Teledyne operating instructions Operational Theory Model 3000PA

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2 Operational Theory		Model 3000PA

In the presence of oxygen the cell generates a current. A current to voltage amplifier converts this current to a voltage, and then the voltage is amplified in the second stage amplifier.

The second stage amplifier also supplies temperature compensation for the oxygen sensor output. This amplifier circuit incorporates a thermistor, which is physically located in the cell block. The thermistor is a temperature dependent resistance that changes the gain of the amplifier in proportion to the temperature changes in the block. This change is inversely proportional to the change in the cell output due to the same temperature changes. The result is a signal that is temperature independent. The output from the second stage amplifier is sent to an 18 bit analog to digital converter controlled by the microprocessor.

The digital concentration signal along with input from the control panel is processed by the microprocessor, and appropriate control signals are directed to the display, alarms and communications port. The same digital information is also sent to a 12 bit digital to analog converter that produces the 0-1 V dc analog percent-of-range signal output and the analog range ID output. Models with the –MA option also have a 4-20 mA dc percent-of- range signal output and analog range ID output.

Signals from the power supply are also monitored by the microproces- sor, and the system failure alarm is activated if a malfunction is detected.

2-10	Teledyne Analytical Instruments

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Contents Model 3000PA Model 3000PA Teledyne Analytical InstrumentsPercent Oxygen Analyzer Specific Model Information IiiInstrument Serial Number Includes the following options OperationalTheory Model 3000PA Table of Contents IntroductionInstallation OperationPercent Oxygen Analyzer MaintenanceAppendix Combustible GAS Usage Warning Typical Applications Main Features of the AnalyzerOverview Percent Oxygen Analyzer IntroductionModel Designations Introduction Model 3000PAFront Panel Operator Interface Model 3000PA Front PanelIntroduction Model 3000PA Rear Panel Equipment Interface Recognizing Difference Between LCDAnalog Outputs Network RS-232 PortRemote Probe OptionalPercent Oxygen Analyzer Operational Theory Operational Theory IntroductionMicro-Fuel Cell Sensor Principles of OperationOperational Theory Model 3000PA Anatomy of a Micro-Fuel CellElectrochemical Reactions + 2H O + 4e → 4OHCalibration Characteristics Effect of PressureClass A-3 Cell Micro-Fuel Cell ClassClass A-5 Cell Class B-1 Cell Hydrogen and/or Helium ServiceSample System Class B-3 CellPiping Layout and Flow Diagram for Standard Model Electronics and Signal Processing Span Zero SampleBlock Diagram of the Model 3000P Electronics Operational Theory Model 3000PA Unpacking the Analyzer Percent Oxygen Analyzer InstallationMounting the Analyzer Installation Model 3000PA Rear Panel ConnectionsGas Connections Rear Panel of the Model 3000PAElectrical Connections Percent Oxygen Analyzer Installation Teledyne Analytical Instruments Percent Oxygen Analyzer Installation Command Description Parameter Setting Remote Probe ConnectorInstalling the Micro-Fuel Cell Testing the SystemPercent Oxygen Analyzer Operation Auto Ranging onUsing the Data Entry and Function Buttons Operation Model 3000PASystem Function Hierarchy of Functions and SubfunctionsSetting the Display Percent Oxygen Analyzer Operation Setting up an Auto-Cal Password ProtectionEntering the Password Installing or Changing the Password Logout Version Screen Span Functions Cell FailureAuto Mode Spanning Span CalAlarms Function Manual Mode SpanningInstallation AL-1 AL-2 Choose Alarm Setting the Analog Output Ranges Range FunctionOperation Model 3000PA Autoranging Analysis Fixed Range AnalysisVoltage Signal Current Signal Output V dc Output mA dc Signal OutputAnalyze Function Range Voltage Current mA Percent Oxygen Analyzer Maintenance Routine MaintenanceCell Replacement Storing and Handling Replacement CellsMaintenance Model 3000P When to Replace a CellIndex Removing the Micro-Fuel CellRemoving or Installing a Micro-Fuel Cell Cell Warranty Fuse Replacement System Self Diagnostic TestAnalog PowerMajor Internal Components PreampCleaning Rear-Panel ScrewsSolution TroubleshootingPossible Cause Maintenance Model 3000P Teledyne Analytical Instruments Model 3000PA Specifications Percent Oxygen Analyzer AppendixAppendix Model 3000PA Recommended 2-Year Spare Parts List Qty Part Number DescriptionDrawing List 19-inch Relay Rack Panel MountSeries Analyzers Calibration GAS Conversions Zero Cal ZeroSettlingMan ENT To Begin