EPA7600/R-15/119
UNITEC SENS-IT
cience
Citize
Operating Procedure
Office of Research and Development
National Exposure Research Laboratory
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EPA/600/R-15/119 | May 2015 | www.epa.gov/ord
UniTec Sens-It
Citizen Science Operating Procedure
Ron Williams
National Exposure Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Research Triangle Park, NC, USA 27711
Amanda Kaufman
ORISE Participant
Oak Ridge Institute for Science and Education
Oak Ridge, TN, USA 37831
Sam Garvey
Alion Science and Technology
Research Triangle Park, NC 27709
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Contents
UniTec Sens-It 1
What Are VOCs? 1
What You Will Need 1
Data Acquisition System 1
I mportant Considerations 2
Preparing the Device 2
Making the Connections 2
Installing the Software 4
Configuring the Sampling Parameters 4
Routine Data Collection 7
Recording Data 7
Processing Data 8
For Additional Help 9
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UniTec Sens-It
The UniTec Sens-It is a small gas-sensing device that can measure volatile
organic compounds (VOCs). This sensor is used to measure VOCs in
applications such as urban air quality, roadside pollution, and (solid waste)
landfill monitoring. This operating procedure explains what you need to do to
collect high-quality VOC data using the Sens-It for your monitoring project.
What Are VOCs?
VOCs are common pollutants in both indoor and outdoor environments. VOCs are emitted as
gases from many common household and office products including paints, floor wax, cleaning
supplies, cosmetics, pesticides, building materials, home furnishings, copiers and printers,
permanent markers, and glues and adhesives. Automotive fuels are also made up of organic
chemicals, increasing VOC concentrations near roadways and urban areas. All of these
products and sources can release organic compounds during use and sometimes during
storage. These VOC compounds can have both short- and long-term adverse health effects.
What You Will Need
*I* UniTec Sens-It
<* 12 volt (V) power supply
*** Data acquisition (Daq) hardware (see below)—this operating procedure assumes use of
a Personal Daq/55 (lOtech, Inc., Cleveland, OH)
<• Personal computer (PC) system
<* USB (Universal Serial Bus) cable
Data Acquisition System
A data acquisition system measures electrical or physical conditions—such as voltage, current,
temperature, and pressure—and stores the information in digital form for analysis. Typically,
signals from sensors are recorded, converted to digital information, and stored by a computer.
The data acquisition system therefore consists of a sensor, data acquisition and measurement
hardware, and a computer with programmable software. This procedure assumes the use of an
lOtech Personal Daq/55 data acquisition module connected to the UniTec Sens-It and to a PC
running a Windows 95 or higher operating system. By way of example, we have also included
measurements of relative humidity (RH), temperature, and pressure in this procedure. The
Personal Daq/55 uses DaqView software, which you will need to install on the PC before
collecting data. If you are using other data acquisition hardware, procedures should be similar,
but it is recommended that you consult your data acquisition module User's Manual for details of
your specific configuration.
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Important Considerations
*!» The UniTec Sens-It is delivered already calibrated by the manufacturer. However, the
UniTec Sens-It requires semi-annual (twice per year) calibration to function properly.
The unit should be returned to the manufacturer for this service.
*t* According to the manufacturer, the UniTec Sens-It sensor is not designed for indoor use,
and its use indoors could lead to unreliable response and/or loss of calibration.
*I* The UniTec Sens-It is 'powered-on' as soon as it is connected to the power source. To
turn the unit off, simply disconnect it from the power source. The manufacturer
recommends the UniTec Sens-It remain on, once operation begins, to prevent loss of
calibration. If the sensor is left off for more than one day, let it run for 24 - 48 hours to
stabilize.
*J* The manufacturer notes that vapors from silicone rubber, bitumen, and oil-based paint
can interfere with normal sensor operation. Carefully assess the sensor's surrounding
environment before collecting data and consider using protective housings of materials
such as steel or unpainted aluminum.
Preparing the Device
Making the connections
To collect data with the UniTec
Sens-It, you first need to connect
the device to a 12 V DC power
supply and to a data acquisition
module, commonly called a data
logger, which will record the
measurements. This procedure
uses a Daq/55 data logger. The
Daq/55 uses a USB cable for
data collection (Figure 1). A
single cable to a PC provides
high-speed communication and
power to the Daq/55. Use the
four colored wires, shown in
Figure 2, to connect the com-
ponents as shown in Figure 3.
Figure 1
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Gray: data logger
Green: +V out
Brown: +12 V DC power supply
Gray:
data logger
ground
Green:
+Vout
Temperature/
humidity/
pressure
meter
Brown: +12 V
power supply
Figure 3
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Installing the Software
The only software required for monitoring VOCs with the UniTec Sens-It is the Personal
DaqView software that operates the Daq/55 data acquisition module. This software must be
installed on a computer that meets the following requirements:
*J* PC with Pentium® processor and available USB port
»> Microsoft Windows 95, version 4.00.950 b with USB supplement to OSR2.1, at a
minimum (Note: Windows 98 or higher is strongly recommended)
*!* 16 MBytes (Megabytes) of Random Access Memory (RAM) (Note: 32 MBytes or greater
is recommended)
*J* 'Energy Save' mode is disabled
Procedure: Install Software
1. Insert the Personal DaqView software CD into the PC's CD-ROM drive and wait for the
PC to automatically access the CD.
2. Select 'Personal Daq Support' from the Data Acquisition Software Master Setup
screen.
3. Click'Start Install'.
4. When installation is complete, select the "Exit viewing Readme file" radio button for
important information not available elsewhere.
5. Exit the program.
6. Remove the CD.
7. Shutdown the PC.
Configuring the Sampling Parameters
Sampling parameters must be specified in the Personal DaqView software before beginning
data collection. In Windows, double click the 'Personal DaqView' icon to open the software.
Once the program is running, the software will automatically identify the UniTec Sens-It and
bring up the main control window (Figure 4).
File View Acquire Device Joels indicators Help
4
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Procedure: Configure Channels
1. Click the 'Configure Channel Settings' button (<,§;) on the main control window
toolbar, which will open the Channel Configuration window (Figure 5). (Note that the
example also shows settings for humidity, temperature, and pressure.)
2. On the Analog Input tab, set Scale to 1.0 and Offset to 0.0 by double clicking in each
field.
3. Press the Play button ( >) at any time during recording to update the Reading field in
real time with the data from each channel.
Control
> i
Analog Input | Frequency/Pulse Input Digital Input/Output
p, i Usei Labei On H6c
PD1 A01L UniTecSenslT On
PD1 A01H Off
pDi.Aoa. off
PD1.A02H OH
PD1_A03l RH On
PD1.A03H Temp On
PD1_AQ4L Piess On
PD1 A04H Off
PD1 A05L Off
PD1 A05H Off
ding Range Ur
•10.0to10.0 V
•100.010100,0 V
•100 Olo 100.0 V
•250to2SO V
tf Single-ended/ Measi.
Differential Dm
Single-ended 110ms
Single-ended 110ms
Single-ended 110ms
Single-ended 110ms
"Jj™f* Scale Offset
1.0 00
10.0 0.0
10.0 0.0
10.0 00
Procedure: Configure Data Acquisition
1. Click the 'Configure Acquisition' button ((§)) on the main control window toolbar.
2. Select the 'Trigger' tab (Figure 6) and set Source to Immediate using the pull-down
menu.
3. In the Averaging section of the screen, use the pull-down menu to set 'Type' to 'Block
Average' and 'Count' to '32' as shown. This means that averages will be calculated and
recorded for each block of 32 measurements.
4. Set 'Scan Rate' in the 'Acquisition Parameters' section of the same screen to '1.875
sec'. This will result in a text file being updated every minute with an average of 32
immediate measurements taken 1.875 seconds apart.
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5. Under the 'Post-Trigger" tab (Figure 7), use the pull-down menu to set 'Stop On' to
'Duration'. Then set 'Duration' to '1440 Scans'. This will create a text file that stops
updating after 1440, 1-min measurements, or 24 hours.
Configure Ac
Pre-T rigger
J figger || Posl-T rigger
Source: j Immediate
Channel: F
Condition: |Rising
Threshold:
Hysteresis:
Figure 6
Averaging
Type:
Count:
Block Average *\ \32
Acquisition Parameters
Min. Period: 0.858 sec Max. Period: 1500.000 sec
ScanRate: | 1.875 ^j sec
l~~ Continuous Calibration (• Period
^ Overrange Protection : Frequency
J
Cancel
Trigger ! Post-Trigger
Pre-Trigger
Stop On: | Duration
Duration: \
1440 ; Scans
Figure 7
Averaging
Type:
Count:
| Block Average Vj J32 _-J
Acquisition Parameters —
Min. Period: 0.858 sec Max. Period: 1500.000 sec
Scan Rate: f 1.875 "Hfsec
Continuous Calibration
V Overrange Protection
<* Period
1 Frequency
UK. | Cancel
Procedure: Configure Data Destination
1. Click the 'Configure Data Destination' button (®) on the main control toolbar.
2. In the Configure Data Destination window (Figure 8), assign a Folder where you want
the data to be stored.
3. Create a File name to contain the data.
4. Use the 'Auto Rearm' feature to create a sequence of text files so that recording of data
will continue with the creation of a new file after the Stop On duration set in step 5 of
Configure Acquisition has been reached. Each file created using Auto Rearm will have
a number appended to the end of the file name that indicates its position in the
sequence as shown in Figure 8.
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Configure Data Destination
Folder:
| C: \Program Files\pDaqView WpplicationsSDATAWS Cl I \
File'
D265 05-31 -13.BIN
Browse... Conversion Formats
F i Q LJ r6 8
w ^^^^^^^^^^^^^^^H
.
^^^^^^^^^•1
17 Auto Rearm
Starting Index: | 0 ^Tj
S tailing File: D 265 05-31 -1 3_0. B 1 N
Ending File: D265Q5-31-13_99.BIN
li OK il Cancel
Routine Data Collection
Once the data logger is properly connected to the PC and the UniTec Sens-It, the system is
ready to begin collecting data.
Recording Data
The Personal Daq/55 records the signals received from the UniTec Sens-It as voltage (V) in a
text file that can be transferred easily to spreadsheet software for simple processing. The
Daq/55 records time, date, and the output of any sensors connected to it, including VOC
concentration from the UniTec Sens-It, measured in volts, as 1-min averages (Figure 9). The
values for each property (e.g., time, date, etc.) are separated, or 'delimited', by tabs. Any non-
alphanumeric character can be used to separate the values, but the most common delimiters
are the comma, tab, and colon. Most spreadsheet programs are able to read data from a text
file in a delimited format. If you are using a data acquisition module other than the Daq/55,
consult the User's Manual for the delimiter character used by your system to separate data.
Time
13
13
13
13
13
13
13
13
13
13
13
13
13
13
3L3
:19
:20
:21
:22
:23
:24
:25
:26
:27
:28
:29
:30
: 31
:32
^^
:17
:17
:17
:17
:17
:17
:17
:17
:17
:17
:17
:17
:17
:17
^^^^_
Figure 9
Date
4/7/2014
4/7/2014
4/7/2014
4/7/2014
4/7/2014
4/7/2014
4/7/2014
4/7/2014
4/7/2014
4/7/2014
4/7/2014
4/7/2014
4/7/2014
4/7/2014
4/7/2014
4/7/2014
4/7/2014
UniTecSenslT
V
3.
3.
3.
3.
3.
3.
3.
3.
3.
3.
3.
3.
3.
3.
3.
3.
3.
9842416-001
9646816-001
9388296-001
9215066-001
9116176-001
9047386-001
8977466-001
8940536-001
8857996-001
8857276-001
8776906-001
8743706-001
8739676-001
8769126-001
8838636-001
8858106-001
8881316-001
RH
V
4.
5.
4.
4.
4.
4.
4.
4.
4.
4.
5.
5.
5.
4.
5.
5.
5.
9982646+001
0004216+001
9993026+001
9967276+001
9938426+001
9953386+001
9973906+001
9980326+001
9977956+001
9993526+001
0006746+001
0003886+001
0014286+001
9984336+001
0000316+001
0002156+001
0007766+001
Temp
V
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
2.
5376506+001
5375796+001
5378836+001
5392926+001
5398646+001
5388656+001
5378756+001
5378276+001
5377986+001
5365876+001
5362616+001
5358476+001
5356626+001
5362916+001
5355196+001
5356226+001
5350426+001
Pressure
V
5.
5.
5.
5.
5.
5.
5.
5.
5.
5.
5.
5.
5.
5.
5.
5.
5.
7524916-001
7426206-001
7681036-001
7459316-001
7471806-001
7468346-001
7441786-001
7468566-001
7504986-001
7488736-001
7471196-001
7500396-001
7517616-001
7498736-001
7531616-001
7513336-001
7507686-001
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Procedure: Acquire Data
1. In Windows, double click the 'Personal DaqView' software icon to open the software.
2. Using the main control toolbar, ensure all sampling parameters are properly configured
for channel, acquisition, and data destination as described above.
3. Click the record button ( jy) on the toolbar to begin recording data.
Data acquisition will continue until the sequence specified using Auto Rearm is complete.
Processing Data
To process the data collected from the UniTec Sens-It, you will need to transfer the text file
created by the data logger into a spreadsheet. When using the Daq/55, data are stored as tab-
delimited text files that can be imported into a spreadsheet. We have assumed the use of
Microsoft Excel spreadsheet software for this procedure.
Procedure: Process Data
1. Open a new Microsoft Excel
spreadsheet and select Data >
Get External Data > From
Text.
2. When prompted, use Windows
Explorer to navigate to the
folder containing the text file
previously specified in the
'Configure Data Destination'
window.
3. When prompted, in the next
screens select 'Delimited' and
'Tab-delimited'.
4. Press 'Finish' to display the
data in columns in the Excel
spreadsheet (Figure 10).
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DEVELOPER
General
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Number
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UniTecSensIT
V
19:17 4/7/2014
20:17 4/7/2014
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3.98E-01
3.96E-01
3.94E-01
3.92E-01
3.91E-01
3.90E-01
3.90E-01
3.89E-01
3.89E-01
3.89E-01
3.88E-01
3.87E-01
3.87E-01
3.88E-01
3.88E-01
3.89E-01
D
RH
V
5.00E+01
5.00E+01
5.00E+01
5.00E+01
4.99E+01
5.00E+01
5.00E+01
5.00E+01
5.00E+01
5.00E+01
5.00E-I-01
5.00E+01
5.00E+01
5.00E+01
5.00E+01
5.00E+01
E
Temp
V
2.54E+01
2.54E+01
2.54E+01
2.54E+01
2.54E+01
2.54E+01
2.54E+01
2.54E+01
2.54E+01
2.54E+01
2.54E+01
2.54E+01
2.54E+01
2.54E+01
2.54E+01
2.54E+01
F
Pressure
V
5.75E-01
5.74E-01
5.77E-01
5.75E-01
5.75E-01
5.75E-01
5.74E-01
5.75E-01
5.75E-01
5.75E-01
5.75E-01
5.75E-01
5.75E-01
5.75E-01
5.75E-01
5.75E-01
Figure 10
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For Additional Help
Sens-It Installation Guide, UniTec Sri, www.unitec-srl.com, last accessed May 13, 2015.
Personal Daq/50 Series: USB Data Acquisition Modules, User's Manual, lOtech, Inc., 25971
Cannon Road, Cleveland, OH 44146-1833,
http://www.mccdaq.com/PDFs/manuals/personal daqSO series.pdf, last accessed May 13,
2015.
The purpose of this document is to provide general operating guidelines and
the U. S. Environmental Protection Agency (EPA) does not assume any
liability regarding any aspect of its use. Reference herein to any specific
commercial products, process, or service by trade name, trademark,
manufacturer, or otherwise, does not necessarily constitute or imply its
endorsement, recommendation, or favoring by the EPA. The views and
opinions of authors expressed herein do not necessarily state or reflect
those of the EPA, and shall not be used for advertising or product
endorsement purposes. The EPA assumes no liability associated with any
errors in the suggested procedures, errors potentially made by the
instrument in questions, user misuse of the instruments or data collected, or
costs due to any damage the instrument might experience under any
circumstance or use. This user guide is specific to the make/model, and
version number of the instrument identified in the document and is not
generalizable to any other sensor. The users should understand that they
should develop operating guidelines specific to their own research needs
and any general document of this nature would be limited in meeting their
full need.
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x>EPA
United States
Environmental Protection
Agency
PRESORTED STANDARD
POSTAGE & FEES PAID
EPA
PERMIT NO. G-35
Office of Research and Development (8101R)
Washington, DC 20460
Official Business
Penalty for Private Use
$300
"V
Recycled/Recyclable Printed on paper that contains a minimi
50% postconsumer fiber content processed chlorine free
minimum of
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