Emerson NGA 2000 TO2 Section Description and Specifications, Overview, Typical Applications

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Model NGA 2000 TO2

Instruction Manual

760008-A September 2001

SECTION 1

DESCRIPTION AND SPECIFICATIONS

1-1 OVERVIEW

This manual describes the Trace Oxygen (TO2) Analyzer Module of Rosemount Ana- lytical's NGA 2000 Series of gas analysis components.

The TO2 Analyzer Module is designed to con- tinuously determine the concentration of trace oxygen in a flowing gaseous mixture. The concentration is expressed in parts-per- million.

The TO2 Analyzer Module is configured as a shelf-mount module, designed to be installed external from the platform on an associated shelf capable of holding two modules side-by- side, with gas connections made from the rear. All electronics relative to sample detec- tion and conditioning are included in this module.

1-2 TYPICAL APPLICATIONS

The TO2 Analyzer Module has specific appli- cations in the following areas:

•Trace oxygen in product nitrogen and argon streams from air separation plants

•Trace oxygen in inerting atmos- pheres for heat treat furnaces

•Trace oxygen in glove-box appli- cations

1-3 METHOD OF MEASUREMENT

Coulometric Principle

The TO2 Analyzer Module uses the cou- lometric principle of oxygen detection. This technology is based on the fact that oxygen in the sample is reduced by an electrochemical reaction. This reduction occurs at the cathode and results in the generation of hydroxyl ions. These hydroxyl ions migrate to the anode where they are oxidized to reform oxygen. The oxidation reaction generates four elec- trons which in turn migrate to the anode to participate in the reduction reaction:

(Cathode Reaction)

O2 + 2 H2O + 4 e- → 4 OH- (Anode Reaction)

4 OH- → O2 + 2 H2O + 4 e-

A polarizing voltage of approximately 1.3 VDC is applied between the anode and cathode to drive the oxidation and reduction reactions.

The resulting current flow produced by the flow of electrons is directly proportional to the oxygen content in the sample gas.

1-4 FEATURES

Among the features included in the TO2 Ana- lyzer Module are:

•Quick start feature

•Electrolyte level alarm

•High oxygen protection circuit with alarm

•Sample flow indication.

Rosemount Analytical Inc. A Division of Emerson Process Management

Description and Specifications 1-1

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Contents Model NGA 2000 TO2 Essential Instructions Model NGA 2000 TO2 Table of ContentsMaterial Safety Data Sheet System & Network I/O Module Controls SetupAnalyzer Module Interconnection with Instrument Platform List of IllustrationsModel NGA 2000 TO2 Definitions Preface Intended USE StatementSafety Summary Model NGA 2000 TO2 Compliances DocumentationGlossary of Terms System SoftkeysFeatures Section Description and SpecificationsOverview Typical ApplicationsTrace Oxygen Detector Coulometric Principle Trace Oxygen Analyzer Module Top View General SPECIFICATIONS1Sample PhysicalGas Connections Model NGA 2000 TO2 Unpacking Section InstallationElectrolyte Electrolyte AdditionGAS Connections GasesGAS Overpressure Sample FlowSensor Damage Leak TestElectrical Connections Electrical Shock Hazard Analyzer Module Interconnection with Instrument Platform Outline and Mounting Dimensions Back Panel Connections Displays & Operating Keys OperationMenu Lines & Softkey Functionality Analyzer basic controls calibration & setup…Measure Status… Channel Lock… MFG Data Entering & Changing Variables Signal on mini-bargraphMeasure Back… Ppm O2 Measure Mode DisplayDisplay Status… Main… Channel BasicCal Module Manufacturing Data Displays Startup & Initialization LCDReset AbortInitiate quick start Quick StartMeasure Status… Back… Power supply voltages… Measure Back… Basic CONTROLS, Setup and StatusAnalyzer Channel Status Display Status… Main… ChannelDisplay Status… Single Component DisplayMain… Channel BasicCal Multi Component Display Select Status… Tags Off LCDResetRange number Basic Controls and SetupOperation Status Range numberBrightness and Contrast Display ControlsDisplay controls… Brightness 70 %Analyzer and I/O, expert controls & setup… Expert Controls and SetupAnalyzer module controls… Measure Channel Back…Gas Scale Factor Calibration ProcedureAir background gas concentration Gas scale factor…Span gas 90.0 ppm Measure Status… Back… Span CalibrationAlarms… AlarmsConcentration alarm setup… Measure Back… ClrAlm Alarm generation isReRanges… RangesBegin / end of ranges… Range Begin PpmMeasurement display configuration… Measurement Display ConfigurationLinearization Gas measurement units Concentration MeasurementConcentration measurement… Gas concentration unitsSensor model Temperature compensation at span gasClamp low PVA to Ppm to mg/Nm3 conversion factorFlow measurement… Flow MeasurementFlow lower limit 400 ml/min Temperature measurement… Measure Status… Back… Temperature MeasurementTemperature measurement units System & network I/O module controls… System & Network I/O Module CON Trols Setup37.50 ppm System SIO module…System SIO Analog output setup…Choose signal Analog Output SetupSelect analog output number Choose the analyzer moduleHold output during calibration Signal value for 0% outputHold output during calibration Outputs value on analyzer failure Operation modeOutput number Type of installed serial inter- face Analog Output Updates Per SecondOutput #1 Yes Baud rate 19200Invert signal Relay Outputs SetupCommunication protocol Choose source moduleSystem DIO Choose signal…Function control Input numberSystem Configuration and DIAG- Nostics Load/Save Module Configura- tion Diagnostic MenusAnalyzer Module Diagnostics Security Codes Date and TimeSystem reset Measure Back… System ResetEntering a level locked by security code Model NGA 2000 TO2 Overview Electrical Shock Hazard Section Maintenance and ServiceSensor Caustic Liquid Refilling Sensor Sensor AssemblySensor Replacement Electrolyte ReplacementSensor Lleak Check Linearization Analyzer and I/O expert controls & setup…Do not tilt Sensor excessively as elec- trolyte may leak Time & DateLinearization… Linearization temperature values…0000 ppm Linearization raw values sensor current…Electronic Components Flow Sensor ReplacementFuses Printed Circuit BoardsTroubleshooting Section TroubleshootingFailure to purge down to ppm levels Erratic and very insensitive readingsModel NGA 2000 TO2 Matrix Section Replacement PartsTO2 NGA 2000 TO2 Trace Oxygen Analyzer Module Replacement Parts Section Return of Material Customer ServiceReturn of Material TrainingModel NGA 2000 TO2 Section Index Model NGA 2000 TO2 Product ELECTROLYTE1 Precautions to be taken in handling Emergency & first aid proceduresOther precautions Threshold limit value Routes of entryRosemount Warranty Asia Pacific EUROPE, Middle EAST, Africa Latin America