Geonics Limited EM38-MK2 User manual

EM38MK2
1745 Meyerside Drive, Mississauga, Ontario, Canada L5T 1C6
Tel: [phone] Fax: [phone]
E-mail: [email protected]
Geonics Limited
March, 2008
Version 1.15
EM38-MK2 DATA LOGGING SYSTEM
FOR FIELD COMPUTER Allegro CX Field PC
OPERATING INSTRUCTIONS

Table of Contents
1. Introduction ................................................................................................ 1
1.1 Program Requirements ......................................................................... 2
1.2 Installing EM38MK2 ............................................................................ 2
1.3 Data Files Transfer ............................................................................... 2
1.4 Running EM38MK2 Program ................................................................ 3
1.5 Main Menu......................................................................................... 3
Short description of Main Screen options ...............................................................4
2. Survey Setup ............................................................................................... 5
3. Logger Setup............................................................................................... 9
3.1 Bluetooth Connection of EM38-MK2 and Allegro CX ........................... 10
4. Set Port for GPS......................................................................................... 13
4.1 Monitoring GPS Receiver Output ........................................................ 15
5. Display Options ........................................................................................ 19
6. Logging Data............................................................................................ 21
6.1 Monitoring Mode .............................................................................. 21
Description of Monitoring Mode options..............................................................23
6.2 Stand By Mode.................................................................................. 24
6.3 Logging Mode................................................................................... 25
6.4 Stand By Mode Field Options ............................................................. 26
7. View Data Files........................................................................................... 31
Appendix A ....................................................................................................... 35
A.1 Description of Data File in EM38MK2 Format ...................................... 35
A.2 Example of File in EM38MK2 Format .................................................. 38
Appendix B ....................................................................................................... 39
B.1 Using the EM38MK2 with a GPS Receiver............................................ 39
B.2 Description of GGA and GSA Data Messages...................................... 40

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EM38MK2 Data Logging System (DAS70-CX)
1. Introduction
The EM38-MK2 data acquisition system (DAS70-CX) includes: an Allegro CX eld computer which
is Bluetooth enabled; EM38MK2 software for data acquisition (programmed for the Allegro CX MS
Windows CE.NET V4.2 operating system, specically); DAT38MK2 software for data processing;
and cables to connect the eld computer to either the instrument and / or another serial device.
Two models of the EM38-MK2 are available: EM38-MK2-1 and EM38-MK2-2. Providing similar
functionality, including the simultaneous measurement of both quad-phase (conductivity) and
in-phase (magnetic susceptibility) components, the dening difference between the models is the
number of included receiver coils: the EM38-MK2-1 includes one receiver coil with a 1 meter
transmitter / receiver intercoil spacing; the EM38-MK2-2 includes two receiver coils with 0.5 and
1 meter intercoil spacings. All references to the EM38-MK2 in this manual are applicable to
both of the models described above.
Program EM38MK2 acquires and records survey data from the EM38-MK2 system, under the
control of the operator. It also records various eld information such as survey line number (line
name), starting station, increment, comments, etc. Readings are displayed in real time in mS/m
(conductivity) or ppt (in-phase) in both graphic and numeric modes. In addition, the program al-
lows you to monitor the instrument output while data are not recorded. Program EM38MK2 also
continuously monitors the EM38-MK2 measured components (Conductivity and Inphase), dipole
mode (Vertical or Horizontal), state of ducial marker, as well as GPS signal quality parameters (if
connected to the system) without leaving the program.
The program allows the user to set the EM38MK2 into a specic instrument mode of operation:
AUTO or Manual modes. In AUTO mode readings can be automatically recorded in desired time
intervals, and in MANUAL mode readings are triggered manually by the operator. In AUTO mode
the program can record the EM38-MK2 components (Conductivity and Inphase) and one dipole
mode (Vertical or Horizontal) per station. In Manual mode any combination of dipole modes can
be taken at each station, and data can be averaged at up to 100 samples per reading.
The EM38MK2 will accept NMEA-0183 compatible data from a GPS receiver directly connected
to an Allegro eld computer. GPS data which are embedded in the EM38MK2 data le can be
processed later in the Geonics DAT38MK2 program. The connected GPS must be able to stream
NMEA-0183 compatible messages. The EM38MK2 uses two NMEA messages GGA and GSA.
While message GGA is mandatory, the GSA string is used only to provide information related to
the GPS signal quality during data collection.
The EM38MK2 program records data together with a time stamp at each station. Data les created
with this program can be used to position a survey according to locations recorded separately by a
Global Positioning System (GPS). However direct GPS interface described above is highly recom-
mended as much more accurate and simpler (for data processing) method of GPS positioning.
Survey setup parameters are saved in a le, therefore they can be automatically used during subse-
quent data collection sessions.
The program has an option that allows you to view data les. Data les are saved to the programs
current data directory by default. Data le names, which can be set by the program based on the
computer clock or user specied, have extension names P38. Files can be transferred to a PC com-
puter using a memory card, or by a serial or USB port using the MS ActiveSync program.
Over 1,000,000 readings can be collected in the Allegro eld computer with a standard memory of
64 Mb. The maximum speed of data collection is approximately 21 readings per second assuming
1 Hz (or less) GPS input. In graphic display mode, a prole containing the last 135 data readings
is displayed for each component.

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EM38MK2 Data Logging System (DAS70-CX)
1.1 Program Requirements
To successfully use this software, you will need :
Computer
Field computer Allegro CX
Installed MS ActiveSync software (Version 3.50 or later) in desktop PC, or alternatively
PCMCIA memory card to transfer les.
Geonics EM38-MK2
The EM38-MK2 instrument with associated cables.
The EM38MK2 program for Allegro CX is stored on DAT38MK2 CD disk. All necessary initial
les (with extension names .INI) as well as data folder (DATA38MK2) are created in your eld
computer after the program is run for the rst time. Check that the le EM38MK2.EXE is included
in AllegroCX directory on the CD disk.
1.2 Installing EM38MK2
While using the Allegro CX the EM38MK2.exe le should be transferred from a desktop PC using
MS ActiveSync software and USB or serial cable provided by manufacturer. Optionally the program
can be transferred to an Allegro using the PC memory card.
It is recommended that the program be placed in non-volatile solid state storage. This memory is
represented in the Allegro by the C_Drive icon. In the My Computer on the Allegro, double-tap on
C_Drive icon, then folder C_Program Files will appear. The EM38MK2 program can be placed in
C_Program Files. Folders for data les should be also created in C_Drive, which is a safe area to store
data. The program creates folder DATA38MK2 which is the default folder for EM38MK2 les.
For more information about data storage options, refer to Chapter 3 of the Allegro CX manual.
1.3 Data Files Transfer
Data les are saved in the Allegro with extension N38. Transfer of les to desktop PC can be per-
formed with MS ActiveSync or by PC memory card. Data les with extension N38 are binary raw
data les. These les have to be converted to DAT38MK2 format with extension M38 (option
"Convert Files" in DAT38MK2). They can then be processed in the DAT38MK2 program.

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EM38MK2 Data Logging System (DAS70-CX)
1.4 Running EM38MK2 Program
To run the EM38MK2 program, locate it in the C_Program Files and double-tap its icon. The
EM38MK2 is a Windows CE based, button and dialog driven program designed to be simple to use.
Although the program fully supports touchscreen interface, keyboard entry may be convenient in
some eld applications. The EM38MK2 can be fully operated from the keyboard when touchscreen
functions are disabled by the user.
Options represented by the command buttons can be accessed by a single tap on the button. Buttons
can also be selected from the keyboard by using shortcuts (pressing key corresponding to underline
letter in button caption or by selecting button by pressing TAB and then execute by pressing EN-
TER. Shortcuts are the fastest way of accessing options represented by buttons.
Most options in the dialog windows are given in the form of text boxes and drop-down boxes which
can be accessed using touchscreen or by the keyboard. Each dialog window has a title bar with a
caption describing the dialog function and two buttons OK and X (Cancel). The OK button (or
key ENTER) conrms dialog selection. Tapping on the Cancel button (or pressing Esc key) closes
the dialog and returns to the initial selection.
1.5 Main Screen
The Main Screen always appears after the program is started. It contains the name of the program,
its version number, and a list of buttons representing the available options. The EM38MK2 Main
Screen is displayed below.

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These options are selected by using tapping buttons, or from keyboard using TAB/ENTER or
shortcuts indicated by underline label characters. The Main Screen buttons can be controlled with
the Down and Up arrow keys and <ENTER>.
Short description for each of the options follows.
Short description of Main Screen options
Monitor/Log
This option allows to monitor and log the EM38MK2 output. Monitor/Log screen starts
always in Monitor mode, and then after a data le is created Logging mode is available.
Monitor mode provides initial inspection of the range of the instrument readings at the
particular site, instrument calibration, monitoring the instrument performance, and quick
inspection of the instrument settings.
Survey Setup
The Survey Setup dialog will be displayed. All survey settings (survey line name, increments,
etc.) can be specied in this dialog.
Logger Setup
Dialog window that is associated with this option is used to set the instrument type, serial
port number or Bluetooth connection, and type of pause key.
Set GPS Port
The GPS Port Setup dialog allows to disable and enable GPS data acquisition. This op-
tion is also used to set the serial port number used for GPS input and to specify necessary
serial port communication settings. GPS monitoring window can be accessed from this
dialog as well.
Display Options
The dialog which will allow you to specify colour and thickness of prole lines will appear.
This dialog provides also choice of gid lines for Conductivity or Inphase scale.
View Files
This option allows to review data les saved in Allegro.
Exit
This option will terminate the program execution.

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EM38MK2 Data Logging System (DAS70-CX)
2. Survey Setup
The Survey Setup dialog, presented below, contains several parameters which affect two important
procedures: instrument settings (instrument mode, frequency of data collection, etc.) and survey
geometry layout (survey line names, line spacing, start station, station increment, etc.).
Description of Options and Parameters:
EM38/2 Mode (EM38-MK2 Mode)
This option allows you to select the type of instrument survey mode. Set the EM38MK2 mode of
operation by selecting an item from the drop-down list box labeled EM38/2 Mode. Available modes
are: Auto and Manual. These modes of operation are described below.
Auto Mode
Readings will be triggered automatically at a specied frequency (see option
Readings/s).
In Auto Mode only one dipole mode (Vertical or Horizontal) can be selected.
Manual Mode
Readings will be taken only while the manual trigger (switch on the instrument
console or a handle) is pressed.
In Manual Mode any combination of dipole modes (Vertical, Horizontal or Both)
can be selected.
Please note that when Manual mode is selected options the option Reading/s
changes to option labeled Samples/Rdg.

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EM38MK2 Data Logging System (DAS70-CX)
Readings/s (Readings per second)
When this option is available (only in Auto mode) activate text box by tapping or using
TAB key and then enter desired value.
This parameter describes number of readings per second that will be taken. Any number
larger than zero can be entered, however the EM38-MK2 xed frequency of data output
is 21 readings per second. Therefore any entered value is rounded to the nearest possible
base frequency of the instrument, i.e. user specied frequency of 20 readings/s will result
in the effective data acquisition rate of 21 readings/s (every reading is logged), 9 readings/s
will cause the program to log at a rate of 10.5 readings/s (every second reading from instru-
ment output is logged), etc. At slower rates the difference between specied and effective
frequencies is negligible.
Samples/Rdg (Samples per Reading)
When this option is highlighted the editor is activated and you can enter desired value. The
edit box only accepts numerical positive values.
This parameter describes number of readings that will be taken after the trigger switch is
pressed. At the end of sampling time the logger will beep and an average value will be writ-
ten in to the le and plotted on the screen. During the sampling period interval data are
measured at approximately 20 readings per second. For example by specifying 10 samples,
0.5 second will be used at each station. The maximal sampling is 100 readings which cor-
responds to approximately 5 seconds at each station.
This option could be used to improve quality of data in areas of high industrial noise,
especially if the ground conductivity is relatively low (small response signal).
In cases when multiple sampling is not required (good signal to noise ratio) enter the value
0 or 1 and 1 reading per station will be taken.
This parameter is displayed only when the Manual Mode was selected.
Dipole Mode (instrument dipole mode)
Tapping on the down arrow next to the text box opens a drop-down box showing the available
settings, or when the keyboard is used activate the text box and then by using up or down
arrow keys select one of two or three available items: Vertical, Horizontal, and Both.
When Manual mode was selected three settings are available: Vertical, Horizontal, and
Both (see Figure below).