## Introduction¶

### Performance Characteristics¶

The ADU-08e (Analog Digital Unit) is the core unit of the metronix multi-channel Geophysical Measurement System GMS-08. It is the result of more than 40 years of metronix´ experience in the design and manufacture of electromagnetic geophysical instruments.

The ADU-08e can be equipped with up to 6 measurement channels (5 + one internal wired). The standard configuration for wide band MT and AMT consists of 5 broad band (HF+LF combined on one board) channels. The type of channel-boards which are plugged-in will be detected by the system automatically. Multiple ADU-08e units can be connected to a network .

Each ADU can be operated as a stand-alone system, in a network using standard Local Area Network (LAN) using GigaBit Ethernet, or as part of an array, in which each unit is synchronized by its built-in GPS controlled precision clock. An access via Wireless-LAN is also possible.

The ADU-08e electronics is housed in a small (41cm x 32cm x 17cm) waterproof box only 6.5 kg in weight. In spite of the small size, it contains the complete circuitry for analog signal conditioning of up to 6 channels, 24(HF)/32(LF) Bit A/D conversion and data storage as well as a very precise GPS controlled time base (using GPS and GLONASS).

Data is stored on a removable SD card or on a USB pen drive orexternal USB hard-disk or, via the network, on the hard-disk of the connected control computer.

Either the single ADU-08e or a complete network of several ADUs can be controlled via a standard PC. This may be any (ruggedized) laptop with sufficient performance.

Each ADU can be accessed and controlled by any external PC using a standard Web-browser and aduclient software(Linux, Mac, Windows, Andoid).

All metronix magnetometers like MFS-05, MFS-06(e), MFS-07(e), FGS-02, FGS-03e, SHFT-02(e) can be connected directly to the ADU-08e. It is also possible to connect magnetometers from other companies on option.

The GMS-08 system provides a high degree of flexibility for various sensor setups. Due to its scalable and modular concept it can grow with the requirements of the user. The low number of different components also simplifies the spare part requirement.

### Features¶

• High data quality due to 24 Bit (HF) and 32 Bit (LF) Analog/Digital conversion technology

• Very low system self-noise for best results in the MT “dead band”

• Wide frequency range from DC to 250 kHz. Sampling rates from 256Hz up to 524kHz

• System can be operated as a stand-alone or as a multi-channel network system when connecting multiple ADU-08e in a Local Area Network (LAN). An integrated W-LAN module is now standard.

• ADU-08e is controlled by any Web-browser without need of further software

• ADU-08e is controlled by mobile phone or tablet (adu client software)

• Multiple stand-alone systems are synchronized with GPS clock accuracy.

• Compatible with all metronix sensors.

• Automatic unattended recording mode, pre-configured job-lists

• Plug and Play recording mode if a USB stick with pre-programmed time schedule is inserted

• Automatic detection of magnetometer type and automatic download of calibration function from sensor (Only for MFS-06e, MFS-07e, MFS-10e, SHFT-02e, FGS-03e and future sensors)

• Automated system self-check of ADU-08e and sensors during set up.

• Optional automatic input offset compensation eliminates self-potential of electrodes.

• Real-time data processing on option (the capabilities of this feature will be further enhanced in future software releases).

• 12 V battery powered. Only one battery is required for each ADU-08e incl. sensors.

• Compact, light-weight, ruggedized and water-protected instrument design.

• Low power consumption

• Wide operating temperature range from -30°C to +60°C ambient temperature.

• Multiple methods such as MT, AMT, EMAP, RMT, CSAMT

### Technical Data¶

 Frequency range DC to 524.288 kHz Number of channels 5 (standard) expandable to 6 Native sample rates of A/D converter 256 Hz to 524.288 kHz selectable by power of 2 (lower sampling rates by on-line digital filtering) A/D conversion LF: 32 Bit (data rate max. 4,096 samples/sec) HF: 24 Bit (data rate max 262,144 samples/sec) One A/D conversion unit for each channel Input noise LF-ADB: 12 nV/√Hz @ 0.1 < f < 2 kHz and gain 16 Ultra low noise mode LF: 6 nV/√Hz @gain 64 HF-ADB: 13 nV/√Hz @ f >1kHz and gain 16 Input resistance >10 MΩ Nominal input voltage range (@ gain 1) switchable between +/- 1.25V and +/-10V (is done automatically by selection of sensor type) System computer 32 bit low-power embedded controller with Linux operating system (4 CPU cores) Storage media 32 - 512 GByte SD card (4 TB on external USB disk with ext4), USB-pen-drive or other external USB mass storage device Test facilities Automatic power up self-test of all important system functions including sensors and display of result on the instrument. Automatic creation of log-file Calibration automatic calibration Network connection GBit Ethernet with RJ45 connector, external WiFi module Synchronization 72 channels GNSS synchronized clock, accuracy +/-30ns rms accuracy of 1pps signal, station position is also determined and stored (GPS, Glonass, BeiDou, Galileo) Standard connectors for 5 channel system 1 x Network RJ45 ruggedized socket(s) 3 x Magnetometer 10-pole 4 x E-field input terminal 6-pole 1 x GND terminal 2 x input terminals for 12V battery protected against reverse polarity 1 x ext. satellite antenna MCA-Type socket, 2 x USB2.0 Type A Status Display 5 lines with 64 alpha numeric characters for display of status information and direct parameter entry Case ruggedized, water-resistant case Weight appr. 6.2 kg External dimensions 406*330*174 mm3 Power Input 9V … 15V DC Power consumption 5.5W – 15W depending on operation mode Operating temperature range -30°C to + 60°C

The system is protected against over voltage; around 16.xx V it should switch off.
All components inside the system are industrial (-40°C .. +85°C) grade with the CPUs on the ADB and Clock/GPS even ranging up to 125°C. Lightning protection is up to 1200V, fuses can be exchanged. Above the system will be seriously damaged

## Overview¶

The ADU-08e comes in a waterproof, ruggedized Peli case housing.

The ADU-08e is delivered along with an additional external GPS-antenna and two battery cables.

Figure 3 2 and 2-3 show the ADU-08e and its operating elements. All operating elements are numbered and described in more detail in the following pages.

1. USB Socket

2. GPS Status LED

3. Recording Status LED

4. Battery Status LED

5. GPS antenna

6. Binding posts for auxiliary power supply

8. On/Off button

9. Slot for SD card

10. Display

11. Bridge for internal or external GPS Antenna, left is external, right is internal antenna (as shown in the picture)

Operating elements of ADU-08e left side

1. Network socket

2. USB socket

3. GPS antenna socket

4. Battery sockets

Operating elements of ADU-08e right side

1. E-field connectors

2. GND socket

3. Magnetometer connectors

### USB Type “A” Connectors¶

You will find one USB Type A connector on the front lid and another one on the left side for connection of USB mass storage devices or USB WiFi stick. Mass-storage devices and WiFi sticks will be recognized by the operating system automatically.

### GPS status LED¶

This LED shows 3 states:

 LED off No GPS synchronization or system in clock hold mode. LED blink System has detected sufficient number of satellites, but has not reached the maximum accuracy yet. LED steady green GPS locked and system fully synchronized.

If the LED is not illuminated despite the GPS-antenna is corrected properly, it may be that the antenna does not have an open view to the sky allowing the system to detect at least 4 satellites in track. In this case it may be helpful to look for another location for the antenna.

If the ADU has been transferred to another location which is far away from the last one with a valid GPS lock (more than 300 km), it can take a while until the system has found a sufficient number of satellites. In this case the stored Almanac of the satellite positions is no more valid for the new location and has to be updated first. This procedure can take up to 15 minutes.

It also may take a longer time if a long time span (more than 1 week) has been passed since the last GPS fix.

### Recording status LED¶

The red LED is switched on if a data acquisition is running.

### Battery Status LED¶

In order to get a quick check of the battery voltage without a laptop connected, this LED is provided. The meaning of the different colors is:

 Battery good (voltage higher than 12.0V, fully charged) Battery voltage fair (<12.0V and >10.5V) Battery low (voltage < 10.5 and > 10.0V) shutdown will come soon. The system has shut down and closed all running jobs automatically.

The exact battery voltage and current are also shown on the status display and it is monitored in the log file. If the battery voltage gets low, the ADU will shut-down automatically.

### GPS Antenna¶

The built-in GPS antenna receives the signals from the satellites. It needs to have view to the open sky. In case the built-in antenna is used, the ADU may not be installed in a metal box.

### Binding Posts for Auxiliary Power Supply¶

Here a 9 to 15V power source can be connected in order to power the ADU-08e.

### Button On / Off¶

Pushing this button will start the instrument if connected to a power source. In order to shut down a running instrument press the button for a longer time (5 seconds) until you see the shut-down message in the display. Confirm the shut-down and wait for about 30 seconds until the ADU switches off.

On a running system this button is also used to activate a dark status display.

### Slot for SD card¶

Here an SD card can be inserted. It is used for data storage and can have a size up to 200 GByte presently. The size delivered on standard is 32 GByte.

### Alpha Numerical System Status Display¶

The display shows the status of the system after self-test and many other important parameters and information. The display is switched off automatically after a period of 30 seconds in case no button is pushed. In order to switch it on again you need to press the “On” button (8).

### Battery Connectors¶

The ADU-08e is equipped with 2 battery sockets. You can connect a 12V battery or two batteries in parallel for extended operation time. Before the delivered battery cable can be connected, you have to remove the protection cap of the socket. The input voltage is 12 V nominal; the allowed voltage spans from 10.5V to max. 16V.

The inputs are protected against wrong polarity and over and under voltage. If the ADU should not work, check for wrong polarity or wrong voltage. If the instrument shall be operated without interruption, you may use the second battery input to connect a fresh battery. After having it connected, you may disconnect the old battery from the ADU-08e for recharging. An auxiliary 3rd battery input is provided on the front-panel. Here for instance a small Gel- or Li-Ion battery can be connected in order to provide a continuous power-supply when the system is transported to the next site. It may especially be helpful when the distance between two sites is only a few hundred meters as it could be the case in small scale AMT or RMT surveys.

### Antenna socket for external GPS antenna¶

The ADU comes with a built-in GPS antenna which is sufficient for most cases. We also deliver a second external antenna which may be used in difficult reception situations or when the ADU is housed in a metal case. In this case the cable bridge has to be plug into position EXT.

### Socket for Network¶

The network cable is connected to this socket (RJ45 type).

### USB socket¶

A USB device such as USB key or WLAN key can be connected here.

### E-field connectors for standard and buffered E-field cable¶

These four terminals are used to connect the standard or the buffered E-field cables. The plugs on the E-field cable have 6 pins. The center pin 6 is the pin where the standard E-field cable has to be connected to. In a typical arrangement the ADU is located in the center of the two E-field lines. Plug-in the cable connector in a way that the red dots match on plug and socket and push the plug in until it clicks.

 Socket 6-pole ODU MiniSnap G32KON-T06QP00-000 Pin Signal 1 +12V 2 -12V 3 Sensor GND 4 Sensor GND 5 n.c. 6 Input (+ or -)

Pinning of E-Field socket (front view)

### GND Socket¶

This socket is used to connect the grounding rod or electrode with the ADU. The grounding can be done by a steel rod or an electrode. Grounding should be done closely to the ADU.

Caution

Grounding of the ADU is very important as otherwise the inputs can float and may be saturated.

### Connector for Magnetic Field Sensors¶

On the right side of the ADU-08e you will find 3 sockets (10-pole ODU K-series) to connect the magnetic field sensor cables. Plug-in the cable connector in a way that the red dots match on plug and socket and push the plug in until it clicks.

 Socket 10-pole ODU MiniSnap G32KON-T10QJ00-000 Pin Signal 1 +12V 2 -12V 3 H-Chop 4 Sensor GND 5 Cal Signal+ 6 Cal Signal - 7 Input + 8 Input - 9 $$I^{2}C$$ SDA 10 $$I^{2}C$$ SCL

Pinning of H-Field socket (front view)

## Installation in the Field¶

This chapter describes the setup of the ADU-08e and ADU-08e-2C and of the sensors in the field.

### Definition of Polarities¶

The following polarities are defined in the ADU-08e-2C:

#### E-Fields¶

 EX: NORTH = Plus South = Minus EY: East = Plus West = Minus

When applying a DC voltage to the input terminals of the ADU-08e / ADU-08e-2C as described above, the result will be a positive output on the A/D converter. The time series will show a positive value.

### Standard Setup¶

#### Necessary Components¶

Only a few components are required:

 ADU-08e (9094-0004-05) and /or ADU-08e-2C DataLogger (Metronix Art.No. 9094-0005-02) 4 electric field probes (EFP-06) (Metronix Art.No. 8094-0012) 4 electric field cables (Metronix Art.No. 8094-0040-00) 3 magnetic field cables (Metronix Art.No. 8094-0038-20) (5 channel setup) 3 magnetic sensors MFS or fluxgate / SHFT (5 channel setup) 1 grounding rod + cable or grounding electrode Control computer, mobile phone or tablet computer for system control

#### Placement of Sensors in the Field¶

Typical field setup 2 channels

Typical field setup 5 channels

It is recommended to align the field setup to the north. This means:

• Ground electrode or steel rod should be placed close to the ADU-08e / ADU-08e-2C system.

• Hx is pointing North (cable end South), 5 channel setup with ADU-08

• Hy is pointing East (cable end West), 5 channel setup with ADU-08

• Hz is pointing down (cable end up), 5 channel setup with ADU-08; Hz can be skipped in case (no tipper in this case)

Caution

Swapping the connectors (e.g. North/South for Ex) will invert the recorded time series and finally mess up the measurement results.

Note that this issue can be fixed afterwards by inverting the time series before data processing is done.

Caution

Mixing E-Field channel connectors (e.g. using North/West for Ex and South/East for Ey) will completely mix up the recorded time series.

Such time series cannot be repaired anymore!

Caution

Rotated Setups (sensors not orientated North-South, East-West) can lead to later problems when using third party interpretation software.

#### Set-up of Electrodes¶

In the standard MT field setup the orthogonal electric fields EX and EY are recorded. For the measurement of one electric field component two electrodes (such as EFP-06) are used. They are dug into the soil with a distance of approx. 80 to 100 m. In order to have an optimum common mode rejec­tion of disturbing radio transmitters, the ADU-08e / ADU-08e-2C should be located in the center of the electric field dipoles.

Note

A long(er) dipole gives you some noise-free amplification of the electric field signals.

If an L-shape setup cannot be avoided you should use 4 probes in any case. The electrodes close to the ADU may NOT be connected with the ground electrode because this would induce a higher noise into the electric field inputs.

The exact alignment of the probe’s location must be determined using a compass and a measuring tape. The distance of the N/S and E/W dipole has to be noted and must be entered in the setup menu later on. The probe location can be marked by pickets to find them faster in the field again.

Dig holes of 20 cm to 30 cm depth and plant the probe into the soil after having added some water. Make sure that the bottom of the probe has a good contact with the soil and cover the probes by soil com­pletely. It is important that the soil is pressed down finally in order to obtain a good con­tact. It also may help to improve the ground resistance by mixing a paste of water and soil and planting the probe into that paste.

In case the soil is very dry, the grounding resistance can be diminished using some Ben­tonite which is mixed with soil around the probes and by adding some water. The Bento­nite will keep the moisture for a longer period of time. If you need to do long term measurements in a dry area, the probes should be dug in deeper (>80cm).

The typical probe resistance ranges between a few hundred Ohms up to 10 kOhms. However, it might be much higher in very resistive areas such as deserts and arid areas etc. In this case the use of the optional buffered cables is required especially for higher frequency recordings. Please also make sure that the E-field cables are not positioned too close to the magnetometers (>1m).

Note

If the probes are not used, make sure that the sponge at the bottom of the protection case is wet by water and that its lid is closed. The cap can also be sealed by some adhesive tape if the probe is not used for a longer period of time. The free cable end should be left outside the protection case in order to avoid corrosion on its open end.

Note

The condition of the electrodes can be checked as follows: take a new, fresh electrode and one of the electrodes which are already in use. Put them on a wet cloth or a container filled with some water on its bottom and check the voltage offset between both electrodes. The voltage should be less than 30mV. If it is much higher the old electrode must be replaced.

The cable that comes out of the electrode is connected to the E-Field cable reel.

Finally, the E-Field connector of the cable reel is connected to the E-Field inputs of the ADU-08e / ADU-08e-2C data logger (N, S, E or W).

Note

After some time of usage the cable coming out of the EFP-06 electrode starts to corrode. Make sure to clean the end of the cable before connecting it to the cable roll to make good contact.

Note

Make sure the EFP-06 electrode has good connection to the ground. In very dry areas use Bentonite additionally in order to increase the conductivity between electrode and ground.

Caution

Bad contact between electrode and soil will cause increased noise in your E-Field data. This is most likely detected by big probe resistance values for the E-Field channels during the instrument´s self-test.

Caution

The EFP-06 are Lead/Lead-Chloride electrodes. Take care to wear proper protection gloves or wash hands after handling with it. Do not eat or drink during installation of the EFP-06 electrodes.

Note

Collect electrode waste separately:

The waste electrodes must be collected separately from other (for example municipal) waste and handed over to competent organization for treatment, recycling, etc.

#### Set-up of Grounding Electrode or Steel Rod¶

Place the grounding electrode (or steel rod) close to the ADU-08e / ADU-08e-2C system and connect it to the “Sensor Ground” input of the ADU-08e / ADU-08e-2C system.

Caution

Make sure that the sensor ground has good contact to the earth. Bad contacts for sensor ground may cause floating sensor signals and increased noise inside the time series data.

#### Set-up of Coils¶

By default the coils are connected by a 20m cable; the distance to the ADU-08e is necessary to avoid interference, especially when you work with the ADU and connect a cable or change the battery.

Caution

When you walk beside the coil the soil will vibrate and your measurement is destroyed.
Same applies when using the mobile phone.

Dig a trench at least 30cm deep - oriented North and oriented East; drill a hole as deep as the coil length. The coils must be placed exactly horizontal an vertical (+/- 2 degrees is ok realistically).

Note

Use geographical orientation - not magnetic. Finally you want to plot your data on a map, which are all geographical North orientated.

The MFS coils are not temperature sensitive. The fluxgate is; here you get more stable data if you dig deeper.

Make sure that the cables are not moving in the wind.

Note

The setup spawns a 3D space and all components must be perpendicular.

#### Set-up of GPS Antenna¶

The GPS antenna is connected to the “GPS” input of the ADU-08e / ADU-08e-2C. The antenna itself must be placed somewhere with clear view to the sky and should be protected against strong movement by wind.

Note

If time synchronous data shall be recorded, e.g. for means of remote reference data processing it is most important to provide full GPS synchronisation at any time of the recording.

Note

Note that the ADU-08e / ADU-08e-2C res-syncs to GPS only, if the system is NOT recording data. Therefore make sure that the ADU-08e / ADU-08e-2C is fully synced to GPS before the measurement is started.

When all other components have been installed and connected to the ADU-08e / ADU-08e-2C, the last step is to connect it to a 12V battery. This may be any 12V battery with sufficient capacity (>10Ah). The delivered battery cable is connected to one of the two sockets labeled as „BAT“. Connect the black clamp with the –pole and the red clamp with the +pole of the battery.

Note

A connection with wrong polarity on each of the battery inputs which has been accidentally made will not cause any harm on the instrument.

It will then just simply not start working. After a correct battery connection it will boot up normally.

When the battery has been connected, the ADU-08e / ADU-08e-2C can be switched on by pressing the “Power” button on its front panel.

The ADU-08e / ADU-08e-2C will boot-up and execute the “Self-test” routine. The “Self-test” ends as soon as the “GPS” and “Battery” LEDs on the ADU-08e / ADU-08e-2C Front-panel stop blinking.

#### Connection of The Field Laptop Computer¶

The laptop is connected to the ADU-08e / ADU-08e-2C with a network cable or by a WiFi connection in case a supported WiFi stick is inserted and has been activated. A suitable WiFi stick is delivered along with the instrument. As a network cable you may use any standard Cat5e or better network cable with RJ45 plugs. One end of this cable is connected to the socket labeled „NET“, the other end is connected to the Ethernet socket of the laptop computer.

If the communication is ok and after having entered the proper network address which is written on the sticker inside the front cover into your browser you will be able to contact the ADU-08e / ADU-08e-2C. We recommend to book-mark the ADU´s address in your browser.

Note

Make sure that no Proxy Server is selected in your browser settings! The network parameters of your laptop have to be set in a way that it can access the 192.168.60.xxx network address room for LAN access. The number xxx ranges from 0 to 255 and must be different from the last address number of the ADU.

Please refer to chapter 4.2.8.2 for the necessary setup.

Note

Note that the total length of the network cable between ADU and Laptop may not exceed 100m.

Note

Note that for means of power saving the ADU-08e / ADU-08e-2C will deactivate the WiFi after 15 minutes if no device has been connected. You can reactivate WiFi with help of the power button.

Note

Note that your Laptop needs to have a network interface that is configured to work inside the same network segment as the ADU-08e / ADU-08e-2C system.

As the LAN interface of the ADU-08e / ADU-08e-2C does not provide a DHCP server (it does not configure the network card of your laptop automatically, if being connected), this needs to be done manually.

If you connect via WiFi, the network interface of your Laptop is configured by the ADU-08e / ADU-08e-2C automatically.

A detailed description of how to communicate with the ADU is given in the chapters 5,6 and 7.

#### Manual Configuratioin of LAN Network Interface¶

Example for Windows 10:

 Open the Network Manager and click on “Network Settings” Click on “Ethernet” and afterwards on “Change Adapter Settings” Select the network card that shall connect to the ADU-08e / ADU-08e-2C, right click on the entry and select “Properties” Select TCP/IPv4 and click on “Properties” Select “Manually configure IP address” and configure the IP address to one like 192.168.60.XXX with XXX being different from the one of the ADU-08e / ADU-08e-2C. The ADU number is given on a sticker inside the front panel cover.

Check the connection, using the “ping” Tool:

If successful, the number of lost packets is 0 (0%). If the connection cannot be created the number of lost packets is 4 (100%)

#### Pre-Measurement Checks¶

Once the ADU-08e / ADU-08e-2C has booted up and the self-test has finished (indicated by GPS and Battery LEDs stop blinking), the following checks need to be performed:

• Check on front panel that GPS and STATUS LED are green.

• Check that the Battery LED is also green or at least yellow.

#### Check Self-test Results¶

The self-test results need to be checked, too. In most cases they will be OK. In case of warnings or critical errors the self-test results MUST be checked before the start of the measurement. This can be done in the following ways:

 1.) Check “STR” Button on Main Menu If the buttons colour is green all is OK and the check ends here. If the colour is yellow or red, click on the “STR” Button and continue with 2.). 2.) Check the entries “Severity” and “Message” to find detailed information about the self-test results error.

Web-interface:

 1.) Check status on “Self-test Results” page If it is OK, the checked ends here. If it is Warning or Critical, continue with 2.) 2.) Check the detailed descriptions of the Self-test Results error for each board.

Note

If the Self-test Result is “Warning” the detailed self-test results should be checked. In most cases the measurement can be started.

Caution

If the Self-test Result is “Critical” the reason for the errors MUST be checked and the reason of the problem needs to be fixed before starting any measurements. Otherwise, the system behaviour may be undefined and lead to unusable measurement results.

#### Start Measurement¶

If all checks are OK, the measurement can be started, either via the Mobile App ADUCLIENT (see chapter 6), the Web-interface (see chapter 7) or by a pre-configured USB Mass Storage Device (see Job-listEditor” manual).

During the self-test the required gain- and filter-settings are determined. You should follow these recommendations and use the settings for the recording job. The App ADUCLIENT will always use the determined gain and filter settings. When using the web-interface or the job-list editor you must activate this option (Use Auto-gain/Auto-offset) as described in the corresponding chapters 7.3.1.1 or 7.3.2.7.

## Front Panel Display¶

You can interact with the ADU-08e using the display and the buttons located on the front panel. The display provides 64 characters per line. For navigation you have these keys:

 Function keys F1, F2, F3, F4 The meaning of the keys changes with the context. It is displayed in the last line of the display. Curser keys The curser keys left, right, up, down allow to navigate within the display. Home key Navigates to the Home screen. Back key Skips one menu level back. Enter key Confirms/Selects a menu entry or user input. Power Button The Power Button is used to switch on the Front-panel Display, in case the ADU-08e system is powered on. Long press to the button will open the “Shutdown / Reboot” menu to power off or reboot the system.

### Home Screen¶

You have 8 menu items which can be selected by the curser keys. With the ENTER key you jump into the next menu level. The maximum menu depth is three.

 REC Shows the current recording status which can either be: Idle: no recording active of scheduled Waiting: A job is scheduled in the future and ADU-08e waits for its start-time Recording: A job is currently active and the ADU-08e is recording data GPS Shows the current GPS status (No fix, G1 fix, G2 fix, G3fix, G4fix). The system is only fully synchronized with G4fix status. BAT Shows the current battery status (Supply Voltage and Current drawn from the battery inputs). TMP Shows the current internal system temperature in °C DISK Shows the amount of free disk space on the data SD card

There ar four soft keys that execute the following functions:

 JOBS Enters the “Job Control” submenu that shows detailed information the current job status as well as the ability to stop all / the currently active job. GPS Enters the “GPS” module showing the detailed GPS status as well as providing the ability to reset the GPS (force re-synchronization). SELFT Enters the “Self-test” submenu that gives detailed information about the Self-test results of the system (including all ADB boards). GAINS Enters the “Gains” submenu showing details about the determined AutoGain values.

### Self-test¶

On top of the menu the status of the complete system is shown as follows:

 Overall Status of the complete system (sum of system boards and ADB boards) System Status of system boards, like Main Backplane, Connector Board and GPS Board. ADB Status summary of the ADB boards.

Each one of the Status may be either

 OK All is OK – no problem with the component Warning There is an issue with the board or component – check detailed problem description Critical There is an major problem with the component – detailed problem description MUST be checked and the problem must be solved before continuing the survey.

The softkey BOARD displays detailed results of the self-test for each board showing the status of the ADB boards Self-test result (OK, Warning, Critical), the error number index and finally the detailed error description.

### USB¶

This screen allows you to do operations with the USB devices connected to the ADU.

There are 3 soft keys that execute the following actions:

 EJECT Eject a connected USB mass storage device from the system, making sure that all data is synced (safe remove). CP-TS Copy all the time series data from data SD card to the connected external USB mass storage device. CP-DB Enters the “Self-test” submenu that gives detailed information about the Self-test results of the system (including all ADB boards).

### E-Field¶

The “E-Field” menu shows detailed information about “Probe Resistance” (contact resistance of the E-Field probes to the ground) and the DC-Offset that was measured on the sensor inputs during Self-test.

There are 3 soft keys that execute the following actions:

 DET This will restart the Selfetst Steps that detect the sensors DC offset and probe resistance along with determining best fitting AutoGain values. SPCNG This button will lead into the “Sensor Spacing” submenu that is used to configure the E-Field spacing (see following chapter).

### E-Field Spacing¶

The E-Field Spacing submenu shows the currently configured spacing for the electric fields.

Pressing the “EDIT” button will switch to the edit mode where the spacing can be changed. All changes will become active in Webinterface and Mobile App, too.

### GPS¶

The “GPS” submenu shows detailed information of the GPS, like position, synchronization status to GPS time and current date / time.

There are 2 soft keys that execute the following actions:

 RSTSW This will do a warm-start of the GPS module, just re-synchronising to GPS RSTHW This will do a cold-start of the GPS module, resetting all known Sattelite and Almanach information

Note

In both cases any running measurements are stopped before the GPS reset is done!

### WIFI/NET¶

This submenu gives detailed information about the network connection of the system. It shows IP addresses currently used for LAN and WiFi.

There are 2 soft keys that execute the following actions:

 EDIT This will enter the “Edit” mode to change the IP address settings for LAN and WiFi. Once the updated network settings are saved, they will immediately become active. WIFI This will switch on/off the WiFi. Note that this will only work if an USB WiFi device is connected to the ADU-08e system.

### System¶

This submenu shows the last 10 messages of the ADU-08e System History (log of all executed actions).

There are 4 soft keys that execute the following actions:

 IP This will enter the “WiFi/NET” menu. ← This will scroll to the next System History message. → This will scroll to the prior System History message. CP-DB This will dump the current contents of the ADU-08e system database to disk. It can afterwards be downloaded from “logDBDump”. The dumped database can be send to Metronix for detailed help in case of system problems.

The ADU-08e provides a network file system to easily read recorded measurement data from the system. For this purpose the laptop or mobile device must be connected to the ADU-08e system as described in chapter 4.2.8.1.

Additionally, the measurement data can directly be read from the ADU-08e data SD card that is accessible from the front panel.

Caution

Make sure that the ADU-08e system is powered down before you remove / exchange the data SD card.

Caution

Do not forget to insert an SD card before the ADU is started and a recording shall be made. Otherwise disk space will be very limited as the recorded data would be stored on the internal µSD card.

### Reading data from Windows systems¶

If using a Windows™ operating system follow the following steps to connect to the ADU-08e data directory:

 1.) Open “Explorer”, right click on “This Computer” and afterwards click on “Map Network Drive” 2.) Enter the target IP address and network drive name, e.g. \ \192.168.40.1\data And click on “Finish” 3.) Enter Username and Password Username: aduuser Password: neptun

Now the ADU-08e data directory is directly accessible like a standard Windows network drive in your Explorer.

Hint

Make sure you disconnect the network drive if you disconnect from the ADU-08e system as otherwise the Windows Explorer may show very long time lags as it tries to connect to the non-existing network drive.

Hint

The time series data can be read at any time, even during an active recording.

Caution

Do not move / delete / rename directories or files that are part of the currently active measurement as this will stop the measurement as the ADU-08e is not able to write any data to those files anymore.

### Reading data from Linux systems¶

The easiest way to read data from ADU-08e systems using a Linux Operating System is to mount the ADU-08e data network drive, using the “mount” command:

mount –o username=aduuser,password=neptun //<IP address>/data /<target dir>


As an alternative you may use the standard Linux Explorer (like Dolphin or Konqueror) and directly enter the Samba share name:

smb://aduuser@<IP address>/data


## Transfer Functions¶

### Transfer Function of HF-Channel¶

The theoretical transfer function for the HF-channel is given below:

$$\\F_{HF - Channel} = G_{1} \cdot F_{1} \cdot F_{2} \cdot F_{3} \cdot F_{4}$$

with

$$\\G_{1} = 1$$ or 4, 8, 16 depending on gain setting of first stage

$$\\F_{1} = \frac{1}{1 + P_{1}}$$ ; $$\\P_{1} = i \cdot \frac{f}{338 kHz}$$

$$\\F_{2} = \frac{1}{1 + P_{2}}$$ ; $$\\P_{2} = i \cdot \frac{f \cdot G_{1} }{100 MHz}$$

$$\\F_{3} = \frac{1}{1 + P_{3}}$$ ; $$\\P_{3} = i \cdot \frac{f}{1.59 MHz}$$

$$\\F_{4} = \frac{P_{4}}{1 + P_{4}}$$ ; $$\\P_{4} = i\frac{f}{482 Hz}$$ if high-pass is switched on.

$$\\F_{4} = 1$$ if high-pass is switched off.

(gains and input divider are calibrated in the LSB, you don’t see them)

### Comparison Measured Data and Theoretical Function HF¶

Spectra for non MT usage should be corrected above 20 kHz.

### Comparison Measured Data and Theoretical Function HF with 500 Hz high pass on¶

The small artefact in the measured phase is related to the fact that the signal is suppressed by the filter

Spectra for non MT usage should be always corrected

### Transfer Function of LF-channel¶

The formula for the transfer function of an LF-channel is as follows:

$$\\F_{LF - Channel} = G_{1} \cdot G_{2} (\cdot G_{3}) \cdot F_{1} \cdot F_{2} \cdot F_{3} \cdot F_{4}$$

prefer to set $$\\G_{1}$$ (gain stage 1) ONLY; 4 == excellent, 8 == perfect, 16 not needed, 1 … maybe low

Gains and input divider do not appear in the ats file, they are calibrated into the LSB

$$\\F_{1} = \frac{1}{1 + P_{1}}$$ ; $$\\P_{1} = i\frac{f}{318 kHz}$$

$$\\F_{2} = \frac{1}{1 + P_{2}}$$ ; $$\\P_{2} = i\frac{f }{2 MHz}$$

$$\\F_{3} = \frac{1}{1 + 1.414 \cdot P_{3} + P_{3}^{2}}$$ ; $$\\P_{3} = i \cdot \frac{f}{4Hz}$$ if 4 Hz Low-pass is switched on

$$\\F_{3} = 1$$ if 4 Hz low-pass filter is switched off.

and

$$\\F_{4} = \frac{1}{1 + P_{4}}$$ ; $$\\P_{4} = i \cdot \frac{f}{10.5 kHz}$$ if RF-2 on & DIV-8 = on (default for coil, not used for E)

$$\\F_{4} = \frac{1}{1 + P_{4}}$$ ; $$\\P_{4} = i \cdot \frac{f}{30 kHz}$$ if RF-1 on & DIV-8 = on (not used for E)

$$\\F_{4} = \frac{1}{1 + P_{4}}$$ ; $$\\P_{4} = i \cdot \frac{f}{\frac{0.159}{(R_{sensor} + 200) \cdot 7.27E^{-9}Hz}}$$ if RF-2 on & DIV-1 = on (default for electrodes < 1500 Ohm contact resistance, default for buffer electrodes, not used for H) )

$$\\F_{4} = \frac{1}{1 + P_{4}}$$ ; $$\\P_{4} = i \cdot \frac{f}{\frac{0.159}{(R_{sensor} + 200) \cdot 470E^{-12}Hz}}$$ if RF-1 on & DIV-1 = on ( electrodes > 1500 Ohm contact resistance, not used for H)

### Summary¶

For MT corrections are useless because channels are divided.

Additionally you may use f_sample / 4 as highest interpretation frequency; with the LF Board your are also already in the linear range.

For the HF board @65 kHz you have f_sample / 4 as highest interpretation frequency 16 kHz where the influence is still tiny.

For f_sample 130, 260 and 524 kHz corrections may apply for non MT applications

## Declaration of EU Conformity¶

The ADU-08e complies with all EU standards relevant for this product (see below).

## Terms and Abbreviations¶

WindowsTM is a trademark of “Microsoft Corporation”

LinuxTM is a trademark of “The Linux Foundation”

## Safety Notes¶

The ADU is a data logger for geophysical applications. It digitizes and records data from electric and magnetic field sensors. It may only be used for this purpose. Any usage apart from this application is not covered by this manual and must be avoided.

### Used Symbols¶

Note

Important information and notes.

Caution

Non-observance may result in severe property damages.

Danger

Non-observance may result in property damages and in personal injuries.

 Electric Shock! Risk of electric shock. Grounding Symbol: System needs to be grounded.

### Danger Resulting From Misuse¶

Danger

If the ADU is used during thunderstorms it can happen that a direct lightning strike hits a connection cable especially an electric field cable. This can destroy the system.

If the ADU is operated during such conditions personal injury and even death of the operating person can occur. Operation during thunderstorms is not allowed.

Caution

The ADU corresponds to IP 6 degree of protection as well as pollution degree 5. Make sure that the environment corresponds to this degree of protection and pollution degree (IP65).

Caution

Only use replacement parts and accessories approved by the manufacturer.

Note

The safety rules and regulations of the country in which the device will be operated must be complied with.

Caution

The environment conditions defined in the product documentation must be kept. Safety-critical applications are not allowed, unless specifically approved by the manufacturer.

Note

For notes on installation corresponding to EMC, please refer to chapter 9. The compliance with the limits required by national regulations is the responsibility of the manufacturer of the machine or system.

Caution

The technical data and the connection and installation conditions for the ADU are to be found in this product manual and must be met.

Danger

The general setup and safety regulations for work on power installations (for example DIN, VDE, EN, IEC or other national and international regulations) must be complied with.

Non-compliance may result in death, personal injury or serious property damages.

Note

Without claiming completeness, the following regulations and others apply:

 VDE 0100 Erection of power installations with nominal voltages up to 1000 V EN 60204-1 Safety of machinery - Electrical equipment of machines Part 1: General requirements EN55011:2009 + A1:2010 Industrial, scientific and medical (ISM) radio-frequency equipment – Electromagnetic disturbance characteristics – Limits and methods of measurement. EN61000-4-6-2014 Electromagnetic compatibility (EMC) - Part 4-6: Testing and measurement techniques - Immunity to conducted disturbances, induced by radio-frequency fields (IEC 61000-4-6:2013); German version EN 61000-4-6:2014 EN61000-4-8-2010 Electromagnetic compatibility (EMC) - Part 4-8: Testing and measurement techniques - Power frequency magnetic field immunity test (IEC 61000-4-8:2009); German version EN 61000-4-8:2010 EN ISO 12100 Safety of machinery - General principles for design - Risk assessment and risk reduction

### Safety Notes for Assembly and Maintenance¶

The appropriate DIN, VDE, EN and IEC regulations as well as all national and local safety regulations and rules for the prevention of accidents apply for the assembly and maintenance of the system. The plant engineer or the operator is responsible for compliance with these regulations:

Caution

The ADU must only be operated, maintained and/or repaired by personnel trained and qualified for working on or with the system.

Caution

Prevention of accidents, injuries and/or damages:

• Take care of heavy components, like MFS-06e/07e sensors. Getting hit by these components may cause serious injuries.

• Keep the electrical equipment voltage-free disconnecting the battery and protect it from being switched on, in the case of:

• Maintenance and repair work

• Cleaning

• long machine shutdowns

•  Prior to carrying out maintenance work make sure that the power supply has been turned off and locked, batteries have been disconnected. The external supply battery may push very big currents, if being shorted.
• Be careful during the assembly. During the assembly and also later during operation of the ADU, make sure to prevent from being flooded by water (e.g. during very heavy rain fall). Additionally take care that the maximum ambient temperature of 50°C is not exceeded, e.g. by protecting the ADU against direct impact from the sun.

• Electronic devices are never fail-safe. It is the user’s responsibility, in the case an electrical device fails, to make sure the system is transferred into a secure state.

### Protection against Contact With Electrical Parts¶

The appropriate DIN, VDE, EN and IEC regulations as well as all national and local safety regulations and rules for the prevention of accidents apply for the assembly and maintenance of the system. The survey manager is responsible for compliance with these regulations:

 DANGER! Risk of electric shock! The external supply battery may push very big currents, if being shorted.

### Protection against Electrical Shock By Means Of Protective Extra-low Voltage (PELV)¶

All connections and terminals of the ADU are at a level of +/- 12VDC and therefore are protective extra-low voltage.

It is designed safe from contact in correspondence with the following standards:

• International: IEC 60364-4-41

• European countries within the EU: EN 61800-5-1

Danger

High electrical voltages due to wrong connections must be avoided!

Danger to life, risk of injury due to electrical shock!

Only devices, electrical components and wires with a protective extra low voltage (PELV) may be connected to connectors and terminals with voltages between 0 to 50 Volts.

### Protection against Dangerous Movements¶

Not applicable as the ADU does not contains any moving parts.

### Protection against Contact with Hot/cold Parts¶

Danger

In case the ADU is operated during very hot/cold weather the housing parts of the ADU may get very hot/cold. In this case the risk of injury is given, if the system is touched.

### Protection during Handling and Assembly¶

Handling and assembly of certain parts and components in an unsuitable manner may under adverse conditions cause injuries.

Danger

Risk of injury due to improper handling!

Personal injury due to pinching, shearing, cutting, crushing!

The following general safety notes apply:

Note

• Comply with the general setup and safety regulations on handling and assembly.

• Use suitable assembly and transportation devices.

• Prevent incarcerations and contusions by means of suitable protective measures.

• Use suitable tools only. If specified, use special tools.

• Use lifting devices and tools appropriately.

• If necessary, use suitable protective equipment (for example goggles, protective footwear, protective gloves).

• Do not stand underneath hanging loads.

• Remove leaking liquids on the floor immediately to prevent slipping.

## General Notes¶

In case of damage resulting from non-compliance with the safety notes in this manual, metronix Meßgeräte und Elektronik GmbH will not assume any liability.

Note

Prior to the initial use you must read chapter 1.

If the documentation in the language at hand is not understood accurately, please contact and inform your supplier. Sound and safe operation of the instrument requires proper and professional transportation, storage, mechanical installation, and project planning – with a consideration of the risks as well as the protective and emergency measures – plus the proper and professional electrical installation, operation, and maintenance of the devices. Only trained and qualified personnel is authorised to handle electrical devices and systems:

TRAINED AND QUALIFIED PERSONNEL

in the sense of this product manual or the safety notes on the product itself are persons who are sufficiently familiar with the project, the setup, assembly, commissioning and operation of the product as well as all warnings and precautions as per the instructions in this manual and who are sufficiently qualified in their field of expertise:

• Education and instruction concerning the standards and accident prevention regulations for the application, or authorisation to switch devices/systems on and off and to ground them as per the standards of safety engineering and to efficiently label them as per the job demands.

• Education and instruction as per the standards of safety engineering regarding the maintenance and use of adequate safety equipment.

• First aid training.

The following notes must be read prior to the initial operation of the system to prevent personal injuries and/or property damages:

Note

The following notes must be read prior to the initial operation of the system to prevent personal injuries and/or property damages:

• These safety notes must be complied with at all times.

• Do not try to install or commission the ADU before carefully reading all safety notes contained in this document. These safety instructions and all other user notes must be read prior to any work with the ADU.

• In case you do not have any user notes for the ADU, please contact your sales representative. Immediately demand these documents to be sent to the person responsible for the safe operation of the ADU.

• If you sell, rent and/or otherwise make this device available to others, these safety notes must also be included.

• The user must not open the ADU for safety and warranty reasons.

• Professional site layout and survey planning is a perquisite for sound operation of the ADU!

Danger

Inappropriate handling of the ADU and non-compliance with the warnings as well as inappropriate intervention in the safety features may result in property damage, personal injuries and electric shock.