Analytical Industries GPR-2500 S User Manual

GPR-2500 S

Oxygen Analyzer

Ambient Area Monitoring

Owner’s Manual

2855 Metropolitan Place, Pomona, CA 91767 USA ♦ Tel: [phone], Fax: [phone], e-mail: [e-mail], www.aii2.com

Table of Contents

Introduction

Quality Control Certification

Safety

Features & Specifications

Operation

Maintenance

Spare Parts

Troubleshooting

Warranty

Material Safety Data Sheets

1
2
3
4
5
6
7
8
9
10

2

1 Introduction

Your new oxygen analyzer incorporates an advanced electrochemical sensor specific to oxygen along with state-of­the-art digital electronics designed to give you years of reliable precise oxygen measurements in variety of
industrial oxygen applications.

The GPR-2500S is generally used to monitor the oxygen content of a confined space or control room occupied by
humans for a deficiency of oxygen. This configuration requires the operator calibrate the monitor with a certified
span gas from a cylinder and not the ambient air surrounding the monitor. Failure to heed this instruction may
result in injury or death .

To obtain maximum performance from your new Ambient Oxygen Monitor, 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
monitor for superior performance and minimal cost of ownership. This monitor 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 monitor is your assurance that we stand behind every
monitor sold.

The serial number of this monitor may be found on the inside the monitor. 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-2500S Ambient Oxygen Monitor
Sensor ( ) GPR-11-32-4 Oxygen Sensor

( ) XLT-11-24-4 Oxygen Sensor
( ) Other _____________________

Serial Nos.: Monitor: Sensor:
Accessories: Owner’s Manual

( ) A-2344 Calibration Flow Adapter (GPR-2500S)
( ) Remote sensor requires: A-2070 Bracket Mount, A-2781 Nut Retaining

Configuration: A-1151-E-L2 PCB Assembly Main / Display
Software rev:
Ranges: 0-1%, 0-5%, 0-10%, 0-25%
Power: 12-36V DC two wire loop power
NEMA 4 rated wall mount enclosure
Barometric pressure compensation

Test: Default zero (without sensor)
Default span @ 40uA
Analog signal output 4-20mA full scale
Calibrates with adequate span adjustment within 10-50% FS

Span adjustment within 10-50% FS
Final: Overall inspection for physical defects

Options:
Notes:

Baseline drift on zero gas < ± 2% FS over 24 hour period
Noise level < ± 1.0% FS

4

3 General Safety & Installation

General

This section summarizes the essential precautions applicable to the GPR-2500S Ambient Oxygen Monitor. Additional
precautions specific to individual monitor are contained in the following sections of this manual. To operate the
monitor 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 monitor 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 monitor, 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 monitor.

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

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

Maintenance

Serviceability: Except for replacing the oxygen sensor, there are no parts inside the monitor 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 monitor is faulty.

Do not attempt to service the monitor 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 monitor 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 monitor is equipped with a range switch advance the switch to the OFF position and
disconnect the power when the monitor is left unused for a long period of time.

5

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.

Inlet Pressure: The GPR-2500S is designed for in-situ ambient or area
monitoring and has no sample system because the sensor is intended to be
exposed directly to the surrounding ambient atmosphere which it is sampling and
to operate at atmospheric pressure, however, slightly positive pressure has
minimal effect on accuracy.

Further, applications situations may dictate that the sample be transported from a
semi-sealed area to a safe area where the analyzer is located. In these cases the
analyzer can be readily adapted to include optional pumps, tubing and connection
fittings. Users interested in adding their own sample conditioning system should
consult the factory.

6

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.

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

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. 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 delrin (stainless steel is optional) 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 provided 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. 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.

Application Pressure - Atmospheric or Slightly Negative: An optional external sampling pump should be
positioned upstream of the sensor to draw the sample from the process, introduce it at a predetermined flow rate
of 2 SCFH to 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 -

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wipe away.

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.

¾ Calibrate ambient area monitors with a certified span gas/
¾ Avoid calibration of ambient area monitors with the surrounding atmosphere unless assured the oxygen

content is 20.9%.

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.

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. Oxygen
analyzers designed for ambient area monitoring expose the sensor directly to the atmosphere being sampled and
thus have no gas connections.

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 powere d heater.

4 Features & Specifications

See last page, left blank intentionally.

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5 Operation

Principle of Operation

The GPR-2500S Ambient Oxygen Monitor incorporates a variety of advanced galvanic fuel cell type sensors. The
monitor is configured in a general purpose NEMA 4X rated enclosure and meets the intrinsic safety standards
required for use in Class 1, Division 1, Groups A, B, C, D hazardous areas when operated in conjunction with the
manufacturer’s recommended optional intrinsic safety barriers.

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.

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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.

A 4-20mA signal output is provided from a two-wire 12-36VDC loop power source such as a PLC and is represented
on full scale oxygen readings to an external device. When operated in conjunction with the manufacturer’s
recommended optional intrinsic safety barriers the GPR-2500S meets the intrinsic safety standards required for use
in Class 1, Division 1, Groups A, B, C, D hazardous areas.

In compliance with OSHA specifications, the standard unit includes two oxygen alarms which have been set by the
factory to energize audio and visual alarms when oxygen levels fall below CAUTION (20.0% O
(19.5% O

). Optionally, these alarms can be configured as HIGH O2 and LOW O2 based on customer

2

) and DANGER

2

requirements. The two-color alarm LED indicators display green for safe and red for alarm conditions. The alarms
remain energized until the oxygen level rises above (and/or below with the optional high, low configuration) the
alarm set points. Power interruptions do not interfere with the alarms of a u n it installed and operated properly.

The GPR-35 is unique in that it automatically compensates the sensor output for pressure changes thereby
eliminating the false alarms. Unlike competitive analyzers the GPR-35 is not affected by changes in the barometric
pressure that can temporarily impact the sensor output and analyzer reading to the extent that most analyzers
produce false alarms. In addition to being irritating, false alarms can be costly in terms of interrupting projects,
tests or production processes.

Sample System:

The GPR-35 designed for in-situ ambient or area monitoring and has no sample
system because the sensor is intended to be exposed directly to the surrounding
ambient atmosphere which it is sampling and to operate at atmospheric
pressure, however, slightly positive pressure has minimal effect on accuracy .

Further, applications situations may dictate that the sample be transported from
a semi-sealed area to a safe area where the analyzer is located. In these cases
the analyzer can be readily adapted to include optional pumps, tubing and
connection fittings. Users interested in adding their own sample conditioning
system should consult the factory. Contact us at 909-392-6900 or e-mail us at [e-mail]

with any questions.

Mounting the Analyzer

The GPR-2500S Ambient Oxygen Monitors has been calibrated at the factory prior to
shipment and is fully operational from the shipping container. The enclosure’s 4x9x3”
configuration is designed to be mounted directly to any flat vertical surface, wall or bulkhead
plate with the appropriate screws. To facilitate servicing the interior of the monitors, position
it approximately 5 feet off the floor.

1. 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.

2. Locate the mounting holes cast into the bottom section of the enclosure and the black
sensor. Orient the enclosure by locating the sensor at six (6) o’clock.

3. Secure the bottom section of 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.

4. 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.

10

5. The monitors 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. 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.

6. As described below the power connection is made through the junction box on the left side of the enclosure.

Gas Connections:

As described above, the sensor in the GPR-2500S ambient monitor configuration is exposed directly to ambient air
through the bottom section of the enclosure and designed to continuously monitor the oxygen content in the
atmosphere of the surrounding area, confined spaces and control rooms where the potential for a lethal deficiency
of oxygen exists.

For calibration, the user is responsible for calibration gases and
the required components, see Span Gas Preparation below,
supplying an adequate amount of Tygon tubing to pipe the span
gas to the flow through adaptor, regulating the pressure of the
span gas between 5-30 psig and controlling the flow rate to
approximately 2 SCFH or 1 liter per minute.

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).

Calibration Gas Connections – Integral and Remote Sensor:

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

2. Review the illustration below and locate Item A-2344 Calibration Flow Through Adapter and the installed Item
FITN-1029 Connector, Barbed Tubing.

3. Review Span Gas Preparation section below – regulate the pressure and control the flow rate as directed.

4. Caution: When configured for ambient monitoring of oxygen deficiency in a confined space or room do not
calibrate the unit in the atmosphere to be monitored. Use a certified span gas of a known oxygen
concentration approximating 20.9% oxygen balance nitrogen or clean compressed air.

5. Apply a little lubricant to the o-ring, a dry o-ring can make insertion difficult, of the Calibration Flow Through
Adapter Assembly, A-2344.

6. Insert the flow through adapter into the throat of the sensor.

7. Connect the 1/8” ID Tygon tubing from the flow meter vent to Item #4 Connector, Barbed Tubing.

8. Proceed to Span Calibration section.

Legend:

1. CONN-1014 Sensor Cable

2. GPR-11-32-4R Oxygen Sensor

3. A-2079 Bracket Sensor Mounting

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4. FITN-1029 Connector, Barbed Tubing

5. A-2344 Calibration Flow Through Adapter

(Calibration use only)

6. A-2781 Nut Sensor Retaining

Electrical Connections

Remove the front cover of the junction box located on left side of the monitors by removing the four (4) screws
securing the cover and set them aside for reinstallation.

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

Power requirements consist of a two wire shielded cable and a 12-36V DC with negative ground power supply.

Procedure:

1. Loosen the n u t on the cable gland.

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

3. Thread the wires through the cable gland into the inside of the
junction box.

4. Connect the two wires to the two (2) screw type terminals of the
barrier strip inside the junction box.

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

6. Connect the shielding of the cable to the copper ground screw inside
the junction box.

7. Replace the junction box cover ensuring the gaskets are in place and
tighten the four (4) screws.

8. Tighten the cable gland to maintain NEMA 4 rating.

Hazardous Area Installation:

The GPR-2500S monitors may be installed in a hazardous area with
specific intrinsic safety barriers and a barrier enclosure approved for use
with the safety barrier selected.

MTL 702 type barriers and a 24VDC power supply with two (2) wire shielded cable are recommended.
Requirements include a 4-20mADC two (2) wire signal and a power requirement of 20mADC per channel at 24VDC
minimum.

The following chart identifies the required wire based on the distance from the safety barriers to the two wire
monitors.

4,500 ft. – 22 AWG
7,200 ft. – 20 AWG

11,500 ft. – 18 AWG

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