Teledyne 3020T operating instructions Temperature Control

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2 Operational Theory

Model 3020T

 

 

 

 

 

 

 

 

 

In the presence of oxygen the cell generates a current. A current to voltage amplifier converts this current to a voltage, which 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 4-20 mA dc and the 0-1 V dc analog concentration signal outputs, and the analog range ID outputs.

Signals from the power supply are also monitored, and through the microprocessor, the system failure alarm is activated if a malfunction is detected.

2.5 Temperature Control

For accurate analysis this instrument is temperature controlled not to fall beneath a certain temperature. This temperature is 22oF. This is to prevent the sensor from freezing in cold environments.

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Teledyne Analytical Instruments

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Contents Model 3020T Teledyne Analytical InstrumentsModel 3020T Copyright 1999 Teledyne Analytical InstrumentsSpecific Model Information Trace Oxygen AnalyzerIii 3020T-IInstallation Table of Contents IntroductionOperational Theory Maintenance OperationAppendix Overview Main Features of the AnalyzerTrace Oxygen Analyzer Introduction Typical ApplicationsModel Designations Model 3020TModel 3020T Controls, Indicators, and Connectors Trace Oxygen Analyzer Introduction Operator InterfaceESCAPE/ENTER Switch 1 UP/DOWN SwitchPWD Equipment Interface Electrical Connector PanelRecognizing Difference Between LCD DisplaysRS-232 Port Remote ValvesRemote Sensor Gas Connector PanelNetwork I/O Optional Micro-Fuel Cell Sensor Operational Theory IntroductionPrinciples of Operation Operational Theory Anatomy of a Micro-Fuel CellElectrochemical Reactions + 2H 2O + 4e → 4OHCalibration Characteristics Effect of PressureCharacteristic Input/Output Curve for a Micro-Fuel Cell Sample SystemElectronics and Signal Processing Span Zero SampleBlock Diagram of the Model 3020T Electronics Temperature Control Unpacking the Analyzer Trace Oxygen Analyzer InstallationMounting the Analyzer Front View of the Model 3020T Simplified Electrical Connections Required Front Door ClearanceFuse Installation Primary Input PowerAnalog Outputs Examples Analog Output ConnectionsAlarm Relays Range Voltage Current mADigital Remote Cal Inputs Types of Relay ContactsZero 8 RS-232 Port Range ID RelaysNetwork I/O RS-232 Sig RS-232 Pin PurposeParameter Setting Command DescriptionRemote Sensor and Solenoid Valves Installing the Micro-Fuel Cell Remote Solenoid Return Connector PinoutsGas Connections Gas Connector Panel Testing the System Trace Oxygen Analyzer Operation Using the ControlsAuto Ranging on Setup Mode Analysis ModeMode/Function Selection Trace Oxygen Analyzer Enter Data EntryEscape PWD Password Function Trace Oxygen Analyzer Operation AUTO-CALFunctionOnly one password can be defined Entering the PasswordInstalling or Changing the Password Logout Function Version ScreenTrace Oxygen Analyzer Operation SELF-TESTFunction Zero and Span FunctionsAuto Mode Zeroing Zero CalManual Mode Zeroing Cell Failure Auto Mode SpanningSpan Cal Manual Mode Spanning Alarms Function InstallationAL-1 AL-2 Choose Alarm Setting the Analog Output Ranges Range FunctionFixed Range Analysis Contrast Function Standby FunctionAnalysis Mode Operation Routine Maintenance Trace Oxygen Analyzer MaintenanceMajor Internal Components Cell Replacement Major Internal ComponentsStoring and Handling Replacement Cells When to Replace a CellRemoving the Micro-Fuel Cell Exploded View of Cell Block and Micro-Fuel Cell Installing a New Micro-Fuel Cell Cell Warranty Fuse ReplacementL-2C cell is not designed for applications where CO2 is a System Self Diagnostic Test Removing Fuse Cap and Fuse from HolderAnalog PowerPreamp Maintenance Specifications Trace Oxygen Analyzer AppendixOperating Temperature 0-50 C Recommended 2-Year Spare Parts List Qty Part Number DescriptionDrawing List Series Analyzers Restrictor KIT Conversions