Document Outline

• Model 755A Oxygen Analyzer
• Essential Instructions
• Rosemount Analytical Inc., Process Analytic Division
• Table of Contents
  • List of Illustrations
  • List of Tables
  • List of Drawings
• Preface
  • Definitions
  • Intended Use Statement
  • Safety Summary
  • Authorized Personnel
  • General Precautions for Handling and Storing High Pressure Gas Cylinders
  • Documentation
  • Compliances
• 1-0 Description and Specifications
  • 1-1 Overview
  • 1-2 Oxygen Range on Front Panel Digital Display
  • 1-3 Oxygen Ranges for Recorder Readout
  • 1-4 Recorder Voltage and Current Outputs
  • 1-5 Automatic Pressure Compensation
  • 1-6 Options
    • a. Alarm
    • b. Case Mounting
    • c. Electrical Power
  • 1-7 Specifications
    • a. General
    • b. Sample
    • c. Electrical
    • d. Physical
• 2-0 Installation
  • 2-1 Unpacking
  • 2-2 Location and Mounting
  • 2-3 Voltage Requirements
  • 2-4 Electrical Connections
    • a. Line Power Connections
    • b. Recorder Connections
    • c. Potentiometric Output
    • d. Isolated Current Output (Optional)
    • e. Output Connections for Dual Alarm Option
    • f. Alarm Output Connections
    • g. Alarm Relay Characteristics
  • 2-5 Calibration Gases
    • a. Zero Calibration Gas
    • b. Downscale Standard Gas
    • c. Upscale Standard Gas
  • 2-6 Sample Handling
    • a. Sample Temperature Requirements
    • b. Sample Pressure Requirements - General
    • c. Normal Operation at Positive Gauge Pressures
    • d. Operation at Negative Gauge Pressures
    • e. Sample Flow Rate
    • f. Corrosive Gases
  • 2-7 Leak Test
  • 2-8 Purge Kit (Optional)
• 3-0 Operation
  • 3-1 Overview
  • 3-2 Selection of Recorder Oxygen Range
    • a. Recorder Oxygen Range Selection Procedure
    • b. Readout of Applied Zero-Suppression Voltage on Digital Display
  • 3-3 Startup Procedure
  • 3-4 Calibration
    • a. Calibration Using Digital Readout for Oxygen Readout
    • b. Calibration Using Recorder for Oxygen Readout
    • c. Calibration with Downscale and Upscale Standard Gases
    • d. Calibration of Automatic Pressure Compensation
  • 3-5 Compensation for Composition of Background Gas
    • a. Oxygen Equivalent Values of Gases
    • b. Oxygen Equivalents of Gas Mixtures
    • c. Computing Adjusted Settings for Zero and Span Controls
  • 3-6 Dual Alarm Option
    • a. Initial Calibration and Selection of Setpoints for Alarms
    • b. Selection of Deadband
  • 3-7 Routine Operation
  • 3-8 Effect of Barometric Pressure Changes on Instrument Readout
  • 3-9 Calibration Frequency
• 4-0 Theory
  • 4-1 Principles of Operation
    • a. Magnetic Displacement Force
    • b. Physical Configuration of Detector/Magnet Assembly
  • 4-2 Variables Influencing Paramagnetic Oxygen Measurements
    • a. Pressure Effects
    • b. Temperature Effects
    • c. Interferents
    • d. Vibration Effects
  • 4-3 Electronic Circuitry
    • a. Detector/Magnet Assembly
    • b. Control Board and Associated Circuitry
    • c. Case Board
    • d. Isolated Current Output Board
    • e. Alarm
• 5-0 Circuit Analysis
  • 5-1 Overview
  • 5-2 +/- 15VDC Power Supply
  • 5-3 Case Heater Control Circuit
  • 5-4 Detector Heater Control Circuit
  • 5-5 Detector Light Source Control Circuit
  • 5-6 Detector with First Stage Amplifier and Pressure Compensation Circuits
    • a. Pressure Compensation Circuit
    • b. Pressure Signal Circuit
    • c. Positive and Negative Reference Voltage Circuits
  • 5-7 Buffer Amplifiers U10 and Associated Anticipation Function
  • 5-8 Digital Output Circuit
  • 5-9 Analog Output Circuits for Recorder and Alarms
• 6-0 Service and Maintenance
  • 6-1 Initial Checkout with Standard Gases
  • 6-2 Detector Component Checks
    • a. Detector
    • b. Source Lamp
    • c. Photocell
    • d. Suspension
  • 6-3 Detector Component Replacement
    • a. Detector Replacement
  • 6-4 Source Lamp Replacement
    • a. Photocell Replacement and Adjustment
  • 6-5 Heating Circuits
    • a. Case Heater Control Circuit
    • b. Detector/Magnet Heating Circuit
• 7-0 Replacement Parts
  • 7-1 Circuit Board Replacement Policy
  • 7-2 Selected Replacement Parts
  • 7-3 Matrix
• 8-0 Return of Material
  • 8-1 Return of Material
  • 8-2 Customer Service
  • 8-3 Training
• Appendix A - Vaisala Barometric Pressure Transducer
  • A-1 Overview
  • A-2 Circuit Function
  • A-3 Installation
  • A-4 Adjustment
  • A-5 High Altitude Version (Option)
• Warranty
• Emerson Process Management - Worldwide
• Figures
  • 1-1 Model 755A Oxygen Analyzer
  • 1-2 Model 755A Component and Adjustment Locations
  • 2-1 Electrical Connections
  • 2-2 Control Board
  • 2-3 Connections for Potentiometric Recorder with Non-Standard Span
  • 2-4 Model 755A Connected to Drive Several Current-Activated Output Devices
  • 2-5 Typical Alarm Settings
  • 2-6 Relay Terminal Connections for Typical Fail-Safe Application
  • 2-7 Connection of Typical Gas Selector Panel to Model 755A Oxygen Analyzer
  • 2-8 Installation of Purge Kit (Optional)
  • 3-1 Model 755A Front Panel Controls
  • 3-2 Model 755A Internal Adjustments Locations
  • 3-3 Calibration by Pressure Decrease Setup
  • 4-1 Spherical Body in Non-Uniform Magnetic Field
  • 4-2 Functional Diagram of Model 755A Paramagnetic Oxygen Measurement System
  • 4-3 Detector/Magnet Assembly
  • 5-1 Schematic - Two-Comparator OR Circuit
  • 5-2 Schematic - Ramp Generator
  • 5-3 Schematic - Case Heater Control Circuit
  • 5-4 Schematic - Case Heater Circuit
  • 5-5 Schematic - Detector Heater Control Circuit
  • 5-6 Schematic - Detector Light Source Control Circuit
  • 5-7 Schematic - Detector with First Stage Amplifier and Pressure Compensation Circuits
  • 5-8 Schematic - Pressure Signal and Reference Voltage Circuits
  • 5-9 Schematic - Buffer, Anticipation, and Digital Output Circuit
  • 5-10 Schematic - Simplified Analog Output Circuit for Recorder (showing three ranges)
  • 6-1 Detector/Magnet Assembly
  • 6-2 Detector/Magnet Assembly Wiring
  • 6-3 Detector Adjustment
  • 6-4 Modification of 633689 Connector Board for Compatibility with Replacement Lamp
  • 6-5 Lamp Alignment
  • x
• Tables
  • 3-1 Standard Gases Recommended for Calibration of Various Oxygen Ranges on Analog Output
  • 3-2 Model 755A Internal Adjustments
  • 3-3 Oxygen Equivalents of Common Gases
• Drawings
  • 617186 Schematic Diagram, Case Board
  • 617731 Pictorial Wiring Diagram, Model 755A
  • 620434 Schematic Diagram, Current Output Board
  • 632349 Installation Drawing, Model 755A
  • 652219 Schematic Diagram, Control Board
  • 652222 Schematic Diagram, Transducer