Analytical Industries GPR-1500 A User Manual

Advanced Instruments Inc.

GPR-1500-A
PPM Oxygen Transmitter

Owner’s Manual

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

Advanced Instruments, Inc

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
H2S Scrubber, Sample System, Media MSDS Appendix F
Maintenance H2S Scrubber & Coalescing Filter Appendix G

The appendices referenced above are an integral part of the documentation, installation and maintenance of
this analyzer to comply with all applicable directives. It is important that users review these documents
before proceeding.

Appendix B

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1. Introduction

Your new oxygen transmitter incorporates 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 a 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 enclosure. 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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3. General Safety & Installation

This section summarizes the essential precautions applicable to the GPR-1500IS Oxygen Transmitter.
Additional precautions specific to individual transmitter are contained in the following sec tions 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.

Warning: This symbol is used throughout the Owner’s Manual to Warn and alert the user of the
presence of electrostatic discharge.

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 O wner’s Manu al 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.

Analyzer label

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2. Quality Control Certification

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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 arou nd the sensor or sensor housing, as
either could be a form of electrolyte. Leaking sensors should be disposed of in accordance with loc al
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 pers onnel.

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.

Installation

This analyzer has been constructed in compliance with

EN 60079-0 : 2006
EN 60079-1 : 2004

Gas Sample Stream: Ensure the gas stream composition of the application is consistent with the
specifications and if in doubt, review the application and consult the factory before initiating the install ation.
Note: In natural gas applications such as extraction and transmission, a low voltage current is applied to the
pipeline itself to inhibit corrosion of the pipeline. As a result, electronic devices connected to the pipeline can
be affected unless they are adequately grounded.

Contaminant Gases: A gas scrubber and flow indicator with integral metering valve are requir ed upstream
of the analyzer to remove any interfering gases such as oxides of sulfur and nitrogen or hydrogen sulfide
that can interfere with measurement and cause reduction in the expected life of the sensor. Consult the
factory for recommendations concerning the proper selection and installation of compone nts.

Expected Sensor Life: With reference to the publish specification located at the last page of this manu al,
the expected life of all oxygen sensors is predicated on oxygen concentration (< 1000 PPM for PPM sensor
or air for % sensor), temperature (77°F/25°C) and pressure (1 atmosphere) in “normal” applications.
Deviations from standard conditions will affect the life of the sensor. As a rule of thumb sensor life is
inversely proportional to changes in the pressure and temperature.

Accuracy & Calibration: Refer to section 5 Operation.

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Materials: Assemble the necessary zero, sample and span gases and optional components such as valves,
coalescing or particulate filters, and pumps as dictated by the application. Stainless steel tubing is esse ntial
for maintaining the integrity of the gas stream for low % or PPM O

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 1,800 ºF to ambient. The recommended operating temperature is below 35 ºC. However,
the analyzer may be operated at temperature up to 45 ºC on an intermittent basis but the user is expected to
accept a reduction in expected sensor life –as a rule of thumb, for every degree ºC increase in temperature
(above 25 ºC), the sensor life is reduced by approximately 2.5%.

Heat: Situate and store the analyzer away from direct 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, knobs or other mechanical components. Before
moving your analyzer be sure to disconnect the wiring/power cord and any ca bles connected to the output
terminals of the analyzer.

level analysis.

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Sample Pressure and Flow

All electrochemical oxygen sensors respond to partial pressure cha nges 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 in a control room or an open area arou nd a landfill or
bio-pond). The following is applicable to analyzers equipped with fuel cell type oxyg en sensors.

Analyzers designed for in-situ ambient or area monitoring has no real sample inlet and vent. The sensor is
exposed directly to the sample gas and it is intended to operate at atmospheric pressure. The analyzer has
a built-in pressure sensor and the sensor output is automatically compensated for any atmospheric pressure
changes.

Inlet Pressure: For the analyzers designed to measure oxygen in a flowing gas stream, the inlet

sample pressure must be regulated between 5-30 psig. Although the rating of the SS tubing and tube
fittings/valves itself is considerably higher (more than 100 psig), a sample pressure of 5-30 psig is
recommended for ease of control of sample flow.

The analyzer equipped with a sample system has designated SAMPLE and VENT ports. Connect SAMPLE
gas to SAMPLE and the vent to the VENT ports only.

Caution: If the analyzer is equipped with an optional H2S scrubber, sample inlet pressure must
not exceed 30 psig.

Outlet Pressure: In applications where sample pressure is positive, the sample must be vented to an

exhaust pipe at a pressure less than the inlet pressure so that the sample gas can flow through the sensor
housing. Ideally, the sample must be vented to atmospheric pressure.

Note: The sensor may be used at a slight positive pressure (e.g., when sample is vented to a common
exhaust where the pressure might be higher than 1 atmosphere). However, the pressure at the sensor must
be maintained at all times including during the span calibration. This may be accomplished by using a back­pressure regulator at vent line of the analyzer. Caution: A sudden change in pressure at the sensor may
result in the sensor electrolyte leakage.

Flow rates of 1-5 SCFH cause no appreciable change in the oxygen reading. Ho wever, flo w rates above 5
SCFH may generate a slight backpressure on the sensor resulting in erroneous oxygen readings.

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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).

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 a
separate flow control valve and a flow indicator is used, position flow control valve upstream of the sensor
and position a flow indicator downstream of the sensor. If necessary, a pressure regulator 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 % oxygen

measurements, an optional external sample pump may be used upstream of the sensor to push the sample
across the sensor and out to atmosphere. For PPM 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. However, if the sample pump can pull/push more than 5 SCFH, a flow control must
be used to control the sample flow. The flow control valve must be positioned in such a way that it does not
generate any vacuum on the sensor.

Caution: If the analyzer is equipped with a flow indicator with integral metering valve or a
metering flow control valve upstream of the sensor and the pump is installed downstream of
sensor- open the metering valve completely before turning the pump ON 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.

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 other optional components. Moisture and/or particulates do not
necessarily damage the sensor. However, collection of moisture/particulate 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. Consult the factory for recommendations concerni ng the proper
selection and installation of optional components.

Moisture and/or particulates generally can be removed from the sensor by opening the sensor housing and
either blowing on the sensing surface or gently wiping or brushin g 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 after the cleaning
process is completed.

Mounting: The analyzer is approved for indoor as well as outdoor use. However, avoid mounting in an

area where direct sun might heat up the analyzer beyond the recommended operating temperature range. If
possible, install a small hood over the analyzer for rain water drain and to prevent over-heating of analyzer.

Gas Connections: The Inlet and outlet vent gas lines require 1/8” or ¼” stainless steel compression

type tube fittings. The sample inlet tubing must be metallic, preferably SS. The sample vent line may be of
SS or hard plastic tubing with low gas permeability.

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Power: Supply power to the transmitter only as rated by the specification or markings on the analyzer

enclosure. The GPR-1500-A is a DC powered analyzer. The input power must be between 12-24 VDC. The
wiring that connects the analyzer to the power source should be installed in accordance with recognized
electrical standards. Ensure that the analyzer case is properly grounded and meets the requirements for
area classification where the analyzer is installed. Never yank wiring to remove it from a terminal connection.

The transmitter consumes no more than 7 Watts of power.

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4. Features & Specifications

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5. Operation
Principle of Operation

The GPR-1500-A Oxygen Transmitter incorporates advanced galvanic fuel cell type oxygen sensors. These
sensors are very specific to oxygen and generate an electrical signal proportional to the amount of oxygen
present in a gas stream. The selection of a particular type of sensor depends on the composition of the
sample gas stream. Consult the factory for recommendation.

The transmitter is configured with two integral electronic PCB. The signal processing electronics PCB and
the power supply, signal output, and alarm relays PCB are housed in a metal enclosure. The two PCBs are
interconnected via a ribbon cable.

Clean all surfaces with a damp cloth to avoid electrostatic discharge.

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Advanced Galvanic Sensor Technology

All galvanic type sensors function on the same principle and are specific to oxygen. They measure the
partial pressure of oxygen from low PPM to 100% levels in inert gases, gaseous hydrocarbons, helium,
hydrogen and mixed gases

Oxygen, the fuel for this electrochemical transducer, diffusing into the sensor, reacts electrochemically at the
sensing electrode to produce an electrical current output proportional to the oxygen concentratio n in the gas
phase. The sensor’s signal output is linear over all measuring ranges and remains virtual ly 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 this extremely versatile
oxygen sensing technology. Sensors for low % analysis recover from air to low % levels in seconds, exhibit
longer life and reliable quality. The expected life of our new generation of percentage range sensors now
range from 32 months to 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. Contact factory for more specific information about your application.

The PPM sensors recover from an upset condition to low PPM level in a matter of few minutes. These
sensors show excellent stability over its useful life.

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 cause d b y ambient
temperature changes. The result is a very stable signal. Sample oxygen is analyz ed 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 of the low range. Oxygen readings may be recorded by
an external device via the 4-20 mA or 1-5V (by converting 4-20 mA in to voltage signal by using a 250 oh ms
resistor) signal output.

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Sample System

The standard GPR-1500-A transmitter is supplied without a sample conditioning s ystem thereby giving users
the option of adding their own or purchasing a factory designed sample conditi oning system, see section 2
QC Certification for optional equipment ordered. Whatever the choice, the sample must be properly
conditioned before introducing it to the sensor to ensure an accurate measurement.

Users interested in adding their own sample conditioning system should consult the factory. Advance d
Instruments Inc. offers a full range of sample handling, conditioning and expertise to meet your application
requirements. Contact us at 909-392-6900 or e-mail us at [e-mail]

.

Calibration & Accuracy Overview

Single Point Calibration: As previously
described the galvanic type 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 must be the
same.

Temperature: The rate at which 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 and
a network of resisters offsets this effect with an accuracy of +
range e.g., 5-45
temperature. There is extremely low error in measurement if the calibration and sampling are performed at
similar temperatures (within +/- 5 ºC. Conversely, a temperature variation of 10 ºC may produce an error of <
2% of full scale.

Accuracy:

errors: 1) 'percent of reading errors', illustrated by Graph A below, is contributed by the temperature
compensation
tolerances in resistors values and the accuracy in the measuring devices, e.g., LCD display and 2) 'percent
of full scale errors', illustrated by Graph B, such as1-2% offset errors in readout and calibration devices.
Other errors are 'spanned out' during calibration, especially when analyzer is calibrated close to the top end
of the measuring range.

Graph C illustrates these 'worse case' specifications that are typically used to develop an overall accuracy
statement of < 1% of full scale at constant temperature or < 5% over the operating temperature range. The
QC testing error is typically < 0.5% prior to shipment of analyzer from the factory.

o

C can be obtained thus the signal output remains virtually independent of ambient

In light of the above parameters, the overall accuracy of an analyzer is affected by two types of

circuit (tolerance in the thermistor value, variation in temperature coefficient of the thermistor,

5% or better over a wide operating temperature

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Example 1: As illustrated by Graph A, any error during a span adjustment at lower end of the scale, e.g.,

20.9% (air) on a 100% full scale range, would be multiplied by a factor of 4.78 (100/20.9) when making
measurements close to 100% O2. Conversely, an error during a span adjustment close to the top end of the
range, e.g., at 100% is reduced proportionately for measurements of oxygen concentrations near the bottom
end of the range.

Graph B represents a constant error over the entire measuring range. This error is generally associated with
the measuring e.g., LCD and or calibrating devices, e.g., current simulator or current/voltage measuring
devices.

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Mounting the Transmitter

The GPR-1500-A consists of metal enclosure and a sensor housing (without any optional sampl e
conditioning system) and measures 7”H x 4”W x 4.5”D. This configuration is designed to be mou nted directly
to any flat vertical surface or bulkhead plate by using four (4) mounting studs at the back of front panel..

To facilitate servicing the interior of
the transmitters, secure the
transmitter 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) 6-32 hex nuts.

Caution: Do not remove
or discard the gaskets

around the front panel.
Failure to reinstall the gaskets will
allow dust and/or moisture
condensate to accumulate on the
electronics PCBs and cause
possible failure.

The transmitters design provides
immunity from RFI/EMI by
maintaining a good conductive
contact between the transmitter enclosure and a good ground. Ensure that ground is connected to the rear
of the enclosure marked with the symbol ground..

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Gas Connections

The GPR-1500-A with its standard flow through sensor housing configuration is designed for positive
pressure samples and requires connections for incoming sample and outgoing vent lines. The user should
adhere to the recommendation in terms of using the type of fittings, tubing, sample/span/zero gas pressure
and sample flow rates. Failure to do so may cause permanent damage to the sensor.

Procedure:

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

1. If analyzer has no marking for sample inlet and sample vent, designate one of the bulkhead tube fittings

as the VENT and the other as SAMPLE.

2. Regulate the sample pressure as described in “Pressure and Flow” section above.

3. Connect a 1/8” or a ¼” vent line to the compression fitting to be used for venting the sample.

4. Connect a 1/8” or ¼” sample line to the compression fitting to be used to bring SAMPLE gas to the

analyzer.

5. If equipped with optional SPAN and/or ZERO ports, connect the SPAN and the ZERO gas lines to the

respective SPAN and ZERO ports of the analyzer

6. Set the SAMPLE, SPAN and the ZERO gas pressure between 5-30 psig..

7. Select sample gas and allow it to flow through the transmitters and set the flow rate to1- 2 SCFH.

Flow rates of 1-5 SCFH cause no appreciable change in the oxygen reading. Ho wever, flo w rates above 5
SCFH may generate a backpressure and cause erroneous oxygen readings due to fact that the smaller
diameter of the integral sample system tubing cannot vent the sample gas quickly at higher flow rates. If the
analyzer is not equipped with an integral flow control valve, a flow control metering valve with a flow
indicator upstream of the sensor must be installed to control the flow rate of the sample gas. A flow rate of 1­2 SCFH or 0.5-1 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
sudden vacuum on the sensor and may lead to electrolyte leakage thus causing damage to the

sensor (will void sensor warranty).

Electrical Connections

Incoming power and signal output connections are made to terminal blocks mounted on a PCB located in
the metal enclosure and accessible from the rear of the enclosure.

Do not supply voltage more than specified in this manual and noted near the power input
terminal of the transmitter.

Install all power, alarm relay and signal output connections in accordance with recognized
electrical standards. Supply power to the terminal marked “POWER”. Do not exceed the
recommended power rating.

Ensure the positive and negative terminals of the power supply are connected to the appropriate
terminals of the terminal block as marked.

Avoid electrostatic discharge - Clean all surfaces with a damp cloth only.

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