Analytical Industries GPR-7500 User Manual

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GPR-7500 AIS PPM H2S Transmitter

Advanced Instruments, Inc.

Owner’s Manual

2855 Metropolitan Place, Pomona, California 91767 USA ♦ Tel: 909-392-6900, Fax: 909-392-3665, email: info@aii1.com

Introduction

1 Quality Control Certification

Safety

3 Features & Specifications

4 Operation

Maintenance

Spare Parts

Troubleshooting

8 Warranty

Material Safety Data Sheets

Drawings

A/R

Explosion Proofing Electrical Connections

Appendix

Correlating readings – LCD display to 4-20mA signal output

Appendix

H2S Scrubber, Sample System, Media MSDS

Appendix

Maintenance H2S Scrubber & Coalescing Filter

Appendix

Table of Contents

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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.

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1. Introduction

Your new hydrogen sulfide transmitter incorporates an advanced electrochemical sensor specific to hydrogen sulfide along with state-of-the-art digital electronics designed to give you years of reliable precise measurements of hydrogen sulfide in a variety of industrial applications. More importantly, it has been constructed as intrinsically safe in accordance with ATEX Directives 94/9/EC for use in hazardous areas in zone 1 Group C and D

The transmitter design also complies with NEC intrinsic safety standards for use in Class 1, Division 1, Group C, D hazardous areas. Please refer to Appendix A for information on making electrical connections that maintain the desired level of protection.

To obtain maximum performance from your new hydrogen sulfide 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.

3. General Safety & Installation

This section summarizes the essential precautions applicable to the GPR-7500 AIS 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.

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 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.

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2. Quality Control Certification

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3. Maintenance

Serviceability: Except for replacing the hydrogen sulfide 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.

H2S 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.

Non-use Period: 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 EN 60079-11 : 2007

It must be installed in accordance with EN 60079-14

Sampling 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 installation. 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/Liquids in Sample Stream: A sample flow indicator with integral

metering valve is required upstream of the analyzer to remove any interfering gases such as oxides of sulfur and nitrogen that can interfere with measurement. Sample must be free from any condensable liquid. With gas streams containing condensable liquids, a coalescing filter must be installed upstream of the sensor. Consult the factory for recommendations concerning the proper selection and installation of sample conditioning requirements.

Expected Sensor Life: With reference to the publish specification located in Section 4 of this

manual, the expected life of all H2S sensors is predicated on the rate of loss of electrolyte from the sensor at

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temperature of 77°F/25°C and pressure of1 atmosphere in “normal” applications. Deviations from standard conditions will affect the life of the sensor (temperature higher than 770C and pressure less than atmospheric would cause a reduction in the sensor life).

Accuracy and Calibration: Refer to section 5 Operation. Material and Gases: 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 essential for maintaining the integrity of the gas stream for low PPM H2S level analysis.

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: Install the analyzer away from direct sun and from any source of heat. Situate and store the

analyzer away from direct sources of heat.

Liquid and Solid 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 on or 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 cables connected to the output terminals of the analyzer.

Sample Pressure and Flow

All electrochemical sensors respond to partial pressure changes in the gas of interest. The sensors are equally capable of analyzing the H2S content of a flowing sample gas stream or monitoring the H2S concentration in ambient air (such as a confined space in a control room or an open area around a landfill or bio-pond). The following is applicable to analyzers equipped with electrochemical 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. The analyzers function equally well with sample gas flowing across the sensor provided the sample does not produce any positive pressure or create a partial vacuum on the sensor. For positive sample pressure applications, suitable means must be employed to control the sample flow without subjecting the sensor to high sample pressure. For applications where the sample is less than atmospheric pressure, consult factory before initiating installation.

Inlet Pressure: For the analyzers designed to measure H

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 coalescing filter, 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, (set at no greater than 0.5 PSIG) at vent line of the analyzer. Caution: A sudden change in pressure at the sensor may result in the sensor electrolyte leakage and permanent damage to the sensor.

S in a flowing gas stream, the inlet sample

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Application, Positive-Pressure 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.

Flow rates of 1-5 SCFH cause no appreciable change in the H2S reading. However, flow rates above 5 SCFH may generate a slight backpressure on the sensor resulting in erroneous readings.

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).

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

Application, Atmospheric or Slightly Negative-Pressure: For such measurements,

an optional external sample pump may be used upstream of the sensor to push the sample across the sensor and out to atmosphere. 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 factory for recommendations concerning the proper selection and installation of optional components.

Moisture and/or particulates generally can be removed from the sensor by removing the sensor from the housing and either blowing gas on the sensing surface or gently wiping the sensing surface with a damped cloth.

Mounting of the Transmitter: The transmitter 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.

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

the analyzer enclosure. The GPR-7500AIS is powered by 12-24 VDC or 100/230 VAC supply (check the QC certificate to ensure the power requirement of your analyzer). 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.

Power Consumption: The maximum power the analyzer consumes is no more than 7 Watts.

4. Features & Specifications

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5. Operation Principle of Operation

The GPR-7500AIS H2S Transmitter incorporates a variety of advanced electrochemical sensors. These sensors are very specific to H2S and generate an electrical signal proportional to the amount of H2S present in a gas stream. The selection of a particular type of sensor depends on the maximum concentration of H2S contents in the sample stream. Consult the factory for recommendation.

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 of power input, signal output and the 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. Once connected, the intrinsic safety barriers limit the amount of power that flows to and from the signal processing electronics effectively preventing an explosive condition. The analyzer design conforms to the ATEX directive for equipment as intrinsically safe.

The GPR-7500AIS also meets the intrinsic safety standards required for use in Class 1, Division 1, Group C, D hazardous areas.

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Advanced Electrochemical Sensor Technology

All electrochemical sensors driven by a bias potential (three electrode configuration) function on the same principle and are specific to a certain gas. They measure the partial pressure of the target gas from low PPM to up to 1% levels in air, inert gases and gaseous hydrocarbons.

The target gas, in this case, Hydrogen Sulfide, diffuses into the sensor through a diffusion limiting membrane, reacts electrochemically at the sensing electrode and produces an electrical current output proportional to the H2Sconcentration in the gas phase. The sensor’s signal output is linear over all measuring 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 the design and chemistry of the sensor’s components add significant advantages to this extremely versatile H2S sensing technology. The sensor maintains its sensitivity to with +/-5% of its span (it does not sleep during continuous use; a typical symptom seen with conventional electrochemical H2S sensors)) over a 1-3 months period. To maintain accuracy over the useful life of the sensor, calibrate the sensor every 1-3 months. Under normal use, the sensor is expected lost from 18-24 months.

The H2S sensor recovers from an upset condition (exposure to very high H2S) to low PPM level in a matter of few minutes.

Electronic

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. The result is a very stable signal that reflects H2S concentration in the sample very accurately. Response time of 90% of full scale is less than 60 seconds on all ranges (actual experience may vary due to the integrity of sample line connections, dead volume and flow rate selected) under ambient analysis conditions. Sensitivity is typically 0.5% of full scale of the low range. The display has the resolution of 0.1 PPM H2S (on 0-20 PPM Full scale range). The analog output signal may be recorded by on external device via the 4-20 mA or optional 1-5V signal.

Sample System

The standard GPR-7500AIS is supplied without a sample conditioning system thereby giving users the option of adding their own or purchasing a factory designed sample conditioning system, see section 2 QC Certification for optional equipment ordered. Whatever the choice, the sample must be properly conditioned before introducing it to the analyzer sampling system to ensure accurate measurements.

The GPR-7500AIS is generally supplied with a minimum of a sample flow control valve and a flow meter. A coalescing filter (installed at the sample inlet) and an H2S scrubber (installed at the sample vent line to remove H2S from sample before venting) are most common optional components. A pressure regulator, with or without a pressure gauge is also available as an option. Users interested in adding their own sample conditioning system should consult the factory. Advanced 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 info@aii1.com for recommendation.

Calibration and Accuracy Overview

Single Point Calibration: As previously described, the electrochemical H

electrical current proportional to the H2S concentration in the sample gas. In the absence of H2S the sensor exhibits an absolute zero, e.g. the sensor does not generate a current output in the absence of H2S. Given these linearity and absolute zero properties, single point calibration is possible.

Sample Pressure: Since the sensor is sensitive to the partial pressure of H

output is a function of the number of molecules of H2S per unit volume. When sample is vented to the atmosphere the sensor essentially remains at atmospheric pressure. However, a positive or negative

S sensor generates an

S in the sample gas, the

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pressure on the sensor will alter the output of the sensor and unless the sensor is calibrated under the same analysis conditions, a significant error in measurements will occur.

For positive sample pressure applications, the sample pressure must be regulated by using a pressure regulator. The sample pressure between 5-30 PSIG offers a good compromise between delivering a reasonable gas flow (1-2 SCFH) and the ease of controlling the sample flow by using the integral flow control valve. Any blockage of the sample vent line will cause an increase in the pressure at the sensor thus causing erroneous readings. If sample is to be vented into a pipe above atmospheric pressure, a pressure regulator set at 0.5 PSIG must be installed to maintain constant pressure on the sensor. For vent pressure above0.5 PSIG, consult factory for proper selection of electronics.

Ambient Temperature: The rate at which H

Teflon membrane otherwise known as an ' H2S diffusion limiting barrier'. All diffusion processes are temperature sensitive, therefore, the fact that the sensor's electrical output will vary with temperature is normal. Under typical applications, this variation is relatively constant and the measurement accuracy remains within the published specifications over the recommended operating rage of temperature. The accuracy of +5% or better over an operating temperature range e.g., 5-45oC can be obtained. The measurement accuracy will be the highest if the calibration and sampling are performed at similar temperatures (a temperature variation of 10 ºC may produce an error of >+/-2% of full scale).

S molecules diffuse into the sensor is controlled by a

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

of errors, 'percent of reading errors', illustrated by Graph A below and the 'percent of full scale errors', illustrated by Graph B. The percent of reading error is contributed by incorrect calibration procedure whereas the percent of full scale error is contributed by tolerance in components and the measurement device. These errors are 'spanned out' during calibration, especially when span calibration is done close to the top end of the measuring range followed by a zero calibration.

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 at the factory is typically < 0.5% of full scale.

Example 1: Graph A, percent of reading error, this error is more pronounced when a span adjustment is carried out at the lower end of the scale, e.g., when span calibration is done by 20 PPM span gas on a 100 PPM full scale range, any error at 20 PPM span gas would be multiplied by a factor of 5 (100/20) when making measurements close to 100 PPM. Conversely, an error during a span adjustment close to the top end of the range, e.g., at 100 PPM would reduce the error proportionately for measurements 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.

Graph C shows the overall accuracy of the measurement.

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Mounting of the Transmitter

The GPR-7500AIS transmitter 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 by using eight (4) of the appropriate screws.

To facilitate servicing the interior of the transmitters, secure the back plate 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 Ex enclosure or the fiberglass enclosure. Failure to reinstall either of the gaskets will void the

NEMA 4 rating and the immunity to RFI/EMI. The transmitters design provides immunity from

RFI/EMI by maintaining a good conductive contact between the two halves of the enclosures via a conductive gasket (the smaller enclosure containing signal processing electronics). The surfaces contacting the conductive gasket are unpainted. Do not paint these areas. Painting will negate the RFI/EMI protection.

Note: If equipped with optional H2S scrubber, the H2S from the sample gas will be removed by the scrubbing material. The scrubbing material changes its color from purple to light pale. Replace scrubbing material when 2/3 of the material had changed its color from purple to pale.

As a safety, connect the vent line of analyzer to a vent pipe for safe venting of sample gas that might contain un-scrubbed H2S

If equipped with optional coalescing filter, mount the entire panel to any vertical flat surface. If possible,

connect the drain valve outlet to a vent pipe.

Keep the drain valve on coalescing filter closed during normal operation. To drain liquid, open the drain valve. After draining the liquid, turn the drain valve off.

Do not leave the drain valve open when the drain outlet is not connected to a vent pipe. Failure to do so will cause H2S to leak into atmosphere and cause potential hazard.

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Sample system shown with optional coalescing filter and H2S scrubber

Coalescing filter drain valve

Gas Connections

The GPR-7500AIS with its standard flow through configuration is designed for positive pressure samples and requires connections for an incoming sample and an outgoing vent line. Zero and span inlet ports are offered as part of the optional sample systems. The user is responsible for calibration gases and other required components, see below.

Procedure

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

1. If analyzer has a sample inlet and a sample vent line, connect the sample to SAMPLE and vent to the

VENT line.

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

3. Connect a ¼” vent line to the compression fitting to be used for venting the SAMPLE.

4. Connect a 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, keep the sample, span and

zero gas pressure within 5 PSIG of each other for better gas flow control..

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

8. Note: If equipped with the optional coalescing filter, regulate the inlet pressure less than 30 psig.

9. Flow rates of 1-5 SCFH cause no appreciable change in the sample reading. However, flow rates above

5 SCFH may generate a backpressure on the sensor and cause erroneous sample readings due to the 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 sample flow rate. A flow rate of 1-2 SCFH or 0.5-1 L/min (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).

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As a safety, connect the vent line of analyzer to a vent pipe for safe venting of sample gas that might contain un-scrubbed H2S

If equipped with optional coalescing filter, mount the entire panel to any vertical flat surface. If possible,

connect the drain valve outlet to a vent pipe.

Keep the drain valve on coalescing filter closed during normal operation. To drain liquid, open the drain valve. After draining the liquid, turn the drain valve off.

Do not leave the drain valve open when the drain outlet is not connected to a vent pipe. Failure to do so will cause H2S to leak into atmosphere and cause potential hazard.

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1 A Fuse

Analyzer ground terminal must be connected to ground

Power In Alarms Signal Out

Electrical Connections

The Incoming power, alarm relays, and signal output connections are made to terminal blocks mounted on a PCB located in the explosion proof enclosure.

Do not supply voltage above the noted value in

this manual and noted near the power input terminal of the analyzer.

The PCB in the explosion proof enclosure contains a power limiting intrinsic safety barrier that limit the total power available at the PCB electronics mounted in the general purpose enclosure.

With proper insulation of the incoming power, this configuration of the GPR-7500AIS conforms to the ATEX directives for equipments for use in hazardous area. The analyzer meets the following area classification:

The GPR-7500AIS also meets the intrinsic safety standards required for use in Class 1, Division 1, Group C, D hazardous areas.

The A-1166-H2S A IS PCB in the Ex enclosure contains two fuses, one plug-in (brown color) rated at 50 mA and the second mounted on the PCB (after the DC voltage is regulated to lower safe value, this fuse meets barrier network standard EN 50020).

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

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1 A fuse

Hazardous Area Installation

The GPR-7500AIS may be installed in a hazardous area when adhered to the recommended installation procedure.

Power Input

A 12-28 VDC or 100/230 VAC power supply with a shielded power cable is recommended. The power cable to the Ex enclosure must be supplied through a conduit approved for use in hazardous area. Secure the wires to the power input terminal block by using the integral screws of the terminal block. Do not substitute terminal screws. With AC power, the power ground must be connected to the ground terminal marked on the enclosure.

CAUTION: Check the QC for the proper power requirement. Incorrect power will severely damage the analyzer

Output Connections

The transmitter has two adjustable alarms, one power fail alarm and 4-20 mA or 1-5 VDC signal output connections. CAUTION: The 4-20mA circuit does not require external power. Supplying external power to

the PCB will permanently damage the PCB.

The HI and LOW alarms are user configurable. The relays are rated at 5A @ 250 VAC. The power failure alarm is a dry contact that will close when power is turned OFF. This relay is rated at 5A

@ 250 VAC. CUTION: Do not exceed the recommended rating of the relays. Excessive power through the relays can

severely damage the relays and the PCB.

Fuse 50 mA

Power 12-28 VDC or 100/230 VAC

Alarm Relays and 4-20 mA Signal Intrinsically Safe Ex d enclosure Fiber Glass enclosure

Procedure

Power requirements consist of a 12-28 VDC or 100/230 VAC power supply. Check the QC and analyzer cover plate for proper power requirement.

Unscrew the cone shaped cover from the lower enclosure. Separate the shielding from the wires of the cable. Ensure the positive and negative terminals of the power supply are connected to the appropriate terminals of

the terminal block as marked. For AC power, connect primary, neutral and power ground to the respective terminals.

Connect the shielding of the cable to the ground screw inside the enclosure. Replace the cover.

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Sensor shown with ribbon cable half inserted showing the conducting bars facing COND on PCB

Levers on side of ribbon cable connector

Note: The male and female power terminals snap together, making it difficult to detach them when connecting the shield to the ground. However, after connecting the shield, ensure that the male terminal is fully inserted and secured into the female terminal block.

Installation of H2S Sensor

The GPR-7500AIS Oxygen Transmitter is equipped with SS sensor housing. This housing offers ease of replacement of sensor and at the same time prevents any leakage into the system. The sensor is screwed in and makes the seal against the flat surface of the sensor housing with the integral O-ring on the sensor’s threaded front end. The integrity of the sensor and the sensor housing has been tested at the factory prior to shipment and is fully operational from the shipping container.

Caution: DO NOT dissect 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 off in a manner similar to that of a common battery in accordance with local regulations.

Should the transmitter come without sensor installed or need to install a new sensor, follow the guidelines give below.

Procedure

1. Remove the two (2) clamps securing the right side

corners and open the door of the fiber glass enclosure.

2. Remove the PCB along with the ribbon cable from the

top of the sensor by gently pulling the connector on the sensor PCB.

3. Remove the ribbon cable from the PCB by gently

pulling the two small levers on the side of the ribbon cable connector (unlocking the ribbon cable).

4. Remove the PCB from the sensor by gently pulling it

off.

Avoid electrostatic discharge – touch a metal surface with your bare hand before contacting the PCB. Clean all surfaces with a damp cloth only

5. Turn the sensor anti clockwise until loosen and then pull it off the housing.

6. Remove the new sensor from the bag.

7. Screw the new sensor in to the sensor housing until finger tight.

8. Align 4 pins of the sensor PCB with 4 pins of the sensor and gently push the PCB on to the sensor until

it is firmly seated.

9. Insert the ribbon cable into the connector with bare conducting bars facing COND on the PCB and push

the two side levers on the connector (locking the ribbon cable).

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Span Gas Preparation

Note: The GPR-7500AIS can be calibrated by using a certified span gas, preferably 50-80% of the full scale

of the least sensitive range. After initial calibration, subsequent calibration should be carried out by using a span gas between 50 to 80% of the range of interest or one range above the range of interest.

Caution: Do not inhale the H2S span gas. If the analyzer is installed in an enclosed area, when using a span gas, ensure the area is being ventilated by circulating air to flush out H

Required Components

1. Certified span gas cylinder with an H2S concentration, balance nitrogen or air, approximating 50-80% of

the full scale of the measuring range or one range above the intended measuring range. For example, for analysis on 0-500 PPM range, use a span gas with H2S concentration ranging from 250-400 PPM

2. A pressure regulator to set the span gas pressure between 5 and 30 psig.

3. A flow meter to set the flow between 1-5 SCFH (if the transmitter is not equipped with a flow meter),

4. Suitable tube fittings and a 4-6 ft. length of 1/8” dia. metal tubing to connect the cylinder regulator to the

flow meter inlet. (bypass step 4, 5 if the transmitter is equipped with a flow meter and connect the tubing from regulator directly to the SPAN inlet of the transmitter)

5. Suitable tube fittings and a 4-6 ft. length of 1/8” dia. metal tubing to connect from the flow meter vent to

tube fitting designated as SAMPLE IN or SPAN IN at the analyzer.

Procedure

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

2. Keep the regulator’s exit valve closed and open the cylinder’s control knob slowly.

3. Open the cylinder valve completely.

4. Set the pressure between 5-30 psig using the pressure regulator’s control knob. 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 damage the sensor

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START-UP TEST

ELECTRONICS – PASS TEMP SENSOR – PASS BAROMETRIC SENSOR – PASS

REV 2.40

12 PPM

Auto Sampling 0-500 PPM Range

76 F 97 Kpa LO1 0 PPM HI 40 PPM

MAIN MENU

AUTO SAMPLE

MANUAL SAMPLE CALIBRATION CONFIG ALARMS ALARM BYPASS

Establishing Power to Electronics

Once the two power input wires of the shielded cable are properly connected to the terminals inside the Ex enclosure as described above, connect the other end of the two wires to a suitable 12-24 VDC power source such as a battery, PLC, DCS, etc.

The digital display responds instantaneously. The transmitter performs several self-diagnostic system status checks termed as “START-UP TEST” as illustrated below:

After self diagnostic tests, the analyzer turns itself into the sampling mode. And displays H2S contents the sensor is exposed to, the analysis range, the ambient temperature and pressure, High and Low alarm set points.

Manu Navigation

The four (4) pushbuttons located on the front of the transmitter control the micro-processor functions: Blue ENTER (select) Yellow UP ARROW Yellow DOWN ARROW Green MENU (escape)

Main Menu

To access the MAIN MENU, press the MENU (ESC) key and the following screen will appear.

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MAIN MENU

AUTO SAMPLE

MANUAL SAMPLE CALIBRATION CONFIG ALARMS ALARM BYPASS

12 PPM

Auto Sampling 0-500 PPM Range

76 F 97 Kpa LO1 0 PPM HI 40 PPM

MAIN MENU

AUTO SAMPLE

MANUAL SAMPLE

CALIBRATION CONFIG ALARMS BYPASS ALARMS

MANUAL RANGE

2000 PPM 1000 PPM 500 PPM

This screen shows various options available. You can use the UP and DOWN arrow key to move the cursor and highlight the desired function. After moving the cursor to the desired function, press ENTER to access that function.

Range Selection

The GPR-7500 AIS transmitter is equipped with three (3) standard measuring ranges (see specification) and provides users with a choice of sampling modes. By accessing the MAIN MENU, users may select either the AUTO SAMPLING (ranging) or MANUAL SAMPLING (to lock on a single range) mode.

Note: For calibration purposes, use of the AUTO SAMPLE mode is recommended. However, the user can also select the MANUAL SAMPLE mode for calibration but the span gas must not exceed the full scale of the manual range selected – for example, a span gas with15 PPM H2S concentration in nitrogen would dictate the use of the 0-20 PPM full scale range for calibration.

Auto Sampling

1. Access the MAIN MENU by pressing the MENU key.

2. Advance the reverse shade cursor using the ARROW keys to highlight AUTO SAMPLE.

3. Press the ENTER key to select the highlighted menu option. The display returns to the sampling mode:

4. The display will shift to the next higher range when the H2S reading exceeds 99.9% of the upper limit of

the current range. The display will shift to the next lower range when the H2S reading drops to 85% of the next lower range. For example, if the transmitter is reading 2 PPM on the 0-20 PPM range and an upset occurs, the display will shift to the 0-50 PPM range when the H2S reading exceeds 19.99 PPM. Conversely, once the upset condition is corrected, the display will shift back to the 0-20 PPM range when the H2S reading drops to 17 PPM (85% of 20 PPM).

Manual Sampling

1. Access the MAIN MENU by pressing the MENU key.

2. Advance the reverse shade cursor using the ARROW keys to highlight MANUAL SAMPLE.

3. Press the ENTER key to select the highlighted menu option. The following display appears:

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12 PPM

Manual Sampling 0-500 PPM Range

76 F 97 Kpa LO1 0 PPM HI 40 PPM

65 PPM

OVERRANGE

Manual Sampling

0-500 PPM Range

76 F 97 Kpa LO1 0 PPM HI 40 PPM

4. Advance the reverse shade cursor using the ARROW keys to highlight the desired MANUAL RANGE.

5. Press the ENTER key to select the highlighted menu option. The following display appears with the range selected and oxygen concentration of the sample gas:

6. If the value of H2S goes above the full scale range selected, display will not shift to the next higher

range. Instead, when the H2S reading exceeds 125% of the upper limit of the current range, an OVER RANGE warning will be displayed.

7. Once the OVER RANGE warning appears the user must advance the transmitter to the next higher

range.

8. NOTE: With H2S reading above 125% of the selected range, the mA signal output will increase but will

freeze at a maximum value of 24 mA. After the sample reading falls below the full scale range, the mA signal will become normal.

Calibration of Transmitter

The electrochemical H2S sensors generate an electrical current that is linear or proportional to the H2S concentration in a sample gas. In the absence of H2S the sensor exhibits an absolute zero, i.e., the sensor does not generate a current output in the absence of H2S. Given the properties of linearity and an absolute zero, a single point calibration is possible.

As described below, zero calibration is recommended only when the application (or user) demands optimum accuracy of below 5% of the most sensitive or lowest range available on the transmitter. Span calibration, in one of the forms described below, is necessary to adjust the analyzer sensitivity for accurate measurements of H2S. As a rule of thumb, zero calibration should be carried out after span calibration.

Zero Calibration

Despite the absolute zero inherent to the electrochemical H2S sensors, the reality is that analyzers may display H2S reading even when sampling a zero gas (H2S free gas) due to:

1. Contamination or questionable quality of the zero gas

2. Minor leakage in the sample line connections

3. Residual electrical current generated by the sensor

4. Tolerances in the electronic components

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The maximum zero offset of every transmitter is checked prior to shipment. However, due to the fact that the factory sample system conditions differ from that of the user, no ZERO OFFSET adjustment is made at the factory

Typical offset seen is less than 0.5-1 PPM. Therefore, for most applications, a Zero calibration is not required. However, ZERO calibration option has been provided to allow the user to precisely measure H2S concentration at the very low levels (less than 0.5 PPM). As described below, accomplishing either objective places a degree of responsibility on the user.

Determining the true offset requires the user to wait (see Online Recovery Time section) until the analyzer reading is no longer trending downward (best evidenced by a constant horizontal trend on an external recording device.

The zero offset adjustment is limited to 5-20% of the most sensitive range of the analyzer. At factory, analyzer is QC tested to confirm that the maximum offset is less than 5% of the most sensitive range available. Should you observe a zero offset more than 5% of the lowest range, check sample system for any possible leaks, integrity of the zero gas and assure that the analyzer has been given enough time to stabilize on zero gas before initiating the” ZERO CALIBRATION”.

Caution: If adequate time is not allowed for the analyzer to establish the true baseline and a ZERO calibration is performed, the analyzer will, in all probability, display a negative reading in the sample mode after a certain period of time. If a negative reading is seen, perform ZERO calibration again

Span Calibration

Involves periodically, see Intervals section below, checking and/or adjusting the electronics to the sensor’s

signal output at a given H2S standard. The frequency of calibration varies with the application, e.g., the degree of accuracy required by the application and the quality assurance protocol of the user. However, the interval between span calibrations should not exceed three (3) months.

Note: Regardless of the value of the standard used, the span calibration process takes approximately 10-15 minutes

Factors to Consider when calibrating

1. When it comes to the calibration of transmitter, circumstances vary widely from the ideal conditions that

exist at the factory to a variety of differing circumstances users encounter in the field. The following describes the most common factors and reasons that influence the calibration procedures.

2. All electrochemical sensor based devices require periodic calibration, e.g. weekly intervals to a 3 month

maximum, to ensure accuracy and ascertain the integrity of the sensor

3. For optimum accuracy, calibrate the analyzer at or close to the temperature and pressure of the sample

gas

4. The priority users place on getting or keeping an analyzer online is “the” most significant factor involved

in calibration and troubleshooting issues” the time it takes an analyzer/transmitter to come down to a specific level after installation or calibration. A new sensor would require 30-60 minute settling time after installation before commencing calibration. If a sensor has been in service, calibration can be performed any selected time.

5. For optimum accuracy, the H2S concentration of a span gas should be approximate 50-90% of the full

scale range of analysis or one range above the analysis range, e.g. 50-80 PPM on the 0-100 PPM range.

6. Use of span gas less than 50% of the full scale range of measurements will introduce an “expanding

error” as illustrated by Graph A in Example 1 in the Accuracy section above, close to the top end of the range.

7. Prematurely initiating the SPAN CALIBRATION function (before the analyzer reading has stabilized)

can result in erroneous readings as follows:

Zero Calibration Procedure

Zero calibration should be carried out after the span calibration has been performed. Normally, zero calibrations are performed when a new sensor is installed or changes are made in the sample system connections.

Before performing a ZERO calibration, it is highly recommended to perform a factory default zero. This will eliminate previous zero offset adjustment that might have been made. With factory default setting, if the zero

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MAIN MENU

AUTO SAMPLE MSNUAL SAMPLE

CALIBRATION

CONFIG ALARMS BYPASS ALARMS

CALIBRATION

SPAN CALIBRATE

ZERO CALIBRATE

DEFAULT SPAN DEFAULT ZERO OUTPUT SPAN

ZERO CALIBRATION ENTER TO CALIBRATE MENUE TO ABORT

PASSED CALIBRATION

FAILED CALIBRATION

offset does not exceed 50% of the lowest range, this indicates that the integrity of the sensor, the analyzer/transmitter sample system and the sample line bringing in the sample gas is maintained.

1. Access the MAIN MENU by pressing the MENU key.

2. Advance the reverse shade cursor using the ARROW keys to highlight CALIBRATION.

3. Press the ENTER key to select the highlighted menu option. The following displays appear:

4. Advance the reverse shade cursor using the ARROW keys to highlight ZERO CALIBRATE.

5. Press the ENTER key to select the highlighted menu option. The following displays appear:

6. Press the ENTER key to calibrate or MENU key to abort and return to SAMPLING mode.

7. Allow approximately 60 seconds for the calibration process while the microprocessor determines

whether the signal output or reading has stabilized within 50% of the full scale low range. If the offset is less than 50% of the lowest range, by pressing ENTER, message PASSED CALIBRATION will appear and return to the Sample mode. On the other hand, if the offset is above 50%, pressing ENTER, message FAILED CALIBRATION will appear and the analyzer will return to Sample mode without completing the Zero calibration.

Both the Zero Calibrate and Span Calibrate functions result in the following displays:

Factory Default Zero Calibration

The feature will eliminate any previous zero calibration adjustment and display the actual signal output of the sensor at a specified oxygen concentration. For example, assuming a zero gas is introduced, the display above 0.00% will reflect an actual zero offset. This feature allows the user to ensure that the accumulative zero offset never exceeds 5-20% of the lowest range limit. To perform Default Zero,

1. Access the MAIN MENU by pressing the MENU key.

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MAIN MENU

AUTO SAMPLE MSNUAL SAMPLE

CALIBRATION

CONFIG ALARMS BYPASS ALARMS

CALIBRATION

SPAN CALIBRATE ZERO CALIBRATE DEFAULT SPAN

DEFAULT ZERO

OUTPUT SPAN OUTPUT ZERO

FACTORY DEFAULTS SET

MAIN MENU

AUTO SAMPLE MANUAL SAMPLE

CALIBRATION

CONFIG ALARMS BYPASS ALARMS

CALIBRATION

SPAN CALIBRATE ZERO CALIBRATE DEFAULT SPAN DEFAULT ZERO OUTPUT SPAN

OUTPUT ZERO

2. Advance the reverse shade cursor using the ARROW keys to highlight CALIBRATION.

3. Press the ENTER key to select the highlighted menu option. The following displays appear:

4. Advance the reverse shade cursor using the ARROW keys to highlight DEFAULT ZERO.

5. Press the ENTER key to select the highlighted menu option. The following display appears and after 3 seconds the system returns to the SAMPLING mode:

Adjustment of 4 mA Analog Output

In rare instances the 4-20mA signal output may not agree to the reading displayed on the LCD. This feature enables the user to adjust the 4mA signal output when the LCD displays 0000.

Note Adjust the 20mA signal output with the OUTPUT SPAN option described below.

1. Access the MAIN MENU by pressing the MENU key.

2. Advance the reverse shade cursor using the ARROW keys to highlight CALIBRATION.

3. Press the ENTER key to select the highlighted menu option and the following displays appear:

4. Advance the reverse shade cursor using the ARROW keys to highlight OUTPUT ZERO.

5. Press the ENTER key to select the highlighted menu option and the following display appears:

1 0 0 OUTPUT ZERO OFFSET PRESS UP OR DOWN

TO CHANGE VALUE ENTER TO SAVE MENU TO RETUE

MAIN MENU

AUTO SAMPLE

MANUAL SAMPLE CALIBRATION CONFIG ALARMS

12 PPM

Auto Sampling 0-500 PPM Range

76 F 97 Kpa LO1 0 PPM HI 40 PPM

MAIN MENU

AUTO SAMPLE

MANUAL SAMPLE CALIBRATION CONFIG ALARMS BYPASS ALARMS

CALIBRATION

SPAN CALIBRATE

ZERO CALIBRATE DEFAULT SPAN DEFAULT ZERO OUTPUT SPAN

OUTPUT ZERO

6. The default setting of 100 illustrates no adjustment to the 4 mA signal. Adjust the initial value to above

100 to increase the analog signal value or decrease it below 100 to decrease the analog signal.

7. Press the ENTER key to advance the underline cursor right or press the MENU key to advance the

underline cursor left to reach to the desired digit.

8. Press the ARROW keys to change the value.

9. Press ENTER to accept 4 mA offset.

10. If 4 mA is still off, repeat steps 7 through 9 until the output is 4 mA .

After adjustment, the system automatically returns to the SAMPLING mode.

Span Calibration Procedure

This procedure assumes a span gas under positive pressure. To assure an accurate calibration, the temperature and pressure of the span gas must closely match with

the sample gas. For calibration purposes, use of the AUTO SAMPLE mode is recommended.

1. Access the MAIN MENU by pressing the MENU key.

2. Advance the reverse shade cursor using the ARROW keys to highlight AUTO SAMPLE.

3. Press the ENTER key to select the highlighted menu option. The following displays appear:

4. Return to the MAIN MENU by pressing the MENU key.

5. Advance the reverse shade cursor using the ARROW keys to highlight CALIBRATION.

6. Press the ENTER key to select the highlighted menu option.

7. Repeat to select SPAN CALIBRATE The following displays appear:

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0000 PPM PRESS UP OR DOWN

TO CHANGE VALUE ENTER TO SAVE MENUE TO ABORT

625 PPM

SPAN CLAIBRATION ENTER TO CALIBRATE MENU TO ABORT

PASSED CALIBRATION

8. After selecting the SPAN CALIBRATION, the following displays appear:

9. Press the ENTER key to advance the underline cursor right or press the MENU key to advance the

underline cursor left to reach to the desired digit of the alarm value.

10. Repeat until the complete span value has been entered and press ENTER. The following display will

appear.

11. Press the ENTER key to accept SPAN CALIBRATION. After successful calibration, the analyzer will

display a message “PASSED CALIBRATION” and return to the Sample mode.

NOTE: The analyzer is allowed to accept calibration only when O2 reading is within 50% of the span gas value. If the O2 reading is outside of this limit, by pressing ENTER to accept calibration will result in “FAILED CALIBRATION” and the analyzer will return to the Sample mode without completing Span calibration.

If the calibration is unsuccessful, return to the SAMPLING mode with span gas flowing through the transmitter, make sure the reading stabilizes, reaches within 30-50% (see below) of the span gas value (after factory default span setting) and repeat the calibration before concluding the equipment is defective.

Before disconnecting the span gas line and connecting the sample gas line (if the analyzer is not equipped with a SPAN/SAMPLE vale option), flow the sample gas for 1-2 minutes to purge the air inside the sample line. Disconnect the span gas line and replace it with the sample gas line.

Factory Default Span

With factory default span, previous calibration data stored in the memory is removed and the sensitivity of the analyzer is reset to the value based on the average output of the oxygen sensor at a specific oxygen concentration. For example, with factory default settings, when a span gas is introduced, the microprocessor will display oxygen reading within 30-50% of the span gas value, indicating that the sensor output is within the specified limits. This feature allows the user to check the sensor’s signal output without removing it from the sensor housing.

1. Access the MAIN MENU by pressing the MENU key.

2. Advance the reverse shade cursor using the ARROW keys to highlight CALIBRATION.

3. Press the ENTER key to select the highlighted menu option. The following display appears:

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MAIN MENU

AUTO SAMPLE MANUAL SAMPLE

CALIBRATION

CONFIG ALARMS

BYPASS ALARMS

CALIBRATION

SPAN CALIBRATE ZERO CALIBRATE

DEFAULT SPAN

DEFAULT ZERO OUTPUT SPAN

OUTPUT ZERO

12 PPM

Auto Sampling 0-500 PPM Range

76 F 97 Kpa LO1 0 PPM HI 40 PPM

FACTORY DEFAULTS SET

MAIN MENU

AUTO SAMPLE MANUAL SAMPLE

CALIBRATION

CONFIG ALARMS BYPASS ALARMS

CALIBRATION

SPAN CALIBRATE ZERO CALIBRATE DEFAULT SPAN DEFAULT ZERO

OUTPUT SPAN

4. Advance the reverse shade cursor using the ARROW keys to highlight DEFAULT SPAN.

5. Press the ENTER key to select the highlighted menu option. The following displays appear and after 3 seconds the system returns to the SAMPLING mode:

Adjustment of 20 mA Analog Output

In rare instances the 4-20mA signal output may not agree to the reading displayed by the LCD. This feature enables the user to adjust the 20mA signal output should the LCD display not agree.

Note: Adjust the 4mA signal output with the OUTPUT ZERO option described above.

1. Access the MAIN MENU by pressing the MENU key.

2. Advance the reverse shade cursor using the ARROW keys to highlight CALIBRATION.

3. Press the ENTER key to select the highlighted menu option. The following displays appear:

4. Advance the reverse shade cursor using the ARROW keys to highlight DEFAULT SPAN.

5. Press the ENTER key to select the highlighted menu option. The following display appears

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100.0 OUTPUT SPAN OFFSET PRESS UP OR DOWN

TO CHANGE VALUE ENTER TO SAVE MENU TO RETURN

6. The default setting of 100 illustrates no adjustment to the analog output signal. Adjust the initial value to

above 100 to increase the 20 mA analog signal value or decrease it below 100 to decrease the 20 mA analog signal.

7. Press the ENTER key to advance the underline cursor right or press the MENU key to advance the

underline cursor left to reach to the desired digit of the OUTPUT SPAN OFFSET value.

8. Press the ARROW keys to enter the desired digit. After entering the digit press ENTER and the 20 mA

signal will adjust to the new value.

9. If the 20 mA signal still does not match with 20 mA signal, repeat steps 7 through 8 the 20 mA matches

with the display..

10. Save the adjustment value by pressing the ENTER key or abort by pressing the MENU key. The system returns to the SAMPLING mode.

Sampling

GPR-7500 AIS H2S Transmitter requires a positive pressure to flow the sample gas across the sensor to measure the H2S concentration in a sample gas.

Procedure

Following calibration, the transmitter automatically returns to the SAMPLE mode.

1. Select the desired sampling mode - auto or if manual, the range that provides maximum resolution – as

described above.

2. Use metal tubing to transport the sample gas to the transmitter.

3. The main consideration is to eliminate air leaks which can affect oxygen measurements above or below

the 20.9% oxygen concentration in ambient air - ensure the sample gas tubing connections fit tightly into the sample input port.

4. For sample gases under positive pressure, the user must provide a means of controlling the inlet

pressure between 5-30 psig and the flow of the sample gas between 1-5 SCFH, a flow rate of 1-2 SCHF is recommended

5. For sample gases under atmospheric or slightly negative pressure, an optional sampling pump is

recommended to push the sample the sensor housing. Generally, when using a pump, no pressure regulation or flow control device is involved. However, a flow meter upstream of analyzer is recommended to ensure that the sample flow is adequate.

6. Assure the sample is adequately vented for optimum response and recovery – and safety.

7. Allow the oxygen reading to stabilize for approximately 10 minutes at each sample point.

8. Note: To avoid erroneous oxygen readings and damage to the sensor, 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).

9. Assure there are no restrictions in the sample or vent lines

10. Avoid drawing a vacuum that exceeds 14” of water column pressure – unless done gradually

11. Avoid excessive flow rates above 5 SCFH which may generate backpressure on the sensor.

12. Avoid sudden releases of backpressure that can severely damage the sensor.

13. Avoid the collection of particulates, liquids or condensation on the sensor that could block the diffusion

of oxygen into the sensor.

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14. 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

Setting Alarms

The analyzer is equipped with two programmable alarm relays. The two alarms set points are user adjustable and can be set either as LOW/HIGH, LOW/LOW or HIGH/HIGH.

Setting Alarm Delays

Alarm delay option allows the user to ignore the alarm should a sudden short spike in the oxygen reading occurs.

Setting Alarm Bypass

The alarms bypass feature allows the user to bypass the alarm during trouble shooting/repair or test run. However, once the alarm bypass is selected, alarm will remain disabled even if the oxygen reading is over/under the alarm set point. The alarm will re-arm itself only after the fault condition has been reverted.

The alarms are automatically disabled during SPAN/ZERO calibration. The relays are rated at 5A @ 250V.

CAUTION; When using these relays, do not exceed the recommended rating.

Power Failure Alarm

A relay contact that is normally energized (normally open) during operation, is closed if the power to the analyzer is turned OFF.

The relay is rated at 5A @ 250V.

CAUTION: When using this relay, do not exceed the recommended rating.

Standby

The transmitter has no special storage requirements. The sensor should remain inside of the sensor housing and connected to the electronics during storage

periods. Before turning the sample gas OFF, ensure that sample/bypass valve (if analyzer equipped) is at the BYPASS position. This will keep the sensor isolated from ambient air and would be ready to use again when required with very short down time.

NOTE: Under isolated conditions, some oxygen will diffuse into the sample system/sensor housing and the sensor out will slowly climb up but after 2-3 hours, it will reach a Plato, generally less than 400 PPM

Store the transmitter with the power OFF at a safe location and away from a direct heating source. If storing for an extended period of time, protect the analyzer from dust, heat and moisture.

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Item No.

Description

GPR-11-72-BE

H2S sensor for measuring up to 2000 PPM H2S

GPR-11-72-B1

H2S Sensor for measuring up to 100 PPM H2S

Item No.

Description

MTR-1011

Meter Digital Panel LCD (Standard)

MTR-1014

Meter Digital Panel LCD (Low Temperature)

A-1188-AIS-2000

PCB Assembly Main signal processing and display

A-1166-AIS-2000 A-1196

PCB Assembly Power Supply PCB sensor

6. Maintenance

Generally, replacing the sensor periodically or replacing filter element of the coalescing filter is the extent of the maintenance requirements of this transmitter.

Serviceability: Except for replacing the 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.

7. Spare Parts

Recommended spare parts for the GPR-1500 IS Oxygen Transmitter:

Other spare parts:

Symptom

Possible Cause

Recommended Action

Slow recovery

At installation, defective sensor

Air leak in sample system connection(s)

Abnormality in zero gas Damaged in service -

prolonged exposure to air, electrolyte leak

Sensor nearing end of life

Replace sensor if recovery unacceptable or O2 reading fails to reach 10% of lowest range

Leak test the entire sample system: Vary the flow rate, if the O2 reading changes inversely with the change in flow rate indicates an air leak - correct source of leak

Qualify zero gas (using portable transmitter)

Replace sensor

High O2 reading after installing or replacing sensor

Transmitter calibrated before sensor stabilized caused by:

1) Prolonged exposure to ambient air, worse if sensor was un-shorted

2) Air leak in sample system connection(s)

3) Abnormality in zero gas

Allow O2 reading to stabilize before making the span/calibration adjustment

Continue purge with zero gas

Leak test the entire sample system (above)

Qualify zero gas (using portable transmitter)

High O2 reading Sampling

Flow rate exceeds limits Pressurized sensor Improper sensor selection

Correct pressure and flow rate Remove restriction on vent line Replace GPR/PSR sensor with XLT

sensor when CO2 or acid gases are present

8. Troubleshooting

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Symptom

Possible Cause

Recommended Action

Response time slow

Air leak, dead legs, distance of sample line, low flow rate, high volume of optional filters and scrubbers

Leak test entire sample system, reduce dead volume or increase flow rate

H2S reading doesn’t agree to expected values

Pressure and temperature of the sample is different than span gas

Error in calibration Abnormality in gas

Calibrate the transmitter (calibrate at pressure and temperature similar to that of sample)

Repeat calibration Qualify the integrity of the sample gas (use

a portable analyzer as a secondary check)

Erratic H2Sreading or No H2S reading

Sudden Changes in sample pressure

Loose sensor cable and or sensor PCB

Incorrect polarity of ribbon cable

Corroded sensor PCB

Liquid covering sensing area

Sensor nearing end of life

Calibrate the transmitter (calibrate at pressure and temperature similar to that of sample)

Maintain sample pressure to within recommended range

Secure ribbon cable firmly by fully inserting the ribbon cable into its mating socket on the sensor PCB

Ensure that sensor PCB is firmly secured on sensor

Ensure that the conductors of ribbon cable align with COND on sensor PCB

Replace sensor PCB

Replace sensor . Replace sensor

Cannot span calibrate

Cannot zero calibrate

Incorrect span gas Span gas pressure too high Span flow rate too high Incorrect sensor Sensor nearing end of life

Zero offset outside of recommended range

High sample/zero gas flow causing back pressure on sensor

Defective sensor

Check span gas with a secondary analyzer Set span gas pressure within

recommended range Set flow rate within recommended range Replace sensor

Allow enough time for sensor to settle with zero gas

Set sample/zero gas flow within recommended range

Replace sensor

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9. Warranty

The design and manufacture of GPR Series oxygen transmitters/analyzers, monitors and oxygen sensors are performed under a certified Quality Assurance System that conforms to established standards and incorporates state of the art materials and components for superior performance and minimal cost of ownership. Prior to shipment every analyzer is thoroughly tested by the manufacturer and documented in

the form of a Quality Control Certification that is included in the Owner’s Manual accompanying every

analyzer. When operated and maintained in accordance with the Owner’s Manual, the units will provide many years of reliable service.

Coverage

Under normal operating conditions, the monitor, analyzers and sensor are warranted to be free of defects in materials and workmanship for the period specified in accordance with the most recent published specifications, said period begins with the date of shipment by the manufacturer. The manufacturer information and serial number of this analyzer are located on the rear of the analyzer. Advanced Instruments Inc. reserves the right in its sole discretion to invalidate this warranty if the serial number does not appear on the analyzer.

If your Advanced Instruments Inc. monitor, analyzer and/or oxygen sensor is determined to be defective with respect to material and/or workmanship, we will repair it or, at our option, replace it at no charge to you. If we choose to repair your purchase, we may use new or reconditioned replacement parts. If we choose to replace your Advanced Instruments Inc. analyzer, we may replace it with a new or reconditioned one of the same or upgraded design. This warranty applies to all monitors, analyzers and sensors purchased worldwide. It is the only one we will give and it sets forth all our responsibilities. There are no other express warranties. This warranty is limited to the first customer who submits a claim for a given serial number and/or the above warranty period. Under no circumstances will the warranty extend to more than one customer or beyond the warranty period.

Limitations

Advanced Instruments Inc. will not pay for: loss of time; inconvenience; loss of use of your Advanced Instruments Inc. analyzer or property damage caused by your Advanced Instruments Inc. analyzer or its failure to work; any special, incidental or consequential damages; or any damage resulting from alterations, misuse or abuse; lack of proper maintenance; unauthorized repair or modification of the analyzer; affixing of any attachment not provided with the analyzer or other failure to follow the Owner’s Manual. Some states and provinces do not allow limitations on how an implied warranty lasts or the exclusion of incidental or consequential damages, these exclusions may not apply.

Exclusions

This warranty does not cover installation; defects resulting from accidents; damage while in transit to our service location; damage resulting from alterations, misuse or abuse; lack of proper maintenance; unauthorized repair or modification of the analyzer; affixing of any label or attachment not provided with the analyzer; fire, flood, or acts of God; or other failure to follow the Owner’s Manual.

Service

Call Advanced Instruments Inc. at 909-392-6900 (or e-mail info@aii1.com) between 7:30 AM and 5:00 PM Pacific Time Monday thru Thursday or 8:00 AM to 12:00 pm on Friday. Trained technicians will assist you in diagnosing the problem and arrange to supply you with the required parts. You may obtain warranty service by returning you analyzer, postage prepaid to:

Advanced Instruments Inc. 2855 Metropolitan Place Pomona, Ca 91767 USA

Be sure to pack the analyzer securely. Include your name, address, telephone number, and a description of the operating problem. After repairing or, at our option, replacing your Advanced Instruments Inc. analyzer, we will ship it to you at no cost for parts and labor.

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Product Identification

Product Name

H2S sensor Series - GPR

Synonyms

Electrochemical Sensor

Manufacturer

Advanced Instruments Inc., 2855 Metropolitan Place, Pomona, CA 91767 USA

Emergency Phone Number

909-392-6900

Preparation / Revision Date

January 1, 1995

Notes

H2S sensors are sealed, contain protective coverings and in normal conditions do not present a health hazard. Information applies to electrolyte unless otherwise noted.

Specific Generic Ingredients

Carcinogens at levels > 0.1%

None

Others at levels > 1.0%

Acetic Acid or sulfuric acid

CAS Number

Acetic Acid = 64-19-7

Chemical (Synonym) and Family

Potassium Hydroxide (KOH) – Base or Acetic Acid (CH3CO2H) – Acid, Lead (Pb) – Metal

General Requirements

Use

Acid - as electrolyte

Handling

Rubber or latex gloves, safety glasses

Storage

Indefinitely

Physical Properties

Boiling Point Range

Acetic Acid = 100 to 117 C

Melting Point Range

Acetic Acid – NA, Lead 327 C

Freezing Point

Acetic Acid = -40 to -10 C

Molecular Weight

Acetic Acid – NA, Lead = 207

Specific Gravity

Acetic Acid = 1.05 @ 20 C

Vapor Pressure

Acetic Acid = 11.4 @ 20 C

Vapor Density

Acetic Acid = 2.07

Acetic Acid = 2-3

Solubility in H2O

Complete

% Volatiles by Volume

None

Evaporation Rate

Similar to water

Appearance and Odor

Aqueous solutions Colorless, vinegar-like odor, sulfuric acid, no odor

Fire and Explosion Data

Flash and Fire Points

Not applicable

Flammable Limits

Not flammable

Extinguishing Method

Not applicable

Special Fire Fighting Procedures

Not applicable

10. MSDS – Material Safety Data Sheet

Advanced Instruments, Inc.

Unusual Fire and Explosion Hazards

Not applicable

Reactivity Data

Stability

Stable

Conditions Contributing to Instability

None Incompatibility

Acid = Avoid contact with strong bases

Hazardous Decomposition Products

Acid = Emits toxic fumes when heated Conditions to Avoid

Heat above 70 degree C

Spill or Leak

Steps if material is released

Sensor is packaged in a sealed plastic bag, check the sensor inside for electrolyte leakage. If the sensor leaks inside the plastic bag or inside analyzer sensor housing do not remove it without rubber or latex gloves and safety glasses and a source of water. Flush or wipe all surfaces repeatedly with water or wet paper towel (fresh each time).

Disposal

In accordance with federal, state and local regulations.

Health Hazard Information

Primary Route(s) of Entry

Ingestion, eye and skin contact

Exposure Limits

Acetic Acid - ACGIH TLV / OSHA PEL 10 % (TWA)

Ingestion

Acetic Acid = Oral LD50 (RAT) = 6620 mg/kg

Eye

Electrolyte is corrosive and eye contact could result in permanent loss of vision.

Skin

Electrolyte is corrosive and skin contact could result in a chemical burn.

Inhalation

Liquid inhalation is unlikely.

Symptoms

Eye contact - burning sensation. Skin contact - soapy slick feeling.

Medical Conditions Aggravated

None

Carcinogenic Reference Data

Acetic Acid = NTP Annual Report on Carcinogens - not listed; LARC Monographs - not listed; OSHA - not listed

Other

none.

Special Protection Information

Ventilation Requirements

None

Eye

Safety glasses

Hand

Rubber or latex gloves

Respirator Type

Not applicable

Other Special Protection

None

Special Precautions

Precautions

Do not remove the sensor’s protective Teflon and PCB coverings. Do not probe the sensor with sharp objects. Wash hands thoroughly after handling. Avoid contact with eyes, skin and clothing.

Empty sensor body may contain hazardous residue.

Transportation

Not applicable

Advanced Instruments, Inc.

Analytical Industries GPR-7500 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual