West Systems Portable diffuse flux meter User manual

Portable diffuse
flux meter
Release 9.1
January 2019

WEST Systems
WEST Systems

Warranty information
Each West Systems instrument is warranted by West Systems Srl to be free from defects
in material and workmanship under normal operating conditions; however, West
Systems's sole obligation under this warranty shall be to repair or replace any part of
the instrument which West Systems 's examination discloses to have been defective in
material or workmanship without charge and only under the following conditions, which
are:
1. The defects are called to the attention of West Systems in writing within one year
after the shipping date of the instrument.
2. The instrument has not been maintained, repaired or altered by anyone who was not
approved by West Systems.
3. The instrument was used in the normal, proper, and ordinary manner and has not
been abused, altered, misused, neglected, involved in an accident or damaged by act
of God or other casualty.
4. The purchaser, whether it is a distributor or direct customer of West Systems or a
distributor's customer, packs and ships or delivers the instrument to West Systems (at
West Systems 's main office in Pontedera (PI) Italy, within 30 days after West Systems
has received written notice of the defect. Unless other arrangements have been made
in writing, transportation to West Systems is at customer expense.
5. No-charge repair parts may be sent at West Systems 's sole discretion to the
purchase for installation by purchaser.
6. West Systems 's liability is limited to repair or replace any part of the instrument
without charge if West Systems 's examination disclosed that part to have been
defective in material or workmanship.
7. Before returning an instrument for repair, the Customer must obtain a Return Goods
Authorization (RGA), writing to [e-mail] and providing information
about part number, serial number and description of the issue. Instructions on
packaging and shipping will be e-mailed back to the Customer. The company-issued
RGA number must be displayed on the return package.
The laws of some locations may not allow the exclusion or limitation on implied
warranties or on incidental or consequential damages, so the limitations here in may
not apply directly. This warranty gives you specific legal rights, and you may already
have other rights which vary from location to location. All warranties that apply, whether
included by this contract or by law, are limited to the time period of this warranty which
is a twelve-month period commencing from the date the instrument is shipped to the
customer.
Responsibility
West shall not be held responsible for any damage to the equipment or for any physical
injury or death resulting in whole or in part from the inappropriate use, installation or
storage of the equipment, which is the result of not complying with the instructions and
warnings, and/or with the standards and regulations in force.
READ THESE INSTRUCTIONS CAREFULLY BEFORE THE FIRST USAGE.
IMPORTANT INFORMATION FOR CORRECT DISPOSAL OF THE
PRODUCT IN ACCORDANCE WITH EC DIRECTIVE 2002/96/EC.
At the end of its working life, the product must not be disposed of as urban
waste. It must be taken to a special local authority differentiated waste
collection centre or to a dealer providing this service. Disposing of a
household appliance separately avoids possible negative consequences for
the environment and health deriving from inappropriate disposal and enables the
constituent materials to be recovered to obtain significant savings in energy and
resources. As a reminder of the need to dispose of household appliances separately, the
product is marked with a crossed-out wheeled dustbin.

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The West Systems fluxmeter complies with the requirement of EU directives.
For conformity information, contact West Systems at
[e-mail].
If your equipment requires maintenance in Italy
Before shipping the instrument back to Italy, remember:
- When you ask your shipping agent to send the instrument to Italy check that on the
Air Waybill the Airport of destination is Pisa. Any other airport of destination creates a
lot of problems in delivering the items (delay, costs, custom problems, etc).
- Check that the Company your shipping agent chooses lands in Galileo Galilei Airport
in Pisa. If not, ask your shipping agent to change the Company or send the items by
DHL or UPS or FedEx
- Mark each item with a serial number, if not already present, and write this number
on the document (proforma or original invoice or item list) where you list the parts
you are sending back to Italy.
- Specify a correct value of the parts you are sending back in the documents
mentioned above. Pay attention to these rules because Custom law in Italy is very
complicated and probably different from your Country.
If you follow these suggestions everything will be easier for you and for us.

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Index
Introduction............................................................................... 7
1.1 Safety information....................................................................... 7
Preliminary operations............................................................... 8
2.1 Content of the package................................................................ 8
2.2 Batteries .................................................................................... 8
2.3 Filters and tubes ......................................................................... 8
2.4 Backpack ................................................................................... 9
2.5 Powering On............................................................................... 9
2.6 Warm up...................................................................................10
2.7 Accumulation chamber................................................................10
2.8 Powering Off..............................................................................10
FluxManager software.............................................................. 11
3.1 Installation................................................................................11
3.2 Bluetooth connection ..................................................................13
3.3 Measurement.............................................................................14
3.4 Saving a measurement ...............................................................16
3.5 Transfer data to a PC..................................................................20
3.6 Map..........................................................................................21
3.7 Preferences ...............................................................................22
Measuring flux ......................................................................... 26
4.1 Theory of operation ....................................................................26
4.2 The measurement ......................................................................28
4.3 Quantifying the flux....................................................................32
Components ............................................................................. 37
5.1 Accumulation chamber................................................................37
5.2 Pump........................................................................................42
5.3 Fluxmeter battery ......................................................................44
5.4 Fluxmeter battery charger...........................................................45
5.5 Backpack ..................................................................................47
5.6 Tubes .......................................................................................47
5.7 Filters .......................................................................................49
5.8 Fittings .....................................................................................49
Calibration of the flux meter .................................................... 50
6.1 Fluxmeter calibration ..................................................................50
6.2 The influence of pumping flow .....................................................51
6.3 Influence of the mixing device rotation speed ................................52
FluxRevision............................................................................. 53
7.1 Report file .................................................................................58
LI-COR Carbon dioxide detector ............................................... 60
8.1 Calibration check........................................................................60
8.2 Calibration ................................................................................61
WS-CH4-TLD Methane Detector................................................ 64
9.1 Detector specifications................................................................65
9.2 Computing flux ..........................................................................67
9.3 Calibration ................................................................................69
WS-TOX-H2S Hydrogen sulfide detector................................... 70
10.1 Calibration..............................................................................72
10.2 Replacing the sensor head........................................................77
10.3 Flux measurement...................................................................79

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WS-VOC Volatile Organic Compounds detector ........................ 83
11.1 Specifications..........................................................................84
11.2 Measuring principle..................................................................85
11.3 Warm-up................................................................................85
11.4 VOC fluxes measurement .........................................................85
11.5 Calibration check.....................................................................86
11.6 Calibration..............................................................................88
11.7 VOC correction factors .............................................................93
References ............................................................................. 102

1 Introduction
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Introduction
1.1 Safety information
Carbon dioxide is a toxic gas. Carbon dioxide is colourless,
odourless, tasteless and is heavier than air. Air concentration
higher than 5000 ppm can cause dizziness, shortness of breath,
rapid pulse. Higher concentrations of carbon dioxide can be
lethal; the short-term exposure limit (STEL) recommended by
NIOSH is 30,000 ppm (3%).
Hydrogen Sulfide is a poisonous gas: air concentration higher
than a few ppm can be lethal; the short-term exposure limit
(STEL) recommended by NIOSH is 10 ppm.
Diffuse carbon dioxide fluxes are normally related to anomalous
carbon dioxide air concentration. The user must verify the safety
conditions before entering dangerous areas using specific and
approved instrumentation.
The flux meter described in this manual is designed to measure
diffuse emission of soil gases and CANNOT be used for different
purposes, especially if related with safety.
The instrument and the electronic accessories are NOT designed
to work in explosion risk areas.

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Preliminary operations
Read carefully the instructions and the recommendations of the following
chapter before proceeding.
2.1 Content of the package
The package content may vary depending on the selected configuration.
When you first open the package, check the items with the packing list which is
attached to the shipping.
2.2 Batteries
The standard package contains 4 batteries:
-N.2 NiMH 14.4 V, 4.5 Ah battery. One is shipped inside the fluxmeter.
One is packed as spare.
-Accumulation chamber battery.
-Smartphone battery. The smartphone is shipped in its original box which
contains the battery charger.
Charge all the batteries before continuing.
In order to preserve the battery life:
-Charge the batteries after each utilization of the fluxmeter.
Do not store the batteries if not fully charged.
-In case of long periods of inactivity: perform a full charge
of the batteries at least every 3 months.
2.3 Filters and tubes
Connect the chamber to the fluxmeter using the provided black/blue twin tubes.
In some cases the colour of the twin tubes can be white/blue.
The tube connected to the chamber filter (by convention black or white) must
be always connected to the inlet port, as shown in the figure of paragraph 5.6.
Before powering on the fluxmeter, check that the pneumatic connections are
correct. An uncorrect or insufficient fitration could cause a damage to the gas
analysers due to dirt entering in the measuring cells.
-The tubes inside the fluxmeter are made of clear plastic. Check visually
the presence of traces of dirt inside the tube. If so, replace them.
-Check that the filter inside the fluxmeter is installed, as first element of
the circuit at the inlet of the case.
-Check that the filter on the chamber is placed and clean. Replace it in
case it show traces of dirt. The filter has a direction, indicated on the
label, that must be respected.
-Check that the pair of tubes that connects the chamber to the fluxmeter
is not swapped.

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2.4 Backpack
Assemble the fluxmeter on the backback and secure it using the provided knob
on the internal side of backpack.
2.5 Powering On
Press and hold for about 2 seconds the On/Off button on the external connection
panel.
The On/Off button is equipped with a LED with the following meaning:
-Solid red: powering on. Hold it until it turns green to switch on he
fluxmeter.
-Solid green: the fluxmeter is on.
-Flashing red/green: low battery charge. Replace the battery.
In order to preserve battery-life, the instrument will turn off automatically after
one hour if not under the control of FluxManager software.
Once powered, the fluxmeter runs the initialization process which takes about
20 seconds. During the initialization the fluxmeter executes a scan of all the
connected sensors. If you add or remove a sensor from the instrument, you
need to restart the fluxmeter in order for the sensor list to be refreshed. When
the initialization is completed, the fluxmeter is ready for connection.
The Bluetooth LED has the following meaning:
-Flashing at 20 Hz frequency: the fluxmeter is during the initialization.
-Flashing at 2 Hz frequency: the Bluetooth is in advertising mode, meaning
that is visible by the smartphone and is ready for connection.
Gas inlet
Gas outlet
On/Off button
Bluetooth LED
RS485 port
RS232 port

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-Solid blue: the Bluetooth is connected. During this phase it is not visible
by other devices.
The pump is managed by the instrument and it won’t turn on until a
measurement is started by FluxManager software.
2.6 Warm up
If your instrument is equipped with a LI-COR LI-830/LI-850 carbon dioxide
analyzer: the sensor is temperature-stabilized in order to reduce the
interferences due to the gas sample temperature.
If the temperature of the sensor is less than 50°C, the signal can suffer of a
thermal drift causing an underestimate or overestimate of the CO2flux.
The FluxManager software will check the sensor temperature and, in case the
value is below 50°C, it will ask the user if he wish to continue. The user can
continue being aware of the previous considerations.
Normally the sensor, after a cold startup, requires about 15-20 minutes to reach
the 50°C temperature.
We advice to switch on the instrument as first operation as you arrive to the
sampling site.
If your instrument is equipped with a WS-TOX-H2S hydrogen sulfide analyzer:
we recommend a 15-20 minutes warm-up with the pump on, to give time to the
sensor to adapt to the pressure variation induced by the pump.
2.7 Accumulation chamber
Turn on the chamber using the switch on the accumulation chamber handle.
This activates the internal Bluetooth making the device discoverable by the
FluxManager app.
2.8 Powering Off
Press the On/Off button on the connection panel.
The LED on the button will become RED immediately, hold the button until the
LED is off.

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FluxManager software
3.1 Installation
West Systems provides the portable fluxmeter with an Android based mobile
device (smartphone / tablet / handheld computer). The Android device is
necessary as interface to the portable fluxmeter to manage the measurement,
display and store the data.
The app is compatible with all devices running Android version 5.1 or higher.
The app FluxManager (as well as Calibra) are
freely available on Google Play Store. The mobile
device comes from West Systems with the app
pre-installed. In case you acquired the mobile
device separately, install the app by opening
Google Play Store from the device and looking
for “Fluxmanager2”.
Click INSTALL to install the app; click OPEN when the installation is completed.
The first time the app is launched (after the installation or after the app data
has been cleared, for example to free up space), it will prompt the user to get
the following permissions:
1. Access to device files. This is necessary to save the measurement files.
2. Access to device location. This is necessary to get the GPS position of the
measurements.
Depending on the Android version, it may be necessary to launch the app a
second time to grant the second permission.

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3.2 Bluetooth connection
There is no need to pair the Bluetooth devices
before launching the FluxManager app.
As you launch the app, FluxManager2
automatically scans for available Bluetooth
devices in range, for 5 seconds.
As soon as one or more portable fluxmeters,
accumulation chambers or soilboxes are
recognized, they are added to the list, showing the
serial number of the instrument and the MAC
address.
Note: a device will be detected only if in
advertising mode (Bluetooth LED blinking once
every 2 seconds).
The accumulation chamber and the soilbox are
immediately in advertising mode as soon as they
are switched on. The portable fluxmeter runs an
initialization which takes about 20 seconds. During
the initialization, the LED blinks at a greater
frequency, twice per second. When the
initialization is completed, the fluxmeter is in
advertising.
In case a Bluetooth device doesn’t appear on the list once the scan operation is
completed, you can repeat it by pressing the Scan button.
On the contrary, if all the expected instruments are on the list, the user can
proceed with pressing the Connect button. It is not necessary to wait for the
scan operation to complete before proceeding to connection.
When the user press the CONNECT button, the app
tries to connect to one device of each category, if
available. If more that one fluxmeters are in the
range, hence recognized by the app, the user will
be prompted to select which one to connect to.
The same applies to chambers and soilboxes. In
any case the app will try to connect to more that
one fluxmeter at the same time.
Once the connection is established, the Bluetooth
device stop advertising (so they will not be visible
to any Blueooth device). The LED passes from the
blinking to steady-on.
The app shows the sensors detected on each
Bluetooth device. In this phase the sensors are
shown all together.
The real-time reading is shown for each sensor
and updated once per second. The system is now
ready for starting a flux measurement.
The Battery information indicates the voltage of
the 14.4 Volts NiMH battery which supplies the
fluxmeter, placed inside the case.

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3.3 Measurement
Press the START button to start the measurement.
The graphical visualization takes place of sensor list.
At this point only one sensor at a time is displayed.
Switching sensor
In case there are more than one sensor with track enabled, only the one in
foreground is shown. Press the NEXT button to switch between the sensors.
Example:
CO2 CH4 H2S
NEXT NEXT
NEXT
Alternatively you can use the up/down volume buttons of the Android device to
browse through the sensors.
The recording remains active for all the sensors regardless of whether or not
the sensor is in fogeround or background, or has the track disabled.
Initially only current reading and the elapsed time are displayed.
Touching the display on the plot will cause the positioning of the left cursor.
Touching the plot a second time will cause the positioning of the right cursor.
Once both cursors are placed, the flux data is visualized in the top panel. It
contains the values of the flux (or the slope, depending on the chosen flux unit)
and the R2regression quality coefficient.
At the same time the regression line is drawn, in red, over the plot.
Sensor in the
foregound
Current
reading of
the sensor
Elapsed time
X axis scale:
seconds
Y axis scale:
unit of
measurement
of the sensor
Sensor plot

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Note: the regression is computed on the points included within the left and right
cursors. All the other points are ignored by the calculation.
The selection of the flux curve interval where to compute the flux is critical and
a wrong selection can cause an error on the estimation of the flux. In the
following pages some examples of the correct interval selection are shown.
To change the interval move the left and right cursors to the desired position.
To move the cursors you have to touch the screen close to the limit you want
to move and drag it to the correct position. The software will move the limit that
is closer to the point you touch on the screen.
Once having selected the interval FluxManager will compute the regression and
the results will be shown as text and as best fit line.
Each flux curve (e.g. CH4, H2S, CO2) has a distinct regression interval, then after
the computation of the regression of one flux curve you have to select, using
the NEXT button, the other gas flux curve and select the appriopriate regression
interval.
Left cursor
Right cursor
Flux data
Regression line

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3.4 Saving a measurement
Normally a flux measurement requires from 90 up to 480 seconds. The sampling
time of a single flux measurement is chosen by the operator on the run.
The time usually depends on the extent of the soil flux. A weak flux will result
in a low R2parameter, forcing the user to go on with the measurement hence
increasing the sampling time.
Once the sampling is completed, press the Stop button to end the acquisition.
The chamber and the pump will continue to run for a number of seconds, usually
30 seconds but it can be overwritten by the user (see cleaning time in the
parameters section).
Note: the H2S and VOC sensors are particularly influenced by pressure
variation. Both turning on and off the pump causes a strong pressure variation
which needs time for the mentioned sensors adapt. For this reason, if the H2S
or VOC sensors are present, once the pump is turned on, it never stops running,
even after the cleaning time.
Press the
NEXT
button to
switch sensor

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Note: if you press the Start button again
without saving, the following screen appears:
Press Continue to discard the measurement
and go on with a new one. Otherwise press
Save to go directly to the saving window.
Once the measure is stopped, you can press the Save button to save the
measurement.
An information summary form appears:
Site: Please enter in this field the name of the
sampling site. This is meant to be a descriptive
name which helps identifying a set of data.
Once the name of the site is inserted the first
time, the application will automatically fill the
field with the last used site name.
Note: the name of the site is used to display the
recorded points on the map. Only the points
related to the most recent site name will be
displayed. Hence changing the name of the site
in the middle of a campaign will result in the
map not showing all the campaign files.
Point: is a numerical index that allows the uset
to identify every point in your map. This field is
automatically increased by the app every time
a file is saved.
Air temperature [°C]: if the accumulation
chamber is connected, the field is automatically
filled with the value recorded by the thermo-
hygrometer placed inside the chamber (average
value of the 1 Hz sampling during the
measurement). If this value is not available, or
if the user prefers to use its own thermometer, he can replace the value. The
final value to then written inside the output file. The value alos is used in the
ppm/sec-moles conversion.

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Barometric pressure [mBar]: if the accumulation chamber is connected, the
field is automatically filled with the value recorded by the barometer placed
inside the chamber (average value of the 1 Hz sampling during the
measurement). If this value is not available, or if the user prefers to use its own
barometer, he can replace the value. The final value to then written inside the
output file. The value is also used in the ppm/sec-moles conversion.
Soil Volumetric Water Content [%]: if a TDR probe is connected, the field
is automatically filled with the value recorded by the probe (average value of
the 1 Hz sampling during the measurement). If this value is not available, or if
the user prefers to use its own sensor, he can replace the value. The final value
to then written inside the output file.
Soil temperature [°C]: if a soil PT100 probe is connected, the field is
automatically filled with the value recorded by the probe (average value of the
1 Hz sampling during the measurement). If this value is not available, or if the
user prefers to use its own sensor, he can replace the value. The final value to
then written inside the output file.
Notes: User sampling note. Feel free to insert any note here, which might help
the postprocessing work (example: “strong wind” or “point near well P7”.
Chamber: Select the accumulation chamber you are using. Tagging the file with
the correct accumulation chamber type is fundamental as the flux is proportional
to the volume/area ratio of the chamber (see chapter 3 for details), and different
types of chamber have different shapes. Choosing an incorrect chamber leads
to an incorrect calculation of the flux from the [ppm/sec] raw data.
If the accumulation chamber is connected, the field is automatically filled with
the corresponding type.
Press the Save button to save the file. Once the save button is pressed, a text
file is generated on the Android device internal memory, in the folder
\FluxManager\data.
The files are store in
\FluxManager\data

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The file name has the following format:
[SITE NAME]_[POINT]_[DATE]_[TIME].txt
The date is in the format YYYYMMDD
The time is in the format HHMMSS
For example: site1_3_20180101_183500.txt
Backup copy
As soon as the user press the Save button, the file is saved in the folder
\FluxManager\data, as previously specified.
At this point a second window appears, to allow the user to save a backup copy
of the file. The purpose of this function is to provide more security to the data,
placing the file on different drive or in remote locations.
The most common locations where to save the backup copy are:
3. SD card. In this case the data is still lost in case of loss or theft of the
smartphone, but is safe in case of damage of the smartphone flash
memory or in case of accidental deletion of the files.
Note: the Android device is not supplied with SD card, it must be inserted
by the user.
4. Google Drive. Drive is the cloud service provided by Google free of cost
for the first 15 GB. This option offerst the maximum security against data
loss since the data is is copied on Google servers.
Note: you need a Google account registered in the smartphone and an
Internet connection (e.g. wifi or mobile data).
In order to save the backup copy on the SD card, you may need to enable it by
pressing on the Show SD card button on the top right corner.

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The backup copy has to be created by the user manually, because the
FluxManager app is not allowed by the Android operating system to write silently
on paths other than the internal memory of the device.
If you are not interested to create a second copy of the file, press back and
you’ll be redirected to the sampling window where you can start the following
measurement.
3.5 Transfer data to a PC
In order to transfer the files to a PC for editing them with FluxRevision software,
connect the Android device using an USB cable.
When the cable is plugged, you should be able to select on the device the MTP
mode.
Once the smartphone is connected, open the file explorer on the PC and navigate
inside the Android device internal memory. You can find the files in the folder:
/FluxManager/data.
Note: depending on the Android version, you might need to
restart the Android device to make all the recorded files visible
through the MTP mode.
SD card
In case the data has been saved also to the SD card, it’s possible to extract the
SD card from the smartphone and insert into a SD card reader connected to the
PC. The files are then available on the PC through external storage.
Google Drive
In case the data has been saved also on Google Drive, it’s possible to just
download them on the PC from the Google servers without connecting the
smartphone to the PC.