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Trace Oxygen Analyzer
OPERATING INSTRUCTIONS FOR
MODEL MODEL OT-3 OT-3
Trace Oxygen Analyzer
P/N M74173
10/28/2001
ECO#
DANGER
Toxic gases and or flammable liquids may be present in this monitoring system.
Personal protective equipment may be required when servicing this instrument.
Hazardous voltages exist on certain components internally which may persist
for a time even after the power is turned off and disconnected.
Only authorized personnel should conduct maintenance and/or servicing.
Befor
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Model OT-3 Copyright © 2000 Teledyne Analytical Instruments All Rights Reserved. No part of this manual may be reproduced, transmitted, transcribed, stored in a retrieval system, or translated into any other language or computer language in whole or in part, in any form or by any means, whether it be electronic, mechanical, magnetic, optical, manual, or otherwise, without the prior written consent of Teledyne Analytical Instruments, 16830 Chestnut Street, City of Industry, CA 91749-1580. Warran
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Trace Oxygen Analyzer Specific Model Information The instrument for which this manual was supplied may incorporate one or more options not supplied in the standard instrument. Commonly available options are listed below, with check boxes. Any that are incorporated in the instrument for which this manual is supplied are indicated by a check mark in the box. Instrument Serial Number: _______________________ Teledyne Analytical Instruments iii
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Model OT-3 Important Notice Model OT-3 complies with all of the requirements of the Commonwealth of Europe (CE) for Radio Frequency Interference, Electromagnetic Interference (RFI/EMI), and Low Voltage Directive (LVD). The following International Symbols are used throughout the Instruction Manual for your visual and immediate warnings and when you have to attend CAUTION while operating the instrument: STAND-BY: Instrument is on Stand-by, but circuit is active GROUND: Protective Earth CAUTION:
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Trace Oxygen Analyzer This instrument is designed for CL1 DIV II hazardous locations. It is the customer's responsibility to ensure safety especially when combustible gases are being analyzed since the potential of gas leaks always exist. The customer should ensure that the principles of operating this equipment are well understood by the user. Misuse of this product in any manner, tampering with its components, or unauthorized substitution of any component may adversely affect the safety of t
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Model OT-3 Table of Contents List of Figures.............................................................................viii Introduction....................................................................................1 1.1 Overview 1 1.2 Main Features of the Analyzer 1 1.3 Front Panel Description 2 1.4 Rear Panel Description 4 Operational Theory........................................................................6 2.1 Introduction 6 2.2 Micro-fuel Cell Sensor 6 2.2.1 Principles of Operat
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Trace Oxygen Analyzer 3.4 Gas Connections 18 3.5 Sample System 20 3.6 Installation Checklist 21 Operation......................................................................................23 4.1 Introduction 23 4.2 Using the Function and Data Entry Buttons 24 4.3 Setting the Analysis Ranges 24 4.3.1 HI Range 25 4.3.2 LO Range 25 4.4 Setting the Alarm Setpoints 25 4.4.1 Set Alarm 1 25 4.4.2 Set Alarm 2 26 4.4.3 Power Failure Alarm 26 4.5 Alarm Delay 26 4.6 Keypad Lockout 27 4.7 Selecting a Fix
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Model OT-3 List of Figures Figure 1-1: Front Panel...................................................................3 Figure 1-2: Rear Panel (AC Version)..............................................5 Figure 1-3: Rear Panel (DC Version)..............................................5 Figure 2-1: Cross Section of a Micro-fuel Cell ................................7 Figure 2-2: Characteristic MFC Input/Output Curve .....................10 Figure 2-3: Block Diagram of the Signal Processing Ele
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Trace Oxygen Analyzer Introduction Introduction 1.1 Overview The Teledyne Electronic Technologies Analytical Instruments (TET/AI) Model OT-3 is a microprocessor-based trace oxygen analyzer for real-time measurement of the parts per million of oxygen in inert gases, or in a wide variety of gas mixtures. It features simple operation, fast response, and a compact, rugged construction. Typical applications of the Model OT-3 include monitoring natural gas pipelines, wellheads, and compressor/blowers.
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Introduction OT-3 The Model 3300/OT-3 Control Unit has its own long list of features including: • Keypad lockout feature • Two user settable fail-safe alarms (with a user settable 0-20 min. time delay ) • Two user settable ranges (from 0-10PPM – 0-9999PPM) with user selectable auto-ranging. • Power fail alarm • SSR power output (Solid State Relay power available on AC control units) • Micro processor based electronics 8 bit ADC & 18 bit DAC • Large 3 ½ digit LED O2 concentration read-out • 7 bu
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Trace Oxygen Analyzer Introduction Figure 1-1: Front Panel Function Keys: Seven push-button membrane switches are used to select the function performed by the analyzer: Set Alarm 1: Set Alarm 1 Hi or Low, and the concentration at which alarm 1 activates. Set Alarm 2: Set the Alarm 2 Hi or Low, and the concentration to which alarm 2 activates. Set HI Range: Set the high analysis range for the instrument (up to 0-9999ppm). Set LO Range: Set the low analysis range for the instrument (down to 0-10p
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Introduction OT-3 Meter Readout: As the meter readout, it displays the oxygen concentration currently being measured. Measurement Parameters Readout: It also displays user-definable alarm setpoints, ranges, and span calibration point when they are being checked or changed. 1.4 Rear Panel Description The rear panel contains the electrical input and output connectors. The connectors are described briefly here and in detail in the Installation chapter of this manual. The rear panels for the AC and
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Trace Oxygen Analyzer Introduction Figure 1-2: Rear Panel (AC Version) Figure 1-3: Rear Panel (DC Version) Teledyne Analytical Instruments 5
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Installation OT-3 Operational Theory 2.1 Introduction The analyzer is composed of two subsystems: • 3300/OT-3 control unit • OT-3 sample sys. The OT-3 sample system is designed to accept the sample gas and direct it to the sensitive surface of the Micro-fuel Cell sensor. The Micro-fuel Cell is an electrochemical galvanic device that translates the amount of oxygen present in the sample into an electrical current. The 3300/OT-3 control unit processes the sensor output and translates it into elect
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Trace Oxygen Analyzer Installation between a battery and a true fuel cell. (All of the reactants are stored externally in a true fuel cell.) 2.2.2 Anatomy of a Micro-fuel Cell The Micro-fuel Cell is made of extremely inert plastic (which can be placed confidently in practically any environment or sample stream). It is effectively sealed, though one end is a gas permeable membrane. At the permeable end a screen retains a diffusion membrane through which the oxygen passes into the cell. At the oth
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Installation OT-3 electrical circuitry, to one of the external contacts in the connector receptacle, which is on the top of the cell. 2.2.3 Electrochemical Reactions The sample gas diffuses through the Teflon membrane. Any oxygen in the sample gas is reduced on the surface of the cathode by the following half reaction: - - O +2H O + 4e — 4OH (cathode) > 2 2 In this reaction, four electrons combine with one oxygen molecule—in the presence of water from the electrolyte—to produce four hydroxyl io
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Trace Oxygen Analyzer Installation 2.2.4 The Effect of Pressure In order to state the amount of oxygen present in the sample as a percentage of the gas mixture, it is necessary that the sample diffuse into the cell under constant pressure. If the total pressure increases, the rate that oxygen reaches the cathode through the diffusing membrane will also increase. The electron transfer, and therefore the external current, will increase, even though the oxygen concentration of the sample has not ch
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Installation OT-3 Figure 2-2: Characteristic MFC Input/Output Curve 2.3 Electronics 2.3.1 General ® The signal processing uses an Intel microcontroller with on-board RAM and ROM to control all signal processing, input/output, and display functions for the analyzer. System power is supplied from a universal power supply module designed to be compatible with most international power sources. The power supply circuitry is on the Power Supply PCB, which is mounted vertically, just behind the rear p
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Trace Oxygen Analyzer Installation 2.3.2 Signal Processing Figure 2-3 is a block diagram of the signal processing electronics described below. Figure 2-3: Block Diagram of the Signal Processing Electronics In the presence of oxygen the cell generates a current. The sensor has an internal thermistor compensation network. The output of the sensor is converted to voltage millivolt range. This output is fed to a voltage amplifier. The internal thermistor network provides temperature compensation of
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Installation OT-3 The same digital information is also sent to a 12-bit digital to analog converter (DAC) that produces the 0-10 V dc analog concentration signal and the 0-10 VDC analog range ID output. A voltage to current converter (E–I CONV) produces the 4-20 mA DC analog concentration signal. Teledyne Analytical Instruments 12
