2B Technologies Model 408 User manual

Model 408 NO Calibration Source Manual Rev. D-3
i
Nitric Oxide Calibration Source
2BTechnologies
OPERATION MANUAL
Model 408
© Copyright 2018, 2B Technologies
All rights reserved.
Technical Support:
https://twobtech.com/tech-support.html
[email protected]
[phone]

Model 408 NO Calibration Source Manual Rev. D-3
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Contents
IDENTIFICATION RECORDS iii
PRINTING HISTORY iv
WARRANTY STATEMENT v
SAFETY INFORMATION vii
WARNINGS viii
1. INTRODUCTION 1
1.1 Description...............................................................................................................................1
1.2 Theory of Operation.................................................................................................................1
2. SPECIFICATIONS 4
3. INSTALLATION 5
3.1 Shipping Box Contents ............................................................................................................5
3.2 Attachment of the N2O Cartridge.............................................................................................5
3.3 Attaching the NO Calibration Sourceto a NO Monitor.........................................................6
4. OPERATION 7
4.1 Flw (Flow Menu) ......................................................................................................................8
4.2 Adv (Advanced Menu) .............................................................................................................8
4.2.1 Cfg (Configuration Menu)...........................................................................................8
4.2.2 NO (Nitric Oxide Menu) ............................................................................................10
4.2.3 Zer (Zero Menu) .......................................................................................................10
4.3 Reentering the Menu .............................................................................................................10
4.4 Viewing of Flow Rates Outside of the Menu..........................................................................10
4.5 Collecting Diagnostic Data over the Serial Port in Real Time ...............................................11
4.6 Cal Menu................................................................................................................................11
4.6.1 Fm1 (N2O flow cal factor) .........................................................................................11
4.6.2 Fm2 (output flow cal factor)......................................................................................12
4.6.3 NO (NO cal factors):.................................................................................................12
4.7 Error Codes............................................................................................................................12
5. MAINTENANCE/TROUBLESHOOTING 14
6. LABELED INSTRUMENT PHOTOS 17

Model 408 NO Calibration Source Manual Rev. D-3
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IDENTIFICATION RECORDS
Record the following information for future reference:
Unit serial number:
Warranty start date:
(date of receipt)

Model 408 NO Calibration Source Manual Rev. D-3
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PRINTING HISTORY
This manual covers the Model 408 NO Calibration Source used as a portable source
of nitric oxide that allows one to calibrate any nitric oxide monitor. The instrument
scrubs NO from ambient air and produces either zero air or air having a mixing ratio of
NO in the range 20-1,000 parts-per-billion by volume (ppb).
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 A .................................................................................................January 2007
Revision B ......................................................................................................June 2007
Revision C...............................................................................................February 2008
Revision D................................................................................................... March 2015
Revision D-2..........................................................................................December 2017
(Several corrections, edits for clarification, and formatting changes were made.)
Revision D-3..........................................................................................November 2018
(Updated schematic in Section 1.2; updated web links; other minor copy edits.)
TRADEMARKS & PATENTS
2B Technologies, 2B Tech, 2Band NO Calibration Source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 2018, 2B Technologies
All rights reserved.

Model 408 NO Calibration Source Manual Rev. D-3
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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 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.
Warranty Service
Warranty Service is provided to customers through phone support, Monday - Friday,
from 9:00 a.m. to 5:00 p.m., Mountain Time USA and via our web-based Technical
Support system at https://twobtech.com/tech-support.html where a customer support
ticket may be logged. In some cases the instrument may be repaired by the customer
using parts supplied by 2B Tech. If a customer repair is not possible or effective, the
product may be returned to 2B Technologies for repair or replacement. Prior to
returning the product, a Returned Merchandise Authorization (RMA) number must be
obtained from the 2B Technologies Service Department and an RMA form completed.
The RMA form allows us to identify the owner of the instrument and provides a return
shipping address. Please do not return any of the accessories (power pack, serial
cable, connecting tubing, etc.) with the instrument.
Shipping
2B Technologies will pay freight charges for replacement or repaired products shipped
to the customer. Customers shall pay freight charges for all products returned to 2B
Technologies.
Conditions
The foregoing warranty shall not apply to defects resulting from improper or
inadequate maintenance, adjustment, calibration or operation by the customer.
Maintenance, adjustment, calibration or operation must be performed in accordance
with instructions stated in the Nitric Oxide Calibration Source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

Model 408 NO Calibration Source Manual Rev. D-3
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any other legal theory. The Nitric Oxide Calibration Source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 Nitric Oxide
Calibration Sourcemanual and its accompanying related materials. Warranty is
valid only for the country designated on the 2B Technologies quote or invoice.

Model 408 NO Calibration Source Manual Rev. D-3
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SAFETY INFORMATION
WARNING: This device produces toxic gas. The toxic gas produced is nitric oxide
(NO) dilute in air. The purpose of the Nitric Oxide Calibration Source is to produce
known concentrations of NO/Air in the range 20-1000 parts per billion by volume
(ppb). Nitric oxide is a toxic gas and should be handled with caution. The same kind
of care should be taken in handling the output of the Nitric Oxide Calibration Source
as for NO dispensed from a compressed gas cylinder. Under normal operating
conditions, the instrument will produce nitric oxide in air at concentrations up to ~2
parts per million by volume (ppm); however, an instrument failure could result in small
volumes of air containing NO at higher concentrations. The NIOSH exposure limit for
nitric oxide is 25 ppm (8-hour time-weighted average).
The output of the NO Calibration Source also contains approximately 3% nitrous oxide
(N2O). The nitrous oxide is supplied by a cartridge containing liquid N2O having a
vapor pressure inside the cartridge of 58.5 bar at 20°C. These cartridges are the
same or similar to ones sold as a consumer product for producing whipped cream.
Nitrous oxide or “laughing gas” is also used as a general anesthetic at concentrations
up to 50% and is thus well tolerated by humans. There are no known toxicological
effects of N2O other than asphyxiation at extremely highly concentrations due to
exclusion of oxygen. N2O is not itself combustible, but it strongly supports combustion
of organic materials and reducing agents. Contact with liquid N2O can cause frost bite
due to cooling as the liquid rapidly evaporates.
N2O Cartridge and Regulator Warnings:
•Do not exceed the minimum or maximum temperature listed on the N2O
cartridges.
•Store N2O cartridges out of the reach of children.
•Do not use N2O cartridges for any purposes not described in this manual.
•Never use excessive force to remove or install N2O cartridges. Contact 2B
Tech if you are having trouble installing or removing cartridges.
•Whenever there is a pressurized N2O cartridge in the regulator assembly, keep
the instrument level and do not invert the N2O cartridge.
•Do not make any modifications or repairs to the pressure regulator assembly
yourself.
•Never use the pressure regulator assembly if dropped or damaged (e.g.,
cracked or dented). If the pressure regulator is dropped or damaged, it should
be returned to 2B Tech for a safety inspection.
The Material Safety Data Sheet (MSDS) for N2O may be found here:
https://www.airgas.com/msds/001042.pdf
The MSDS for NO may be found here:
https://www.airgas.com/msds/001039.pdf
USE ONLY SUPPLIED AC/DC ADAPTER

Model 408 NO Calibration Source Manual Rev. D-3
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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 408 NO Calibration Source Manual Rev. D-3
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1. INTRODUCTION
1.1 Description
The Nitric Oxide Calibration Sourceis a portable source of nitric oxide that allows
one to calibrate any nitric oxide monitor. The instrument scrubs NO from ambient air
and produces either zero air or air having a mixing ratio of NO in the range 20-1,000
parts per billion by volume (abbreviated in this manual as ppb). The desired NO
concentration is chosen from the easy-to-use menu using a rotary Select Switch. The
instrument can be programmed to output up to 10 individual NO step concentrations
over a chosen time interval. The total output volumetric flow rate is 3.0 L/min, and the
NO mixing ratio is controlled so as to be independent of ambient temperature,
pressure and humidity.
You can attach the NO Calibration Sourceoutput directly to the inlet of any nitric
oxide monitor (providing that its sampling rate is less than 3.0 L/min); the excess flow
must be vented through an external overflow tee. Besides portability, an important
advantage of the Model NO Calibration Source is that it provides a known
concentration of NO in ambient air containing the same level of humidity as the air
sample to be measured.
The NO Calibration Sourceis factory calibrated against a NIST-traceable standard.
However, the calibration parameters may be changed in the menu in case the user
wants to recalibrate the NO Calibration Sourceagainst a separately maintained
standard; i.e., the NO Calibration Sourcecan be used as a transfer standard. The
NO Calibration Sourcemay be used, for example, for maintaining the calibration of
a large number of NO monitors in the field relative to a highly stable laboratory
instrument. In this case, a huge advantage of the NO Calibration Sourceis its
portability.
1.2 Theory of Operation
The Nitric Oxide Calibration Sourcemakes use of a low-pressure mercury lamp to
photolyze nitrous oxide (N2O) and produce NO in a patent-pending process. The
vacuum UV emission lines of mercury near 185 nm are absorbed by N2Oto produce
electronically excited oxygen atoms, O(1D2). A large fraction of these highly energetic
oxygen atoms react with N2O to form NO:
N2O + h→N2+ O(1D2) (1)
O(1D2) + N2O →2 NO (2)
_________________________
Net: 2 N2O + h→N2+ 2 NO (3)
where hsymbolizes a photon of light. Other reactions produce a small amount of
molecular oxygen as well. The concentration of NO produced in a flowing stream of

Model 408 NO Calibration Source Manual Rev. D-3
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air depends on the intensity of the photolysis lamp, the concentration of N2O
(determined by pressure and temperature), and the residence time in the photolysis
cell (determined by volumetric flow rate and cell volume). By holding these
parameters constant, it is possible to produce a flow of air containing a constant
concentration of NO, and the concentration of NO produced can be varied most
conveniently by varying the lamp intensity. Figure 1 is a schematic diagram of the NO
Calibration Source.
Figure 1. Schematic diagram of the NO Calibration Source
 .
An air pump draws air in through NO and ozone scrubbers to remove any ambient
NO.The air flow rate is controlled by use of restrictors (not shown) and a needle
valve that vents part of the flow and is measured by a flow meter. A constant fraction
of the flow bypasses the flow meter (not shown) so that the flow through the meter is
in the range 0-1 L/min. The needle valve is adjusted to produce a total output
volumetric flow rate of ~3.0 L/min. Nitrous oxide is supplied by a cartridge containing
liquid N2O with a headspace pressure of ~50 atmospheres. The internal pressure is
dropped by a combined cracker/regulator and additional flow restrictor, which also is
used to provide coarse adjustment of the flow rate of N2O to be in the range 60 10

Model 408 NO Calibration Source Manual Rev. D-3
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cc/min. A pressure relief valve inside the instrument housing prevents over
pressurization by opening to the atmosphere if the pressure exceeds 25 psig. A
Voltage Sensitive Orifice (VSO) valve is used to provide fine control of the N2O flow
rate to ± 1 cc/min. Within the photolysis chamber, a very small fraction of the N2O is
converted to NO and N2by absorption of light at wavelengths near 185 nm.
Measurements of the output of the photolysis chamber show that no insignificant
concentration of NO2is produced. The lamp intensity at 254 nm is monitored by a
photodiode and controlled by the microprocessor. The photodiode voltage is
calibrated against the output NO concentration. Pressure within the gas stream is
measured but not controlled. Instead, the lamp intensity is varied to compensate for
changes in pressure and flow rate using a proprietary algorithm. Air containing nitric
oxide at a selected concentration in the range 20-1,000 parts-per-billion by volume
exits the instrument.

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2. SPECIFICATIONS
Method for Producing NO
Photolysis of N2O at 185 nm
Output Concentration of NO
0 and 20-1,000 ppb
Programmable
Yes; up to 10 steps over chosen time interval
Precision and Accuracy of NO
Output
Greater of 3 ppb or 3% of reading
Total Output Flow Rate
3.0 Liter/min
Rise Time
< 30 s to reach 95% of selected concentration
Display Output
LCD
Diagnostic Data Output
RS232, baud rate 19200
Operating Temperature Range
10°C to 40°C
Transportation and Temperature
Storage Ranges
-20°C to 60°C
Relative Humidity Range
0-80%, non-condensing
Altitude Range
0-2000 meters
Power Requirements
12 V dc or 120/240 V ac, 50-60 Hz, 2.5 A; 21 watt
Size
3.7 × 8.5 × 9.5 in (9.4 × 21.6 × 24.1 cm)
Weight
5.2 lb (2.4 kg)
Ratings for Usage
Indoor use only; ordinary protection (not protected
against harmful ingress of moisture); Class I Equipment
(grounding required for safety); Installation (Overvoltage)
Category II for Transient Overvoltages; Pollution Degree 2;
compliant with CE regulations of the European Union;
mains supply voltage fluctuations are not to exceed ±10%
of the nominal supply voltage
MEANING OF SYMBOLS ON BACK PANEL OF INSTRUMENT
Inlet connector for N2OOutlet connector for NO in Air
Certified Compliant with CE regulations of the European Union.

Model 408 NO Calibration Source Manual Rev. D-3
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3. INSTALLATION
Please read all the following information before attempting to install the Nitric Oxide
Calibration Source. For assistance, please call 2B Technologies at [phone]
or email us at [email protected].
NOTE:
Save the shipping carton and packing materials that came with the NO
Calibration Source. If the instrument 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 Attachment of the N2O Cartridge
Nitrous oxide is supplied to the instrument by means of N2O cartridges. Either 16 g or
8 g cartridges may be used, allowing for 2 hours or 1 hour of continuous operation,
respectively, at a flow of 60 mL/min. Thus, several calibrations can be carried out
using a single cartridge. The pressure inside the cartridge remains nearly constant as
N2O evaporates and flows out of the cartridge. The evaporation of N2O causes the
N2O cartridge to cool, which, in turn, slightly reduces the internal pressure of ~50
atmospheres.
The Model 408 comes with an attached Portable N2O Source (see photo below). To
use an N2O cartridge, follow these steps:
1) Make sure N2O flow is off by closing regulator knob of the Portable N2O Source
(turn all the way clockwise).
2) Remove bottom black cartridge holder, place a 16-g or 8-g N2O cartridge into
black holder and re-insert by screwing into regulator. If using an 8-g cartridge,
the removable insert (provided) must be in the bottom of the black cartridge
holder. If using a 16-g cartridge, remove the insert from the bottom of the black
holder.
Warning: If an N2O cartridge is punctured outside the cracker/regulator,
liquid N2O can escape, and if it evaporates on skin it will cause frost bite.
The cartridge will also act as a “rocket” if the seal is punctured outside the
cracker/regulator. However, the N2O cartridges are commonly used
consumer products available commercially, and are safe to handle if the
following procedure is followed.

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3) When prompted by the Model 408 LCD to set the N2O flow, open the regulator
by turning black knob counter-clockwise until the desired flow of ~60 cc/min is
achieved. Generally a ¼- ½ turn of the knob will work.
See also the online manual for the Portable N2O Source:
https://twobtech.com/docs/manuals/Portable_N2O_Source_revB-2.pdf
3.3 Attaching the NO Calibration Sourceto a NO Monitor
For calibration of a NO Monitor, outlet 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 NO 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 NO loss and an unrestrictive over flow T is needed at the inlet of the NO
monitor to be calibrated. Tygon, polypropylene (which may look like Teflon), and
metal tubing should not be used. Teflon-lined Tygon tubing, which is supplied with the
instrument, provides the flexibility of Tygon and the inertness of Teflon.
CAUTION: Be sure that the pressure relief hole, located just above
black cartridge holder on the regulator, is not pointed at you when
installing a new N2O cartridge.
Portable N2O
Source
N2O Cartridge
Holder
Select Switch
Regulator
Knob

Model 408 NO Calibration Source Manual Rev. D-3
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4. OPERATION
To operate the Nitric Oxide Calibration Source, connect it to an external power
source and turn the instrument on by flipping the back panel on/off switch (see Section
6, Figure 6.2). The instrument requires a 12 V DC source which is supplied by the
110-240 V AC power adapter (2.5 amp) provided. Do not use any other power
adapter.
Once turned on, the instrument will briefly display the version number of the software
installed on the microprocessor. The instrument will then display
Warming up …
delT = -xx.x
where delT is the deviation of the temperature of the photolysis chamber from the set
point of 310 K (37°C). As the chamber warms up, the temperature deviation will be
continuously displayed. During the warm up period, the photolysis lamp is turned off.
Once delT is within 1°C of the set point, the display will briefly read
Temperature Set
followed by a brief display of:
Set N2O Flow
This will be followed by a prompt to open the regulator of the N2O cartridge and set
the flow rate: Target=60 +/-10
N2O Flow = xx.x
where xx.x is the measured N2O flow rate. At this point turn the black knob on the
N2O regulator until the measured flow is ~60 mL/min. Once the flow is in range, press
the black Select Switch on the front panel of the instrument. When the menu appears,
release the Select Switch. (Note: You may enter the menu without waiting for the
warm up to be complete and without setting the N2O flow rate; however, the NO
concentration selected will not be accurately output unless the NO flow is in the
appropriate range and the set point temperature is reached.) The main menu will be
displayed as: Menu
200 1000 Flw Adv
Rotating the Select Switch will move the blinking cursor to highlight the first character
of each of the four submenus, 200, 1000, Flw and Adv. One can enter any one of
these submenus by rotating the Select Switch to move the blinking cursor over the
first letter of the submenu and then momentarily pressing (“clicking”) the Select
Switch. Selecting either 200 or 1000 will have the 408 output NO concentrations of
200 ppb or 1000 ppb respectively.

Model 408 NO Calibration Source Manual Rev. D-3
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4.1 Flw (Flow Menu)
Choosing the Flw menu allows one to continuously view the air flow rate (Air) and N2O
Flow rate (N2O). The flow rates are displayed on the LCD in VOLUMETRIC FLOW
units (cc/min), for example, as follows:
Air = 3012 cc/min
N2O = 65.7 cc/min
This menu may be used to adjust the air flow rate using the recessed needle valve in
the back of the instrument as described below, and the N2O flow rate using the N2O
regulator valve.
4.2 Adv (Advanced Menu)
Selecting Adv will access the advanced menu and the LCD will display:
Cfg NO Zer
4.2.1 Cfg (Configuration Menu)
Selecting the Cfg menu will produce the following display:
Cfg Menu
Err Prg Run 
The purpose of the return symbol () is to return to the previous menu; i.e.,
depressing the Select Switch when is highlighted allows one to move one level up
in the menu.
Err is a submenu for displaying error code definitions across the LCD. The user can
scroll through the error code definitions by rotating the Select Switch. The list of error
codes and definitions can be found in Section 4.7 of this manual below.
Prg is a submenu for defining a programmed series of step NO concentrations.
Choosing Prg results in the following submenu:
Prg Menu
Num Steps= x 
Note: In order to obtain accurate results, the air flow rate may need to be adjusted
to 3.0 L/min (3000 cc/min) when first used. This is because the air flow was set at
an altitude of 1.6 km at the factory, and the air pump may produce a different flow
rate at other altitudes. The instrument compensates for variations in flow rate, but
for best results the flow should be as close to 3.0 L/min as possible. To set the air
flow rate, enter the Cfg/Flw submenu and use a flathead screwdriver to adjust the
air flow needle valve on the back of the instrument until the flow reads close to 3.0
L/min. Rotating the valve clockwise increases the air flow rate, and counter
clockwise decreases the flow rate.

Model 408 NO Calibration Source Manual Rev. D-3
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Upon placing the cursor under the currently set value x and clicking, a blinking cursor
will appear. You may now rotate the Select Switch to obtain the number of steps, up
to 10, you wish to have in your program. Clicking again will turn off the blinking cursor
and you may return the cursor to to begin defining the program. After choosing the
number of steps, the following submenu will appear:
Prg Menu
Time/Step= x 
You may now move the cursor to the currently set time/step value x, click to obtain a
blinking cursor and rotate the Select Switch to choose a step time in the range 1 to 60
minutes. (NOTE: the 408 will take a few minutes to get up to concentrations and it is
recommended to run step functions for at least 8 minutes for best results.) To select
the value, click to remove the blinking cursor, then use to begin defining the target
concentrations of each of the steps. The following submenu will now appear:
Select NO Step
Step[1]= xxxx 
Where xxxx is the target NO concentration in ppb that is currently being used for the
first step of the program. You may now change the NO concentration for the first
concentration step in the same way that the Time/step was changed. Executing 
will bring up the following submenu and allow you to set the target concentration for
the next step:
Select NO Step
Step[2]= xxxx 
This process is repeated until the target concentrations are set for all of the steps in
your program.
This program resides in memory until the next time you choose to change it.
Choosing Run executes the program of concentration steps you have stored in
memory (under Adv/Cfg/Prg). The target concentrations are displayed as the
instrument steps through the program. For example, the first display might read
Step[1]=100 ppb
delT=0.2 ▌▌▌▌▌
if you have chosen 100 ppb as the target concentration for your first step and the
photolysis chamber is higher than the target value by 0.2°C. The five solid bars
indicate that the cell temperature, N2O flow rate, total flow rate and lamp intensity are
within range for accurate output of the selected NO concentration. If any critical
parameter or combination of parameters is out of range, an error code will appear in
place of the bars.

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4.2.2 NO (Nitric Oxide Menu)
By selecting NO from the Adv menu the user may choose to output a constant NO
concentration. Upon selecting NO, the following submenu will appear:
Select Amount
NO= xxx 
You may change the desired target NO concentration (20-1000 ppb) by selecting the
individual digits (x) and rotating the Select Switch to choose a values for those digits,
as described above for setting the calibration parameters. To start producing that
concentration of NO, click on . The instrument will now output the selected
concentration of NO until you enter the menu again and change the target
concentration. As an example, the display may read as follows
Target= 150 ppb
delT=-0.1 ▌▌▌
if you have chosen 150 ppb as the target concentration and the instrument needs a
few more seconds to reach that concentration (five bars).
The selected target NO concentration will remain in memory until the next time you
change it. Bear in mind that the instrument will output 20-1,000 ppb of NO reliably. It
is not recommended using the 408 for concentrations less than 20ppb (other than
zero) or concentrations greater than 1000 ppb.
4.2.3 Zer (Zero Menu)
Selecting Zer from the Adv menu allows the user to produce zero air from the 408.
This submenu provides a rapid way to produce air containing 0 ppb of NO. In this
mode, the photolysis lamp is turned off. When running zero air the 408 LCD will
display
Target= 0 ppb
delT=-0.1 ▌▌▌
4.3 Reentering the Menu
The menu may be reentered at any time by holding in the Select Switch until the menu
appears.
4.4 Viewing of Flow Rates Outside of the Menu
It is easy to view the instantaneous air and N2O flow rates while outputting NO.
Simply rotate the Select Switch one click clockwise to view the N2O flow rate and one
click to the left to view the air flow rate. The flow rates are also displayed on the serial
output header.

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4.5 Collecting Diagnostic Data over the Serial Port in Real Time
To transmit diagnostic data to a computer over the serial port in real time, connect the
NO Calibration Sourceto the serial port of the computer using the 9-pin cable
provided. If your computer does not have a serial port, you can use a serial-to-USB
adapter. Activate your data acquisition software; e.g., Hyperterminal (provided with
early versions of Windowsplatforms, usually in Start/All Programs/Accessories/
Communications/HyperTerminal) or Tera Term (free download available at
https://twobtech.com/teraterm-4.100.exe). The latter software is preferred since
Hyperterminal has a 500-line buffer limit, but the user may set the maximum buffer
size for Tera Term to 10,000 lines. Both programs allow you to log data to a computer
file with no limit on the number of data lines. Using these terminal emulation
programs, data may be saved to a text file and then opened in Microsoft Excel (or
other spread sheet program) where it may be converted to formatted data in columns
by defining delimiters (such as commas and carriage returns) for data manipulation
and graphing.
For data transfer the correct settings are:
Baud rate: 19,200
Data bits: 8
Parity: None
Stop bits: 1
Flow control: None or hardware
Serial data lines are output approximately once every second as follows:
Lamp Intensity (arbitrary units), Temperature (K), Pressure (Torr), Air Volumetric Flow
Rate (mL/min), N2O Volumetric Flow Rate (mL/min), Lamp Duty Cycle (%), Heater
Duty Cycle (%), Target/Measured Lamp Intensity Ratio, Error Code
Collecting serial data for a few minutes can be extremely useful in diagnosing a
problem with the Nitric Oxide Calibration Source. If you have a problem, please
collect a data file and email it to [email protected] along with a description
of the problem.
4.6 Cal Menu
To access the calibration menu, where the instrument calibration factors are stored,
hold down the Select Switch while powering on the instrument. The LCD will display,
Cal Menu
Fm1 Fm2 NO 
4.6.1 Fm1 (N2O flow cal factor)
This is the flow meter cal factor for the N2O flow. This is calibrated at 2B Technologies
and it is strongly recommended to NOT change this cal factor.

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4.6.2 Fm2 (output flow cal factor)
This is the cal factor for the output air flow of the 408 NO Calibration Source. If the
user has access to a reliable flow meter and finds a difference in actual flow versus
the flow readout, this can be adjusted as needed. To determine the flow cal factor, set
Fm2 =1.00 then use: (Actual vol. flow/readout vol. flow)=Fm2 cal factor and adjust this
cal factor as needed.
4.6.3 NO (NO cal factors):
Selecting this option takes the user to the 408 NO cal factors and the LCD will display,
NO Cal Menu
Cal_l Cal_h 
The 408 NO Calibration Sourcemakes use of 2 sets of calibration factors both with
Z (offset) and S (slope or sensitivity) for different selected NO concentrations. Cal_l
menu contains the low concentrations cal factors and uses these factors when
selecting concentrations of 20-250 ppb. Cal_h is a different set of cal factors used
when selecting concentrations 251-1000 ppb. Every 408 NO Calibration Sourceis
shipped with a NIST-traceable calibration. Both Cal_l and Cal_h calibration factors (Z
and S) are set in the instrument and recorded in the instrument’s calibration document
and birth certificate. However, you may choose to change the calibration factors so
that the instrument output agrees with your own nitric oxide standard. You can always
return the instrument to its factory calibration if desired. To change the calibration
factor, place the cursor over the digit (x) you wish to change and hold in the Select
Switch until the cursor blinks. You may now change the value of the digit by rotating
the Select Switch. Once the desired value of a digit is selected, momentarily press
the Select Switch such that the cursor no longer blinks. You may now rotate the
Select Switch to choose another digit to change. The Zparameter is a “zero” or
“offset”, and the Sparameter is a “gain” (“slope” or “sensitivity”) factor. Increasing the
Zparameter increases the concentration of NO produced in an additive way. For
example, changing Zfrom 1.3 to 2.4 will cause the NO output to increase by 1.1 ppb.
Increasing the Sparameter increases the NO output concentration linearly; i.e., for
S=1.10, the NO concentration produced will be 10% higher than for S=1.00, and for
S=0.95 it will be 5% lower. Once the desired value of a digit is selected, momentarily
press the Select Switch such that the cursor no longer blinks. You may now exit the
Cal submenu by selecting and clicking on .
4.7 Error Codes
Error codes are displayed if any of the four key parameters (temperature, air flow rate,
N2O flow rate, and lamp intensity) are out of range as follows:
Code
Error
1
N2O flow out of range (40 –80 mL/min)
2
Air flow rate out of range (3.3 –3.8 L/min)