Analytical Industries GPR-1800 User Manual

Advanced Instruments Inc.

GPR-1800 AIS

ppm Oxygen Transmitter

with Optional Sample System

(shown with optional sample conditioning system)

Owner’s Manual

2855 Metropolitan Place, Pomona, California 91767 USA ♦ Tel: [phone], Fax: [phone], e-mail: [e-mail]

Table of Contents

Introduction 1
Quality Control Certification 2
Safety 3
Features & Specifications 4
Operation 5
Maintenance 6
Spare Parts 7
Troubleshooting 8
Warranty 9
Material Safety Data Sheets 10
Drawings A/R
Explosion Proofing Electrical Connections Appendix A
Correlating readings – LCD display to 4-20mA signal output Appendix B
H2S Scrubber, Sample System, Media MSDS Appendix F
Maintenance H2S Scrubber & Coalescing Filter Appendix G

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1 Introduction

Your new oxygen transmitter incorporated an advanced electrochemical sensor specific to oxygen along with state-of-the-art
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 transmitter, 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 transmitter for
superior performance and minimal cost of ownership. This transmitter 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 transmitter is your assurance that we stand behind every transmitter sold.

The serial number of this transmitter may be found on the inside the transmitter. 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:

Sensor:

Accessories: Owner’s Manual
Configuration: A-1151-AIS-1 PCB Assembly Main Processing Software Ver: ___________

Test: Pass Pass

GPR-1800AIS ppm Oxygen Transmitter S/N __________________

( ) GPR-12-333 ppm Oxygen Sensor
( ) XLT-12-333 ppm Oxygen Sensor
( ) XLT-12-333-F ppm Oxygen Sensor S/N __________________

Power: ( ) A-1166-AIS-AC PCB Assembly Alarms/AC Power 110V & Interconnection
( ) A-1166-AIS-DC PCB Assembly Alarms/DC Power 9-28V & Interconnection
( ) A-1153-AIS-DC PCB Assembly Alarms/DC Power 9-28V & Interconnection
SPDT relays (B-3208, A-3267, Ex-proof window cover)

Ranges: 0-10 ppm, 0-100, 0-1000 ppm, 0-25%
Barometric pressure and temperature compensation
NEMA 4X rated wall mount enclosures

Set default zero Noise level < ± 1.0% FS
Set default span @ 600uA Alarm delay
Zero calibration Alarm bypass
Span Calibration Alarm configurations; ALARM 1, ALARM 2
Analog signal output 4-20mA full scale Alarm function; ALARM 1, ALARM 2
Calibrates with adequate span adjustment within 10-50% FS Alarm relays; ALARM 1, ALARM 2
Baseline drift on zero gas < ± 2% FS over 24 hour period Alarm system fail, dry contact
Overall inspection for physical defects

Options:

Notes:

( x ) A-3393 H2S Scrubber System
( x ) MRT-1014 LCD Display Low Temperature
( x ) HTR-1004 Heater Low Power Sensor Housing

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3 Safety

General

This section summarizes the essential precautions applicable to the GPR-1800AIS ppm Oxygen Transmitter. Additional
precautions specific to individual transmitter are contained in the following sections of this manual. To operate the transmitter
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 transmitter 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 all warnings on the transmitter, accessories (if any) and in this Owner’s Manual.
Follow Instructions: Observe all precautions and operating instructions. Failure to do so may result in personal injury or

damage to the transmitter.

Pressure and Flow

Inlet Pressure: GPR-1800AIS ppm Oxygen Transmitters are designed for flowing samples, equipped with 1/8” 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.

Caution: If equipped with an optional H2S scrubber, inlet pressure must not exceed 30 psig.
Outlet Pressure: The sample gas vent pressure should be atmospheric.

Installation

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 the Owner’s Manual appendix. 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.

Mounting: The transmitter is approved for indoor or outdoor use. Mount as recommended by the manufacturer.
Power: Supply power to the transmitter only as rated by the specification or markings on the transmitter enclosure. The wiring

that connects the transmitter to the power source should be installed in accordance with recognized electrical standards and so
they are not pinched particularly near the power source and the point where they attach to the transmitter. Never yank wiring
to remove it from a terminal connection. Power consumption is 30 watts, 40 watts with the optional DC powered heater.

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Operating Temperature: The maximum operating temperature is 45º C on an intermittent basis unless the user is willing to
accept a dramatic reduction in expected sensor life – refer to analyzer specification where expected sensor life is specified at
less than 1000 ppm oxygen at 25°C and 1 atmosphere of pressure.

Heat: Situate and store the transmitter away from sources of heat.
Liquid and Object Entry: The transmitter 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 transmitter.
Handling: Do not use force when using the switches and knobs. Before moving your transmitter be sure to disconnect the

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

Maintenance

Serviceability: Except for replacing the oxygen sensor, there are no parts inside the transmitter 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 the Owner’s Manual appendix. 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
transmitter is faulty. Do not attempt to service the transmitter beyond those means described in this Owner’s Manual.

Do not attempt to make repairs by yourself as this will void the warranty as per Section 10 and may result in electrical shock,
injury or damage. All other servicing should be referred to qualified service personnel.

Cleaning: The transmitter 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: If the transmitter is equipped with a range switch advance the switch to the OFF position and disconnect the
power when the transmitter is left unused for a long period of time.

4 Features & Specifications

Specifications and pricing are subject to change without notice. See last page for current specifications.

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5 Operation

Principle of Operation

The GPR-1800AIS oxygen transmitter incorporates a variety of ppm
range advanced galvanic fuel cell type sensors. The transmitter is
configured in two sections. The signal processing electronics and
sensor are housed in a general purpose NEMA 4X rated enclosure.
The terminals for incoming power, power supply, signal output, alarm
relay contacts and intrinsic safety barriers are mounted on a PCB
housed in an explosion proof enclosure.

The two sets of electronics are interconnected using an explosion
proof Y-fitting, explosion proof packing fiber and sealing cement –
see Appendix A. Once connected, the intrinsic safety barriers limit the
amount of voltage that flows to and from the signal processing
electronics effectively preventing an explosive condition and meets
the intrinsic safety standards required for use in Class 1, Division 1,
Groups B, C, D hazardous areas.

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 and reliable quality. 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. Another significant development involves expanding the operating temperature range for percentage range
sensors from -30°C to 50°C.

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.

The circuit for the 4-20mA signal output and two adjustable alarms is powered by a DC/DC transformer that requires a 12-28
VDC power source and separate wiring for the outputs. A loop power source is not sufficient to power to the circuit. The 4­20mA output is also represented on full scale oxygen readings to an external device.

Sample System:

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The GPR-1800AIS is supplied without a sample conditioning system thereby giving users the option of adding their own or
purchasing a factory designed sample conditioning system. Whatever the choice, 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. 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]

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. 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 +
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 +
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 1: 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

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5% or better and generates an output function that is

5% temperature compensation circuit, tolerances

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Zero Calibration: In theory
signal output when exposed to an oxygen free sample gas. In reality
sampling oxygen free sample gas due to contamination or quality of the zero gas; minor leakage in the sample line connections;
residual oxygen dissolved in the sensor’s electrolyte; and, 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.

Recommendation 1: Zero calibration, see Determining True Zero Offset below, is recommended only
performing continuous analysis below 5% of the lowest most sensitive range available with a ppm analyzer, e.g. analysis below

0.5 ppm on the 10 ppm range, or below 0.1% (1000 ppm) with a percent analyzer.
Note 1: Once the zero offset adjustment is made, zero calibration is not required again until the sample system connections are

modified, or, when installing a new oxygen sensor. As a result, zero calibration is not practical and therefore not recommended
for higher ranges or portable analyzers.

Determining True Zero Offset:
stable reading or horizontal trend on an external recording device.
Note 2: 24 hours is required to assure the sensor has consumed the oxygen that has dissolved into the electrolyte inside the
sensor while exposed to air or percentage levels of oxygen. For optimum accuracy, utilize as much of the actual sample system
as possible.

Span Calibration: Involves adjusting the transmitter electronics to the sensor’s signal output at a given oxygen standard.
Regardless of the oxygen concentration of the oxygen standard used, a typical span calibration takes approximately 10 minutes.

Note 3: The amount time required to get the analyzer back on line for normal use is influenced by a.) the level of oxygen
analysis anticipated during normal operation (also determines the initial analyzer selection), and, b.) whether the sensor is new
or has been in service for at least two weeks. General guidelines
exposure to a zero/purge/sample gas with an oxygen content below the stated thresholds:

¾ measurements above 1000 ppm or 0.1% require less than 3 minutes
¾ measurements above 100 ppm (parts-per-million analyzer) require less than 10 minutes
¾ measurements below 10 ppm (part-per-million analyzer) require 20 minutes if the sensor has been in service at ppm levels

for at least two weeks, and, 60 minutes if the sensor is new assuming the zero/purge/sample gas has an oxygen
concentration below 1 ppm

Recommendation 2: For 'optimum calibration accuracy' calibrate with a span gas approximating 80% of the full scale range
one or two ranges higher than the full scale range of interest (normal use) to achieve the effect illustrated on Graph A and
Example 1. Always calibrate at the same temperature and pressure of the sample gas stream.

Note 4: Calibrating with a span gas approximating 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. Calibrating at the same 10% of the full scale range for measurements at the higher end of the
range results in magnification of errors as discussed in Graph A and Example 1 and is not recommended. Of course the user can
always elect at his discretion to accept an accuracy error of +

Air Calibration:
calibrate the 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 – there is no need to recalibrate the analyzer with span gas containing a lower
oxygen concentration. Calibrating either a ppm or percent analyzer with ambient air (with the exception of Oxygen Purity
Analyzers intended to measure elevated oxygen levels ranging from 50-100% oxygen) on the CAL or 0-25% range meets the
80% criteria discussed in Recommendation 2.

Recommendation 3: Air calibrate the analyzer (with the exception of Oxygen Purity Analyzers intended to measure elevated
oxygen levels ranging from 50-100% oxygen) when operating a percent analyzer, installing and replacing a ppm oxygen sensor,
to verify the oxygen content of a certified span gas or when a 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 per Note 3).

Based on the inherent linearity of the electrochemical galvanic fuel cell type oxygen sensor enables the user to

, the electrochemical galvanic fuel cell type oxygen has an absolute zero meaning it produces no

, expect the analyzer to generate an oxygen reading when

for online analyzers

Allow the transmitter approximately 24 hours to stabilize with flowing zero gas as evidenced by a

for analyzers to come online following span calibration and

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

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Installation Considerations

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 if necessary 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 transmitter
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.

Optimum Accuracy: Determine if Zero Calibration is recommended for your application. If it is Zero Calibration should
precede Span Calibration and both should be repeated after the analyzer has been allowed to stabilize, typically 24-36 hours
after installation. For Span Calibration use a certified span gas with an oxygen content (balance nitrogen) approximating 80% of
the next higher full scale range above the intended measuring range is recommended for optimum accuracy, see Calibration
and Accuracy.

Assuming the initial zero is performed according to the procedure described herein, the analyzer should not require Zero
Calibration again until the either the sensor is replaced or a change is made to the sample system or gas lines, and, it should
not require Span Calibration again for up to 3 months under “normal” application conditions as described in the published
specifications. One of the unique features of analyzers based on the electrochemical galvanic fuel cell type oxygen sensor is the
fact that it can be field calibrated at the user’s discretion to whatever standard of certified span gas the user elects to use.

Zero Calibration: In theory
reality, expect the transmitter to generate an oxygen reading when sampling oxygen free sample gas due to contamination or
quality of the zero gas; minor leakage in the sample line connections; residual oxygen dissolved in the sensor’s electrolyte; and,
tolerances of the electronic components.

Zero calibration, see Determining True Zero Offset below, is recommended only
analysis below 5% of the lowest most sensitive range available with a ppm analyzer, e.g. analysis below 0.5 ppm on the 10 ppm
range, or below 0.1% (1000 ppm) with a percent analyzer. Note : Once the zero offset adjustment is made, zero calibration is
not required again until the sample system connections are modified, or, when installing a new oxygen sensor. As a result, zero
calibration is not practical and therefore not recommended for higher ranges or portable analyzers.

Determining True Zero Offset:
stable reading or horizontal trend on an external recording device. Note: 24 hours is required to assure the sensor has
consumed the oxygen that has dissolved into the electrolyte inside the sensor while exposed to air or percentage levels of
oxygen. For optimum accuracy, utilize as much of the actual sample system as possible.

Span Calibration: Involves adjusting the transmitter electronics to the sensor’s signal output at a given oxygen standard, e.g.
a certified span gas with an oxygen content (balance nitrogen) approximating 80% of the next higher full scale range above the
intended measuring range is recommended for optimum accuracy, see Calibration and Accuracy.

, the oxygen sensor produces no signal output when exposed to an oxygen free sample gas. In

for online analyzers performing continuous

Allow the transmitter approximately 24 hours to stabilize with flowing zero gas as evidenced by a

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Recommendation: Based on the inherent linearity of the galvanic oxygen sensor enables the user to calibrate the 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 – there is no need to recalibrate the analyzer with span gas containing a lower oxygen
concentration.

Calibrating either a ppm or percent analyzer with ambient air (with the exception of Oxygen Purity Analyzers intended to
measure elevated oxygen levels ranging from 50-100% oxygen) on the CAL or 0-25% range meets the 80% criteria discussed
above. Air calibrate the analyzer (with the exception of Oxygen Purity Analyzers intended to measure elevated oxygen levels
ranging from 50-100% oxygen) when operating a percent analyzer, installing and replacing a ppm oxygen sensor, to verify the
oxygen content of a certified span gas or when a 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).

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.

Temperature: The sample must be sufficiently cooled before it enters the transmitter 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.

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).

Sample systems and/or flowing gas samples are generally required for applications involving oxygen
measurements at levels other than ambient air and when the pressure exceeds ambient. 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 transmitter. 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.

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 equipped with a

H2S scrubber, inlet pressure must not exceed 30 psig.

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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 transmitter 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 (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 transmitter 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.

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 Connection: Locate the appropriate power source to meet the analyzer or transmitter requirements, ensure that is
properly grounded and meets the area classification.

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Mounting the Transmitter

The GPR-1800AIS consists of two interconnected enclosures (without the optional
sample conditioning system and panel) and measures 8”H x 15-3/4”W x 7”D. This
configuration is designed to be mounted directly to any flat vertical surface, wall or
bulkhead plate with eight (8) of the appropriate screws. To facilitate servicing the
interior of the transmitters, position it approximately 5 feet off ground level.

Remove the four (4) screws securing the top section of the enclosure, set them
aside for reinstallation and raise the hinged top section 180º until it locks in place.
Locate the mounting holes cast into the enclosure.

Secure the enclosure to a vertical surface approximately 5 feet from the floor or a level accessible to service personnel. This
requires the user to supply four (4) additional proper size screws and anchors.

Caution: Do not remove or discard the gaskets from either the enclosure or junction box. Failure to reinstall either gasket will
void the NEMA 4 rating and RFI protection. The transmitters design provides protection from RFI that is maintained by leaving
specific mating areas of the enclosure unpainted to maintain conductivity the gasket, top and bottom sections of the enclosure.

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These unpainted areas are protected by gaskets and contribute to maintaining the NEMA 4 rating. Do not paint these areas.
Painting will negate the RFI protection.
Note: If equipped with the optional H2S sample conditioning system, the transmitter and sample system are mounted to a back
panel which has four (4) holes for mounting the 15-3/4”H x 15-3/4”W x 7”D panel to any vertical flat surface.

The GPR-1800AIS with its standard flow through configuration is designed for positive pressure samples and requires
connections for incoming sample and outgoing vent lines. Zero and span inlet ports are offered as part of the optional sample
systems. The user is responsible for calibration gases and the required components, see below.

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. 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).

Procedure:

1. Caution: Do not change the factory setting until instructed to do in this manual.

2. Designate one of the bulkhead tube fittings as the VENT and the other SAMPLE.

3. Regulate the pressure as described in Pressure and Flow above.

4. Connect a 1/8” vent line to the compression fitting to be used for venting the sample.

5. Connect a 1/8” ZERO, SPAN or SAMPLE line to the fitting designated SAMPLE.

6. If equipped with optional fittings and/or sample system, connect the ZERO and SPAN gas lines.

7. Allow gas to flow through the transmitters and set the flow rate to 2 SCFH.

8. Note: If equipped with the optional H2S sample conditioning system: Regulate the pressure so that it does not exceed
30 psig use ¼” tubing to make the appropriate connections as labeled on the sample panel.

Gas Connhections

Electrical Connections

Incoming power, power failure and set point alarm, and, output connections are
made to a terminal block mounted on a PCB located in the lower explosion proof
enclosure.

The PCB also includes a transformer to power the alarm relays and intrinsic
safety barriers that limited the amount of voltage going to the upper electronics
enclosure. With proper insulation of the incoming power (see Appendix A), this
configuration the GPR-1800AIS meets the intrinsic safety standards for use in
Class 1, Division 1, Groups A-D hazardous areas.

Caution: The integral 4-20mA converter is internally powered and does not
require external power. DO NOT supply any voltage to either of the two
terminals of the 4-20mA output or the 4-20mA converter will be damaged.

To assure proper grounding, connect the 4-20mA signal output to the external device (PLC, DCS, etc.) before attempting any
zero or span adjustments.

Procedure:

Power requirements consist of a two wire shielded cable and a 12-28V DC with negative ground power supply.

1. Unscrew the cone shaped cover from the lower enclosure.

2. Separate the shielding from the wires of the cable.

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Advanced Instruments Inc.

3. Ensure the positive and negative terminals of the power supply are connected to the appropriate terminals of the barrier
strip as marked.

4. Connect the shielding of the cable to the ground screw inside the enclosure. Note: The terminals snap together, making it
possible to detach the section with the ground, install the shielded cable and reinstall.

5. Replace the cover.

6. The 4-20mA current output is obtained by connecting the current measuring device between the positive and negative
terminals labeled OUTPUT 4-20mA.

7. To check the signal output of the 4-20mA E/I integrated circuit connect an ammeter as the measuring device and confirm
the output is within +

8. Caution: To assure proper grounding, connect the 4-20mA signal output to the external device (PLC, DCS, etc.) before
attempting any zero or span adjustments.

Installing the Oxygen Sensor

The GPR-1800AIS ppm Oxygen Transmitter is equipped with an integral oxygen sensor.
They have been tested and calibrated by the manufacturer prior to shipment and are fully
operational from the shipping container.

Caution: All transmitters must be calibrated once the installation has been completed and
periodically thereafter as described below. Following the initial installation and calibration,
allow the transmitters to stabilize for 24 hours and calibrate with certified span gas.

Caution: DO NOT open the oxygen 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 the Owner’s
Manual appendix. 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
manner similar to that of a common battery in accordance with local regulations.

Procedure:

1. The sensor has not been installed at the factory (in standard configuration there are no valves
to isolate the sensor) and it will be necessary to install the sensor in the field.

2. Caution: Do not change the factory settings until instructed to do in this manual.

3. Connect the gas lines as previously described.

4. Purge the oxygen trapped in the newly connected gas lines for 3-5 minutes.

5. Flow zero gas or sample gas with a low ppm oxygen concentration to the analyzer at the
predetermined flow rate of 2 SCFH.

6. Using the 5/16 wrench supplied loosen but do not remove the clamp bolt located under the
sensor housing, see photo.

7. Rotate the upper section of the sensor housing 90º to disengage from the clamp.

8. Remove the upper section by pulling it straight up and place it on a smooth surface.

9. Select the AUTO RANGING option from the SAMPLE menu with gas flowing to the analyzer.

10. Remove the oxygen sensor from the bag and remove the red shorting device (including the gold ribbon) from the PCB
located at the rear of the sensor. Minimize the time the sensor is exposed to ambient air.

11. Immediately place the sensor in the bottom section of the sensor housing with the PCB facing up.

12. Immediately place the upper section of the sensor housing over the sensor, gently push the upper section downward and
rotate 90º to engage the clamp.

13. Finger tighten the clamp bolt and then tighten it one full turn with the 5/16 wrench to securely lock the two sections of the
sensor housing.

14. The analyzer will OVER RANGE for a short period of time as indicated by the graphical LCD display.

15. Wait until the display shows a meaningful oxygen reading and begins to approach the expected oxygen content of the
sample gas.

0.1mA of 4mA.

Span Gas Preparation

Caution: Do not contaminate the span gas cylinder when connecting the regulator. Bleed the air filled regulator (faster and
more reliable than simply flowing the span gas) before attempting the initial calibration of the instrument.

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Advanced Instruments Inc.

Required components:

1. Certified span gas cylinder with an oxygen concentration, balance nitrogen, approximating 80% of the full scale range
above the intended measuring range.

2. Regulator to reduce pressure to between 5 and 30 psig.

3. Flow meter to set the flow between 1-5 SCFH,

4. Suitable fittings and a 4-6 ft. in length of 1/8” dia. metal tubing to connect the regulator to the flow meter inlet

5. Suitable fitting and a 4-6 ft. in length of 1/8” dia. metal tubing to connect from the flow meter vent to tube fitting
designated SAMPLE IN on the GPR-1200.

Procedure:

1. With the span gas cylinder valve closed, install the regulator on the cylinder.

2. Open the regulator’s exit valve and partially open the pressure regulator’s control knob.

3. Open slightly the cylinder valve.

4. Loosen the nut connecting the regulator to the cylinder and bleed the pressure regulator.

5. Retighten the nut connecting the regulator to the cylinder

6. Adjust the regulator exit valve and slowly bleed the pressure regulator.

7. Open the cylinder valve completely.

8. Set the pressure between 5-30 psig using the pressure regulator’s control knob.

9. Caution: Do not exceed the recommended flow rate. Excessive flow rate could cause the backpressure on the sensor and
may result in erroneous readings and permanent damage to the sensor.

Establishing Power to the Electronics

Once the two wires of the shielded cable are properly connected to the terminals inside the junction box as described above,
connect the other end of the two wires to a suitable 12-28V DC power supply with negative ground such as a PLC, DCS, etc.

The digital display responds instantaneously. When power is applied, the transmitter performs several diagnostic system status
checks termed “START-UP TEST” as illustrated below:

START-UP TEST

ELECTRONICS – PASS
TEMP SENSOR – PASS
BAROMETRIC SENSOR – PASS

REV. 1.61

Note: The transmitter display defaults to the sampling mode when 30 seconds elapses without user interface.

3.3 PPM

AUTO SAMPLING

10 PPM RANGE

24.5 C 100 KPA
LO1 2PPM 10PPM HI2

Menu Navigation

The four (4) pushbuttons located on the front of the transmitter operate the micro-processor:

1. blue ENTER (select)

2. yellow UP ARROW

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