Analytical Industries GPR-2000 User Manual

Advanced Instruments Inc..

GPR-2000 / GPR-2000 P

Portable Oxygen Analyzer

Owner’s Manual

2855 Metropolitan Place, Pomona, CA 91767 USA ♦ Tel: [phone], Fax: [phone], e-mail: [e-mail], www.aii1.com

Table of Contents

Introduction

Advanced Instruments Inc.

1

Quality Control Certification
Safety
Features & Specifications
Operation
Maintenance
Spare Parts
Troubleshooting
Warranty
Material Safety Data Sheets
Correlate LCD to Signal Output
Portable Pump Options

Appendix B
Appendix C

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3
4
5
6

7
8
9

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1 Introduction

Your new portable oxygen analyzer incorporated an advanced electrochemical sensor specific to oxygen along with state-of-the­art digital electronics designed to give you years of reliable precise oxygen measurements in variety of industrial oxygen
applications. To obtain maximum performance from your new oxygen analyzer, please read and follow the guidelines provided
in this Owner’s Manual.

Every effort has been made to select the most reliable state of the art materials and components, to design the analyzer for
superior performance and minimal cost of ownership. This analyzer was tested thoroughly by the manufacturer prior to
shipment for best performance.

However, modern electronic devices do require service from time to time. The warranty included herein plus a staff of trained
professional technicians to quickly service your analyzer is your assurance that we stand behind every analyzer sold.

The serial number of this analyzer may be found on the inside the analyzer. You should note the serial number in the space
provided and retains this Owner’s Manual as a permanent record of your purchase, for future reference and for warranty
considerations.

Serial Number: _______________________

Advanced Instruments Inc. appreciates your business and pledges to make every effort to maintain the highest possible quality
standards with respect to product design, manufacturing and service.

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2 Quality Control Certification

Date _________ Customer _______________________ Order No.: _____________________ Pass
Model ( ) GPR-2000 Portable O2 Analyzer (A-1163 Battery Assy)

( ) GPR-2000M Portable O2 Analyzer, Flowmeter
( ) GPR-2000CM Portable O2 Analyzer, Coalescing Filter, Flowmeter, Panel
( ) GPR-2000P Portable O2 Analyzer, Integral Pump (A-1157 Battery Assy, A-2166-4)
( ) GPR-2000PC Portable O2 Analyzer, Integral Pump, Coalescing Filter
( ) GPR-2000PI Portable O2 Analyzer, Integral Pump, Intrinsically Safe (A-1158, A-2166-5)
( ) GPR-2000PCI Portable O2 Analyzer, Integral Pump, Coalescing Filter, Intrinsically Safe
( ) GPR-2000PCM Portable O2 Analyzer Integral Pump, Coalescing Filter, Flowmeter, Panel
( ) GPR-2000PCMI Portable O2 Analyzer Integral Pump, Coalescing Filter, Flowmeter,
Panel, Intrinsically Safe (A-1158, A-2166-5)

Sensor

Serial Nos.
Accessories Owner’s Manual
( ) PWRS-1002 9VDC Battery Charger/Adapter 110VAC

CONN-1034 Plug Mini Phone .141 Dia Black Handle
Configuration A-1151-E-2 PCB Assembly
Software version ___________________
Range: 0-1%, 0-5%, 0-10%, 0-25%
Electronics LED indicators: Low battery, charge
Electronic offset
Analog signal output 0-1V
Gas Phase Baseline drift on zero gas < ± 2% FS over 24 hour period on 0-1% range
Noise level < ± 0.5% FS
Span adjustment within 10-50% FS
Final Overall inspection for physical defects
Options
Notes

( ) GPR-11-32-RT Oxygen Sensor ( ) XLT-11-24-RT Oxygen Sensor
( ) GPR-11-21-RT Oxygen Sensor

Analyzer ______________________________ Sensor __________________________

( ) PWRS-1003 9VDC Battery Charger/Adapter 220VAC
( ) PWRS-1008 9VDC Battery Charger/Adapter 12VDC Auto Cigarette Lighter

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3 General Safety & Installation

Safety

This section summarizes the basic precautions applicable to all analyzers. Additional precautions specific to individual analyzer
are contained in the following sections of this manual. To operate the analyzer safely and obtain maximum performance follow
the basic guidelines outlined in this Owner’s Manual.

Caution: This symbol is used throughout the Owner’s Manual to Caution and alert the user to recommended safety and/or
operating guidelines.

Danger: This symbol is used throughout the Owner’s Manual to identify sources of immediate Danger such as the presence of
hazardous voltages.

Read Instructions: Before operating the analyzer read the instructions.
Retain Instructions: The safety precautions and operating instructions found in the Owner’s Manual should be retained for

future reference.
Heed Warnings Follow Instructions: Follow all warnings on the analyzer, accessories (if any) and in this Owner’s Manual.

Observe all precautions and operating instructions. Failure to do so may result in personal injury or damage to the analyzer.

Heat: Situate and store the analyzer away from sources of heat.
Liquid and Object Entry: The analyzer should not be immersed in any liquid. Care should be taken so that liquids are not

spilled into and objects do not fall into the inside of the analyzer.
Handling: Do not use force when using the switches and knobs. Before moving your analyzer be sure to disconnect the

wiring/power cord and any cables connected to the output terminals located on the analyzer.

Maintenance

Serviceability: Except for replacing the oxygen sensor, there are no parts inside the analyzer for the operator to service.
Only trained personnel with the authorization of their supervisor should conduct maintenance.

Oxygen Sensor: DO NOT open the sensor. The sensor contains a corrosive liquid electrolyte that could be harmful if touched
or ingested, refer to the Material Safety Data Sheet contained in this Owner’s Manual. Avoid contact with any liquid or crystal
type powder in or around the sensor or sensor housing, as either could be a form of electrolyte. Leaking sensors should be
disposed of in accordance with local regulations.

Troubleshooting: Consult the guidelines in section 8 for advice on the common operating errors before concluding that your
analyzer is faulty. Do not attempt to service the analyzer beyond those means described in this Owner’s Manual.

Do not attempt to make repairs by yourself as this will void the warranty, as detailed by section 9, and may result in electrical
shock, injury or damage. All other servicing should be referred to qualified service personnel.

Cleaning: The analyzer should be cleaned only as recommended by the manufacturer. Wipe off dust and dirt from the outside
of the unit with a soft damp cloth then dry immediately. Do not use solvents or chemicals.

Nonuse Periods: Disconnect the power when the analyzer is left unused for a long period of time.

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Installation

Gas Sample Stream: Ensure the gas stream composition of the application is consistent with the specifications and review the
application conditions before initiating the installation. Consult the factory to ensure the sample is suitable for analysis. Note: In
natural gas applications such as extraction and transmission, a low voltage current is applied to the pipeline itself to inhibit
corrosion. As a result, electronic devices can be affected unless adequately grounded.

Contaminant Gases: A gas scrubber and flow indicator with integral metering valve are required upstream of the of the
analyzer to remove interfering gases such as oxides of sulfur and nitrogen or hydrogen sulfide that can produce false readings,
reduce the expected life of the sensor and void the sensor warranty if not identified at time of order placement. Installation of a
suitable scrubber is required to remove the contaminant from the sample gas to prevent erroneous analysis readings and
damage to the sensor or optional components. Consult the factory for recommendations concerning the proper selection and
installation of components.

Expected Sensor Life: With reference to the publish specification located as the last page of this manual, the expected life of
all oxygen sensors is predicated on oxygen concentration (< 1000 ppm or air), temperature (77°F/25°C) and pressure (1
atmosphere) in “normal” applications. Deviations are outside the specifications and will affect the life of the sensor. As a rule of
thumb sensor life is inversely proportional to changes in the parameters.

Accuracy & Calibration: Refer to section 5 Operation.
Materials: Assemble the necessary zero, purge and span gases and optional components such as valves, coalescing or

particulate filters, and, pumps as dictated by the application; stainless steel tubing is essential for maintaining the integrity of
the gas stream for ppm and percentage range (above or below ambient air) analysis; hardware for mounting.

Operating Temperature: The sample must be sufficiently cooled before it enters the analyzer and any optional components.
A coiled 10 foot length of ¼” stainless steel tubing is sufficient for cooling sample gases as high as 1,800ºF to ambient. The
maximum operating temperature is 45º C on an intermittent basis unless the user is willing to accept a reduction in expected
sensor life – refer to analyzer specification - where expected sensor life is specified at an oxygen concentration less than 1000
ppm oxygen for ppm analyzers and air (20.9% oxygen) for percent analyzers, but in all instances at 25°C and 1 atmosphere of
pressure. Expected sensor varies inversely with changes in these parameters.

Pressure & Flow

All electrochemical oxygen sensors respond to partial pressure changes in oxygen. The sensors are equally capable of analyzing
the oxygen content of a flowing sample gas stream or monitoring the oxygen concentration in ambient air (such as a confined
space such in a control room or an open area such as a landfill or bio-pond). The following is applicable to analyzers equipped
with fuel cell type oxygen sensors. With respect to analyzers equipped with Pico-Ion UHP and MS oxygen sensors, refer to the
analyzer’s specifications.

Analyzers designed for in-situ ambient or area monitoring have no real inlet and vent pressure because the sensor is exposed
directly to the sample gas and intended to operate at atmospheric pressure, however, slightly positive pressure has minimal
effect on accuracy.

Inlet Pressure: Analyzers designed for flowing samples under positive pressure or pump vacuum (for samples at atmospheric
or slightly negative atmospheres) that does not exceed 14” water column are equipped with bulkhead tube fitting connections
on the side of the unit (unless otherwise indicated, either fitting can serve as inlet or vent) and are intended to operate at
positive pressure regulated to between 5-30 psig although their particular rating is considerably higher. Caution: If the
analyzer is equipped with an optional H2S scrubber, inlet pressure must not exceed 30 psig.

Outlet Pressu

Sample systems and flowing gas samples are generally required for applications involving oxygen measurements at a pressure
other than ambient air. In these situations, the use of stainless steel tubing and fittings is critical to maintaining the integrity of
the gas stream to be sampled and the inlet pressure must always be higher than the pressure at the outlet vent which is
normally at atmospheric pressure. Flow Through Configuration: The sensor is exposed to sample gas that must flow or be
drawn through metal tubing inside the analyzer. The internal sample system includes 1/8” compression inlet and vent fittings, a
stainless steel sensor housing with an o-ring seal to prevent the leakage of air and stainless steel tubing.

re: In positive pressure applications the vent pressure must be less than the inlet, preferably atmospheric.

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Flow rates of 1-5 SCFH cause no appreciable change in the oxygen reading. However, flow rates above 5 SCFH generate
backpressure and erroneous oxygen readings because the diameter of the integral tubing cannot evacuate the sample gas at
the higher flow rate. The direction the sample gas flows is not important, thus either tube fitting can serve as the inlet or vent –
just not simultaneously.

A flow indicator with an integral metering valve upstream of the sensor is recommended as a means of controlling the flow rate
of the sample gas. A flow rate of 2 SCFH or 1 liter per minute is recommended for optimum performance.

Caution: Do not place your finger over the vent (it pressurizes the sensor) to test the flow indicator when gas is flowing to the
sensor. Removing your finger (the restriction) generates a vacuum on the sensor and may damage the sensor (voiding the
sensor warranty). To avoid generating a vacuum on the sensor (as described above) during operation, always select and install
the vent fitting first and remove the vent fitting last.

Application Pressure - Positive: A flow indicator with integral metering valve positioned upstream of the sensor is
recommended for controlling the sample flow rate between 1-5 SCFH. To reduce the possibility of leakage for low ppm
measurements, position a metering needle valve upstream of the sensor to control the flow rate and position a flow indicator
downstream of the sensor. If necessary, a pressure regulator (with a metallic diaphragm is recommended for optimum
accuracy, the use of diaphragms of more permeable materials may result in erroneous readings) upstream of the flow control
valve should be used to regulate the inlet pressure between 5-30 psig.

Caution: If the analyzer is equipped with a H2S scrubber as part of an optional sample conditioning system, inlet pressure
must not exceed 30 psig.

Application Pressure - Atmospheric or Slightly Negative: For accurate ppm range oxygen measurements, an optional
external sampling pump should be positioned downstream of the sensor to draw the sample from the process, by the sensor
and out to atmosphere. A flow meter is generally not necessary to obtain the recommended flow rate with most sampling
pumps.

Caution: If the analyzer is equipped with an optional flow indicator with integral metering valve or a metering flow control
valve upstream of the sensor - open the metering valve completely to avoid drawing a vacuum on the sensor and placing an
undue burden on the pump.

If pump loading is a consideration, a second throttle valve on the pump’s inlet side may be necessary to provide a bypass path
so the sample flow rate is within the above parameters.

Recommendations to avoid erroneous oxygen readings and damaging the sensor:

¾ Do not place your finger over the vent (it pressurizes the sensor) to test the flow indicator when gas is flowing to the

sensor. Removing your finger (the restriction) generates a vacuum on the sensor and may damage the sensor (thus voiding
the sensor warranty).

¾ Assure there are no restrictions in the sample or vent lines
¾ Avoid drawing a vacuum that exceeds 14” of water column pressure – unless done gradually
¾ Avoid excessive flow rates above 5 SCFH which generate backpressure on the sensor.
¾ Avoid sudden releases of backpressure that can severely damage the sensor.
¾ Avoid the collection of liquids or particulates on the sensor, they block the diffusion of oxygen into the sensor
¾ If the analyzer is equipped with an optional integral sampling pump (positioned downstream of the sensor) and a flow

control metering valve (positioned upstream of the sensor), completely open the flow control metering valve to avoid
drawing a vacuum on the sensor and placing an undue burden on the pump.

Moisture & Particulates: Installation of a suitable coalescing or particulate filter is required to remove condensation, moisture
and/or particulates from the sample gas to prevent erroneous analysis readings and damage to the sensor or optional
components. Moisture and/or particulates do not necessarily damage the sensor, however, collection on the sensing surface can
block or inhibit the diffusion of sample gas into the sensor resulting in a reduction of sensor signal output – and the appearance
of a sensor failure when in fact the problem is easily remedied by blowing on the front of the sensor. Consult the factory for
recommendations concerning the proper selection and installation of components.

- wipe away.

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Moisture and/or particulates generally can be removed from the sensor by opening the sensor housing and either blowing on
the the sensing surface or gently wiping or brushing the sensing surface with damp cloth. Caution: Minimize the exposure of
ppm sensors to air during this cleaning process. Air calibration followed by purging with zero or a gas with a low ppm oxygen
concentration is recommended following the cleaning process. Moisture and/or particulates generally can be removed from the
sample system by flowing the purge gas through the analyzer at a flow rate of 4.5-5 SCFH for an hour.

Mounting: The analyzer is approved for indoor use, outdoor use requires optional enclosures, consult factory. Mount as
recommended by the manufacturer.

Gas Connections: Inlet and outlet vent gas lines for ppm analysis require 1/8” or ¼” stainless steel compression fittings; hard
plastic tubing with a low permeability factor can be used percentage range measurements.

Power: Supply power to the analyzer only as rated by the specification or markings on the analyzer enclosure. The wiring that
connects the analyzer to the power source should be installed in accordance with recognized electrical standards. Ensure that is
properly grounded and meets the requirements for area classification. Never yank wiring to remove it from a terminal
connection. AC powered analog analyzers consume 5 watts, digital analyzers 50 watts without optional heaters. Optional 110V
and 220V heaters AC powered heaters consume an additional 100-150 watts; DC powered digital analyzers consume 30 watts,
40 watts with the optional DC powered heater.

4 Features & Specifications

See last page, this page left blank intentionally.

5 Operation

Principle of Operation

The GPR-2000 Series of portable oxygen analyzers incorporate a variety of percentage range advanced galvanic fuel cell type
sensors. The analyzers are configured in a general purpose NEMA 4 rated enclosure. Units configured without integral sample
pumps meet the intrinsic safety standards required for use in Class 1, Division 1, Groups A, B, C, D hazardous areas. Two
integral sampling pump options are available – one that meets the intrinsic safety standards and a less expensive option for
general purpose service.

Advanced Galvanic Sensor Technology

The sensors function on the same principle and are specific for oxygen. They measure the partial pressure of oxygen from low
ppm to 100% levels in inert gases, gaseous hydrocarbons, helium, hydrogen, mixed gases, acid gas streams and ambient air.
Oxygen, the fuel for this electrochemical transducer, diffusing into the sensor reacts chemically at the sensing electrode to
produce an electrical current output proportional to the oxygen concentration in the gas phase. The sensor’s signal output is
linear over all ranges and remains virtually constant over its useful life. The sensor requires no maintenance and is easily and
safely replaced at the end of its useful life.

Proprietary advancements in design and chemistry add significant advantages to an extremely versatile oxygen sensing
technology. Sensors for low ppm analysis recover from air to ppm levels in minutes, exhibit longer life, extended operating
range of -20°C to 50°C, excellent compatibility with CO
significant advantage over the competition.

The expected life of our new generation of percentage range sensors now range to five and ten years with faster response
times and greater stability. Other significant developments involve the first galvanic oxygen sensor capability of continuous
oxygen purity measurements and expanding the operating temperature range from -40°C to 50°C.

and acid gases (XLT series) and reliable quality giving them a

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Advanced Instruments Inc.

Electronics

The signal generated by the sensor is processed by state of the art low power micro-processor based digital circuitry. The first
stage amplifies the signal. The second stage eliminates the low frequency noise. The third stage employs a high frequency filter
and compensates for signal output variations caused by ambient temperature changes. The result is a very stable signal.
Sample oxygen is analyzed very accurately. Response time of 90% of full scale is less than 10 seconds (actual experience may
vary due to the integrity of sample line connections, dead volume and flow rate selected) on all ranges under ambient
monitoring conditions. Sensitivity is typically 0.5% of full scale low range. Oxygen readings may be recorded by an external
device via the 0-1V signal output jack.

Power is supplied by an integral rechargeable lead acid battery which provides enough power to operate the analyzer
continuously for approximately 60 days. Expect 8-10 hours service from a single battery charge when using the pump on a
regular basis. An LED located on the front panel provides a blinking 72 hour warning to recharge the battery. A 9VAC adapter
(positive pole located on the inside of the female connector) can be used to recharge the battery from a convenience outlet.
The analyzer is designed to be fully operational during the 8-10 hour charging cycle which is indicated by a second continuously
lit LED.

Sample System

The GPR-2000 is supplied without a sample conditioning system for maximum portability. However the sample must be properly
presented to the sensor to ensure an accurate measurement. Users interested in adding their own sample conditioning system
should consult the factory.

The GPR-2000P is equipped with an integral sampling pump positioned upstream of the sensor and generates a predetermined
flow rate of 2 SCFH. This analyzer can also be used in positive pressure applications by simply placing the ON/OFF toggle switch
in the OFF position.

A variety of sample conditioning options are available including coalescing filters, flow meters, etc which are mounted on an
auxiliary panel attached to the side of the analyzer. Advanced Instruments Inc. offers a full line of sample handling, conditioning
and expertise to meet your application requirements. Contact us at 909-392-6900 or e-mail us at [e-mail]

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Accuracy & Calibration

Single Point Calibration: As previously described the
galvanic oxygen sensor generates an electrical current
proportional to the oxygen concentration in the sample gas.

Absolute Zero: In the absence of oxygen the sensor exhibits
an absolute zero, e.g. the sensor does not generate a current
output in the absence of oxygen. Given these linearity and
absolute zero properties, single point calibration is possible.

Pressure: Because sensors are sensitive to the partial pressure
of oxygen in the sample gas their output is a function of the
number of molecules of oxygen 'per unit volume'. Readouts in
percent are permissible only when the total pressure of the
sample gas being analyzed remains constant. The pressure of
the sample gas and that of the calibration gas(es) must be the
same (reality < 1-2 psi).

Temperature: The rate oxygen molecules diffuse into the sensor is controlled by a Teflon membrane otherwise known as an
'oxygen diffusion limiting barrier' and all diffusion processes are temperature sensitive, the fact the sensor's electrical output
will vary with temperature is normal. This variation is relatively constant 2.5% per ºC.

A temperature compensation circuit employing a thermistor offsets this effect with an accuracy of better than +
entire Operating Range of the analyzer) and generates an output function that is independent of temperature. There is no error
if the calibration and sampling are performed at the same temperature or if the measurement is made immediately after
calibration. Lastly, small temperature variations of 10-15º produce < 1% error.

Accuracy:

producing 'percent of reading errors', illustrated by Graph A below, such as +5% temperature compensation circuit, tolerances
of range resistors and the 'play' in the potentiometer used to make span adjustments and 2) those producing 'percent of full
scale errors', illustrated by Graph B, such as +
technology and the fact that other errors are 'spanned out' during calibration. Graph C illustrates these 'worse case'
specifications that are typically used to develop an transmitter's overall accuracy statement of < 1% of full scale at constant
temperature or < 5% over the operating temperature range. QC testing is typically < 0.5% prior to shipment.

Example: As illustrated by Graph A any error, play in the multi-turn span pot or the temperature compensation circuit, during
a span adjustment at 20.9% (air) of full scale range would be multiplied by a factor of 4.78 (100/20.9) if used for
measurements of 95-100% oxygen concentrations. Conversely, an error during a span adjustment at 100% of full scale range is
reduced proportionately for measurements of lower oxygen concentrations.

In light of the above parameters, the overall accuracy of an analyzer is affected by two types of errors: 1) those

1-2% linearity errors in readout devices, which are really minimal due to today's

5% (over the

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Zero Calibration

In theory, the galvanic fuel cell type oxygen has an absolute zero meaning it produces no signal output when exposed to an
oxygen free sample gas. In reality

¾ Contamination or quality of the zero gas
¾ Minor leakage in the sample line connections
¾ Residual oxygen dissolved in the sensor’s electrolyte
¾ Tolerances of the electronic components

The Zero Offset capability of the analyzer is limited to 50% of lowest most sensitive range available with the analyzer.
As part of our Quality Control Certification process, the zero capability of every ppm analyzer is qualified prior to shipment.
However, because the factory sample system conditions differ from that of the user, no ZERO OFFSET adjustment is made to
analyzer by the factory.

Recommendations:
¾ Zero calibration is recommended only

sensitive range available with a ppm analyzer, e.g. analysis below 0.05 ppm on the 0-1 ppm range, 0.5 ppm on the 10 ppm
range, or below 0.1% (1000 ppm) with a percent analyzer.

¾ Determining the true Zero Offset requires approximately 24 hours to assure the galvanic fuel cell sensor has consumed the

oxygen that has dissolved into the electrolyte inside the sensor while exposed to air or percentage levels of oxygen. Allow
the analyzer to stabilize with flowing zero gas as evidenced by a stable reading or horizontal trend on an external recording
device. For optimum accuracy, utilize as much of the actual sample system as possible.

¾ Zero calibration is not practical and not recommended for portable analyzers or measurements on higher ranges. However,

satisfying these users that the zero offset is acceptable for their application without the 24 hour wait can be accomplished
by introducing a zero gas (or sample gas with a low ppm oxygen concentration) to the analyzer. Unless the zero gas is
contaminated or there is a significant leak in the sample connections, the analyzer should read less than 100 ppm oxygen
within 10 minutes after being placed on zero gas thereby indicating it is operating normally.

¾ Zero calibration should precede span calibration.
¾ Initiate the DEFAULT ZERO and DEFAULT SPAN procedures before performing either a ZERO or SPAN CALIBRATION.
¾ Caution: Prematurely initiating the ZERO CALIBRATION function can result in negative readings near zero.
¾ Once the zero offset adjustment is made, zero calibration is normally not required again until the sample system

connections are modified, or, when installing a new oxygen sensor.

, expect the analyzer to generate an oxygen reading when sampling a zero gas due to:

for online analyzers performing continuous analysis below 5% of the lowest most

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Span Calibration

Span Calibration involves adjusting the transmitter electronics to the sensor’s signal output at a given oxygen standard.
Maximum drift from calibration temperature is approximately 0.11% of reading per °C. The frequency of calibration varies with
the application conditions, the degree of accuracy required by the application and the quality requirements of the user.
However, the interval between span calibrations should not exceed three (3) months.

Note: Regardless of the oxygen concentration of the standard used, the span calibration process takes approximately 10
minutes, however, the time required to bring the analyzer back on-line can vary depending on a combination of fac tors and
assume exposure to a zero/purge/sample gas** with an oxygen content below the stated thresholds immediately after span
calibration:

* Refer to analyzer specifications for comparable data on the Pico-Ion UHP and MS oxygen sensors.
Recommendations General:

¾ The interval between span calibrations should not exceed three (3) months.
¾ Initiate the DEFAULT ZERO and DEFAULT SPAN procedures before performing either a ZERO or SPAN CALIBRATION.
¾ Caution: Prematurely initiating the SPAN CALIBRATION function before the analyzer reading has stabilized can result in

erroneous readings. This is especially true when installing a new sensor that must adjust to the difference in oxygen
concentrations. It should take about 2 minutes for the sensor to equilibrate in ambient air from storage packaging.

¾ Always calibrate at the same temperature and pressure of the sample gas stream.
¾ For 'optimum calibration accuracy' calibrate with a span gas approximating 80% of the full scale range one or a higher

range than the full scale range of interest (normal use) to achieve the effect of “narrowing the error” by moving downscale
as illustrated by Graph A in the Accuracy & Calibration section.

¾ Calibrating with a span gas approximating 5-10% of the full scale range near the expected oxygen concentration of the

sample gas is acceptable but less accurate than ‘optimum calibration accuracy’ method recommended – the method usually
depends on the gas available.

¾ Calibrating at the same 5-10% of the full scale range for measurements at the higher end of the range (example:

calibrating an Oxygen Purity Analyzer in air at 20.9% oxygen with the intention of measuring oxygen levels of 50-100%)
results in the effect of “expanding the error” by moving upscale as illustrated by Graph A and Example 1 in the Accuracy &
Calibration section above and is not recommended. Of course the user can always elect at his discretion to accept an
accuracy error of +

Recommendations Air Calibration:

¾ Do not calibrate an analyzer employing the Pico-Ion UHP or MS sensor, or, an oxygen purity sensor with air.
¾ The inherent linearity of the galvanic fuel cell type oxygen sensor enables the user to calibrate any analyzer with ambient

air (20.9% oxygen) and operate the analyzer within the stated accuracy spec on the lowest most sensitive range available
with the analyzer – it is not necessary to recalibrate the analyzer with span gas containing a lower oxygen concentration.

¾ When installing or replacing a ppm or percent oxygen sensor.
¾ To verify the oxygen content of a certified span gas.
¾ When certified span gas is not available to calibrate a ppm analyzer (immediately following air calibration reintroduce a gas

with a low oxygen concentration to expedite the return to ppm level measurements as described above **).

2-3% of full scale range if no other span gas is available.

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