Instruction Manual

245364-V May 2002

Model 755A

LIST OF ILLUSTRATIONS

Figure 1-1.

Model 755A Oxygen Analyzer ...............................................................................

1-1

Figure 1-2.

Model 755A Component and Adjustment Locations .............................................

1-3

Figure 2-1.

Electrical Connections ...........................................................................................

2-2

Figure 2-2.

Control Board.........................................................................................................

2-3

Figure 2-3.

Connections for Potentiometric Recorder with Non-Standard Span .....................

2-3

Figure 2-4.

Model 755A Connected to Drive Several Current-Activated Output Devices .......

2-4

Figure 2-5.

Typical Alarm Settings ...........................................................................................

2-6

Figure 2-6.

Relay Terminal Connections for Typical Fail-Safe Application..............................

2-6

Figure 2-7.

Connection of Typical Gas Selector Panel to Model 755A Oxygen Analyzer .......

2-8

Figure 2-8.

Installation of Purge Kit (Optional).......................................................................

2-12

Figure 3-1.

Model 755A Front Panel Controls .........................................................................

3-2

Figure 3-2.

Model 755A Internal Adjustments Locations .........................................................

3-7

Figure 3-3.

Calibration by Pressure Decrease Setup ..............................................................

3-9

Figure 3-4.

Schematic Circuit of Alarm Relay Assembly .......................................................

3-13

Figure 4-1.

Spherical Body in Non-Uniform Magnetic Field.....................................................

4-2

Figure 4-2.

Functional Diagram of Model 755A Paramagnetic Oxygen Measurement

 

 

System ...................................................................................................................

4-3

Figure 4-3.

Detector/Magnet Assembly....................................................................................

4-4

Figure 5-1.

Two-Comparator OR Circuit ..................................................................................

5-2

Figure 5-2.

Ramp Generator ....................................................................................................

5-3

Figure 5-3.

Case Heater Control Circuit...................................................................................

5-4

Figure 5-4.

Case Heater Circuit ...............................................................................................

5-5

Figure 5-5.

Detector Heater Control Circuit..............................................................................

5-6

Figure 5-6.

Detector Light Source Control Circuit ....................................................................

5-7

Figure 5-7.

Detector with First Stage Amplifier and Pressure Compensation Circuits ..........

5-10

Figure 5-8.

Pressure Signal and Reference Voltage Circuits ................................................

5-10

Figure 5-9.

Buffer, Anticipation, and Digital Output Circuit ....................................................

5-11

Figure 5-10.

Simplified Analog Output Circuit for Recorder (Showing Three Ranges) ...........

5-14

Figure 6-1.

Detector/Magnet Assembly....................................................................................

6-4

Figure 6-2.

Detector/Magnet Assembly Wiring ........................................................................

6-4

Figure 6-3.

Detector Adjustment ..............................................................................................

6-5

Figure 6-4.

Modification of 633689 Connector Board for Compatibility with Replacement

 

 

Lamp ......................................................................................................................

6-6

Figure 6-5.

Lamp Alignment.....................................................................................................

6-6

LIST OF TABLES

Table 3-1.

Standard Gases Recommended for Calibration of Various Oxygen Ranges on

 

 

Analog Output........................................................................................................

3-5

Table 3-2.

Model 755A Internal Adjustments..........................................................................

3-6

Table 3-3.

Oxygen Equivalents of Common Gases..............................................................

3-11

iv

Contents

Rosemount Analytical Inc. A Division of Emerson Process Management