SatisGeo PMG-2 User manual

2021
SatisGeo s.r.o.
1/29/2021
PMG-2 User Manual

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Contents
1. Introduction...................................................................................................... 3
2. Specifications................................................................................................... 4
3. Description of the instrument............................................................................ 5
3.1. Measuring Sensor With Accessories............................................................. 5
3.2. Processing Unit ............................................................................................ 6
3.3. Operation Principle....................................................................................... 7
3.4. PMG-2 Magnetometer Operating Controls.................................................... 7
3.5. Main Menu.................................................................................................... 7
3.6. Setup Menu.................................................................................................. 8
3.7. Device Menu................................................................................................. 9
4. Putting the instrument into operation...............................................................11
4.1. Power Supply ..............................................................................................11
4.2. Switch On/Off ..............................................................................................11
4.3. Battery Condition Check..............................................................................11
5. Basic setting of the instrument ........................................................................12
5.1. Setting The Internal Clock............................................................................12
5.2. Tuning Of The Magnetometer......................................................................12
5.3. Setting The Backlight...................................................................................14
5.4. Selection Of The Sensor Configuration........................................................14
5.5. Walk Sample Rate Configuration.................................................................14
5.6. Setting The Time Interval To Switch Off.......................................................14
5.7. Setting The Position.....................................................................................14
5.8. Recalling Stored Data..................................................................................15
6. Measurement..................................................................................................16
6.1. Instrument Setup.........................................................................................16
6.2. Sensor Orientation.......................................................................................16
6.3. Tuning .........................................................................................................16
6.4. Manual Measuring.......................................................................................16
6.5. Measuring In Walk Mode.............................................................................17
6.6. Measuring In Auto Mode..............................................................................17
7. Data memory...................................................................................................18
7.1. Erasing And Checking Of The Data Memory ...............................................18
7.2. Data Storage In The Data Memory..............................................................18
7.3. Display Of Data Stored In Memory ..............................................................18
7.4. Transmission of the Stored Data to a Computer..........................................18
8. Supplementary information..............................................................................19

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8.1. USB Interface..............................................................................................19
8.2. Charger .......................................................................................................19
8.3. Maintenance And Repair Work....................................................................19
8.4. Storage And Transportation.........................................................................19
8.5. Warranty......................................................................................................19
8.6. Accessories.................................................................................................20

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1.INTRODUCTION
The proton magnetometer and gradiometer PMG2 is a portable instrument which
is powered by an internal battery. It is intended for ground measuring of the absolute
value of the magnetic induction vector of the Earth´s magnetic field by measuring the
frequency of the precession of protons in hydrogen nuclei. The magnetic induction vector
is also called the magnetic field vector.
The magnetometer PMG2 allows the Earth´s magnetic field to be measured in
three modes:
MANUAL mode is used in a profile magnetic survey on a grid. Based on settings
of sensor configuration. In SINGLE sensor configuration, it detects the absolute value of
the magnetic field in the location of the sensor. The sensor is connected to the ‘Up
sensor’ connector. In GRAD sensor configuration, the absolute values of the magnetic
induction vector in the locations of both sensors are measured simultaneously. The
horizontal or vertical gradient of the magnetic field between the two sensors is
determined by subtraction: The value of the field measured in the location of the sensor
connected to the ‘Up sensor’ connector minus the value of the field measured in the
location of the sensor connected to the ‘Down sensor’ connector. The gradient
measurement removes, to some extent, the undesirable influence of disturbing fields,
compensates for the influence of the regional field, and does not depend on diurnal
variations in the Earth´s magnetic field.
WALK mode continually measures the magnetic field based on sensor
configuration in three intervals 0.5s, 1s, 1.5s, 2s, 2.5s, and 3s. The possible sensor
configuration is the same as in manual mode. The measurements in this mode can be
burdened with a more significant error than in MANUAL or AUTO measurements.
AUTO mode allows repeated measurements with one sensor in set time intervals.
Both the starting time and the length of the intervals can be set before the
measurements. This mode is used for measuring diurnal variations in the Earth´s
magnetic field.
The results of the measurements can be stored in internal memory. The data can
be transmitted to a computer through a USB interface using the communication program,
which is supplied with the instrument. The program saves the data in a gzipped XML file
of the external computer.
The magnetometer PMG2 is delivered with a power supply, which is a built-in
lead-acid battery. The non-magnetic rechargeable battery does not contribute enough to
the magnetic moment of the instrument to affect measured values. A battery charger is
also supplied with the device.
All functions of the magnetometer PMG2 are controlled by an internal
microprocessor. This internal microprocessor allows an operator to communicate with the
instrument via a keyboard and LCD display, controls the measurement process, and
transmits the acquired data to an external computer through the USB interface.
The proton magnetometer automatically checks the correctness of the
measurement and of the activities of the operator. If a failure is detected, the operator is
warned with an error message on display.

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2.SPECIFICATIONS
Measuring range
20 000 to 100 000 nT
Resolution
0.01 nT
Absolute accuracy
±0.5 nT
Sensitivity (AUTO, MANUAL, WALK
@ > 1.5s)
0.2nT
Maximum gradient value *
1 000 nT/m
Maximum displayed value of gradient
9999.9 nT
Measuring cycle
ca 0.5 s
Triggering
Manual, automatic in AUTO and WALK mode
Internal clock
day, month, year, hours, minutes and seconds,
independent of battery condition
Data memory
1,800,000+ readings
Universal Serial Bus (USB)
Power supply
internal lead-acid battery 12 V / 3.4 Ah
Battery lifetime
5 000 readings on average in GRAD sensor
configuration
Processing unit
Dimensions
230 x 80 x 170 mm
Weight
3.2 kg including battery
Sensor
Dimensions
dia 80 x 200 mm
Weight
0.7 kg
Operating temperature range
- 10 to 60 °C
Storage temperature range
- 20 to 70 °C
* The maximum gradient 1000nT/m means that if a change in gradient in consecutive
measurements is smaller than 1000nT, there is no need to change the tune significantly,
and we are sure that results are reliable.
Otherwise, there are two scenarios.
1. In the case that there was no need to change the tune for either of the probes
significantly, the results are as well reliable.
2. In the case that there was a need to change the tune for either of the probes
significantly, the results are not reliable. The user is informed that such a situation
occurred and that the tune changed. So to get reliable results, an additional
measurement in the same place needs to be taken.

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3.DESCRIPTION OF THE INSTRUMENT
The proton magnetometer PMG2 consists of a processing unit, measuring
sensors, and a post.
3.1. Measuring Sensor With Accessories
The measuring sensor contains two coils properly arranged to suppress a
disturbing external field. The coils are placed in a laminated cylinder container filled with
a liquid rich in hydrocarbons.
North and south are marked on the container of the sensor. The ‘north’ mark
should point to the geographical north. The orientation of the sensor does not affect the
value of the measured magnetic field, but it does affect the intensity of the signal from the
sensor and, thus, the size of the error of the measurement.
Figure 3.1 - Post assembly for line measurement.
For measurements, the sensor is mounted on a post which is assembled using up
to five half meter long sticks joined with screw coupling. In this way, the sensor can be
set to various heights above the ground –see Figure 3.1. For gradient measurement, an
extension (gradient stick) is used to keep both sensors 0.5 or 1 m apart –see Figure 3.2.
The gradient stick allows the position of the sensors to be set so that the orientation of
both sensors to the Earth´s magnetic field may be the same. For AUTO mode
measurements (diurnal variations), an anchor ring with ropes and pins is supplied to hold
the post in place.
The measuring sensors and the processing unit are connected via 2.5 m long
cables.

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Figure 3.2 –Left –post assembly for gradient measurement.
Right –post assembly for magnetic variation measurement.
3.2. Processing Unit
The processing unit allows for communication with an operator via a keyboard
and a graphic LCD display. It contains circuits for processing and analyzing the
measured signal: tuning circuits, low-noise amplifier, filter, and shaping amplifier.
The processing unit is placed in a duralumin box. Two watertight bayonet
connectors for connecting the sensors are located on the left side of the box. In AUTO
mode, only the upper left connector is used, ‘Up sensor’. In MANUAL and WALK modes,
the booth connectors can be used based on sensor configuration. The gradient is
determined by subtraction: The value of the field measured in the location of the sensor
connected to the ‘Up sensor’ connector minus the value of the field measured in the
location of the sensor connected to the ‘Down sensor’ connector.
There are two connectors on the right side of the box. The upper one serves to
connect to the computer through USB. The connector for charging of the internal battery
is located in the lower part of the instrument. The connector can also be used for an
external power supply after removing the internal battery.
The lead-acid battery is placed in the bottom part of the unit and is accessible by
unscrewing the four bolts in the bottom cover. The battery compartment is hermetically
separated from the electronics.
The display and the keyboard are located on the top side of the unit. The
keyboard contains 16 watertight membrane push-buttons.
The instrument is delivered with a harness to fasten it on the chest of an operator.

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3.3. Operation Principle
The measurement of the magnetic field is conducted in two steps. In the first
measuring step, the polarization current feeds the sensor and causes uniform orientation
of magnetic moments of hydrogen nuclei contained in the liquid in the sensor. The time of
polarization is automatically increased, in MANUAL and AUTO measuring modes,
according to the decreasing source voltage so that the precession signal gained from the
sensor may remain constant. In WALK measuring mode, the polarization time is fixed.
During the polarization cycle, the sensor and the low-noise amplifier are disconnected.
The first step of the measuring sequence is terminated by switching the polarization
current off.
In the second step, due to an interruption of the polarization current in the sensor,
the transient field is dumped, and then the low-noise amplifier is connected to the sensor.
The signal induced in the sensor is amplified, filtered, and shaped to suit the processing
in numeric circuits. In the sampling circuit of the microprocessor, the frequency of
attenuated oscillations of the precession motion of the hydrogen nuclei is evaluated. The
frequency is directly proportional to the measured magnetic field.
The entire measuring cycle is controlled by a microprocessor which computes the
measured magnetic field and statistical error of the measurement from the value of the
frequency of the precession. Both values are displayed and optionally stored in the data
memory.
During the second step, the amplitude of the precession signal and the time
constant of the decay are determined. The supplementary values are also stored in the
data memory.
3.4. PMG-2 Magnetometer Operating Controls
[ON / OFF]
switching on and off
[ENTER]
start of measurement or other selected procedures, setting validity of
modified parameters or data, storing measured data in the memory
[ESC]
termination of any going-on procedure without storing data
[NEXT]
next item
[0] to [9]
loading digits
[ v ]
scanning series of consecutive data towards higher ordinal numbers
[ ^ ]
scanning series of consecutive data towards lower ordinal numbers
Table 3.1 - PMG-2 operating controls.
3.5. Main Menu
After switching the instrument on, by means of the push-button [ON/OFF], the
initial logo appears on display.
After pressing any push-button or after 3 seconds, the main menu appears.
The backlight is switched off automatically 30 seconds (default value is 30 s, other
options selectable) after the last pressing of a push-button. The backlight can be
switched off all the time to save power consumption.

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S 08:04:28
MAIN MENU
1. MEASURE
2. POSITION
3. MEMORY
4. SETUP
Line:+1026 Pos:-0980
The topmost part of the display is reserved for actual time and status information.
The status indicators are:
this icon indicates that the USB cable is connected, and the device is ready for
data transfer.
this is a battery icon to indicate battery status.
S or G symbols indicating the actually select sensor modes Single, Gradient.
Move-in the main menu, and item selection is marked by a cursor, graphically
indicated by the inverted line. Push-buttons [] and [] serve for a cursor move in the
main menu. Menu items 1 - 4 are directly selectable by pressing numerical push-buttons
[1] - [4] on the keyboard.
Push-button [ENTER] serves for item function activation and to confirm the newly
specified parameters. Push-button [ESC] serves to return to the main menu without
modification of parameters.
1. MEASURE –item sub-menu serves to activates measurement. The possible
measurements are MANUAL, WALK, and AUTO. See chapter 6.
2. POSITION - Item serves for the setting of a number of a profile line, position on a
profile, and step of measurement on a profile see chapter 5.7.
3. MEMORY - Item serves for a listing of the items stored in the data memory.
Further, it enables us to erase the data memory and see memory status see
chapter 7.
4. SETUP - Item serves to set up various parameters of the instrument see chapter
3.6.
3.6. Setup Menu
The setup menu serves to set up various parameters, see below. It is activated in
the main menu, item 4.
Move-in the setup menu, and item selection is marked by a cursor, graphically
indicated by the inverted line. Push-buttons [] and [] serve for a cursor move in the
main menu.
Menu items 1 - 5 are directly selectable by pressing numerical push-buttons [1] -
[5] on the keyboard.
Push-button [ESC] serves to return to the main menu.
Push-button [ENTER] serves for item function activation and to confirm the newly
specified parameters.

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Push-button [ESC] serves to return to the setup menu without modification of
parameters.
S 08:04:28
SETUP MENU
1. MODE
2. TUNE
3. WALK MODE
4. DEVICE
1. MODE –item sets the sensor mode (Single or Gradient) for MANUAL and
WAL measure. This item is shown in the case that the device is a gradiometer.
2. TUNE –item servers to select the current field range see chapter 5.2.
3. WALK MODE –item serves to select automatic measure interval for WALK
measure.
4. DEVICE –item serves to select multiple device options. See chapter 5.
3.7. Device Menu
The device menu serves for setting up various device parameters, see below. It is
activated in the setup menu, item 5.
S 08:04:28
DEVICE SETUP
1. BACKLIGHT
2. DATE / TIME
3. OFF TIME
4. INFO
1. BACKLIGHT - Item serves to switch the backlight on / off or to set the time to
elapse. See chapter 5.3.
2. DATE / TIME - item sets up real date (yy.mm.dd, where y- year, m –month, d
–day) and time (hh:mm:ss, where h - hours, m - minutes, s - seconds). The
cursor indicates the number to edit. Editing of numerical values is carried out
by means of push-buttons [0],[1],[2],...[9]. Move the cursor by [], [], and
[NEXT]. The push-button [ENTER] stores the modified date and time into the
memory. The push-button [ESC] returns the control to the parent menu
without any change of the date and time see chapter 5.1.
3. OFF TIME - item serves for setting the switch-off time see chapter 5.6.
4. INFO - Item displays the serial number of the instrument and version of the
software.