2B Technologies 106-H User manual

Model 106-H Ozone Monitor Manual Rev. C
i
Ozone Monitor
2BTechnologies, Inc.
OPERATION MANUAL
Models 106-H
© Copyright 2011, 2B Technologies, Inc.
All rights reserved.
中国总代理:Nano电子商城
Tel: [phone]
E-mail:[email protected]
http://www.19mro.com

Model 106-H Ozone Monitor Manual Rev. C
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TABLE OF CONTENTS
IDENTIFICATION RECORDS iii
PRINTING HISTORY iv
WARRANTY STATEMENT v
WARNINGS vi
OZONE MONITOR INTRODUCTION 1
SPECIFICATIONS 4
OPERATION 5
MENU 8
MAINTENANCE/TROUBLESHOOTING 19
CALIBRATION 22
LABELLED PARTS 25
PARTS LIST 27
SERVICE LOG 28
APPENDIX A: USB INSTALLATION 30
APPENDIX B: USING THE USB CONNECTION 33

Model 106-H Ozone Monitor Manual Rev. C
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IDENTIFICATION RECORDS
Record the following information for future reference:
Unit serial number: ______________________________________
Warranty start date: _______________________________________
(date of receipt)

Model 106-H Ozone Monitor Manual Rev. C
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PRINTING HISTORY
New editions are complete revisions of the manual and incorporate all previous
update pages and write-in instructions. This manual will be revised as
necessary. Revisions can be in the form of new editions, update pages, or
write-in instructions.
Revision A.............................................................................................April 2010
Revision B...................................................................................September 2010
Revision C....................................................................................December 2011
TRADEMARKS & PATENTS
2B Technologies, 2B Tech, 2Band Ozone Monitorare trademarks of 2B
Technologies, Inc.
CONFIDENTIALITY
The information contained in this manual may be confidential and proprietary, and is the
property of 2B Technologies, Inc. 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, Inc.
© Copyright 2011, 2B Technologies, Inc.
All rights reserved.

Model 106-H Ozone Monitor Manual Rev. C
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WARRANTY STATEMENT
2B Technologies, Inc. warrants its products against defects in materials and
workmanship. 2B Technologies will, at its option, repair or replace products which
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 Periods
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,
Inc.
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/techsupport
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 [e-mail] 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.

Model 106-H Ozone Monitor Manual Rev. C
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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.
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 106-H Ozone Monitor Manual Rev. C
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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,
Inc. 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, Inc., 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,
Inc., 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, Inc., 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, Inc. 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, Inc., USA gelden de veiligheidsvoorzieningen niet meer.

Model 106-H Ozone Monitor Manual Rev. C
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1. OZONE MONITOR INTRODUCTION
The 2B Technologies Model 106-H Ozone Monitor is designed to enable
accurate measurements of ozone over a wide dynamic range extending from
0.01 percent by weight in oxygen (Wt.% O2) to an upper limit of 20 Wt.% O2
based on the well established technique of absorption of ultraviolet light at 254
nm. The Ozone Monitor is light weight (4.5 lb, 2.0 kg) and has low power
consumption (3.6 watt) relative to conventional instruments and is well suited
for applications such as:
Monitoring of ozone generator output
Monitoring of residual ozone after a cleaning or oxidation process
Control of industrial ozone processes
Theory of Operation
Absorption of UV light has long been used for measurements of 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 in ozone process streams
absorb at this wavelength.
Figure 1 is a schematic diagram of the Ozone Monitor. Ozone is measured
based on the attenuation of light passing through a 0.1 cm absorption cell fitted
with sapphire windows. A low-pressure mercury lamp is located on one side of
the absorption cell, and a sample 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. A
beamsplitter and reference photodiode are used to monitor the lamp intensity
without the sample in the beam path. The intensity of light is measured from
the reference photodiode (Io) and from the sample photodiode (I).

Model 106-H Ozone Monitor Manual Rev. C
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Ozone concentration is calculated from the measurements of Ioand Iaccording
to the Beer-Lambert Law:






I
I
l
Co
Oln
1
3

where lis the path length (0.1 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.
When there is no ozone in the cell, a difference in light intensity at the reference
and sample photodiodes can be expected, and it will cause a zero offset in the
readings. This light intensity difference is inherent in the instrument due to the
different properties of the two photodiodes, drift in the angle of the beamsplitter,
contamination in the cell and thermal drift in any of the optical components.
The zero drift has been determined to be less than or equal to 2% of full scale
per month, non-cumulative and can easily be corrected for by using the zero
function described below. The zero drift does not affect the slope calibration
factor in any way, and the instrument does not need to be recalibrated after
performing the zeroing function.
Sample
Photodiode
Hg Lamp
Absorption
Cell
Pressure Relief
and Scrubber
Temperature
Sensor
Sample Inlet
Reference
Photodiode
Beamsplitter
Pressure Sensor
Sample Outlet
Figure 1. Schematic Diagram of the Ozone Monitor.

Model 106-H Ozone Monitor Manual Rev. C
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The pressure and temperature within the absorption cell are measured so that
the ozone concentration can be expressed as a mixing ratio in percent by
volume (vol%). The fraction of the sample that is ozone can then be calculated
and used to determine the ozone concentration in percent by weight in either
air (Wt.% air) or oxygen (Wt.% O2). The instrument displays and records the
cell temperature and pressure in addition to the ozone concentration. The cell
pressure is displayed and logged in units of mbar, torr or psia and the cell
temperature in units of either oC or K.
In principle, the measurement of ozone by UV absorption requires only a zero
calibration to account for the different light intensities at the reference and
sample photodiodes. However, non-linearity of the photodiode response and
electronics can result in a small measurement error. Therefore, each
instrument is compared with a reference ozone monitor calibrated to the
International Ozone Association (IOA) buffered KI method. These results are
used to calibrate the Ozone Monitor with respect to a slope (gain). The
correction for slope is recorded in the instrument Birth Certificate. The slope
parameter is entered into the microprocessor prior to shipment. The user may
change the slope parameter from the front panel if desired. It is recommended
that the instrument be recalibrated at least once every year and preferably
more frequently. The zero may drift due to temperature change or chemical
contamination of the absorption cell. As discussed below, an accurate zero
correction can be measured from time to time using zero gas.

Model 106-H Ozone Monitor Manual Rev. C
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OZONE MONITOR SPECIFICATIONS
Power Requirements.......11-28 V DC, nominally 440 mA at 12 V, 5.3 watt
Dimensions (with case) ...............3.75” x 8.5” x 8.5” (9.5 x 21.6 x 21.6 cm)
Dimensions (OEM version)..................2.5”x 7” x 9” (6.4 x 17.8 x 22.9 cm)
Weight (with case)................................................................ 4.5 lb (2.0 kg)
Weight (OEM version).......................................................... 3.0 lb (1.4 kg)
Precision .........................greater of 0.01 Wt.% O2or 1% of measurement
Accuracy ..........................greater of 0.02 Wt.% O2or 2% of measurement
Zero Drift....................................... 1% of full scale/month, non-cumulative

Model 106-H Ozone Monitor Manual Rev. C
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2. OPERATION
Please read all the following information before attempting to install the Ozone
Monitor. For assistance, please call 2B Technologies at [phone].
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.
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.
Operation of the Ozone Monitor
To operate the Ozone Monitor, connect it to an external power source and
power the instrument by switching the power switch on. The instrument
requires a 12 V DC source, which can be in the range 11-28 V DC without any
detrimental effects on the measurement.
Once turned on, the instrument will display the version number of the software
installed on the microprocessor. After a few seconds, the instrument will start
displaying readings for ozone. 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 first 20-30 minutes required for the lamp, photodiodes,
and internal temperature of the absorption cell to stabilize.
Inlet tubing may be attached to the ¼ inch stainless steel Swagelok fitting on
the back of the instrument. The inlet tubing should be made of PTFE (Teflon),
PFA, FEP, PVDF 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 (preferably
not more than a few feet) to minimize ozone destruction within the inlet tubing.
Tygonand polypropylene (which may look like Teflon) should not be used.

Model 106-H Ozone Monitor Manual Rev. C
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The Ozone Monitor has an internal pressure relief device that protects the
instrument from excessive pressure. The device vents through an ozone
scrubber when the inlet pressure exceeds 50 psi and is not meant to be used in
normal operation. Although the ozone scrubber is made with an ozone
destroying catalyst that has very high ozone capacity, it may not scrub 100% of
the ozone if the flow exceeds several liters per minute. Operators of the
instrument should not rely on the pressure relief device as a pressure
regulating device or expose the instrument to pressures above 50 psi.
Measurement of the Zero Offset
If the instrument has not been used recently, check the zero measurement
before use. The zero offset of the instrument can be measured by first purging
the instrument with zero gas at a minimum flow rate of 0.2 L/min for at least 2
minutes. For an accurate measurement, the instrument must have been turned
on long enough for the internal temperature to stabilize. The observed offset
can be corrected for by running the zeroing function, as described below.
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 (free download from
http://twobtech.com/software.htm). Other terminal emulation software such as
HyperTerminal (a program provided with Windows) or Tera Term Pro may be
used as well.
The ozone concentration, internal cell temperature, cell pressure, reference
photodiode voltage (volts), sample photodiode voltage (volts), time and date
are sent as comma-delimited ASCII text to the serial and USB ports (2400,
4800 or 19200 baud as selected in menu; 8 bits; no parity; 1 stop bit) every two
seconds, 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).
A typical data line would read:

Model 106-H Ozone Monitor Manual Rev. C
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1.03,31.7,835.9,1.28888,0.99086,01/03/10,08:40:55
where:
Ozone = 1.03 Wt.% O2
Cell temperature = 31.7 ˚C
Cell pressure = 835.9 mbar (1 atm = 1013 mbar)
Reference Photodiode voltage = 1.28888 volts
Sample Signal = 0.99086 volts
Date = January 3, 2010
Time = 8:40:55 am
If outputting logged data, the output serial data line will be preceded by the log
number; e.g.,
2893, 1.03,31.7,835.9,1.28888,0.99086,01/03/10,08:40:55
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 106-H Ozone Monitor Manual Rev. C
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Menu
The following diagram summarizes the complete instrument Menu.
Admin
Dat Avg Cfg Lmp
1h10s 5m
Log EndXmt
D/T Cal I/O Unt
D/T: 10:32:21
14/10/2009
Bdr Ext Hrs
T/P
Cfg
V_In V_Out
1m
O3
Main Menu
Zero
Figure 2. Instrument Menu.

Model 106-H Ozone Monitor Manual Rev. C
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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 may be logged in the internal data logger. Up to 32,736
data lines containing log number, ozone concentration, internal temperature,
internal pressure, reference photodiode voltage, sample photodiode voltage,
time and date may be stored in internal memory, corresponding to an
operational time of 3.8 days. Averaging times of 2 s, 1 min, 5 min and 1 hr also
may be selected from the menu, thereby allowing the instrument to operate for
18.2 hours, 22.7 days, 113 days and 3.7 years, respectively, before filling the
memory.
Selecting the Menu
The menu is accessed using the Select button on the front panel of the
instrument. To reach the menu, hold in the Select button until
Menu
is displayed, then release the Select button. After a few seconds the menu will
appear: Menu
Zero Admin 
where Zero and Admin are submenus that may be selected. A blinking cursor
will show across the Zof the Zero submenu. The Select button may be rotated
clockwise or counterclockwise to move the cursor under the first letter of
another submenu. To select a particular submenu, move the cursor under the
first letter of a submenu and momentarily press (“click”) the Select button. To
exit the Main Menu and begin making measurements again, select and click on
the left arrow ().
To Auto-Zero the Instrument
Select and click on Zero to display:
Providing Zero
Air? Yes Cancel
Before continuing, purge the instrument with zero gas at a minimum flow rate of
0.2 L/min for at least 2 minutes and then select Yes.For an accurate

Model 106-H Ozone Monitor Manual Rev. C
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measurement, the instrument must have been turned on long enough for the
internal temperature to stabilize. You will then see the status message:
Zeroing…
When the zeroing function is complete, you will see the status message:
Zeroing…
Found New Zero
The Ozone Monitor will then exit the Menu and return to measuring ozone.
To Log Data
Select and click on Admin, and then on Dat using the Select button. The
display will now show: Dat Menu
Xmt Log End 
To start logging data, rotate the Select switch to move the cursor to Log and
click to select the logging mode. You will then receive the prompt:
Overwrite Data?
No Yes 
Warning: If you start logging, all data previously stored in the logger will
be irretrievably lost. If you have data in the logger that you want to keep, be
sure to download it (see below) before starting logging. Click on Yes if you are
sure you want to start logging new data. This will return you to the Dat Menu.
Click on to return to the main Menu, and click on again to exit the Menu
and start making measurements. Note that “” always takes you up one level
in the menu.
The Ozone Monitor will then alternate every 5 seconds between displaying the
most recent 10-s measurement and the current average value. For example,
the display might read O3= 0.50 Wt.% O2
T=33.3 P=989.7
where the current 10-s measurement is 0.50 Wt.% O2, the temperature is 33.3
oC and the pressure is 989.7 mbar. If 10-second averaging (no averaging) has
been selected, five seconds later, this display might be followed by

Model 106-H Ozone Monitor Manual Rev. C
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O3= 0.50 Wt.% O2
19:55 05/02/2010
showing that the time of the measurement is 7:55 pm and the date is 2 May
2010. If averaging has been selected, the above display will be replaced by
Avg O3= 0.55 Wt.% O2
19:55 05/02/2010
for example, where the most recent average value of ozone computed is 0.55
Wt.% O2.If data are being logged, the log number and number of new
measurements made for the next average (minus 1) are displayed in place of
the data and time; e.g.,
Avg O3= 0.12 Wt.% O2
Log= 193:4
where Avg O3 is the average ozone value most recently written to the logger,
and the current log number is 193. 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 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. 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. Data sets will be
separated by the data interrupt message.
To Stop Logging Data
Hold in the Select button 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 return to the Dat menu to transmit the data to a
computer by clicking on Xmt (see below). 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.

Model 106-H Ozone Monitor Manual Rev. C
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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.
To Average Data
Hold down the Select button to obtain the Menu. Select and click on Admin,
and then on Avg to enter the Avg menu:
Avg Menu
2s 10s 1m 5m 1h 
Use single clicks to move the cursor to 2s, 10s, 1m, 5m or 1h for averaging
times of 2 s, 10 s, 1 min, 5 min or 1 hr averaging, respectively. Then click on
the averaging time you want to use. You will be returned to the main Menu.
To exit the Main Menu and start acquiring data, click on again.
While in averaging mode, the current 10-s measurement is displayed
alternately with the average value at 5-s intervals, as discussed above.
Averaged data may be logged, thereby greatly extending the length of time that
the data logger can be used.
To Transmit Logged Data to a Computer Using the USB or Serial Port
Connect the USB or serial port of the instrument to your computer using the
appropriate cable. Enable a data acquisition program on the computer such as
the 2B Technologies Display and Graphing Software, which can be
downloaded at:
http://twobtech.com/software.htm
Alternatively, HyperTerminal can be used (available on most Windows
platforms, usually in Start/All Programs/Accessories/Communications/Hyper
Terminal) or Terra Term Pro, which can be downloaded at:
http://hp.vector.co.jp/authors/VA002416/teraterm.html
As mentioned earlier, the disadvantage of HyperTerminal is that it has a 500
line buffer limitation, but this limitation can be circumvented by logging the data
to a file as it is transmitted from the Ozone Monitor. The correct settings for
receiving data are: chosen baud rate (2400, 4800 or 19200); 8 bits; no parity; 1
stop bit.

Model 106-H Ozone Monitor Manual Rev. C
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Click the Select button to obtain the Main Menu. Go to the Dat submenu by
clicking on Dat. Next, click on Xmt. The message “Logged Data” will be
written to the serial port, followed by a carriage return and all of the lines of
logged data. After all data are transmitted, the message “End of Logged Data”
and a carriage return are written. After transmission is complete, you can
return to any position in the menu or resume ozone measurements. The
logged data continues to be available for transmission until a new data log is
started.
To Change the Calibration Parameters
The instrument is calibrated at the factory where a slope parameter is entered
into the instrument’s memory. This preset calibration parameter is given in the
instrument’s Birth Certificate and recorded on the calibration sticker on the back
of the instrument. However, the calibration parameters may be changed by the
user. For example, it may be desirable to provide a positive offset by a known
amount (e.g., 0.10 Wt.% O2) if the analog output is being used for external data
logging since the analog voltage output does not go negative below zero Wt.%
O2, and the current output does not go below 4 mA. Because of noise and/or
an inherent offset, some measured values will be below zero at very low ozone
concentrations or while zeroing the instrument with zero gas. Also, the
instrument zero may drift by a few hundredths of 1 Wt.% O2over time. For this
reason, zeroing of the instrument using zero gas to determine the offset is
recommended. Any change in the slope (gain) of the instrument is likely due to
a serious problem such as contamination, but it also can be adjusted. Once the
zero of the instrument is corrected, the slope may be adjusted so that the
instrument readout agrees with the readout from another instrument whose
calibration is considered to be accurate.
To change the calibration parameters, choose the Cfg submenu from the main
Menu and click on Cal to obtain the display
Cal Menu
Z= 0.03 S= 1.012
Here Z is an applied offset (in this case 0.03 Wt.% O2) and S is the slope
applied (in this case 1.012). The value of Z will be 0.00 if you have performed
the auto-zeroing procedure described above. You can provide an offset,
however, by changing the value of Z here. When reporting ozone, the value of
S is multiplied by the measured ozone value and then the value of Z is added.
During calibration, the instrument is first auto-zeroed and checked to make sure
that a reading of zero is obtained with sampling air or oxygen containing no
ozone. The value of S is set to 1.000 and ozone having a know concentration