction is clockwise.
Picture below illustrates coordinates definition:
Tow winch
Position of main ORE
hydrophone to be
calculated with
"GPS" reference
Target or
shifted point
Acoustic / shifted point
target as reference
Four positions are to be calculated at time of every magnetometer sample: ORE main
hydrophone position on the star side of the boat and positions for three magnetometers. To
calculate first point GPS is taken as reference point; to calculate magnetometer positions
acoustic target or shifted point serves as reference. For example, if distance between
acoustic target and MAG3 is 10 meters specify distance as 10 and azimuth as 180.
In general the positions will be specified differently depending on the type of reference
point you are using.
Reference Point:
Shifted Point
Horizontal distance from
GPS to desired position
Horizontal distance from
shifted point to desired
position point.
Distance from target.
Azimuth Angle:
Angle between direction of
boat and the point to be
Angle between direction of
cable and the point to be
If not equal 180 program
uses sequence of target’s
position to find direction. If
equal 180 dragging
approach is used to find
Note: Always use 180 degrees azimuth if magnetometer is connected to the acoustic
target with cable.
17.2.6 “Net” Dialog
This dialog box allows you to configure parameters for data output via a TCP/IP network
or serial connection. Your specific output format should be configured using the “Output
Devices / Interpolator output” dialog box (see “Interpolator Output:”) prior to enabling
output transmission.
Enable TCP /UPD transmission: This enables output via a TCP/IP network connection.
You will need to have a TCP/IP network installed for this to work properly.
Mode: MagLog can work as a TCP/IP server or client (for Interpolator data transmission)
as well as send or broadcast in UDP mode, depending on the Mode selected. Available
modes are:
TCP Point-to-Point connection, Server mode. Only one client at a time is allowed.
There is no need to specify host name or IP in this case.
TCP Point-to-Point connection, Client mode. You should type the server IP or
symbolic name in the space provided.
UDP connection to the desired host. This mode allows passing through a network
gateway and broadcasting to the host of another network. The name of the host or
its IP address is required.
UDP broadcast connection to any host on the local network.
Please consult your network administrator for an unoccupied TCP port number. We
provide an example below of how data can be received on another workstation when
MagLog is working in server mode:
Server: This field must be filled in with a valid host address or IP. It is needed only when
MagLog is operating in TCP client mode or sends UDP packets to a specific host.
When MagLog is working in server mode:
Assume the computer with MagLog running has an IP address, and
the port number is set to 14001, and TCP transmission is enabled. The computer is
connected to the local network.
On another computer, start the command shell (in a DOS window by going to
Start, Run, CMD, ok) and type the command: “telnet 14001”. You
should see the transmitted Interpolator data coming on the screen.
Another way of accomplishing the link is use the Windows™ Hyperterminal
program that is part of Windows™ installation. Start Hyperterminal and select
“Connect using” as TCP/IP (Winsock). Then type “Host address” as
and “Port number” as 14001. You should see data coming on the screen.
At present MagLog allows connection to one client. This means that if a
connection has been established, no other client can concurrently connect to
MagLog. (For instance, using “telnet” a second time without closing first session
will fail).
Note that MagLog itself can be used as a client to re-display Interpolator data. A
typical application would be to run MagLog on a remote computer and transmit the
essential data via the TCP network to another instance of MagLog for display and
QC control.
When in client mode there must be a server set up and running on the network which will
allow MagLog to connect to it. A typical example of this is the use of a TCP to serial
converter such as that produced by LanTronix. In this case the user has to specify a server
IP address.
When the recipient computer is in TCP “Server” mode, the “Status” value changes to
“Connected”. If the user closes the survey with the client receiving data, a pop up warning
window is displayed.
Enable serial output: This will enable output out of a communications port. You can
specify the output port and the baud rate. The baud rate must be high enough to transmit
the data at the specified sample rate of the magnetometer and accessories package. For a
magnetometer sampling rate of 100 ms (10 Hz), you should be able to transmit at least
2000 characters. We recommend a baud rate of at least 38400 BAUD.
17.3 Interpolator Output
The Interpolator output dialog is called by selecting “Output Devices / Interpolator
output” menu item. This allows the user to select which fields to output, their order and to
format each field as needed (for instance Latitude / Longitude can be formatted as degrees
/ minutes or degrees / minutes / seconds). A variety of options is available: 1) include field
names (which can be re-assigned by the user) into the stream, 2) add prefix / postfix, 3)
output each field on separate line (multi-string output), 4) decimate data (output each 10th
or so string to reduce network overhead), 5) select separators (space, tab or
comma), and 6) append checksum to each string or not. Position information can be sent
out in the form of NMEA GGA messages to be accepted by another MagLog copy or
other navigational software.
Below is the Interpolator output configuration dialog:
The following controls are available:
Available fields list all Interpolator output fields by their internal names. By
selecting the field and pressing the “Add” button, the field can be moved into the
“Selected output fields” list. Only fields in the output list are transmitted. Each
field from the available field list can be represented only once in the output list.
Add>> Selecting field on the left and pressing “Add” button displays the
following dialog:
Here the user can specify how to output a selected field. It is possible to re-assign
the output field name (for example, “MAG1” could be replaced by “mag”) and the
output format. The following selections are available in the “format” field:
Original, Decimal, Degrees minutes, minutes, Degrees minutes seconds. If
“original” is selected field is sent out the same way it is saved in the Interpolator
log file. “Decimal” and other selections allows re-formatting of the field value
before transmission using the “Digits after dot” value.
Edit… this button changes the output attributes for the field already selected for
output. It displays the same dialog as “Add: button for field selected in the output
Remove field. Removes currently selected field from the output list.
Include field names in the output. Output field names are transmitted along with
field values if this box is checked.
Add checksum to the output. Each output string can be appended by star sign “*”
and checksum similar to NMEA messages if this box is checked. Symbol “*” is
not included in checksum computation.
Output format. Two options are available: single string and multi string. In the
first case all fields selected for output are concatenated into a single string
terminated by CR LF characters. Checksum is computed only once for the whole
string. In the second case each field selected for output generates a separate string
in the output, each with its own checksum.
Output field separator. Space, tab sign or comma can separate output fields.
Output prefix. Output string can start with user-selected prefix. Prefix may
include spaces (in fact, the prefix should have its last character as a space to
provide separation for the first field).
Output postfix. String can be appended by user-selected postfix. Postfix appears
before checksum.
Decimate data for output. This option allows reduction transmission and file size
reduction. By default the Interpolator computes a position for each magnetometer
string. For instance if the magnetometer runs at 10 Hz, the Interpolator computes
10 strings per second. If the “Decimate” control is set to “1” then each of these
strings is transmitted (note that transmission speed is not uniform if GPS is running
at different rate, say 1Hz). If “Decimate” is set to 10 only every 10th string is
transmitted, reducing output rate by factor of 10.
Save protocol file. This option allows saving a description of the output into a
separate ASCII file. The file can be viewed in notepad and printed if needed.
Configure GGA output. Position fields can be output in GGA format. In this case
each GGA string occupies a separate string. GGA format compiles with NMEA
specification. By pressing this button the following dialog is called:
Check “Enable GGA output” to make MagLog output position information in
GGA form. Then “Latitude” and “Longitude” should be selected accordingly.
Output prefix (2 characters) appears immediately after the leading “$” in GGA
string (in this example selecting ML generates an Interpolator output string starting
with $MLGGA).
Here is an example of Interpolator output with settings as indicated in dialog boxes above:
$MAG1 20295.746*79
$DEPTH1 164.043*72
$MAG1 19882.415*7A
$DEPTH1 164.043*72
$MAG1 19564.913*74
$DEPTH1 164.043*72
$MAG1 19183.721*76
$DEPTH1 164.043*72
Note that only 4 fields from GGA message are included in the string: latitude, longitude,
GPS QC and height.
17.4 How Interpolator calculates shifted position (“Dragging” algorithm)
In this section we provide a brief description of the method used to calculate the position
of the Fish being dragged behind a boat.
Let’s consider an object (magnetometer Fish) being dragged behind the boat with a
constant (and known) tow cable length. The boat is equipped with a GPS receiver and
therefore its position is available. The task is to provide a reasonable approximation for
the magnetometer Fish position based on GPS readings and cable length.
The picture below illustrates the Dragging Algorithm solution:
Solution is approximate and does not take into account 3-D configuration (depth) and
physical effects like friction or side currents. Nevertheless it provides a reasonable model
for fish behavior even if the ship makes a turn.
We assume that we know position of the ship (A) and the magnetometer (N) at time t0 and
we know the cable length. At time t 1 we know the position of the ship (B) but do not
know the position of the Fish (M.) To find it we draw a straight line NB between old
magnetometer position N and new ship position B. Then we count the cable length from B
towards N. A new point M is the estimated position of the magnetometer sensor at time t1
It can happen that distance BM is greater then BN (if ship does a sharp turn). In this case
magnetometer position not changed (literally it would sink).
The method explained above assumes that the magnetometer sensor position at time t0 is
known but it is unknown at the start of the line. Therefore to start calculation process we
need to find somehow initial magnetometer position. Different techniques might be
employed but one of the easiest is to use an initial part of the recorded path to find
direction of motion. We can approximate these positions with a straight line using leastsquares method and count cable length back along this line. This gives a reasonable
estimation for the initial magnetometer position. After a short time the influence of the
initial position becomes negligible.
It should be noted that this method is not designed to work in sharp turns. It is also does
not take into account the depth of the Fish (if Fish is deep then horizontal distance is less
then total cable length). Another problem is that the GPS normally is not mounted at the
same point as the tow winch; therefore the effective cable length should include the
distance from the GPS to the winch.
17.5 Interpolator Examples
This shows a few commonly used configurations and how you might want to set up the
17.5.1 GYRO, GPS, and Cable length using transverse horizontal gradiometer.
The system components we have in this example are:
b) GPS
c) Cable length measuring device (payout indicator)
d) 2 magnetic sensors separated by 20 meters (transverse horizontal gradiometer)
The positions we want to output are:
a) GPS
b) Tow point
c) Shifted point behind boat
d) Sensor 1
e) Sensor 2
Output is to go to file.
Output specifications are geographical coordinates, and the GPS outputs latitude and
longitude coordinates ($GPGGA messages).
A graphic describing this is:
Tow point Y
Cable length (variable)
X offset= - 2m
Sensor 2
Sensor 1
The Interpolator setup is as follows:
1) Fill out the “Mags” screen:
Since we have a GYRO, we are able to specify a tow point that will be recalculated.
Here, the magnetometer array offset is zero because there is a cable length measuring
device. Additionally, since there is a GYRO, the position of the tow point can be
accurately calculated. The offsets for the tow point must then be put in (-2, -10) taking
into account that this is relative to the GPS antenna and that starboard is positive.
2) Fill out the “TRK” screen:
This is not needed because there is no ORE. Make sure that the option: “Use ORE
Trackpoint II” is disabled.
3) Fill out the “UTM” screen:
As shown below:
Here, “Use Internal UTM” is specified because the output of the GPS is in latitude and
longitude coordinates. The UTM specific parameters must be filled out correctly, and
“Northing” and “Easting” remain at 0 (we ignore the offsets here).
“Geographical Output” box specifies that the all coordinates should be output in a
latitude/longitude format.
Entering the correct value for the Central Meridian is crucial. If this value is not correct,
the Interpolator will not work, and you will see a warning message on start up. Please use
UTM zones table and your current position to find appropriate Central Meridian value or
have you GPS connected during wizard set up so that the program will automatically
detect your position and set the proper Central Meridian
4) “Positions” Dialog:
There are two sensor positions that should be calculated here. The positions are filled out
as follows:
The first sensor position is specified as below:
Here we are using the shifted point (a point behind the tow point that in this case refers to
the center point of the gradiometer array) as a reference point. Since the sensor is 20
meters from the tow point, and it is the left sensor of a horizontal gradiometer, we specify
the distance as 20 m, and the azimuth angle as 270 (360 + -90) degrees.
Note: If we were to use the GPS as a reference point, we would use a distance of 22
meters (20m + 2m antenna offset) and an azimuth angle of 270 degrees.
The second sensor position is also specified:
Again, the parameters are set with respect to the shifted point. The distance is 20 meters,
and the azimuth angle is 90 degrees.
If the GPS were used as the reference point, you would specify a distance of 18 (20m
– 2m antenna offset) and an azimuth angle of 90 degrees.
The final screen should look like the screen below:
5) “Net” Dialog (network connection setup)
In this case this dialog box is not used because there are no serial or Ethernet output
Important: MagLog will use the GYRO information in position calculations when it
is available. However, you need to check the calculations box for those that require
GYRO input because by default, they are disabled (e.g., for tow point calculations).
17.5.2 ORE Trackpoint II, GYRO, and three sensors:
This example has an ORE and a serial GYRO (Gyro is not connected to the ORE but IS
connected directly to the logging computer running MagLog).
The system components are:
a) Serial GYRO
b) GPS
c) ORE
d) 3 sensors -- sensor one is 5 meters behind acoustic target,
sensor two is 10 meters behind acoustic target,
and sensor three is 20 meters behind the acoustic target.
The positions that we would like to compute and output are:
a) Tow Point (when a tow point is specified, it is output instead of the GPS)
b) Shifted Point position
c) Position of acoustic target
d) Sensor 1
e) Sensor 2
f) Sensor 3
The output is to be written to file and we would also like to do a real time Ethernet transfer
of the data to another computer on the network.
Output specifications are UTM coordinates, and the GPS outputs latitude and longitude
A graphic describing this configuration is shown below:
Tow point Y
Xoffset = -1 m
ORE main
Y offset = -3 m
X offset= - 2m
Acoustic Traget
Azimuth 180°
Sensor 1
10 m
Sensor 2
Sensor 3
1) Fill out “Mags” screen:
It is beneficial to specify the magnetometer offset and the tow point as a backup
calculation. If the ORE were to malfunction, there would still be a valid calculation of the
magnetometer positions using the tow point and dragging algorithm.
The magnetometer offset is specified to be 50 m (or if there was a cable length measuring
device, this would be specified as 0). The X and Y offsets are measured from the GPS to
the tow point (as seen in example A).
2) Fill out “TRK” Screen:
The “Use ORE Trackpoint II” option must be enabled in order for any ORE calculations to
take place. There is only one acoustic target.
The X and Y offsets are specified with regard to the tow point. In this case, we are using a
serial GYRO (the GYRO is not connected to the ORE) so we need to check the “Enable
Serial Gyro to calculate position” option box . (The offsets cannot be entered until this is
checked). We also specified a tow point (under “MAG” tab, see above), so the offsets
must be given with respect to this tow point. If we hadn’t specified a tow point, these
offsets would be given with respect to the GPS position.
We have also decided to enable median filtering with a filter size of 10 readings (not
mandatory but this will smooth the results).
3) “UTM Screen:
Here, we enable “Use Internal UTM” because the GPS outputs geographical
(latitude/longitude) coordinates ($GPGGA messages). All known GPS receivers export
data in this format and therefore this box always should be checked. We then need to
specify the ellipsoid parameters and UTM projection parameters. These parameters are
position dependent and need to be looked up (or automatically calculated if GPS is
plugged in and working).
Entering correct value for Central meridian is crucial. If this value is not correct the
Interpolator will not work, and you will see a warning message at start up. Please use
UTM zones table and your current position to find appropriate Central Meridian value or
connect GPS to the system and allow it to properly calculate the proper Central Meridian.
We don’t specify “northing” or “easting” here because we want the final output
coordinates to be true coordinates, rather than adjusted coordinates.
We also leave “Geographical output” unchecked because we want the output in UTM
rather than recomputed into geographical (latitude/longitude) coordinates.
4) “Positions” Dialog:
Here we input the magnetometer positions that we want to track. We have three sensors
so we need to enter three positions. Additionally, since there is an ORE Trackpoint II, we
can easily calculate the position of the acoustic target, so this is the best reference point to
The final position screen should look like the following:
Here we specify the sensor distances from the acoustic target. Because sensors are behind
acoustic target azimuth must be 1800 .
5) “Net” Dialog (network connection setup)
Here, we enable Ethernet transmission by checking the box “Enable Ethernet
transmission”. We then need to specify the receiver IP address and the port number.
Your system administrator should know these values. One way of logging these data at a
remote location is to use MagLog or they can be displayed using a terminal emulation
program with TCP/IP capability like Hyperterminal™.
Important Points: It is useful to input tow points when you can because these will
allow MagLog to calculate the sensor positions in more than one way. Then, if you
have a situation where a particular device malfunctions, you have other calculations
that you can fall back on. MagLog will calculate all positions that you specify. For
instance, you could also set up another set of points in the “Positions” dialog that are
based on a shifted point. Since you have a tow point, MagLog will use the cable
length to calculate a shifted point. You could then use this point to get a series of
three sensor position calculations based on this “shifted point” and use these
calculations as back-up calculations. For multiple calculations of this type on the fly
(real time) we suggest a high performance computer with a fast drive and lots of
17.6 Interpolator Diagnostic Messages
In certain cases the Interpolator cannot compute all or some of the requested positions. In
this case the status light will remain red. However when logging is started, the log file size
will increase.
In most cases there will be one-dime diagnostic message on the screen in the form of
dialog box with an “Ok” button. If the “OK” button is pressed, the message disappears. To
see it again the user should start / stop the Interpolator or start / stop the survey. If the
message appears on the screen but Interpolator light is green, this is a result of
initialization of the system, please just disregard the message.
The following section defines Interpolator messages and their meaning:
“Wrong INTERPOLATOR central meridian! Please adjust in Output
Devices / Interpolator / UTM!" Indicates that the Interpolator cannot perform an
internal UTM transformation because the current GPS position is more than 6
degrees away in longitude from the central meridian. Adjust the central meridian
setting in UTM setup. (If GPS is attached and running as it should be you will be
give the opportunity to automatically correct the Central Meridian value).Restart
INTERPOLATOR: cannot accept GPS positions! Interpolator cannot use
positions from the GPS. This typically happens when the user mistakenly requests
“Use position of the tow point instead of GPS” option on Mags tab of Interpolator
setup dialog. To use this function, a GYRO compass must be available. Please
check Mags tab and uncheck the box if needed. Restart survey.
INTERPOLATOR: cannot accept MAG data! Interpolator cannot use
magnetometer data. If the magnetometer is working correctly check if the depth
sensor is calibrated properly and if the depth sensor reading is used in layback
1: INTERPOLATOR: cannot interpolate UTM. Interpolator cannot interpolate
GPS position at magnetometer sample times and shifted positions (this means that
the log file does not have any useful position information). Check if GYRO was
requested (on tab “TRK”) but there is no gyro attached to the computer.
2:3 INTERPOLATOR: cannot interpolate Lat/Lon. This is the same as the
section above but the output has been requested as longitude and latitude.
4:5 INTERPOLATOR: cannot interpolate ORE. If no underwater positioning
system (ORE TrackPoint II) is available but an acoustic target interpolation was
requested, the Interpolator outputs this message. Check the “TRK” tab in
Interpolator setup and make sure “Use ORE Trackpoint II” box is not checked.
Box “Use serial gyro to calculate position” can be checked even if ORE II is pot
present (however GYRO must be connected to the computer in this case).
6: INTERPOLATOR: cannot interpolate aux. points. The usual reason for
this message is that the user requested computation of the auxiliary position based
on a position of the acoustic target when there is no ORE II system. In this case
the Interpolator fails to compute these positions however still computes positions
of the GPS and shifted point. Go to “Check “Positions” tab of the Interpolator
setup and make sure there are no positions with type “Target”. Remove them if
they are present. Restart survey.
18 High precision Land / Airborne / Marine surveys
In the normal MagLog operational mode there are several sources of time inaccuracy
(latency) that can lead to spatial errors in the location computation. There are certain
surveys where even slight inaccuracies in the position of the sensors cannot be
tolerated such as those that have to do with locating Unexploded Ordnance (UXO)
with military MTADS systems or high precision archeological surveys where small
target search is the primary mission. Geometrics has devised a proprietary methods of
dealing with the internal electronic delays that occur in all computational equipment
including GPS’s and PC’s. Here we describe the problem and our solutions.
The GPS receiver has its own internal delay due to the time to calculate position.
This value can vary between less than 10ms to 500ms! This is known as
LATENCY and depends on the GPS model. A time stamp embedded in the GPS
message corresponds to the location at the time it was calculated. However the
transmitted string is delayed due to the internal GPS CPU cycle time. MagLog
records the time when the GPS message becomes available to the computer (or
more exactly to the software) thus there are a series of delays from the time of the
actual position fix to the time that the information becomes available.
MagMap2000 processing software makes use of the PC time stamp to interpolate
magnetometer position and thus ignores the delays. MagMap still has an ability to
take the delays into account if the user explicitly enters the sum of delays. The
delay is assumed to be constant.
Windows family OS has its own delays when processing serial port transmissions.
This means that when data physically arrives at the serial port it does not become
available to the program immediately. The system itself has to spend some time to
present data to the rest of the software. This depends on the speed of the
computer this may vary from 10 ms average to 20 or even 50 ms. It should be
noted that this delay is not constant and depends on the processor load. We have
seen it vary between 2 ms to 500 ms!
Because of these delays, normal MagLog operational mode does not provide the very best
spatial accuracy possible. In simple terms, a solution to this problem is to use UTC GPS
time instead of PC time and the time of the data arrival should be logged without delays.
18.1 Legacy solution: Windows NT only
Our solution is based on a process of external magnetometer triggering that has the ability
to log the time of a specially generated trigger pulse event (with almost no delay) and to
also log the UTC GPS strings together with a corresponding GPS PPS (pulse per second)
UTC synchronized option available on some GPS systems. Geometrics has developed a
special Windows NT driver that allows logging the time of the pulse arrival based using a
parallel port interrupt. The accuracy of such a time stamp is about 1 ms and much less
dependant on overall system load. A special multifunctional card from Keithley Metrobyte
allows generation of the trigger pulse for the magnetometer. Each pulse induces a PC
interrupt. The time of that interrupt can be logged in a manner that is similar to the process
for the parallel port interrupt. These drivers are available for Windows NT only. Here we
discuss the overall acquisition and processing steps necessary to employ this triggering
scheme (see schematic below).
1. GPS system with PPS option. Approximately half a second ahead of each pulse the
GPS generates a serial string with the pulse’s UTC time. Then the pulse itself is
generated. Serial strings are logged with MagLog Generic Serial Device and the
time of the pulse arrival is recorded with a driver. By matching these two pulse
streams it is possible to recalculate PC time into UTC time with a very high
accuracy (about 1ms).
2. GPS also sends its normal navigation message. However the PC time stamp
appended by MagLog is not used for calculation and interpolation of positions;
instead the UTC time is taken from message’s body.
3. The Keithley CTM-10 card is started in pulse generator mode. Each pulse induces
an internal PC interrupt; and the time of this interrupt is logged with a special
driver. The pulse also triggers the magnetometer. Then a serial string with the
magnetic field value is sent from the magnetometer to the computer and logged
with MagLog G-822A device setup.
PC running Windows
IRQ 7, 0x378,
1 mks PPS pulse
UTC serial string
(0.5 ahead of PPS pulse)
Magnetometer counter
Navigation serial message
Trigger pulse out
magnetometer serial data
generic serial driver
generic serial driver
IRQ5, 0x300,
CTM-10/05A card kei.sys
generic serial driver
Magnetic sensors
The PC time stamps in the magnetometer log file are substituted with those from
the trigger file thus providing a higher time accuracy (1ms vs. about 20 ms). Using
the relation between PC and UTC time, the magnetometer times are recalculated
into UTC time.
At this point all time stamps are expressed in the UTC time system and can be used
for data locating directly.
Presently this system is available with G-822A Super Counters and
under Windows NT only.
18.2 The Modern solution: Real-Time Serial driver.
The legacy solution described in the previous chapter may not acceptable today because of
a number of reasons:
It requires additional hardware that has become obsolete.
The trigger option is not available for marine magnetometers because of cable
The PPS output option is uncommon and requires an expensive GPS receiver.
Processing the data is complicated and cannot be performed with standard tools
such as MagMap2000.
Only Windows NT systems are supported.
To provide a more generic solution to the timing problem, the logging system must have
two main features:
1. The ability to log data arrival times with acceptable time accuracy.
2. The ability to synchronize the time of the logging system with GPS supplied UTC
time. If this condition is met GPS UTC time stamps can be used directly and
therefore GPS latency can be eliminated altogether.3
To resolve both these issues special software and hardware must be used as described
18.2.1 Accurate time stamping with COMM/DRV driver.
To provide the minimum delay between data arrival and time stamping a special serial
port driver can be used. This driver gets time stamps as soon as data is available to the
operating system, and is not dependent upon any particular application running on the
operating system.
GPS latency even for moderately priced GPS receivers is not constant and can reach up to 0.5 seconds or
more. For marine survey performed at 4 knots it would mean inherited position error of 1 meter or up to 25
meters for airborne surveys.
At present Willie’s Computer Software Co provides a good solution with their
COMM/DRV software driver. This driver takes over the serial ports and handles input /
output operations in place of the standard windows driver. It also provides a data time
stamping feature that is proven to be accurate to one millisecond or less.
Unfortunately the COMM/DRV software is not compatible with the standard windows
API or with some PC hardware. This implies that serial ports controlled by the
COMM/DRV driver cannot be accessed by standard windows applications such as
HyperTerminal for instance. Only specially developed applications (including MagLog)
can take advantage of the COMM/DRV driver.
COMM/DRV supports many of the serial port types, including standard ISA ports located
on the motherboard and some of the PCI extension cards. However it may not be
compatible will all types of the serial hardware. To avoid incompatibility, the customer
can use serial extension cards produced by the same company as the driver (Willie’s
Computer Software Co).
18.2.2 Installing run-time COMM/DRV environment.
Before installing COMM/DRV driver, remove the existing drivers (Windows or Willie’s).
Run-time licenses for COMM/DRV are distributed by “Geometrics” as separate packages.
To install, run the file “wcsc-setup.exe” The installation script places the files
“cdrvxd32.dll” into your Windows system directory (C:\Windows\System32 on most PCs)
and file “wcsccdrv.sys” into driver’s directory (C:\Windows\System32\drivers) and sets
Registry settings. If there are no conflicts, the driver starts after the next reboot. Now your
can access the MagLog Configure / Map COMM/DRV menu.
You can stop and start COMM/DRV at any time using the following commands:
Open a DOS prompt. Type "net stop wcsccdrv" at the prompt.
Open a DOS prompt. Type "net start wcsccdrv" at the prompt.
Below are registry settings for the COMM/DRV software4. This information is provided
here for troubleshooting purposes only. You can skip to the next section if the driver is
running properly.
The driver is controlled by the registry key:
Value 0
This section is taken from the COMM/DRV manual. COMM-DRV, COMM-DRV/NT, COMM-DRV/Lib,
COMM-DRV/VxD, COMM-DRV/Dos are trademarks of Willies Computer Software Co (WCSC)
COMM-DRV/NT (wcsccdrv.sys)
Value 1
Value 2
Value 3
Value 4
Value 5
Value 6
Value 7
Value 8
Value 9
The keys DisplayName, ErrorControl, ImagePath, Start, and Type, are specific to
Windows NT loading of the kernel device drivers. The keys WCSCMaxPorts,
WCSCInBufLen, WCSCOutBufLen, WCSCInBufHigh, and WCSCInBufLow are specific
to wcsccdrv.sys. Complete information on these keys can be found in the Windows NT
Resource Guide. We will describe them here for completeness.
DisplayName This is the string that will appear for his device in the Service Control
Manager (the dialog box you get when you select Devices from the Control Panel).
ErrorControl Specifies the behavior of the NT loader if an error occurs while loading the
Log error and ignore. Boot process continues.
Log error and display a message box.
Log error and reboot with last known good configuration.
Log error and fail if already using last known good configuration.
ImagePath Specifies the fully qualified path of the driver's image file. If this value is
not specified, the default path is NT_root\system32\Drivers\DriverName.sys, where
DriverName is the name of the driver's Services key (e.g., wcsccdrv).
Start Specifies when to start the driver. One of the following is specified:
Indicates that the driver will be started by the Service Control Manager during
system startup.
Indicates a driver started on demand, by the Service Control Manager (You will
need to start the device with the "net start wcsccdrv" or using the program).
Type Specifies the type of driver. Wcsccdrv.sys must use 0x1 for kernel driver.
the same time.
This is the maximum number of serial ports that may be opened at
This is the size of the input serial communication buffer that will be
used for each opened port. If you lose characters during data reception this value may be
WCSCOutBufLen This is the size of the output serial communication buffer that will
be used for each opened port. This value may be increased to enhance transmission
WCSCInBufHigh This is the character count at which the kernel driver will either
lower the RTS line or lower the DTR line, or send an XOFF to indicate that the remote
should stop sending data. This value only has meaning if flow control is desired.
This is the character count at which the kernel driver will either
raise the RTS line or raise the DTR line, or send an XON to indicate that the remote
should start sending data again. This value only has meaning if flow control is desired.
18.2.3 Using COMM/DRV within MagLog software.
The standard serial port used by MagLog has only two parameters: port number and baud
rate. The serial port controlled by COMM/DRV requires many more, which can be
hardware specific (for instance, PCI and ISA ports have different parameter set). In fact,
COMM/DRV does not use a parameter for “port number”.
To avoid providing a full set of parameters for each device, MagLog maps COMM/DRV
to the logical serial ports prior to the survey. This keeps all COMM/DRV related
information in one place and provides the usual port setup during the survey. To
distinguish between standard and real-time ports, the latter are marked with a star (*). For
instance if COM1 is showed as COM1* during the survey, this means that this port is
controlled by the COMM/DRV and is in fact a real-time port.
To assign COMM/DRV ports start MagLog and proceed to the Configure/Map
COMM/DRV ports menu. If COMM/DRV driver is not properly installed or not running,
the error message “Can not init COMM/DRV service. Check if wcsccdrv.sys is started” is
displayed. In this case user should close MagLog and resolve COMM/DRV installation
problems first.
If driver is installed and running properly, you will see the following mapping dialog:
Each string in the table has ten fields and corresponds to one port. The meaning of the
fields is as follows:
COM port. This is logical name under which port appears in the MagLog. Names
are unique.
Card type. Type of the serial port hardware. Can be ISA (for motherboard ports)
or PCI (for extension card ports).
Sub port. This value should be 0 unless a multi port card is being used. If a multi
port card is being used, then the first serial port on the multi port card is 0. The
second port is 1, and so on.
Base addresses. For ISA: base address of the 8250 (or compatible chip like the
16450,16550, etc. ) port (e.g., 0x3f8). For PCI: Vendor ID of the PCI card.
IRQ. For ISA: 0 – 15 for IRQ1 – IRQ15, for PCI Cards: Device ID of the serial
Card number. For ISA this should be zero. For PCI this is the number used to
distinguish between cards of the same type. The first card is 1, the second card is
2, and so on.
Card Segment: For ISA: In most cases this value should be 0. For the BOCA
Dumb Multiport Port Cards, the value should be ffff. For the WCSC AST
Compatible Four Port Multiport Card (PCCOM4 or LCS 8880) the value should
be 1bf or 2bf depending on whether the first port on the card is 1a0 or 2a0
respectively. For the AST Four Port Multiport Cards the value should be f1bf or
f2bf depending on whether the first port on the card is 1a0 or 2a0 respectively.
For PCI Cards: Index in the area of the PCI configuration space that contains the
base address of the card. It is a value between 0 and 5.
FIFO buffer depth, in bytes,
Raw counter. COMM/DRV driver reports time as a 4-byte value in microseconds.
This value wraps approximately once per hour. It can be added to the device data
stream if this field is set to “Yes”. In most cases it should be set to “No”
Correction, ms. Value in milliseconds to be added to the time stamps. This would
allow real-time correction for devices with known static latency. Note that GPS
latency can not be corrected this way because it is not constant.
To add new ports to the table press button “Add…”. To change settings of the existing
port, select this port in the first column of the table and press “Edit…”. The buttons
“Remove” and “Remove All” delete selected or all port mapping accordingly. Buttons
“Save…” and “Load…” save the table as an ASCII file for future reference or loads a
previously saved table. Note that table is saved anyway along with all MagLog
When “Add …” or “Edit…” button is pressed the following dialog is shown:
This dialog lets the user specify all parameters as described above. If “ISA” is selected
then “ISA setting” section is available, if “PCI” then “PCI settings” If PCI Vendor and
Device IDs are not known press “Select from list” button and the program will show all
PCI devices listed in the windows registry as shown below:
Note: the user may have to guess which string represents his serial hardware and
select it.
After all settings are entered the user has the option to test the port. This is always a
good idea because otherwise it might be hard to track COMM/DRV related problems.
Press “Test port” button and the test dialog is shown:
Connect a device with a known baud rate and format. To test the port, select the
baud rate in the dialog above and press “Start” button. The button will turn into a
“Stop” button and gray out the baud rate and termination char fields. Data is shown
in the middle of the dialog box. It is possible to show data as a hexadecimal dump or
as a decoded EXESS-3 message using the “Display format” selection (remember that
for EXCESS-3 the termination character with a decimal 42 is needed).
As a part of system setup the following procedure can be recommended:
Have manuals on your serial hardware and software readily available,
including this manual.
Select a reliable source of the serial data known to work. Verify the source
using HyperTerminal on a standard serial port or another computer. Connect
the source to the first port you are going to map.
Start MagLog and go to Configure/Map COMM/DRV ports menu and press
“Add…” button. Enter port parameters. Verify port by testing it. If the port is
not working, revise port parameters for possible errors.
If port is working, proceed to the next port. Reconnect your serial source and
repeat the procedure, until all ports are known to work.
Save the resulting table in the separate file for future reference.
Note: The CM201CFG configuration program does not work with COMM/DRV
ports. Please configure the magnetometer and store its configuration prior to the
survey, then disable CM201CFG launch by setting DO NOT CONFIGURE 880=0 in
maglog.ini file (see section Setting options through “Maglog.ini”). In this mode user
is responsible for assigning correct number of analog channels per magnetometer.
After the port mapping is completed, MagLog is ready for the survey. During the survey
configure devices as usual. The only visible difference will be an asterisk (*) after the
COM number which indicates it is a COMM/DRV port.
18.2.4 Using GPSPCI card to synchronize MagLog time with UTC.
COMM/DRV real time serial driver can reduce serial port timing inaccuracy to 1
millisecond or less. However it cannot address problem with GPS latency because this is
due to the GPS, not to the PC or PC software. The only way to resolve this problem is to
synchronize the PC time with UTC time. However the PC time is not accurate and in fact
MagLog does not use PC time. It uses system PerformanceCounter() and
PerformanceFrequency() calls instead.
A special GPS card from MasterClock (see installed in the
PC allows MagLog to obtain the value of the UTC time at the turn of each UTC second
and synchronize the MagLog time system with UTC.5 This leads to the superior timing
performance and allows treating MagLog time stamps as if they were made in UTC time
(local time zone should be taken into account).
Synchronization takes local time zone into account. MagLog time stamps are in the local time.
To take advantage of the GPSPCI card it should be installed in the computer along with its
drivers. The GPS antenna should be able to see enough satellites to operate properly. The
Master Clock device should be added to the MagLog survey. Once added, Master Clock
device will interrogate the GPSPCI card in user-selected intervals (typically one second)
to find the Performance Counter value at the turn of the whole UTC second and correct
MagLog time.
To add Master Clock device do the following:
Go to the menu “Configure / Input devices” and select “Master Clock GPSPCI” in
the list on the left side. Press “Add>>” button.
If for some reason the GPSPCI card or its drivers are not loaded (this would be if
card and / or drivers are not installed) you will see an error message “Cannot load
Master Clock GPSPCI driver”. In this case close MagLog and troubleshoot the
GPSPCI installation.
If card and driver are working, the following device setup dialog will appear:
Here “MCR driver” and “MCR hardware signature” are read from the card. The user
should assign a device alias and Interrogation interval. Check the box “Use Master Clock
to correct time”.
Once started, the Master Clock device outputs the following channels:
1. Correction between Performance Counter clock and UTC time per second, in
microseconds (typical value is about 50 us).
2. GPS status. 1 if GPSPCI has GPS data, 0 if not (in this case internal GPSPCI clock
is used).
3. Correction in milliseconds. Accumulated correction for Performance Counter
clock. This value will grow while the survey is running. A typical value could be
up to 3000 ms per 12 hours operation.
4. Used to correct MagLog time. If user checked the box above, this value is 1.
5. Navigational GPS latency, milliseconds. If a GPS device is used for the survey, the
Master Clock device computes its latency on the fly (this is GPS latency, not
GPSPCI latency).
NOTE: This GPS latency correction may be automatically applied to the interpolator
file output, computing interpolated positions and storing them real-time.
19 Playing existing surveys back – playback feature
19.1 Viewing data with playback
The latest MagLog versions have a new playback feature that allows replaying already
acquired surveys to look for anomalies (set automatic anomaly flags) and to check data
quality. It is important in Playback Mode that the user keep the same sequence of data as
was recorded during the original survey. Simply reading data from the files does not
ensure this because the reading operations are not synchronized between various data
streams coming from the files, you must use Playback Mode. (There is a secondary ability
to read and display data from files - “Reading from Files Mode” - this is the manner in
which we distribute the fully operational program in demo mode and this feature should
be used only for training purposes, not for data evaluation.) Use the new Playback Mode
for proper synchronized review of your recorded data.
Due to nature of playback, some features are not available in this mode including logging
(because these files are used as data sources). On the other hand, almost all MagLog
features are available in the “Reading from Files Mode” which makes it more appropriate
for training. See section 15.2 below on Sample Files under Other Topics for more
information on this feature.
Playback is started by selecting “File / Play back survey” menu as it is shown in the
following picture.
To prepare a survey for playback, MagLog reads all collected log files and sorts their
records with respect to time. This might take a few minutes (depending on the amount of
data). When this is complete, the playback control center dialog starts:
The following controls are available:
• Data playback is offered on a line-by-line basis. The top Scrollbar represents an
entire line in time. When data is not being played, the user can drag the scrollbar
handle to set a time for the playback starting point. The time listed in the upper
middle box is the current playback time. The user cannot drag the scroll bar handle
during data playback, he or she must stop the playback process first by pressing the
“STOP” button.
• “Line to play” select the line to play. Times on the left and right are start and end
times of the line.
• Speed. Depending on your computer hardware performance data can be played up
to 50 times faster then they were recorded. The user can change the speed at any
time. It is allowable for playback to skip same data samples to keep up if speed is
set very high. Move the Scrollbar slider to the most left position and the Speed
control all the way to the left to play all the data at normal acquisition speed.
• “<<” and “ >>” buttons will shift playback time in the past or in the future based
on the time interval entered in the box just left of the “<<” button. In this example
if user presses “<<” playback starting point shifts to 60 seconds back in past.
Pressing “START” restarts the survey from that point. The time interval can be
specified in seconds, minutes or hours.
Start begins playback. To stop playback press ”Stop”. When the end of the line is
reached playback will be stopped automatically.
Typically playback is used for data inspection after the survey. The user can start
playback at a high speed to examine the data, stop it at interesting places, scroll back
and start again slowly. A flag feature used to mark anomalous features in the magnetic
field and on the GPS map can then be employed to specifically locate targets (set
amplitude and time parameters in slot, trace properties). This is a very powerful
technique. Explore the possibilities by stopping the playback at an anomaly and then
right clicking on the peak and valley of the anomaly and selecting FISH FLAG. You
will see the corresponding positions of the sensor at the time the sensor encountered the
anomaly enabling the user to bracket the anomaly for additional survey lines in the
When a MagLog survey is terminated and later restarted, it logs data into the existing
survey files. Therefore, it is possible to use the Playback feature (which cannot run
during normal survey operation) to review the data of several lines over an anomaly.
This allows the operator to evaluate the size and shape of the anomaly by reviewing
several different lines over the anomalous area and restructuring the survey plan to
acquire additional data over the anomaly area. When exiting Playback mode and
restarting the survey the new data will be appended to the existing survey data files.
For surveys where the Interpolator device is enabled, the playback mode uses the
Interpolator file to display GPS and fish position. If the Interpolator device was not
working properly, no GPS display will be available. The program checks the size of
the Interpolator log file and reports the following error if it does not exist or has size
less then 80 bytes:
In this case the user can re-create the Interpolator file in the playback mode (see the
following section)
Some operations that cannot be performed in playback mode:
• Data cannot be logged.
Program does not automatically re-interpolate Fish position. If the Interpolator
was used during the original survey the survey interpolator log file is read in as
it was acquired. There is a re-interpolation feature discussed in the next
Program does not post warning dialogs or verbal alarms (for instance if data
limits exceed preset limits.) However lights on light bar turn into green, red or
yellow as they would during the normal survey.
Duration of the display slot cannot be adjusted, i.e. you cannot make the slot
length change in time, it is fixed to what was set during acquisition. Use
playback speed to change display speed for all displays.
If the user prints the analog traces of the data during playback, the label will be
printed on the right side of the page each 10th reading . Printed time labels
correspond to the survey time, not playback time.
Presently MagLog does not play back the following types of surveys:
• Surveys with non-serial devices (including event marks)
• Surveys with serial binary devices
• Surveys with A/D converted devices.
19.2 Position Interpolation with Playback and Interpolator
Sometimes a survey may be conducted without the use of the Interpolator feature or the
wrong parameters (i.e., layback) may have been used in the Interpolator setup. In this case
it is possible to recreate the interpolated data file using a unique feature of playback mode.
Note that the results will not be completely identical to real-time interpolation because the
real-time Interpolator uses all the data available during survey including those positions
received before logging began. Re-interpolation uses only logged data and therefore
positions may differ at the start of the line from those obtained in real-time. However this
difference is not significant as long as there were no sharp turns before the line started.
The Interpolator log file is used during playback and the user must reload the survey after
re-interpolation is complete in order to observe the interpolated positions. Thus playback
re-interpolation works as a one-way street, although the old Interpolator file is
automatically backed up as a *.bak file as described below.
The re-interpolation procedure is described step by step in the following paragraphs:
1. Start MagLog and load your survey in the playback mode, as described above.
Then initiate the Interpolator:
2. MagLog will warn that the survey will be closed after interpolation is completed or
3. If you answer “Yes”, MagLog proceeds to the standard Interpolator setup screens as
4. Set up the Interpolator or change the settings in the dialog box. Refer to the
Interpolator section of the manual for more information. After “Ok” is pressed
MagLog posts another warning giving you a chance to return to the normal playback
You may enter your choice of what to use for layback values for re-interpolation of the
data. The choices are:
• Use constant layback as set in the Interpolator setup earlier. This means that all
data lines have same cable length.
• Use variable layback as recorded during the survey in the Line Number file. To
adjust those laybacks, use a text editor to modify the file. It is assumed that
cable length does not change within the survey line.
5. The existing Interpolator file (if any) is saved by MagLog with an extension
“BAK”. However if the “BAK” file already exists, the user must pick a different
name (this is the case if the re-interpolation process is used a second time). In this
case a file save prompt appears:
6. Finally MagLog begins the re-interpolation process. To increase interpolation speed
all display windows are automatically closed. The user can observe the playback
dialog as a progress indicator:
The Slider bar shows the progress for the current line and “Line to display” shows
current line number. The only control enabled in this dialog is the “Stop” button.
7. When the user presses “Stop” or when MagLog reaches the end of the survey, the
following message is posted:
Answering “Yes” causes MagLog to automatically re-load the survey in playback
mode. Answering “No” will simply close the survey. In this case to replay it with
the new Interpolator file, reload the survey in playback mode. Re-interpolation
allows the user to see the fish position and additional types of superimposed data
plotting on the track plots (for instance, gradient plot).
If the user cancels re-interpolation, the following message appears:
MagLog restores the original Interpolator device file. Again, answering “Yes” reloads survey in playback mode, answering “No” simply closes the survey.
20 Survey QC checks
20.1 Layback and Latency Test using a Natural In-field Source
This test allows the user to estimate the overall timing and positional accuracies of the
system, including the magnetometer or other sensor positions (i.e., attached to the tow
cable for marine surveys, mounted on the vehicle for land surveys or the stinger for
airborne surveys), the GPS antenna position (connected to the computer via serial link)
and taking into account inherent delays in the computer hardware and software system.
One major reason for these inaccuracies stems from the timing delays present in current
Windows ™ operating systems thus affecting the accuracy of the time stamp placed in the
file when the data arrived, compared to the actual time the reading was acquired. This
affects positioning in real time using the Interpolator feature or using MagMap2000
Interpolation software in post processing.
We note that these latency errors are really only important when either high speed surveys
are being conducted and/or if the positions of small targets (for instance, with anomaly
signatures less than 0.2m) are important. This might be the case in UXO or archaeological
surveys but would not normally be the case in geological or mining or oil/gas type
surveys. The following are error sources considered here:
Errors in cable measurements, including boat dimension measurements.
Latency in the magnetometer to PC channel. Due to nature of the Windows ™
operating system, data arriving into the computer serial port is not immediately
available to the application (MagLog). Data is delayed in the system serial driver
and therefore the time stamp assigned to the data by MagLog can be delayed as
well. Measurements showed that this delay typically does not exceed 20-100 ms
depending on computer performance.
GPS channel has the same source of latency as the magnetometer channel. In
addition, GPS itself reports positions with some time delay due to Differential
Position calculations which are typically around 50 ms.
These delays are dependent upon the hardware used during the survey. Therefore it is
always wise to check positional accuracies before the beginning the survey if there have
been hardware changes.
To test overall system performance a distinctive magnetic anomaly is required. It can be a
natural or artificial source (just piece of magnetic metal on the ground will suffice). The
task is to complete two precise survey lines in opposite directions over the source as
quickly as possible (to minimize diurnal shift offsets).
Layback / latency position errors estimation
Positioning error
survey direction
survey direction
survey surface
After the magnetometer positions are calculated (in real time or in post processing), the
two recorded anomaly profiles should match. If not (as shown above) the distance
between the anomalies represents a positioning error. The following rules apply in
understanding and correcting these errors.
Assuming that there is no notable latency in the GPS and magnetometer channels:
If you have to shift anomalies forward along survey line to match them, the cable
(or antenna to sensor distance) is actually shorter by half of the distance between
If you have to shift anomalies backwards along survey line to match them, the
cable (or antenna to sensor distance) is really longer by half of the distance
between anomalies.
Assuming the cable length is correct, magnetometer and GPS latency issues dominate:
Assuming magnetometer has no latency: if you have to shift anomalies
forward along survey line to match them then the GPS has latency.
Assuming GPS has no latency: if you have to shift anomalies backward along
survey line to match them then the magnetometer has latency.
For marine surveys, the maximum allowable mismatch between anomalies is about 1
meter, depending on GPS accuracy.
This discussion does not cover possible internal GPS errors due to
loss of satellites or differential signal.
20.2 Conducting Laboratory Latency Tests for Magnetometer Data
Acquisition Systems
This document describes how to test the overall latency of the logging computer and
software when engaged in recording and storing magnetometer data. Latency in this case
is defined as the time difference between when the actual reading is taken and when it is
time tagged and written to disk. There is concern about excessive latency because it
translates into position errors visible during data processing (herringbone or scalloped
anomaly structure).
There is virtually no latency delay between time the magnetometer takes a reading and the
time it outputs the reading to its serial port. However, on the data acquisition side of the
system, computers and their serial connections are handled by MS Windows operating
systems (win9x, NT, 2000, XP, etc.), and thus data is not immediately available to the
logging software because the data transfer is delayed by Windows serial drivers. This
delay can lead to position errors because computer generated time stamps are used to
interpolate the locations of the magnetometer.
Here is a simple method to estimate system latency.
20.2.1 Hardware you will need:
• 88X (880/881/882) magnetometer, cable, etc.
• Computer running MagLogLite or MagLog. The computer must have a parallel
printer port.
• A few pieces of wire, total length about 10 ft.
• One D-size battery. It will be good to have a battery holder for it.
• 25 pin male connector to mate to the computer parallel port.
• Double pole single throw switch to close two separate circuits at the same time.
• Soldering iron and solder
20.2.2 Assembly
We are going to make a switch controllable electromagnet to put timing pulses into the
magnetometer sensor. Assemble the components as shown in the figure below. Connect a
fairly long wire to one terminal on the battery (polarity is not important) and then put few
loops around the magnetometer sensor. Connect other end of the wire to one side of the
single throw switch and then connect a wire between the other connection on the switch to
the open terminal on the battery. Now when you close the switch, current in the loop
produces a magnetic field that will be measured by magnetometer and recorded by
MagLog software.
Magnetometer channel latency test
PC running maglog
serial data stream to maglog
Event Mark device
to computer parallel port
880/881 device
Pin 10
Pin 25 (ground)
(close for short time)
880/881 magnetic
24 pin male connector
(front view)
D size battery
Typical maglog recording
(pulses can be positive)
switch open
amplitude 1000 - 5000 nT
switch closed(for short
Solder pin 10 of the 25 pin male connector to one side the other pole of the switch and the
other side of the switch to ground (pins 18 to 25 of the 25 pin D connector are industry
standard specified to be ground on printer ports). Insert the connector into the printer port.
By closing the circuit connection between pin 10 and ground on the parallel port you will
generate a computer interrupt. The time of this interrupt will be recorded with the MagLog
TTL marker device (you must add the MagLog TTL device to Input Devices in MagLog
Configuration setup). This event mark and the anomaly produced by the current in the
electromagnet about the sensor will demonstrate the latency in the computer/software
20.2.3 Operation
Start a MagLog survey as usual and add the “TTL Event mark” to the input device list.
Make a display for the TTL event mark (screen shot is shown on figure below). Make sure
that device is working by closing the switch and observing the result. Consult MagLog
manual or contact Geometrics in case of problems. You may need to reboot the computer
to set the correct parallel port mode in the computer BIOS. We suggest industry standard
ECP Printer Port. Note that Bi-Directional Printer Port mode will not work properly. Due
to contact bounce, you may see two interrupts recorded, one when the switch is closed and
other when it is opened.
Make these tests in a relatively quiet magnetic area and ensure that magnetometer is not in
dead zone, i.e. that it is getting steady data when mounted in a fixed position and the
impulse electromagnet windings are not energized.
When you close the switch for short period of time (as quick as possible, less then 1
second) you should observe spikes in the magnetic field profile. Spikes can be negative or
positive. Typical amplitude would be around 5000 nT. When you see that magnetometer
reacts to the switch closure, you are ready to perform the test.
Simply start MagLog data logging and click the switch a few times back and forth with an
interval of about 20 seconds. Collect 10 events or so.
20.2.4 Analysis
Two MagLog log files will be used in the analysis: magnetometer log file and TTL log
file. Both files have recorded the time when the magnetic reading arrived or when the
event mark occurred. Depending on what you named your survey, the files may be named
simple-latency.Survey.880.mag and simple-latency.Survey.EventMark.TTL. Inspect the
magnetometer log file with an ASCII editor. You will see records similar to the following:
Look for a place where the column before date changes its value. This indicates a new
event mark occurrence. In the example above, values “57”, ‘58” and “59” are event mark
numbers (you will have different numbers). At “58” the switch was closed and
magnetometer started recording a noisy field reading shift caused by the electromagnetic
At “59” the switch was opened and the magnetometer returned to the normal field
readings. Therefore in the above example there is virtually no latency. However, if the
event counter has changed but magnetometer was still recording a steady field, there is
latency in the system that will eventually appear as a position error in the survey results.
This latency can be removed spatially. Let us say that we detect an average latency of
40ms. Let us imagine we are traveling in a boat at 6 knots (about 10 ft per second). Then
the amount of spatial offset is not much, maybe only a few inches.
However, let us say we are traveling in an ultralight aircraft at 60 mph (88ft/sec). Now
40ms latency will result in a 4 ft offset. Latencies in Windows operating systems can be
as much as 100ms and thus this becomes an effective tool to improve mapping and target
21 Other Topics
This section describes other topics not discussed above.
21.1 Password Protection
MagLog has a password feature that allows you to password protect your configuration
settings. If an incorrect password is given, MagLog will block access to device
configuration menus, and the user will only be allowed to log data.
The password is initially specified after the first series of device configuration screens.
You will be asked for your password again if you exit and then re-enter the program.
The password dialog appears below:
If you enter your password and press “OK”, the program will attempt to verify your
password. If you press “Cancel”, you will be allowed into the program, but you will be
unable to change any configuration screens.
The password is part of the hardware configuration and will be copied to the next survey if
you start a new survey and decide to use a previous hardware configuration.
21.2 Sample Files - Reading from Files Mode or DEMO Mode
This feature allows you to use a sample file instead of an incoming serial data string. The
program will act as if a real-time data string were coming in – e.g., you can log your data,
use the Interpolator (if applicable) and set up device displays.
This feature is useful to learn the program and to replay data you have already taken
although precise timing synchronization (and thus positioning) is not maintained. See
Playback Mode in Chapter14 above.
It is important that you do not enter this mode when you are actually performing a real
survey! Data and position information will look as though it is being acquired from
outside sources when in fact it is not. Clicking on “Continue exisiting survey” that is a
demo survey can enter this mode. Always look at your slot header information to make
sure that you are logging from serial or TCP/IP ports and not data files.
This feature is set up through the “Device Configuration” screen. Our example will show
how to set up a sample G-880 magnetometer file.
From your “Input Device Configuration” screen (accessed through the Configuration
menu), add a G-880 magnetometer. (If you don’t know how to do this, refer to chapter 2).
You should see the screen labeled “G-880 Configuration”, and you will probably see an
error message explaining that it cannot parse any incoming data streams. Since you do not
want to use any hardware, press “Cancel”.
You will see a warning message similar to the message below:
Press “OK” to continue.
You should now see the “880 Settings” screen:
From here, press “Port Settings”. You should see the following dialog box:
By default, this is set to use a serial port. To read data from a data file, select “Data File”,
and press “File Name” (under “Data File Setup”) to select a file name.
The "data sampling rate" is how often you will read data from the file. That is to say, to
simulate a magnetometer sending data ten times per second, you should use a data
sampling rate of 100 ms. This option has a minimum time of 20 ms.
You could also use the internal sampling rate. This will look in the file, find out how
often data was logged (using the internal time stamps), and read data from the file at the
same rate.
When you have selected your data file, press “OK”, and fill out the rest of your G-880
parameters as desired.
21.3 Outputting status information for QC purposes
This feature is typically used as a remote quality control device. For instance, let us say
that we wish to remotely monitor the performance of the system via a RS-232 radio link.
The MagLog system may be acquiring data at 100 or 50 or 10 times per second, but we
cannot transmit all this data over a radio link as we are bandwidth limited. But let us say
that we want to periodically SAMPLE the data being stored in order to verify proper
operation and data integrity. In this case we set up an internal Multimedia Timer (a
function inside Windows™) to periodically send a line of data out an available serial Com
port for onward transmission to the control center. This may eliminate the need for a
second person aboard the aircraft or land based survey craft (often referred to as the
This feature is available in MagLog only (not in MagLogLite).
The option "Status" is available under Configure / Output Devices / Status. It retrieves the
dialog box where the user will specify the following:
Status output period, in ms. The program will run a multimedia timer with this
interval and acquire data from MagLog devices for transmission out an available
serial port.
Format: ASCII or binary. In ASCII mode each device is represented by one string
terminated with cartridge return. In binary mode all devices are sent as one binary
parcel (see below). Format is the same for all devices.
Com port and baud rate. Other parameters are: parity none, 8 bit data, 1 stop
Binary header, if binary output is to be used. The header consists of 4 user
specified bytes. Bytes must be specified in hexadecimal notation (as 0xNN, where
NN are between 0 to F) and all bytes must be set. It is recommended to use "-0" as
a special header value. This value should not appear in any other data. For "-0"
header is:
0x00 0x00 0x00 0x80
Note that the IBMPC uses LITTLE ENDIAN format, and therefore the sign bit is
set in the last byte.
Status data to output list This is core of the dialog. Use "Add..." , "Modify" and
"Remove" buttons to populate the list. Pressing “Add...” or “Modify” calls “Add
device to status output” dialog box below:
For each device the following information is needed:
• Device name (the same as on MagLog light bar)
• Channels to output in a space separated list. For example, GPS device has the
following channels: 1 - Lon 2 - Lat 3 - QC - 4 SV. Status list for this device may
look like this:
"1 2 4"
The program will output Lon/Lat and SV. Order in the list is irrelevant.
• Output format. For ASCII mode, this is simply C language format for N double
precision values. Only one format specifier is used - %lf. For example format
GPS Lat:%.2lf Lon%.2lf
will produce output like: GPS Lat: 30.02 Lon: -122.78 The program checks for
proper format before accepting it. In general, N channels should match to N
"%.[n]lf" codes. Here "n" is number of digits after the dot.
In binary mode the program uses its own format codes, which are "D" for double
precision, (8 bytes), "F" for float (4 bytes) "I" for int (4 bytes) "S" for short (2
bytes) and "C" for char (1 bytes). All formats are PC native formats. For example,
GPS channel list "1 2 4" can be used with binary format string "DDC" which will
output Lat/Lon as 8 byte floating point and the number of satellites as a character
(it is unlikely that number of satellites exceeds 128). In this case total length for
GPS data is 8+8+1 = 17 bytes.
In addition to the channels specified by the user the following information will be
appended to the end of the string:
- number of error messages during status interval;
- number of samples during status interval.
These values are sent as integers in ASCII mode and as short values (2 bytes) in binary
For the GPS device in addition to above 2 values, 5 values are appended: number of
messages with GPS QC 0, 1, 2, 3, 4.
The entire data parcel in binary mode has the following structure:
1. Header ( 4 bytes)
2. Data parcel length (including header) - 2 bytes
3. Data for devices, in the same order as they are set in the configuration dialog.
21.4 Setting options through “Maglog.ini”
Some of the options specified in the file “Maglog.ini” are very useful. You can edit this
file by navigating to your Windows directory and selecting the file “maglog.ini”. The
options you might find useful are:
Font: This describes the font used in the docking status bar. By default, it is set to
Info Dialog: This is the dialog where you can fill in parameters such as your survey
name. You can disable this by setting it equal to 0, e.g., the line in Maglog.ini should
Info Dialog = 0
It will be enabled if this is set equal to one.
Password Protection: This allows you to enable or disable password protection. If it is
disabled, any surveys that were password protected before still will be protected.
However, any future surveys will not be. You can enable it by setting “password
protection” equal to one, and disable it by setting it equal to zero.
Demo: This will change the appearance of the “Port Parameters” dialog box when you set
up a new device.
Demo = 0:
This does not allow you to use a sample file but you can specify a
port from which to get data.
Demo = 1:
This allows you get data from a file only (pure demo mode).
Demo = 2:
This allows you to use a sample file or get data from a port.
Warning Increment: MagLog normally automatically increments the line number each
time you stop logging. This allows you to change that behavior.
Warning Increment = 1
A dialog box will give you the option of
incrementing each time you start logging.
Warning Increment = 0
MagLog will automatically increment the line
number when you start logging.
Exit Windows: This will allow you to automatically exit Windows NT when you exit
MagLog. By default it is set to 0, but it will automatically exit if you set it equal to one.
TimerCheckInterval: Controls timeout for every serial device to report “stop data flow”
error. Time in ms.
Console window. If 1, DOS console window is started. All MagLog debug printout is
going there. This is for developers only.
Windows98FontProblem . Some of the early MagLog distributions had problems with
True Type fonts under Windows 98. Setting this value to 1 causes MagLog to always use
system font for slot / map annotations.
KeithleyIntDevice. If “0”, CTM-10 card generates internal interrupts. If “1”, output of
CTM –10 is connected to one of the parallel ports.
ASCII symbol for degree. Decimal value for ASCII symbol to serve as a degree sign. In
most systems this is 176.
[DEFAULT DEVICE BUFFER SIZES] These are variables that control the maximum
history MagLog can acquire and display during survey. For instance if the GPS is
sampling at 10 times per second and GPSMaxSample=7200, then MagLog can display
720 seconds or 12 minutes of GPS position data. If GPS is sampling once per second
MagLog can display 2 hours of GPS history. If the magnetometer is sampling at 10 Hz
and 880MaxSample=2000 then maximum display slot duration is 200 seconds (if the user
sets bigger value, the slot will not be completely filled with the data ). The following
variables control history length:
DO NOT CONFIGURE 880=0 This prevents CM201CFG program from starting when
survey with 880 magnetometer started.
21.5 MagLog printer layout files.
The MagLog printer layout is stored in a separate binary file, not in the survey file.
However the survey file has a link to its printer layout file. Typically the layout file has
the same root name as a survey file with the extension “.page” Note that it is possible to
have multiple layouts for the same survey and even switch them on the fly while the
survey is running.
Layout files are interchangeable between surveys as long as survey has the same device
names (also called aliases). For instance if a layout was created for survey (1) with
magnetometer name “MAG” and GPS name “GPS” it is valid for all surveys where
magnetometer and GPS have these names. It is not valid for survey (2) where
magnetometer is named “880” and GPS “Trimble”. If one would try to use this layout for
survey (2) no magnetometer and GPS information would appear on paper. In this case the
user should re-configure the layout to use it with survey (2). The latter is much easier than
creating a new layout from scratch because only the device name information has to be
corrected (layout retains information about slots, traces, scales etc.).
When a survey is created with the MagLog wizard, a set of pre-defined layouts is used.
These layouts are shipped with MagLog software and after installation can be found in the
same folder as “maglog.exe” program (default location is “C:\Program
Files\Geometrics”). New layouts can be easily added to this default set. Follow the
following steps to add a new layout:
Create a new test survey with your typical hardware using MagLog wizard. Start
the survey and re-configure the layout to match your needs.
In the “Configure printer page dialog” (see “Configuring MagLog page layout.”)
press the “Layout name” button. A dialog with layout description will appear.
Add additional text to the printer layout description (do not erase the existing text!)
to distinguish your new layout.
Save the layout into a “*.page” file and move this file into the MagLog installation
folder (typically C:\Program Files\Geometrics).
The next time you use the MagLog wizard you will see two available layouts on
the windows printer configuration page – the standard one and your newly created
21.6 Configuring marine magnetometers – CM201CFG configuration
Starting with version 2.84, MagLog places a CM201CFG program icon as separate item
on the computer desktop:
This program has a separate value for modern “Geometrics” magnetometers (all firmware
revisions except ‘X’, ‘x’, ‘A’, ‘a’). CM201CFG can be used to configure and permanently
store configurations in the 880/882 magnetometer family running CM221 counter boards
(this coves most of the marine magnetometers, except 877).
The typical usage is for configuring a magnetometer using a short jumper cable instead of
the actual tow cable and then storing the configuration for later use. Here is an example:
The user has 5 marine magnetometers that originally were intended to work in
separate projects. However the customer now wants to build magnetometer array.
It can be the case that the power up defaults for the magnetometers are such that
they will not work together when connected into one array.
To resolve the problem the customer can connect each magnetometer sequentially
to the computer running CM201CFG program. Using the program each
magnetometer can be reconfigured (for instance, default baud rate is set to 19200
instead of 9600) and configuration is stored using the “Store configuration” button.
Now when all 5 magnetometers are re-connected together the system has enough
bandwidth to concatenate them together into one data stream.
Another example would be if the “transmit to sensor” wire in the tow cable were absent.
This would make it impossible for MagLog to configure the magnetometer because
commands cannot propagate from the PC to the sensor. This can be resolved with the
following procedure:
Connect magnetometer to the computer using short jumper cable with all wires in
Configure the magnetometer as needed and store configuration as power up
default using “Store configuration” button (valid for CM221 counters only,
installed routinely after July 2003)
Power down and disconnect magnetometer. To prevent MagLog from attempts to
reconfigure magnetometer each time survey is started set
In maglog.ini file (make sure MagLog is not running when you modify the file)
Now the magnetometer can be powered down and re-connected to the tow cable.
22 Hardware Configuration
This section explains the basic installation procedure for the hardware on your machine.
In case of a complete system failure, you will need to install each of these in sequence.
For less catastrophic situations, you can refer to the appropriate section:
22.1 Windows NT Installation:
The following information is offered for example only. It contains
references to specific computer hardware and accessories that may or
may not be used by your system. In general, MagLog and MagLogLite
will perform well on any Windows platform including Windows 98, 98SE,
ME, NT 4.0, 2000 etc.
You will need:
a) 3 each 1.44 MB Windows NT Workstation setup disks (bundled with your
Windows software).
b) Your Windows NT Workstation CD ROM disk.
c) Your Certificate of Authenticity found with your Windows NT manual.
To begin:
1) Insert Setup disk 1 into your 1.44 floppy drive. Then, reboot your computer. You
should see a blue Windows NT screen appear when the computer begins to load from
the disk. (Alternately use your CD installation disk that came with your computer for
complete recovery process.)
2) When prompted, insert Setup disk 2 in your floppy drive. You should see the computer
load additional files for a while (A gray status bar at the bottom of the screen shows
pertinent events).
1) You will be asked whether you want to repair a Windows NT installation, or install a
new version of Windows NT. If your installation is severely damaged, you will
probably want to completely re-install Windows NT.
Warning: depending upon the extent of your new installation, you may need to
reinstall all of your programs and drivers. Make sure you have good backups of all
data before continuing.
4) To re-install Windows NT, press ENTER.
5) Insert Setup disk 3 when prompted.
6) You should next see a screen that will give you the option of auto-detecting your
devices. This will attempt to find CD ROM drivers, hard drive drivers, and other
applicable devices. Press ENTER to let Windows NT attempt to automatically detect
your devices.
Note: In rare cases, NT will not be able to detect your devices. In these cases,
you will need to manually select your devices, which will involve going
through the installation procedure again. The devices that it should
automatically detect are:
a) IDE ATAPI PCI Controller
b) Adaptec AHA 294X /AHA 394X/AIC78XX SCSI controller.
7) After this is finished locating these, it will ask you to verify whether the devices found
are correct. If they match those listed above, press ENTER. Windows NT will finish
loading necessary drivers.
8) Insert Windows NT Workstation CD when prompted. Be sure to remove your
installation disk from the disk drive. Wait a few seconds and then press ENTER.
9) Windows NT will next show a licensing agreement. You can proceed by using the
Page Down key to get to the bottom of the license agreement, and press F8 to
10) In some cases, you might be told that setup has found Windows NT on your hard disk.
This will happen primarily when you are overwriting an old installation. You can
choose ENTER if you wish to try to preserve existing settings (note: this will probably
NOT fix problems with device drivers, and corrupted program installations.)
To completely overwrite all of your old Windows NT settings, press N.
11) Setup will give you a list of optional keyboard layouts. You can press ENTER to edit
these, or accept the default. NOTE: You can later change (or add) new keyboard and
mouse settings from within the Windows NT Control Panel.
12) You then are given options for creating and deleting disk partitions. It is usually
beneficial to keep existing partitions. To install Windows NT on a selected partition,
press ENTER.
13) You will now be given the option of formatting your selected partition using FAT,
NTFS, or leaving it alone. Any formatting will remove all data, so it is advised to
select the option: “Leave the current file system intact (no changes)”.
Note: If you do select formatting, the type of file system will affect what kinds
of things you can do with your computer.
** FAT is compatible with Windows 95, DOS, and Windows 98.
However, it is not as efficient in managing hard disk space as the NTFS
** NTFS is not compatible with Windows 95, DOS, and Windows 98. It is
beneficial because it allows you to keep one hard drive, rather than having to
make smaller partitions to make the best use of your space.
14) After you have made your selection, Windows will ask for the installation directory.
A good default is \WINNT.
15) You may be asked again if you want to completely overwrite your previous
installation. If you do, press ENTER.
NOTE: If you are not sure, sometimes it is beneficial to create a new Windows NT
installation by using a different directory name, and then deleting the old installation
when you are sure that your new one will work.
16) You are given the option to perform an exhaustive examination of your hard disk.
This usually takes a long time, and sometimes yields useful information. It is usually
safe to skip it by pressing ESC.
16) You should now see setup copy files to your hard disk. It should do this for about five
minutes. After this has completed, you will be prompted to remove all disks from
your computer. It will automatically reboot.
17) When prompted, insert your Windows NT Workstation CD and press OK.
18) The next screen should give you an overview of the different parts of the setup
process. To continue, press Next.
19) Select the type of installation you prefer. You can always add new features later when
needed. If you prefer to customize your installation, you can go into custom, and
manually select the features you need. The following assumes you select typical.
20) Enter a name and organization.
21) The next screen will ask for the Product ID number. This is found on the certificate of
authenticity, which is located on the top page of your Windows NT Workstation
22) You can then enter a computer name and on the following screen, a password.
23) You will then be given the option to create a repair disk. This can also be done later
using an RDISK utility, when you want to save a lot of program settings as well.
24) The next screen gives you the option of installing components. New components can
be installed later from the control panel. After selecting, you enter the Windows NT
Networking by pressing Next.
25) The default configuration for this computer is: “This computer will participate on a
network” “Wired to the network”. This is true if you have a network adapter card,
such as the 3Com Ethernet card sold with the computer.
26) Press Start Search to start searching for your network card. It should locate
3 Com Fast EtherLink XL Adapter (3C905). Press Next to continue.
27) Select : TCP/IP Protocol and NetBEUI Protocol. Select Next to continue.
You will be given the option to dynamically find a TCP/IP address from a DHCP
server. Select No.
27) You should next be prompted to enter an IP address. If you know you have a TCP/IP
address to connect to an outward network, enter it. Otherwise, any number should do
for a local network. For everything else, take the defaults.
28) You may be prompted to pick a proper Internet host name. This is the name that your
computer will be called over the network.
29) The next option allows you to choose whether your computer is a member of a
workgroup or domain. Select WORKGROUP.
30) Press Finish to complete your setup.
31) The next option allows you to select your date and time, and time zone. You can make
changes as needed (or later from your control panel).
32) The Display Properties dialog box allows you to select the type of display you have.
If you want to try a display with a higher resolution, or more colors, it is good practice
to test your settings first. This will allow you to fix it if you select incorrect settings.
33) You should then see setup copy more files and save its configuration. When
prompted, remove the Windows NT Workstation CD ROM, and restart the computer.
22.2 Installation of Digi Adapter (Optional)
1) Insert the Microsoft Windows NT 3.51 and 4.x Digi disk in your floppy drive.
2) Go to the Windows NT control panel.
a) From your start menu, select settings.
b) Select Control Panel.
c) Select Network.
3) Select the Adapters tab. You should already see your 3Com adapter selected. If you
haven’t installed networking, refer to the Digi Software Manual for further
instructions. Otherwise, select Add.
3) Click Have Disk and select A:\i386.
4) From the list of adapters shown, select: DigiAccelePort 8r 920 (ISA) Adapter. The
setup should then install the appropriate drivers.
5) You will be asked for an I/O Base Port address and Memory Base Address. If your
jumper settings on the back of the card (seen from the back of the computer) match
with the settings shown on the picture, it is okay to use the defaults. Otherwise, refer
to the DigiPort Manual.
6) Click OK on the next window to continue.
7) You need to restart your computer for the new settings to take effect.
22.3 Installation of MagLog
1) Insert your MagLog installation disk into your CD.
2) Type a:\setup.
3) The MagLog installation will ask you the installation directory. To keep the default:
C:\Program Files\Geometrics, press Next, or press Browse to continue.
4) You also have the option to create a program group in your start menu. Press Next to
continue. MagLog will then copy needed files to your hard disk.
5) You will need to restart your computer for the new settings to take effect.
22.4 Installation of Printrex Printer (Optional)
In order to be able to print from Windows, you need to install a printer:
1) Go to your Start Menu. Select Settings -> Control Panel ->Printers.
2) Select the Add Printer option.
3) The next dialog box should ask you where your printer would be managed. Select My
4) Check LPT1 as the port you would like to print to and press Next.
5) You will now be asked for the installation disk. Click on Have disk.
6) Then, type in the path where the installation files can be found: namely a:
7) Select 820DL: 1.6 ips.
8) Type in a printer name.
9) For the sharing, select: Not shared.
10) You will then be asked to insert the Windows NT CD ROM and press OK.
11) It will try to copy files from f:\i386. When installation is completed, you will see an
icon of your printer appear in the Printers dialog box.
22.5 Pulse drivers in MagLog distribution
22.5.1 Windows NT
MagLog comes with next drivers available under Windows NT operating system:
wdj.sys: This driver handles TTL pulse which can be connected to LPT1. It is
also used to obtain time stamps for all data streams when program is running under
Windows NT. If for some reason this driver did not start, you see next message
after you start MagLog.
This means that you cannot use pulse devices with Geometrics parallel port driver.
However it is still possible to work with the DRVX28 driver, which however gives
less accuracy.
wdj0.sys: Analog wdj.sys but to handle LPT2. Also can be used to log trigger
pulses if internal CTM-10 interrupt is disabled (additional wiring between CTM10 and LPT2 required).
kei.sys: Driver to control CTM-10 card (if any). If this driver not started on
improper configured you get next message when trying to start trigger device:
All driver files located under C:\WINNT\SYSTEM32\DRIVERS and have their
parameters in the Windows Registry. To check if drivers are started you can use
“Devices” applet from Windows Control Panel:
Here we can see that wdj driver started, and wdj0 not. By means of this applet you can
start and stop drivers. Typically after you change driver’s parameters in the Registry you
have to restart it or by rebooting PC, or by stopping and starting driver by means of
“Devices” applet. You also can check if DRVX28 started.
Note: Be careful stopping and starting drivers while system is running. NEVER
do it when MagLog is running – it will crash the system.
To change driver’s parameters toy should use regedit.exe program that is part of standard
Windows distribution. Be careful using this program and don’t change values you don’t
know. To start regedit.exe go to Windows “Start” menu, then “Run” and type regedit.exe
as it is shown below:
Then locate driver’s entry. They are located at:
For example for wdj.sys driver:
Consult with your PC manual to find out which IRQ and port number your parallel port is
using. If you are using ISA parallel port extension card (PCI extension won’t work) then
you can set these parameters by means of switches on the card. Then go with regedit and
set correct parameters in the registry (DataPort and IrqLevel). Note that regedit is using
hexadecimal format by default.
If you set IrqLevel > 15 (decimal) wdj and kei drivers won’t react to interrupts. However
wdj still can be used to obtain time stamps.
For CTM-10 card IRQ level and port are set with switches on the card. Write down these
parameters and set them into the Registry. Avoid conflicting with other devices.
Here are the most important pins of the main CTM-10 connect. Consult CTM-10 manual
for other connectors.
Pulse outputs:
counter 1:
counter 2:
counter 3:
counter 4:
counter 5:
ATOUT1: 35
ATOUT2: 33
ATOUT3: 31
ATOUT4: 30
ATOUT5: 28
Counter inputs:
counter 1:
counter 2:
counter 3:
counter 4:
counter 5:
ACIN1: 23
ACIN2: 22
ACIN3: 25
ACIN4: 29
ACIN5: 36
If you are using counter for pulse generation you cannot use the same counter for wheel
tick input.
22.5.2 Windows 95/98
Above drivers don’t work under Windows 9x and to log Event Marks MagLog uses win95
version of DRVX28. Installation script sets it up for you; driver started after you reboot
computer during installation. Port address and IRQ in this case are set within MagLog.
Just in case of trouble you may check that registry entry:
exists and is set to the “default” value.
Note that event marker won’t work if parallel port is in bi-directional mode. It can be
changed via BIOS setup program or by means of switches on the ISA parallel port
extension card.
23 Index
8th RMS, 39
AADC, 47, 48
Acoustic Target, 170
Adding Flags, 121
Alias Device Name, 39
amplitude plot, 110
ArcInfo, 13, 14, 103, 108
Atlas Boundary, 109
Auto logging, 159
Automatic printer configuration, 129
Average window, 113
Azimuth angle, 181
Cable payout, 64, 66
calibration, 40, 163, 164, 165, 166, 167
channels, 34, 35, 36, 38, 39, 40, 44, 45,
88, 89, 163, 164
Chart Speed, 151, 152
Clear GPS track, 101
COMM/DRV, 205, 209
comment, 122
cycle time, 36
DAS1700, 45
Data bar, 157
Data Display, 22
data sampling rate, 231
Device Status Bar, 157
Differential GPS fix required, 42
Digital Display, 86
Display Settings, 158
distance units, 12, 113, 161, 167
Echo Sounder, 66
Ellipsoid Parameters, 177
EM61, 61, 62, 63
Enable analog channels, 35
ethernet, 169, 183, 184, 195, 200
Event, 42, 43, 68, 153, 247
feet or meters, 53, 163
Filter Size, 175
Flag, 118, 119, 120, 121
formula, 111
FreePDF, 25
G-858, 64, 65
G-877, iii, 10, 16, 18, 48, 49
G-877 depth calibration, 53
G-880, iii, 10, 15, 16, 34, 35, 39, 48, 82,
89, 91, 93, 147, 156, 157, 158, 162,
163, 167, 169, 229, 231
Generic serial device, 45
Geographical Output, 176, 178, 193
geographical projection, 96
GPS, 37, 41, 42, 82, 91, 96, 97, 98, 100,
103, 109, 150, 151, 153, 156, 157,
158, 162, 169, 170, 172, 173, 175,
176, 181, 183, 190, 192, 193, 194,
195, 197, 198, 199
GR33, 151, 152
GR800, 44, 88, 156
Gradient, 89
Gradient plot, 99
Grid Lines, 86
GYRO, 162, 170, 172, 173, 174, 175,
190, 192, 195, 198
Honeywell PPT, 80
Horizontal Scaling, 86, 89, 149
hot keys, 121
Hyper Terminal, 53
IGRF, 49, 50
Input Devices Configuration, 28, 41, 91,
147, 148
internal sampling rate, 231
Internal UTM, 176, 177, 193, 199
interpolator, 162, 163, 167, 169, 170,
171, 172, 190, 191, 228
Interpolator Output, 183, 185
Latency, 221, 222, 223
line number, 150, 155, 157, 159
logging, 155, 157, 158, 159, 161
longitudinal gradient plot, 110
MagLog page, 124, 127
Maglog.ini, 85
Magnetometer array offset, 172
Master Clock Card, 213
Matrix printer, 152
median filtering, 175, 198
mini-window, 115
Northing/Easting, 178
Number of Satellites, 42
on track plots, 110
Survey, iii, iv, 7, 9, 10, 65, 155, 156,
162, 163, 178
Survey area, 102
Survey plan, 102
Survey units, 12, 161
Target, 181, 183
TCP/IP, 27, 29, 30, 33, 35, 183, 184, 241
Titler, 150
Tow point, 172, 173, 175, 192, 194, 195,
197, 198, 201
trace, 82, 85, 87, 90, 92
Trace, 22, 82, 85, 87, 88, 90, 91, 92, 147,
Transmitters, 144
triggered devices, 73
TTL, 1, 67, 68, 69, 70, 153, 243
Use depth for layback, 18
User lines, 106
User map, 109
User marks, 105
Using comments, 122
UTM, 151, 152, 153, 170, 175, 176, 177,
178, 193, 195, 199
UTM Projection Parameters, 177
Value plot, 114
Vertical Scaling, 85
Width, 149
Windows NT, 238, 239, 240, 241, 242,
Windows printer, 25, 127
Windows Printer, 123
Windows™ printers and print drivers,
Wizard, iii, iv, 10, 11, 13, 15, 17, 18, 20,
X/Y offset for hydrophone, 174
ORE Trackpoint, 43, 170, 174, 192, 195,
Origin, 149
Output Files, 161
Password Protection, 228
Playback, iii, 215, 217, 229
Port Settings, 39, 42, 43, 230
Positive and negative, 113
printer, 28, 147, 148, 151, 152, 153, 156,
Printrex, 243
Pulse 12, 10, 16, 18, 65
PULSE 12, 65, 67
Pulse devices. See
quality control, 39, 40, 41, 42, 97
Real-Time Serial driver, 205
Reference Point, 169, 183
Reset Configuration, 36
Sample Files, 228
Scale factor, 178
Send Configuration, 36
Sensor Positions, 170
serial output, 185, 195
Serial port, 30
Set Flag, 140
Shifted Point, 169, 183
slot, 82, 83, 84, 85, 86, 87, 92, 148
Slot, 82, 83, 84, 85, 86, 87, 92, 148
Software registration, iv, 5
Speedometer, 68, 72
Stack gravity azimuth, 113
Stack plot, 113
stack profile, 110
Stack scale, 113
status bar, 157, 158, 238
survey, 7
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