Optics11 DELTASENS User manual

DELTASENS
USER MANUAL

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CONTACT INFORMATION
Optics11
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[email protected]
www.optics11.com
VISITING ADDRESS
Optics11
VU University Campus
W&N Building room O-236
De Boelelaan 1081
1081 HV Amsterdam
The Netherlands
SHIPPING ADDRESS
Optics11
De Boelelaan 1081
1081 HV Amsterdam
The Netherlands
COMPANY INFORMATION
Optics11 B.V.
KvK/CC: 52469417
VAT: NL850459734B01
Amsterdam, NL
Please see our website
for more information
about our products

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CONTENTS
Revision history 4
Safety 5
Introduction 6
1. Installation 7
1.1. DeltaSens system overview 7
1.1.1. DeltaSens operating principle 7
1.1.2. Connections 8
1.2. Starting the software 10
1.2.1. Setting the unit IP address 10
1.2.2. Setting the SLD power 12
1.2.3. Define sensors 15
Description of the Software 17
1.3. Home panel 17
1.4. Amplitude Spectral Distribution panel 21
1.5. Additional pop-up windows 23
1.5.1. Sensor select 23
1.5.2. Data logging settings 25
1.5.3. Events 26
1.6. Settings panel 27
1.7. Data Viewer panel 32
2. Technology Principle 34
2.1. Principle of operation 34
2.2. Correction spectra 34
2.3. Internal calibration method 35

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3. Technical specifications 36
REVISION HISTORY
Version 0.1 Created February 1, 2018 A. Sielecki New document
Version 0.2 Updated June 25, 2018 A. Sielecki Update
Version 0.3 Updated July 09, 2018 A. Sielecki Update
Version 0.4 Updated July 12, 2018 A. Sielecki Update
Version 1.0 Updated July 31, 2018 M. Jacobs Released
Version 1.1 Updated March 11, 2019 N. Piva Update
Version 1.2 Updated May 16, 2019 N. Piva Update

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SAFETY
The DeltaSens interrogator is equipped with a class 1M laser device. The infrared laser light is coupled
out via the optical fiber connector on the front panel. Do not stare into the laser beam or view it
directly with optical instruments.
Before applying power to the instrument make sure that the voltage rating displayed next to the fuse
port matches the voltage of your local supply. If not, the installed fuses need to be replaced by the
user.
Except for the mains fuses, there are no user serviceable parts in this product.
All statements regarding safety of operation and technical data in this instruction manual will only
apply when the unit is operated correctly.
The unit is equipped with a cord having an equipment-grounding conductor and grounding plug.
Before applying power to the instrument make sure that the plug is connected into a properly
installed and grounded outlet. Improper grounding can cause electric shock with damages to your
health or even death. The instrument must not be operated in explosion-endangered environments.
Do not remove covers.
Refer servicing to qualified personnel only.
Do not obstruct the ventilation vents of the unit.

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INTRODUCTION
This document describes the DeltaSens system installation and usage. The first section describes
system connections and installation, together with a brief introduction to the software and its first
configuration steps. The second section includes a more detailed description of the software and all
its functionalities. In the third section a brief overview of the capabilities of the system and its working
principle are presented. The last section includes the technical specifications of the instrument.

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1. INSTALLATION
This section describes the installation of the DeltaSens system. It provides an overview of the
DeltaSens elements, wiring scheme and actions required to start up and configure the DeltaSens
interrogator unit.
1.1. DeltaSens system overview
The central element of the DeltaSens system is the interrogator unit. It acquires the optical signal
from the array of sensors, processes it and provides the user with both analog and digital outputs to
analyze it. To configure the interrogator and setup the measurement parameters, the unit needs to
be connected to a computer with the DeltaSens software installed on it.
1.1.1. DeltaSens operating principle
DeltaSens is a stand-alone system that simultaneously interrogates multiple Fabry-Pérot (FP) sensors
connected through an optical fiber network. By using a single read-out to measure multiple
transducers, DeltaSens provides a cost-effective sensing solution without compromising on
performances. The distance between the sensors and the read-out can vary from centimeters up to
several kilometers.
DeltaSens uses interferometry to measure multiple low-finesse Fabry-Pérot sensors, and therefore
provides a reduced cost per sensor while maintaining high sensitivity and acquisition speed. In
combination with Optics11 fiber-top technology, it can support the measurement of a broad range
of physical parameters such as acceleration, pressure or temperature.
Figure 1: General schematic of operation

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1.1.2. Connections
The DeltaSens unit houses an optical fiber connector on the front panel and several electrical
connectors on the rear panel. The front panel connector is a FC/APC socket used to connect the
sensing fiber. To connect multiple sensors to a single interrogator unit, one or more fiber splitters
might be needed depending on the use case. The front and rear panels of the unit are presented in
Figure 2.
The rear panel houses the following connectors:
•Power inlet with fuse port (note that to power the unit with 115 V AC, the fuses must be
changed from 0.8 A to 1.6 A and the fuse holder should be reversed.)
•RJ-45 Ethernet port for computer connection.
•USB type A port for debug connection.
•RS232 port for debug connection.
•8 BNC connectors for analog outputs.
•3 BNC connectors for external clock and trigger.
•DB-9 connector for 4 additional analog outputs.
The device must be connected to the power supply with the provided power cable and to a computer
or LAN with the provided Ethernet cable or equivalent ones.
The sensors can be connected to the front FC/APC port using compatible FC/APC fiber connectors.
Both the interrogator FC/APC port and the sensor FC/APC connectors should be kept as clean as
possible and protected with the provided protective cap when not connected. A periodic cleaning of
the FC/APC connectors is required to ensure proper operation of the system. It is recommended to
use tailored cleaning products such as fiber cleaning cloth spools.

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Figure 2: DeltaSens front and rear panels
The interrogator is a standalone device meaning it can operate without being connected to a
computer. If not connected to a computer, the unit will operate according to the latest configurations
set by the user. Such configurations can be edited only by connecting the unit to a computer with the
DeltaSens software installed on it. The software also allows to control the measurement parameters,
acquire and record signals and analyse them.
Before connecting the interrogator to the computer, please install the accompanying software and
necessary drivers.
To configure the interrogator, connect it to the power supply and to the computer (or your LAN
network) with the provided cables. After turning the device on, it will take it around 1 minute to boot
and load the previous configurations. After booting, the device will start operating according to the
latest configurations set via software by the user. It will acquire the signals and generate the digital
and analog output signals according to the loaded settings. After booting, the device can be
accessed via software to update and edit its configurations.

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1.2.Starting the software
1.2.1. Setting the unit IP address
The device connects with the computer using the Ethernet protocol. It can be connected through
LAN or directly to the operating PC. In both cases the IP address of the device must be looked up
and set in the software to allow remote control of the unit. While booting, the software will look for
the interrogator unit at the latest IP address set by the user. If no unit is found at that address, the “IP
Discovery” tool will appear to help the user identifying the unit IP address (see Figure 3).
Figure 3: IP Discovery tool
•Configured IP –last IP address set by the user.
•Available NICs IP –interface controllers IPs available in the network.
•IP to scan –allows to specify the range of IP addresses to scan to search for the unit.
•Port –port used to try to ping with the unit, should be set to 10002 as default.
•Timeout –how long the software will wait for a response when pinging an IP address.
•Box IP –IP address at which the DeltaSens was found by the “Discovery Tool”.

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Depending on how the unit is connected to the computer, its IP address might be assigned by the
computer itself or by the LAN router:
•If the device is connected through LAN, you can limit the search to the IP addresses of your
local network by setting the “IP to scan” field to 10.0.?.?
•If the device is connected directly to the computer running the DeltaSens software, limit the
search to the internal IP addresses by setting the “IP to scan” field to 169.254.?.?
These are the most common subset of IP addresses to scan and they might vary depending on your
local network settings.
By clicking on “Search” the tool will start scanning the range of IP addresses defined by the “IP to
scan” field. This procedure might take some minutes. If the tool successfully locates the DeltaSens
unit, the “Box IP” indicator will be updated with the discovered IP address. By clicking “OK” the user
can exit the tool and store this address into the software settings and start interfacing with the unit.
The IP address used to communicate with the DeltaSens unit can also be set manually by accessing
the “Dev. Mode” menu of the “Settings” panel. The user can manually enter the IP address and ports
used to communicate with the DeltaSens unit under the “ZeroMQ” submenu (shown in Figure 4). The
default ports are 10002 for cmd and 10003 for data. To save the changes click “Save” before quitting
the menu. The lightning bolt indicator located on the right of the top bar indicates if the software is
correctly interfacing with the DeltaSens unit. The indicator will turn yellow if everything is working
correctly (see Figure 5) and grey in case of communication problems.

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Figure 4: ZeroMQ configuration submenu
Figure 5: Connection lightning bolt indicator
1.2.2.Setting the SLD power
When a new sensor / network of sensors is connected to the unit, the output power of the
Superluminescent Diode (SLD) and the conversion efficiency of the spectrometer must be tuned to
ensure proper functioning of the system. The software integrates a tool to calculate and set the
optimum levels of both these parameters. The Auto-power tool settings can be found under the
“AFE.CTRL” submenu of the “Dev. Mode” menu. Make sure that the Auto-power is enabled as shown
in Figure 6. The default settings are meant to ensure a fast and effective tuning and simplify the unit
setup, refer to following section of these manual for a detailed description of them.
If enabled, the Auto-power tool will run automatically every time the user opens the "Sensors select”
menu of the “Home” panel and clicks “OK”. The “Sensors select” menu allows the user to define the
sensors connected to the unit and edit their parameters to properly decode their signal. Before doing

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this, the Auto-power tool must be run by opening the “Sensors select” menu and clicking OK. A
popup window will appear to show the tuning progress and automatically close when the tuning is
completed.
It is possible to check if the Auto-power tool correctly tuned the SLD power and the spectrometer
conversion efficiency by analysing the live raw-data acquired by the spectrometer. These data can be
displayed by opening the “RAW data” submenu of the “Dev. Mode” and clicking “Time domain”. In
case of proper tuning the raw signal should resemble the one shown in Figure 7. In case of multiple
sensors connected to the unit, the raw-signal could slightly differ from the one here presented.
However, the envelope shape and the maximum value of the signal should be comparable with the
ones of Figure 7.
For experienced users, the SLD output power and the spectrometer conversion efficiency can also be
set manually. To ensure proper operation of the system the user should tune these parameters in
order to achieve a good Signal to Noise Ratio (SNR) while avoiding signal saturation. The following
guidelines can help the user in performing such procedure manually:
•Remember to disable the “Auto-power” tool on the “AFE.CTRL” tab of the “Dev. Mode”
menu before performing the following procedure.
•To display and keep track of the raw signal during the tuning process, open the “RAW data”
submenu of the “Time domain” menu and click “Time domain”.
•On the “Settings”panel the user can control the light output power. Under the “SLD (light
source)” submenu set the source current to 600 mA and click save at the bottom right of the
"Settings” panel.
•Now open the “AFE.CTRL” tab of the “Dev. Mode” to set the conversion efficiency of the
spectrometer. Find the minimum value of conversion efficiency for which the raw signal still
saturates. Remember to click “Save” to update the spectrometer settings.
•Now the SLD source current must be lowered in order to achieve a good signal level and avoid
saturation. The “SLD (light source)” submenu of the “Settings” panel allows to display the
maximum of the raw signal spectrum while tuning the SLD source current. Enable the “Display
max” option to display the level at which the signal is saturating on the “Spectrum max”
indicator.
•Tune down the SLD power in order to reach a “Spectrum max” level of around 80% of the
saturation value. Remember to click “Save” on the bottom right of the “Settings” panel for
changes to take place every time you enter a new SLD source current value.

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Figure 6: AFE.CTRL submenu
Figure 7: Raw time domain signal

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1.2.3.Define sensors
The last step required to start measuring and acquiring data with the DeltaSens system is the
definition of the sensors connected to the unit. To properly demodulate their signals, it is necessary
to define each sensor and set its cavity size on the “Sensors Select” menu of the “Home” panel. If
the interrogator is delivered together with a set of sensors, their settings will be already stored into
the unit. If this is not the case, the following instructions shows how to define manually a set of sensors
and decide what sensors signals the unit should decode. Open the “Sensors select” menu of the
“Home” panel as shown in Figure 8.
•Click “Add” on the bottom left corner of the menu to open the ”Sensor Add” window as
shown in Figure 8 b). This popup window allows to define a new sensor connected to the unit.
•Fill the following fields:
oName –custom name of the sensor.
oSignal –should be set to Relative as default.
oGain –scaling value used to convert the sensor cavity length into the measured
physical quantity. This value can be found in the datasheet accompanying the sensor
and it is assessed during the sensor calibration.
oOffset –should be set to 0 as default.
oPhase IPM –defines range and resolution of the sensor. It should be kept at 0 by
default, more detailed description is provided in section 1.6.
oType –informative description of the sensor.
oUnit –unit of measurement to display in the graphs of the demodulated signal (e.g.
“g” for accelerometers)
•To save the changes and add the new sensor to the list click “OK”. The new sensor will be
now displayed in the list with a default cavity size of 0.
•To decode the signal of the new sensor its cavity size must be set. Double click on the sensor
name to extend the “Sensor select” window as shown in Figure 8 c).
•Each peak of the graph displayed in the extended window corresponds to a sensor connected
to the unit. Refer to the cavity size value provided in the sensor datasheet to locate the peak
corresponding to your sensors.
•To select the sensor cavity size, use the cursor to move the yellow line indicator over this peak
as shown in Figure 8 c). Click “Confirm” at the bottom right of the window to save the changes.
•The thick-boxes on the left of each sensor name, allow the user to select of what sensors the
unit should acquire the signal. To add the new sensor to the acquired ones, thick the
corresponding box.

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•Click “OK” to close the window and save the changes.
Figure 8: Sensor select and Sensor add windows
The sensor signal can be displayed by clicking the “Add graph” button on the right side of the
“Home” panel and by selecting the sensor from the mouse-over menu on the left side of the graph.
A more detailed description of the software and its features is provided in the next section of this
manual.
a)
b)
c)

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DESCRIPTION OF THE SOFTWARE
1.3. Home panel
Figure 9: DeltaSens Home panel
Figure 9 presents the DeltaSens software “Home” panel. On the top bar there are 4 buttons to
browse through the four main panel of the software: Home, Amplitude Spectral Density (ASD), Data
Viewer and Settings. On their left is located a lightning bolt indicator, which lights up in yellow when
the software is properly connected with the DeltaSens interrogator. On the right are located several
action buttons:
-Sensor select –opens a window that allows to define and select sensors, edit their parameters,
and visualize the spectral signal to choose the proper cavity length of each one. It is described
more in detail in section 1.5
-Zero offset –in case of strong solicitation of the sensor (out of the dynamic range) the
DeltaSens decoding system could reinitiate the signal acquisition with an unwanted offset.
This action button allows the user to reset such offset to zero.

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-Logging settings –opens a window that allow the user to set data logging preferences such
as file location and acquisition length. It is described more in detail in section 1.5.
-Record data –allows the user to launch the data acquisition. From the moment this action
button is activated the program will follow the settings specified in the “Logging settings”
menu and record the signals acquired by the unit.
-File name –allows the user to specify a name for the recorded data to save. This name will
be concatenated with a time stamp indicating the date and time of the acquisition.
-Add graph –allows to add a new graph to the Home and ALD panels. The software can display
up to 12 graphs at the same time and each graph can display all the currently demodulated
sensors or part of them depending on the user needs.
-Tile graphs –automatically arranges the currently displayed graphs in a default tile pattern.
-Pause graphs –freeze the graphs to allow the user to zoom and look into the data. This action
button does not stop the signal acquisition and data logging which will continue in
background. By unpausing, the graphs will update to their current state.
-Events –opens the events log window which lists any command sent to the box as well as
warnings and errors. If there is any warning listed in the log flow, the “Event” button will turn
orange and red in case of an error.
Figure 10: Home panel displaying a graph

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Figure 11: Home panel displaying multiple graphs
In Figure 11 is shown a typical use case of the software. The system is acquiring signals from 3 different
sensors and displaying them in three different graphs on the “Home” panel. It is possible to select
what signals to display on a graph by selecting the desired sensors from the mouse-over menu on
the left side of each graph as shown in Figure 13.
When created, the graphs are automatically arranged by the software in a tile pattern (3 x 1 in this
case). On the top right of each graph the user can find several control buttons:
Allows the user to unpin the graph from the Home / ALD panel and to manipulate it.
Allows the user to close a specific graph.
Allows the user to activate the auto-scale of each axis.
Allows to browse the graph data by zooming, panning and rescaling it.
The graph axes range can also be fixed manually by typing the desired maximum value at the end of
the axis scale. In this case the auto-scaling option will turn off automatically.

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The mouse-over menu allows also to apply a filter to the displayed signals. The filtering settings are
located on the bottom of the mouse-over menu and can be set independently for each displayed
signal of each graph. The available settings are:
•Filter topology –allows the user to turn ON and OFF the filtering and to select the optimum
filter band-form.
•Filter type –allows to select the filter type between Low-pass, High-pass, Band-pass, Band-
stop.
•Order –allows to control the filter order. Higher values of filter order will result in a filter
approaching and ideal behaviour.
•Cut-off frequencies –controls the cut-off frequencies of the filter. If the “Filter type” is set to
“High-pass” or “Low-pass” the second frequency control is automatically disabled and
greyed out.
As mentioned before, note that each signal of each graph can be filtered independently. This allows
for example to display at the same time in two different graphs the pristine and the filtered signals of
a specific sensor. When a filter is applied to a sensor, a string indicator “(S fil)” will appear on the right
of the sensor name on the mouse-over menu.
Note that the filters are applied only to the signal displayed by the software. The signals recorded
into files and the analog outputs ones are always pristine signals.