2B Technologies 202 User manual

Model 202 Ozone Monitor Manual Rev. J-4
i
Ozone Monitor
2BTechnologies
OPERATION MANUAL
Model 202
© Copyright 2001-2018, 2B Technologies
All rights reserved.
Technical Support:
https://twobtech.com/tech-support.html
[email protected]m
[phone]

Model 202 Ozone Monitor Manual Rev. J-4
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Contents
IDENTIFICATION RECORDS iv
PRINTING HISTORY v
WARRANTY STATEMENT vi
WARNINGS viii
1. OZONE MONITOR INTRODUCTION 1
1.1. Theory of Operation................................................................................................................. 1
1.2. Calibration Overview ............................................................................................................... 3
1.3. Use of DewLineto Remove Humidity Interference .............................................................. 3
2. MODEL 202 OZONE MONITOR SPECIFICATIONS 4
3. INSTALLATION AND OPERATION 6
3.1. Shipping Box Contents............................................................................................................ 6
3.2. Installation of the Ozone Monitor............................................................................................. 6
3.3. Measurement of the Zero Offset ............................................................................................. 7
3.4. Collecting Data from the Analog Output.................................................................................. 7
3.5. Collecting Data over the Serial Port in Real Time................................................................... 7
3.6. Data Averaging and Data Logging Using the Menu................................................................ 9
3.7. Menu Definitions and Menu Tree............................................................................................ 9
3.8. Selecting the Menu................................................................................................................ 10
3.9. To Log Data Using the Internal Data Logger ........................................................................ 11
3.10. To Stop Logging Data Using the Internal Data Logger ......................................................... 12
3.11. To Transmit Logged Data to a Computer Using the Serial Port............................................12
3.12. To Log Data Using the SD Card............................................................................................ 13
3.13. To Average Data ...................................................................................................................14
3.14. To Set the Calibration Parameters........................................................................................14
3.15. To Set the Time and Date .....................................................................................................16
3.16. To Change the Output Baud Rate......................................................................................... 16
3.17. To Turn the Analog Inputs On and Off and Change the Analog Output Scaling Factor.......16
3.18. To Turn the Display Light On and Off....................................................................................17
3.19. To Change the Units for Internal Temperature, Pressure, and Ozone.................................17
3.20. To Test the Lamp Voltage and Precision .............................................................................. 18
3.21. To Read the Number of Hours of Ozone Monitor Use..........................................................18
3.22. To Turn the Optional Lamp Heater On and Off.....................................................................18
3.23. To Read Flow Rate on the Display........................................................................................18
4. ACCESSING THE SERIAL MENU 19
5. MAINTENANCE 20
6. CALIBRATION 21
6.1. Introduction............................................................................................................................ 21
6.2. Ozone Standards...................................................................................................................21
6.3. Equipment Required.............................................................................................................. 21
6.4. Instrument Preparation.......................................................................................................... 22

Model 202 Ozone Monitor Manual Rev. J-4
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6.5. Calibration Setup Preparation ............................................................................................... 22
6.5.1. Setup Check.............................................................................................................23
6.5.2. Ozone Loss Test...................................................................................................... 23
6.5.3. Linearity Check.........................................................................................................23
6.5.4. Intercomparison Test ...............................................................................................24
6.6. Calibration Procedure............................................................................................................ 24
6.6.1. Instrument Preparation............................................................................................. 24
6.6.2. Measurement of Zero Air .........................................................................................24
6.6.3. Measurement of Ozone Standards.......................................................................... 24
6.6.4. Calibration Curve .....................................................................................................25
7. PERIODIC ZERO AND SPAN CHECKS 26
8. TROUBLESHOOTING 27
9. LABELED INSTRUMENT PHOTOS 30
10. PARTS LIST 35
11. SERVICE LOG 36
Appendix A: Using the 2B Technologies Display and Graphing Software 38

Model 202 Ozone Monitor Manual Rev. J-4
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IDENTIFICATION RECORDS
Record the following information for future reference:
Unit serial number: ______________________________________
Warranty start date: _______________________________________
(date of receipt)

Model 202 Ozone Monitor Manual Rev. J-4
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PRINTING HISTORY
This manual covers the Model 202 Ozone Monitor used for measurement of
atmospheric ozone over a wide dynamic range extending from a limit of detection of
3.0 parts-per-billion by volume (ppbv) to an upper limit of 250 parts-per-million (ppmv).
New editions of this manual are complete revisions that reflect updates to the
instrument itself, as well as clarifications, additions and other modifications of the text.
Revision C.................................................................................................October 2005
Revision D............................................................................................September 2008
Revision E.................................................................................................October 2009
Revision F ............................................................................................September 2010
Revision G...............................................................................................February 2011
Revision H......................................................................................................April 2015
Revision I (serial number 1858-1899)....................................................November 2016
Revision J (serial number 1900 and above)..............................................January 2017
Revision J-2................................................................................................ April 2018
(Minor revision: Update Section 2 Specifications table to give GPS detail.)
Revision J-3.......................................................................................November 2018
(Minor revision: Update schematic in Section 1; update several links; other minor edits.)
Revision J-4.......................................................................................November 2018
(Minor revision: Add Section 3.23 and modify Section 3.7 to describe flow rate readout function;
other minor edits.)
TRADEMARKS & PATENTS
2B Technologies, 2B Tech, 2Band Ozone Monitorare trademarks of 2B
Technologies.
CONFIDENTIALITY
The information contained in this manual may be confidential and proprietary and is the
property of 2B Technologies. Information disclosed herein shall not be used to
manufacture, construct, or otherwise reproduce the goods disclosed herein. The
information disclosed herein shall not be disclosed to others or made public in any
manner without the expressed written consent of 2B Technologies.
© Copyright 2B Technologies
All rights reserved.

Model 202 Ozone Monitor Manual Rev. J-4
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WARRANTY STATEMENT
2B Technologies warrants its products against defects in materials and workmanship.
2B Technologies will, at its option, repair or replace products that prove to be
defective. The warranty set forth is exclusive and no other warranty, whether written
or oral, is expressed or implied. 2B Technologies specifically disclaims the implied
warranties of merchantability and fitness for a particular purpose.
Warranty Period
The warranty period is one (1) year from date of receipt by the purchaser, but in no
event more than thirteen (13) months from original invoice date from 2B Technologies.
Warranty Service
Warranty Service is provided to customers via web ticket, email and phone support,
Monday - Friday, from 9:00 a.m. to 5:00 p.m., Mountain Time USA. The preferred
method of contacting us is through our web ticketing software at:
www.twobtech.com/tech-support.html
This way all technical staff at 2B Tech will be alerted of your problem and be able to
respond. When you receive an email reply, please click on the Ticket link provided to
continue to communicate with us directly over the internet. The web ticket approach
to customer service allows us to better track your problem and be certain that you get
a timely response. We at 2B Tech pride ourselves on the excellent customer service
we provide.
You may also contact us by email at [email protected] or by phone at
[phone]. In either case, a web ticket will be created, and future
communications with you will be through though that ticket.
Initial support involves trouble-shooting and determination of parts to be shipped from
2B Technologies to the customer in order to return the product to operation within
stated specifications. If such support is not efficient and effective, the product may be
returned to 2B Technologies for repair or replacement. Prior to returning the product,
a Repair Authorization Number (RA) must be obtained from the 2B Technologies
Service Department. We will provide you with a simple Repair Authorization Form to
fill out to return with the instrument.
Shipping
2B Technologies will pay freight charges for replacement or repaired products shipped
to the customer site. Customers shall pay freight charges for all products returning to
2B Technologies.

Model 202 Ozone Monitor Manual Rev. J-4
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Conditions
The foregoing warranty shall not apply to defects resulting from improper or
inadequate maintenance, adjustment, calibration or operation by customer.
Maintenance, adjustment, calibration or operation must be performed in accordance
with instructions stated in the Ozone Monitor manual. Usage of maintenance
materials purchased from suppliers other than 2B Technologies will void this warranty.
Limitation of Remedies and Liability
The remedies provided herein are the Customer's sole and exclusive remedies. In no
event shall 2B Technologies be liable for direct, indirect, special, incidental or
consequential damages (including loss of profits) whether based on contract, tort or
any other legal theory. The Ozone Monitor manual is believed to be accurate at the
time of publication and no responsibility is taken for any errors that may be present. In
no event shall 2B Technologies be liable for incidental or consequential damages in
connection with or arising from the use of the Ozone Monitor manual and its
accompanying related materials. Warranty is valid only for the country designated on
the 2B Technologies quote or invoice.

Model 202 Ozone Monitor Manual Rev. J-4
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WARNINGS
ENGLISH
WARNING:
Any operation requiring access to the inside of the equipment, could result
in injury. To avoid potentially dangerous shock, disconnect from power
supply before opening the equipment.
WARNING:
This symbol, on the instrument indicates that the user should refer to
the manual for operating instructions.
WARNING:
If this instrument is used in a manner not specified by 2B Technologies,
USA, the protection provided by the instrument may be impaired.
ESPAÑOL
ATENCION:
Cualquier operación que requiera acceso al interior del equipo, puede
causar una lesión. Para evitar peligros potenciales, desconectarlo de la
alimentación a red antes de abrir el equipo.
ATENCION:
Este símbolo, en el instrumento indica que el usuario debería
referirse al manual para instrucciones de funcionamiento.
ATENCION:
Si este instrumento se usa de una forma no especificada por 2B
Technologies, USA, puede desactivarse la protección suministrada por el
instrumento.
FRANÇAIS
ATTENTION:
Chaque opération à l’intérieur de l’appareil, peut causer du préjudice. Afin
d’éviter un shock qui pourrait être dangereux, disconnectez l’appareil du
réseau avant de l’ouvrir.
ATTENTION:
Le symbol, indique que l’utilisateur doit consulter le manuel
d’instructions.
ATTENTION:
Si l’instrument n’est pas utilisé suivant les instructions de 2B Technologies,
USA, les dispositions de sécurité de l’appareil ne sont plus valables.
DEUTSCH
WARNHINWEIS:
Vor dem Öffnen des Gerätes Netzstecker ziehen!
WARNHINWEIS:
Dieses, auf dem Gerät weist darauf hin, dab der Anwender zuerst
das entsprechende Kapitel in der Bedienungsanleitung lesen sollte.
WARNHINWEIS:
Wenn das Gerät nicht wie durch die Firma 2B Technologies, USA,
vorgeschrieben und im Handbuch beschrieben betrieben wird, können
die im Gerät eingebauten Schutzvorrichtungen beeinträchtigt werden.
ITALIANO
ATTENZIONE:
Qualsiasi intervento debba essere effettuato sullo strumento può essere
potenzialmente pericoloso a causa della corrente elettrica.
Il cavo di alimentazione deve essere staccato dallo strumento prima della
sua apertura.
ATTENZIONE:
Il simbolo, sullo strumento avverte l’utilizzatore di consultare il
Manuale di Istruzioni alla sezione specifica.
ATTENZIONE:
Se questo strumento viene utilizzato in maniera non conforme alle
specifiche di 2B Technologies, USA, le protezioni di cui esso è dotato
potrebbero essere alterate.
DUTCH
OPGELET:
Iedere handeling binnenin het toestel kan beschadiging veroorzaken.
Om iedere mogelijk gevaarlijke shock te vermijden moet de aansluiting
met het net verbroken worden, vóór het openen van het toestel.
OPGELET:
Het symbool, geeft aan dat de gebruiker de instructies in de
handleiding moet raadplegen.
OPGELET:
Indien het toestel niet gebruikt wordt volgens de richtlijnen van 2B
Technologies, USA gelden de veiligheidsvoorzieningen niet meer.
CHINESE
警告：
任何需要接触设备内部的操作均可能造成人身伤害。为避免可能
的触电危险，请在打开设备前切断电源。
警告：
这个符号 在仪器上表示用户应参考说明书上的操作指南。
警告 :
如果仪器没有按照美国2B科技公司指定方式操作，仪器的保护性
能会减弱。
JAPANESE
警告：
機器の内部で操作する時、怪我できます。危険な衝撃を回避
するために、機器を開ける前に、電源を切断してください。
警告：
機器でこの記号 を見れば、マニュアルを読んでください。
警告：
この機器は2B テクノロジー会社、
USAの指定でしなければ、機器の保護が損なえます。

Model 202 Ozone Monitor Manual Rev. J-4
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1. OZONE MONITOR INTRODUCTION
The 2B Technologies Ozone Monitor™is designed to enable accurate measurements
of atmospheric ozone over a wide dynamic range extending from a limit of detection of
3.0 parts-per-billion by volume (ppbv) to an upper limit of 250 parts-per-million (ppmv)
based on the well-established technique of absorption of ultraviolet light at 254 nm.
The Ozone Monitor™is light weight (5.5 lb, 2.5 kg) and has a low power consumption
(~7.2 watt) relative to conventional instruments and is therefore well suited for
applications such as:
•vertical profiling using balloons, kites, remotely piloted aircraft, and other aircraft
where space and weight are highly limited
•long-term monitoring at remote locations where power is highly limited
•urban arrays of ground-based detectors
•personal exposure monitoring for studies of health effects of air pollutants
1.1. Theory of Operation
Absorption of UV light has long been used for measurements of atmospheric ozone
with high precision and accuracy. The ozone molecule has an absorption maximum
at 254 nm, coincident with the principal emission wavelength of a low-pressure
mercury lamp. Fortunately, few molecules found at significant concentrations in the
atmosphere absorb at this wavelength. However, interferences, such as organic
compounds containing aromatic rings, can occur in highly polluted air. Mercury vapor
can be a significant interference inside buildings where mercury spills have occurred
in the past and in the vicinity of certain mining operations.
Figure 1-1 is a schematic diagram of the ozone monitor. Ozone is measured based
on the attenuation of light passing through a 15-cm long absorption cell fitted with
quartz windows. A low-pressure mercury lamp is located on one side of the
absorption cell, and a photodiode is located on the opposite side of the absorption
cell. The photodiode has a built-in interference filter centered on 254 nm, the principal
wavelength of light emitted by the mercury lamp. An air pump draws sample air into
the instrument at a flow rate of approximately 1 L/min. A solenoid valve switches so
as to alternately send this air directly into the absorption cell or through an ozone
scrubber and then into the absorption cell. The intensity of light at the photodiode is
measured in air that has passed through the ozone scrubber (Io) and air that has not
passed through the scrubber (I). Ozone concentration is calculated from the
measurements of Ioand Iaccording to the Beer-Lambert Law:






=I
I
l
Co
Oln
1
3

(1)

Model 202 Ozone Monitor Manual Rev. J-4
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where lis the path length (15 cm) and  is the absorption cross section for ozone at
254 nm (1.15 x 10-17 cm2molecule-1 or 308 atm-1 cm-1), which is known with an
accuracy of approximately 1%. The 2B Technologies instrument uses the same
absorption cross section (extinction coefficient) as used in other commercial
instruments.
The logarithm of equation 1 is calculated in the microprocessor of the instrument with
sufficient accuracy to provide five orders of dynamic range; ozone mixing ratios are
measured up to 250 ppmv. The shorter path length of the 2B Tech Model 202 Ozone
Monitor also contributes to the wide dynamic range, which is limited at the high end by
the absorption beginning to become optically thick (base 10 optical absorbance = 0.2).
The pressure and temperature within the absorption cell are measured so that the
ozone concentration can be expressed as a volume mixing ratio in ppbv, ppmv, or
pphmv. The mixing ratio can also be expressed as micrograms per cubic meter (µg
m-3) or milligrams by cubic meter (mg m-3). The instrument displays and records the
cell temperature and pressure in addition to the ozone mixing ratio. The cell pressure
is displayed and logged in units of either torr or mbar and the cell temperature in units
of either °C or K.
FIGURE 1-1. Schematic diagram of the ozone instrument.

Model 202 Ozone Monitor Manual Rev. J-4
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1.2. Calibration Overview
In principle, the measurement of ozone by UV absorption requires no external
calibration; it is an absolute method. However, non-linearity of the photodiode
response and electronics can result in a small measurement error. Therefore, each
instrument is compared with a NIST-traceable standard ozone spectrophotometer in
the laboratory over a wide range of ozone mixing ratios. These results are used to
calibrate the Ozone Monitor with respect to an offset and slope (gain or sensitivity).
The corrections for offset and slope are recorded in the instrument Birth Certificate
and on a calibration sticker that can be viewed by removing the top cover of the
instrument. These calibration parameters are entered into the microprocessor prior to
shipment. The user may change the calibration parameters from the front panel or the
serial menu if desired (see Sections 3.14 and 4). The offset may drift due to
temperature change or chemical contamination of the absorption cell. As discussed
below (Section 3.3 and Section 7), an accurate offset correction can be measured
from time to time using the ozone scrubber supplied with the instrument. It is
recommended that the instrument be recalibrated at least once annually and
preferably more frequently. The calibration procedure is described in detail in Section 6.
1.3. Use of DewLineto Remove Humidity Interference
Shown on Figure 1-1 is the DewLine, which serves to make the humidity entering
the detection cell identical during Iand Iomeasurements. Please see our website for
a technical discussion of the DewLine™ and its importance to ozone measurements:
https://www.twobtech.com/dewline.html. Briefly, water vapor adsorbed to the inner
wall of the detection cell changes the reflectivity of the cell. If humidity is not the same
during Iand Iomeasurements, an offset in the ozone measurement will occur and can
be up to several tens of ppb for sudden changes in ambient humidity. The offset will
change with time as the internal ozone scrubber equilibrates with water vapor. Even
for fixed-site ozone monitors, an offset measurement error will occur if the instrument
is zeroed with dry tank air and then used to measure ozone in humid air. The
DewLinesolution to this often-ignored problem is unique to 2B Tech instruments.

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2. MODEL 202 OZONE MONITOR SPECIFICATIONS
Measurement Principle
UV Absorption at 254 nm
Federal Equivalent
Method (FEM)
Yes, EQOA-0410-190
Linear Dynamic Range
0 ppb to 250 ppm
Resolution
0.1 ppb
Precision (1σ; rms noise)
Greater of 1.5 ppb or 2% of reading
(in 10-s measurement mode)
Limit of Detection (2σ)
3.0 ppb
(in 10-s measurement mode)
Accuracy
Greater of 1.5 ppb or 2% of reading
NIST-Traceable
Calibration
Yes
Measurement Interval
10 s (Data averaging options: 1 min, 5 min, 1 hr)
Flow Rate (nominal)
~1 Liter/min
Flow Rate Requirement
>0.6 L/min
Baseline Drift
<2 ppb/day
<5 ppb/year
Sensitivity Drift
<1%/day
<3%/year
Measurement Time,
Frequency
10 s, 0.1 Hz
Response Time, 100% of
Step Change
20 s, 2 points
Averaging Times
1 min, 5 min, 1 hr
Ozone Units
ppb, pphm, ppm, µg m-3, mg m-3
Pressure Units
mbar, torr
Temperature Units
°C, K
T and P Corrected
Yes
Operating Temperature
Range
0 to 50°C standard; optional -20 to 50°C with low
temperature modifications (pump and lamp heater cold-
weather package)

Model 202 Ozone Monitor Manual Rev. J-4
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Operating Altitude Range
~0-13.5 km (150-1,013 mbar) standard; optional ~0-25 km
(30-1,013 mbar) with upgraded pressure sensor
Power Requirement;
Supplied by battery or
110/220 VAC Power Pack
11-14 V DC or 120/240 VAC, nominally 600 mA at 12 V,
7.2 watt (6.2 watt with cell heater unplugged)
Size
3.7 × 8.5 × 11.8 inches (9.5 × 21.5 × 30 cm)
Weight
5.5 lb (2.5 kg); 2.8 lb (1.3 kg) without instrument case
Internal Data Logger
Capacity
16,383 lines (10-s meas. = 1.9 days; 1-min avg = 11 days;
5-min avg = 1.9 mo; 1-hr avg = 1.9 yr)
SD Card Logger Capacity
Minimum 2 GB (> 5-year capacity for 10-s measurement
mode)
Analog Inputs for Internal
Logging of Other
Instruments
3 Analog Inputs, 0-2.5 V (for example, could log external T,
P, and RH)
Data Outputs
RS232, 0-2.5 V Analog, LCD Display; External USB
Converter (Optional 4-20 mA current; request quote)
Data Transfer Baud
Rates
2400, 4800, 19200
Output Ranges
User-Defined Scaling Factor in Menu
DewLine™
Yes
Flow Meter
Yes
Options
Battery; External Particle Filter, Serial-to-USB Converter;
Bluetooth; 4-20 mA Current Output; GPS (for 10-s data
mode and above); Cold-Weather Package (pump, lamp
heater); High-Altitude Upgrade (pressure sensor); Extra-
Long-Life, Low-Temperature Internal Air Pump; Rack-
Mount Case
Upgradable to Model 205
Dual Beam
Yes

Model 202 Ozone Monitor Manual Rev. J-4
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3. INSTALLATION AND OPERATION
Please read all the following information before attempting to install the Ozone
Monitor. For assistance, please call 2B Technologies at [phone].
PLEASE NOTE:
•Save the shipping carton and packing materials that came with the Ozone Monitor.
•If the Ozone Monitor must be returned to the factory, pack it in the original carton.
•Any repairs as a result of damage incurred during shipping will be charged.
3.1. Shipping Box Contents
Open the shipping box and verify that it contains all of the items on the shipping list. If
anything is missing or obviously damaged, contact 2B Technologies immediately.
3.2. Installation of the Ozone Monitor
To operate the Ozone Monitor, connect it to an external power source and turn the
instrument on by flipping the front panel switch. The instrument requires a 12 V DC
source which can be supplied by: 1) the 110-220 V AC power adapter, 2) a cigarette
lighter adapter plugged into a 12 V DC source such as found in an automobile or
many light aircraft, or 3) a 12 V battery. The source can be in the range 11-14 V DC
without any detrimental effects on the measurement. When using a battery, be certain
to attach the positive (red) and negative (black) wires correctly. A circuit breaker and
diode are installed on the circuit board in case of an electrical short or incorrect battery
attachment. If activated, the breaker will reset itself after a few minutes.
Lead-acid batteries are available from numerous manufacturers in a wide range of
sizes and amp-hour ratings. The larger of these, such as those for automobiles or
boats, will supply power for up to several days. Battery packs in the correct voltage
range may be constructed from nickel-cadmium (rechargeable) or lithium (lightweight
but not rechargeable) batteries for operation for a few hours. Battery options available
through 2B Technologies may be found on our webpage: www.twobtech.com.
Once turned on, the instrument will display the version number of the software
installed on the microprocessor followed by a display of the time and date. After a few
seconds, the instrument will start displaying readings for ozone and the temperature
and pressure of the absorption cell. The first dozen readings (requiring about two
minutes) will be spurious, with large positive and negative swings, due to the rapid
warmup of the lamp and electronics. Also, ozone readings may be inaccurate during
the 10-20 minutes required for the lamp, photodiode, and internal temperature of the
absorption cell to stabilize.

Model 202 Ozone Monitor Manual Rev. J-4
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Inlet tubing may be attached to the ¼ inch nylon Swagelok fitting on the back of the
instrument. The inlet tubing should be made of PTFE (Teflon), PFA, or some other
inert material that does not destroy ozone and that does not desorb plasticizers and
other organics that can contaminate the flow path. The length of tubing should be
kept as short as possible (not more than a few feet) to minimize ozone destruction.
Tygon, polypropylene (which may look like Teflon), and metal tubing should not be
used. Teflon-lined Tygontubing, which is used inside the 2B Technologies
instrument, provides the flexibility of Tygonwith the inertness of Teflon. A Teflon
inlet filter is highly recommended to prevent internal contamination of the tubing and
absorption cell by particulate matter. The filter should be tested for ozone loss by
measuring ambient ozone with and without the filter attached. Tubing, filters, and filter
holders are available through 2B Technologies. See our website: www.twobtech.com.
If the instrument is being flown, the inlet should not point into the wind, because the
resulting pressure fluctuations will result in a noisy signal. Although the instrument
compensates for temperature drift, if strong temperature fluctuations are expected, as
in vertical profiling applications using balloons, the instrument should be placed in a
thermally insulated box
3.3. Measurement of the Zero Offset
The electronic zero of the instrument may be measured by attaching an ozone
destruction cartridge to the air inlet for a period of 5-10 minutes (see Section 7 of this
manual). For an accurate measurement, the instrument must have been turned on
long enough for the internal temperature to stabilize. The observed offset, which can
amount to a few ppbv, can be corrected by changing this calibration parameter from
the front panel, as described below, or by correcting the data at a later time.
3.4. Collecting Data from the Analog Output
The data may be logged in real time using a data logger attached to the BNC analog
output. The range of the analog output is 0-2.5 V. The output is scaled according to a
sensitivity you define in the menu. For example, you may define 1V = 100 ppbv. In
that case, the maximum output is 250 ppbv. There is a small positive offset, typically
2 mV in the analog output, but this offset varies from instrument to instrument. The
offset can be measured by simultaneously observing the panel display and measuring
the analog output with a voltmeter.
3.5. Collecting Data over the Serial Port in Real Time
To transmit data to a computer over the serial port in real time, connect the Ozone
Monitor to the serial port of the computer using the 9-pin cable provided. Note that
this is a “straight-through” female-female serial cable. A “cross-over” cable will not
work. Start your data acquisition software, preferably using the 2B Technologies
Display and Graphing Software (available as a free download from the 2B Tech
website, https://www.twobtech.com/downloads.html). See Appendix A of this manual
for information about working with this software. Other terminal emulation software

Model 202 Ozone Monitor Manual Rev. J-4
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such as HyperTerminal (a program provided with earlier versions of Windows) or Tera
Term may be used as well.
The ozone mixing ratio (ppbv), internal cell temperature (K or °C), cell pressure (torr or
mbar), volumetric flow rate (cc/min), values of three external analog inputs in volts (if
activated from the menu), date, and time are sent as comma-delimited ASCII text to
the serial port (2400, 4800 or 19,200 baud; 8 bits; no parity; 1 stop bit) every ten
seconds, 1 minute, 5 minutes, or 1 hour, depending on the averaging time selected
from the microprocessor menu. Time is provided in 24-hour (military) format, and the
date is given in European style (day/month/year).
With analog inputs activated from the menu, a typical data line might read:
67.4,35.3,980.6,850,1.3876,2.3143,0.1875,15/10/18,18:31:27
where:
Ozone = 67.4 ppbv
Cell temperature = 35.3°C (may be expressed in K if chosen from menu)
Cell pressure = 980.6 mbar (may be expressed in torr if chosen from menu)
Volumetric flow rate = 850 cc/min
Analog input A = 1.3876 volts
Analog input B = 2.3143 volts
Analog input C = 0.1875 volts
Date = October 15, 2018
Time = 6:31:27 pm
The three external inputs are omitted from the data line if they are turned off using the
menu, as described in Section 3.17 below. The analog inputs allow measurements
made by other instruments to be transmitted to a computer simultaneously with those
of ozone and the time and date stamp; these inputs may also be logged in the
instrument’s internal memory, as described below. Examples of external
measurements that are commonly made along with ozone are external temperature,
pressure, and relative humidity, but the outputs of any instrument may be input to the
Ozone Monitor. The analog inputs may range from 0 to +2.5000 volts and are
measured with an accuracy of approximately 0.0001 volt. Caution: An input voltage
greater than +5.0 volts or less than –0.3 volts may permanently damage the instrument.
If the Ozone Monitor has been set to the “log data”mode, the output serial data line
will be preceded by the log number; e.g.,
2893,67.4,35.3,980.6,850,1.3876,2.3143,0.1875,15/10/18,18:31:27
where 2893 is the log number.
In addition to data lines, messages are written to the serial port when logging is begun
or ended, when transmission of data from the logger is begun and ended, when data
collection is interrupted (e.g., due to a power failure), and when the averaging time is
changed.

Model 202 Ozone Monitor Manual Rev. J-4
9
3.6. Data Averaging and Data Logging Using the Menu
When first turned on, the instrument will start making measurements at a rate of once
every 10 s. Data, along with up to three external voltages, may be logged in the
internal data logger. Up to 16,383 data lines containing log number, ozone mixing
ratio, internal temperature, internal pressure, volumetric flow rate, date, and time may
be stored in internal memory, corresponding to an operational time of 1.9 days.
Averaging times of 1 min, 5 min, and 1 hr also may be selected from the menu,
thereby allowing the instrument to operate for 1.6 weeks, 1.9 months and 1.9 years,
respectively, before filling the memory. The maximum number of data lines is halved
if the three analog inputs are logged along with the other data.
3.7. Menu Definitions and Menu Tree
The Menu is accessible from the LCD display of the Model 202 Ozone Monitor. Menu
options are defined in the table below and shown in the drawing on the next page.
Dat: Data Menu
Xmt: Transmit stored logged data
End: End data logging
Log: Start data logging and write over existing logged data
SD:Transmit data to SD data logger
Avg: Averaging Menu
10s: 10 seconds, 1m: 1 minute, 5m: 5 minute, 1h: 1 hour
Cfg: Configurations Menu
D/T: Date and Time Setting
Cal: Calibration Menu
Fm: Flow Meter calibration menu
O3: Ozone measurement calibration menu
I/O: Input and Output Menu
Bdr: Baud Rate selection menu
Ext: External input and output menu
V_In: Voltage Input menu
V_Out: Voltage Output menu
Hrs: Display number of hours of use
LCD: LCD back light menu
Unt: Units menu
T/P: Temperature and Pressure units selection
O3: Ozone units selection
Lmp: Lamp test selection
__________
Note: Rotating the Select Switch while making measurements will momentarily
display the instrument’s flow rate on the screen.

Model 202 Ozone Monitor Manual Rev. J-4
10
Main Menu
Dat Avg Lmp
1h
10s 5m
End LogXmt
D/T Cal I/O Unt
D/T: 10:32:21
14/10/2018 Fm O3
Bdr Ext Lcd
Cfg
V_In V_Out
1m
Hrs
SD
T/P O3
3.8. Selecting the Menu
The Main Menu is accessed using the Select button on the front panel of the
instrument. To reach the menu, hold in the Select button until the display shows: Menu
Then, release the button. The panel will now display:
Menu
Dat Avg Cfg Lmp 
where Dat, Avg, Cfg, and Lmp are submenus that may be selected. A blinking
cursor will show across the Dof the Dat submenu. The Select button may be rotated

Model 202 Ozone Monitor Manual Rev. J-4
11
clockwise or counterclockwise to move the cursor under the first letter of one of the
other submenus. To select a particular submenu, move the cursor under the first
letter of the submenu and click (press in) the Select button. To exit the Main Menu
and begin making measurements again, select and click on the right arrow ().
3.9. To Log Data Using the Internal Data Logger
Select the Dat submenu from the Main Menu using the Select button. The display will
now show: Data Menu
Xmt Log End SD 
To start logging data using the internal data logger, rotate the Select switch to move
the cursor to Log and click to select the logging mode. You will then be asked
whether you want to overwrite the data stored in the logger:
Overwrite Data?
No Yes 
If you select yes and start logging, all data previously stored in the logger will be
irretrievably lost.
Caution: If you have data in the logger that you want to keep, be sure to download it
before starting logging.
If you are ready to start logging, then select Yes by moving the cursor under Yes and
clicking. Either selection will return you to the Main Menu. To start data acquisition,
select and click.
The Ozone Monitor will then alternately display every five seconds: 1) the ozone
measurement and log number and 2) the ozone measurement, internal temperature,
and internal pressure. For example, the display might read:
O3= 56.7 ppb
T=305.6 P=730.4
where the ozone value is the most current ozone measurement, and T and P are the
cell temperature and pressure (in units of K and torr, in this case). After 5 seconds
(midway between the next 10-s measurement cycle), the display will be replaced by:
O3= 56.7 ppb
Log= 193:0
where O3 is the ozone value most recently written to the logger, and the log number is
193.
If averaging has been selected (see To Average Data, Section 3.13), then the above
display will be replaced by:
Avg O3=56.7 ppb
Log= 193:4

Model 202 Ozone Monitor Manual Rev. J-4
12
Again 193 refers to the most recent log number. The “4” in 193:4 refers to the number
of 10-s data points that have been measured so far for inclusion in the next average to
be displayed and logged. If 10-s averaging is used (i.e., no averaging), this number
will always be 0. If 1-min averaging is used, this number will increment from 0 to 5; for
5-min averaging, the number will increment from 0 to 29; and for 1-hr averaging, it will
increment from 0 to 359. This number is displayed so that the user will know how
many more 10-s measurements need to be made before a new average is displayed
and logged.
If there is a power failure while the instrument is in the logging mode, logging will
resume after power is restored. A note of
Data Interruption
will be written to the logger prior to writing the first new data line. In the case of a
power failure, 1 data line may be lost.
The instrument can accommodate multiple data interruptions due to power failures.
For example, one can purposely switch the instrument off, move to another location
and restart logging simply by turning the instrument back on and the data will be
logged with the correct date and time.
3.10. To Stop Logging Data Using the Internal Data Logger
Hold the Select button down to obtain the Menu. Go to the Dat submenu by clicking
on Dat. Choose and click on the End function. This will end data logging. You may
now transmit the data to a computer by clicking on Xmt (see below). Alternatively,
you may return to the Menu by clicking on . The stored data will reside in memory
(even when new measurements are being made) and can be transmitted using the
Xmt function as often as you like. However, all stored data are lost once logging is
started again using the Log function. Thus, you should always transmit your data to a
computer before restarting logging.
If you fail to End logging prior to transmitting the data using the Xmt function, the
instrument will automatically execute the End function for you prior to transmitting the
data.
3.11. To Transmit Logged Data to a Computer Using the Serial Port
Connect the serial port of the instrument to the serial port of your computer using the
cable provided. If your computer does not have a serial port, you can use the USB
port by means of a serial-to-USB adapter. Such adapters are available in most
computer stores or can be supplied by 2B Tech.
Start your data acquisition software, such as the 2B Technologies Display and
Graphing Software, which is available for free download from 2B Tech’s website,
https://www.twobtech.com/downloads.html. See Appendix A of this manual for
information about working with this software.