Rosemount 755 User manual

Rosemount Analytical
MODEL 755
OXYGEN ANALYZER
INSTRUCTION MANUAL
748183-H

NOTICE
The information contained in this document is subject to change without notice.
Manual Part Number 748183-H
November 1997
Printed in U.S.A.
Rosemount Analytical Inc.
4125 East La Palma Avenue
Anaheim, California 92807-1802
Viton® are registered trademarks of E.I. duPont de Nemours and Co., Inc.
Paliney No. 7™ is a trademark of J. M. Ney Co.
SNOOP®is a registered trademark of NUPRO Co.

CONTENTS
748183-H i
Rosemount Analytical
November 1997
PREFACE
INTENDED USE STATEMENT ..........................................................................P-1
SAFETY SUMMARY ..........................................................................................P-1
SPECIFICATIONS - GENERAL .........................................................................P-3
SPECIFICATIONS - SAMPLE............................................................................P-4
SPECIFICATIONS - ELECTRICAL.....................................................................P-4
SPECIFICATIONS - PHYSICAL - GENERAL PURPOSE ENCLOSURE...........P-5
SPECIFICATIONS - PHYSICAL EXPLOSION PROOF ENCLOSURE .............P-5
CUSTOMER SERVICE, TECHNICAL ASSISTANCE AND FIELD SERVICE....P-6
RETURNING PARTS TO THE FACTORY.........................................................P-6
TRAINING ......................................................................................................P-6
DOCUMENTATION............................................................................................P-6
COMPLIANCES .................................................................................................P-7
SECTION 1. INTRODUCTION
1.1 RANGE OPTIONS....................................................................................1-1
1.1.1 Standard Zero-Based Range Options.........................................1-1
1.1.2 Standard Zero-Suppressed Range Options................................1-3
1.1.3 Special Range Options ...............................................................1-3
1.2 ISOLATED CURRENT OUTPUT OPTIONS.............................................1-5
1.3 ALARM OPTION.......................................................................................1-5
1.4 CASE MOUNTING OPTIONS ..................................................................1-5
1.5 ELECTRICAL OPTIONS ..........................................................................1-5

MODEL 755 OXYGEN ANALYZER
ii 748183-HRosemount Analytical November 1997
SECTION 2. INSTALLATION
2.1 UNPACKING............................................................................................ 2-1
2.2 LOCATION............................................................................................... 2-1
2.2.1 Location and Mounting............................................................... 2-1
2.3 VOLTAGE REQUIREMENTS .................................................................. 2-1
2.4 ELECTRICAL CONNECTIONS................................................................ 2-2
2.4.1 Line Power Connections............................................................. 2-2
2.4.2 Recorder Output Selection and Cable Connections................... 2-2
2.4.3 Output Connections, Initial Setup for Dual Alarm Option............ 2-6
2.5 CALIBRATION......................................................................................... 2-10
2.5.1 Downscale Standard Gas........................................................... 2-11
2.5.2 Upscale Standard Gas ............................................................... 2-11
2.6 SAMPLE HANDLING............................................................................... 2-12
2.6.1 Sample Temperature Requirements........................................... 2-12
2.6.2 Sample Pressure Requirements: General................................. 2-13
2.6.3 Normal Operation at Positive Gauge Pressures......................... 2-13
2.6.4 Operation at Negative Gauge Pressures.................................... 2-14
2.6.5 Sample Flow Rate...................................................................... 2-14
2.6.6 Corrosive Gases........................................................................ 2-15
2.7 LEAK TEST.............................................................................................. 2-15
2.8 PURGE KIT (OPTIONAL) ........................................................................ 2-15
SECTION 3. STARTUP
3.1 STARTUP PROCEDURE......................................................................... 3-1
3.2 CALIBRATION......................................................................................... 3-1
3.2.1 Calibration with Downscale and Upscale Standard Gases......... 3-4
3.2.2 Alternate Calibration Procedure Using Upscale Standard
Gas Only....................................................................... 3-5
3.3 COMPENSATION FOR COMPOSITION OF BACKGROUND GAS........ 3-6
3.3.1 Oxygen Equivalent Values of Gases.......................................... 3-7
3.3.2 Computing Adjusted Settings for Zero and Span Controls......... 3-8

CONTENTS
748183-H iii
Rosemount Analytical
November 1997
SECTION 4. OPERATION
4.1 ROUTINE OPERATION ...........................................................................4-1
4.2 EFFECT OF BAROMETRIC PRESSURE CHANGES ON
INSTRUMENT READOUT............................................................4-1
4.3 CALIBRATION FREQUENCY ..................................................................4-2
SECTION 5. THEORY
5.1 PRINCIPLES OF OPERATION ................................................................5-1
5.1.1 Magnetic Displacement Force.....................................................5-3
5.1.2 Physical Configuration of Detector/Magnet Assembly.................5-4
5.2 VARIABLES INFLUENCING PARAMAGNETIC OXYGEN
MEASUREMENTS........................................................................5-5
5.2.1 Pressure Effects..........................................................................5-5
5.2.2 Temperature Effects....................................................................5-6
5.2.3 Interferents.................................................................................5-6
5.2.4 Vibration Effects..........................................................................5-6
5.3 ELECTRONIC CIRCUITRY......................................................................5-7
5.3.1 Detector/Magnet Assembly.........................................................5-7
5.3.2 Control Board and Associated Circuitry ......................................5-7
5.3.3 Case Board Assembly.................................................................5-8
5.3.4 Isolated Current Output Board (Optional)....................................5-9
5.3.5 Alarm Option...............................................................................5-9
SECTION 6. CIRCUIT ANALYSIS
6.1 POWER SUPPLY., ±15VDC ....................................................................6-1
6.2 CASE HEATER CONTROL CIRCUIT ......................................................6-1
6.3 DETECTOR HEATER CONTROL CIRCUIT ............................................6-5
6.4 DETECTOR LIGHT SOURCE CONTROL CIRCUIT................................6-6
6.5 DETECTOR WITH FIRST STAGE AMPLIFIER.......................................6-7
6.6 FINAL OUTPUT AMPLIFIER....................................................................6-10
6.7 ZERO SUPPRESSION MODULE FOR ZERO ADJUSTMENT................6-11

MODEL 755 OXYGEN ANALYZER
iv 748183-HRosemount Analytical November 1997
SECTION 7. SERVICE AND MAINTENANCE
7.1 INITIAL CHECKOUT WITH STANDARD GASES.................................... 7-1
7.2 CHECKOUT AT TEST POINTS ON CASE CIRCUIT BOARD................. 7-2
7.3 DETECTOR COMPONENT CHECKOUT................................................ 7-4
7.3.1 Detector ..................................................................................... 7-4
7.3.2 Source Lamp.............................................................................. 7-4
7.3.3 Photocell..................................................................................... 7-4
7.3.4 Suspension................................................................................. 7-5
7.4 DETECTOR COMPONENT REPLACEMENT ......................................... 7-5
7.4.1 Detector Replacement and Calibration....................................... 7-5
7.4.2 Source Lamp Replacement and Adjustment.............................. 7-8
7.4.3 Photocell Replacement and Alignment....................................... 7-10
7.5 HEATING CIRCUITS............................................................................... 7-11
7.5.1 Case Heater Control Circuit........................................................ 7-11
7.5.2 Detector/Magnet Heating Circuit ................................................ 7-11
SECTION 8. REPLACEMENT PARTS
8.1 CIRCUIT BOARD REPLACEMENT POLICY........................................... 8-1
8.2 REPLACEMENT PARTS ......................................................................... 8-1
GENERAL PRECAUTIONS FOR STORING AND HANDLING HIGH PRESSURE GAS CYLINDERS
WARRANTY
FIELD SERVICE AND REPAIR FACILITIES

CONTENTS
748183-H v
Rosemount Analytical
November 1997
FIGURES
1-1 Model 755 - Front View ............................................................................1-2
1-2 Model 755 - Location of Major Components.............................................1-4
2-1 Electrical Interonnection...........................................................................2-3
2-2 Control Board - Adjustment Locations......................................................2-4
2-3 Potentiometric Recorder with Non-Standard Span...................................2-5
2-4 Model 755 Connected to Drive Current-Activated Output Devices...........2-6
2-5 Typical Alarm Settings..............................................................................2-7
2-6 Relay Terminal Connections ....................................................................2-8
2-7 Alarm Relay Option Schematic Diagram..................................................2-9
2-8 Connection of Typical Gas Selector Panel to Model 755..........................2-12
2-9 Installation of Purge Kit.............................................................................2-17
3-1 Control Board - Adjustment Locations......................................................3-2
5-1 Functional Diagram of Model 755 Paramagnetic Oxygen
Measurement System ...................................................................5-2
5-2 Spherical Body in Non-Uniform Magnetic Field........................................5-3
5-3 Detector/Magnet Assembly.......................................................................5-4
6-1 Two-Comparator OR Circuit.....................................................................6-2
6-2 Case Heater Control Circuit......................................................................6-3
6-3 Ramp Generator.......................................................................................6-3
6-4 Detector Heater Control Circuit.................................................................6-6
6-5 Detector Light Source Control Circuit.......................................................6-7
6-6 Detector with First Stage Amplifier ...........................................................6-8
6-7 Final Output Amplifier...............................................................................6-11
6-8 Zero Suppression Module ........................................................................6-12
7-1 Locations of Case Board Test Points A, B, C and D.................................7-3
7-2 Voltage Test Points ..................................................................................7-4
7-3 Detector/Magnet Assembly.......................................................................7-6
7-4 Detector/Magnet Assembly Wiring ...........................................................7-7
7-5 Modification of 633689 Connector Board for Compatibility with
Replacement Lamp.......................................................................7-9
7-6 Lamp Alignment.........................................................................................7-9
7-7 Photocell Adjustment Voltmeter Lead Location........................................7-10
TABLES
1-1 Front Panel Controls.................................................................................1-3
1-2 Range Options..........................................................................................1-3
2-1 Calibration Range for Various Operating Ranges.....................................2-11
3-1 Control Board - Adjustment Functions......................................................3-3
3-2 Calibration Range for Various Operating Ranges.....................................3-4
3-3 Oxygen Equivalents of Common Gases...................................................3-7

MODEL 755 OXYGEN ANALYZER
vi 748183-HRosemount Analytical November 1997
DRAWINGS (LOCATED IN REAR OF MANUAL)
617186 Schematic Diagram, Case Board
620434 Schematic Diagram, Isolated Current Output Board
624549 Pictorial Wiring Diagram, Model 755
632349 Installation Drawing, Model 755 - General Purpose
638277 Schematic Diagram, Alarm
643127 Installation Drawing, Model 755 Explosion-Proof
652188 Schematic Diagram, Control Board

PREFACE
Rosemount Analytical
748183-H November 1997 P-1
INTENDED USE STATEMENT
The Model 755 is intended for use as an industrial process measurement device only.
It is not intended for use in medical, diagnostic, or life support applications, and no
independent agency certifications or approvals are to be implied as covering such
application.
SAFETY SUMMARY
To avoid explosion, loss of life, personal injury and damage to this equipment and
on-site property, all personnel authorized to install, operate and service the Model 755
Oxygen Analyzer should be thoroughly familiar with and strictly follow the instructions
in this manual. Save these instructions.
DANGER is used to indicate the presence of a hazard which will cause severe
personal injury, death, or substantial property damage if the warning is ignored
WARNING is used to indicate the presence of a hazard which can cause severe
personal injury, death, or substantial property damage if the warning is ignored.
CAUTION is used to indicate the presence of a hazard which will or can cause minor
personal injury or property damage if the warning is ignored.
NOTE is used to indicate installation, operation, or maintenance information which is
important but not hazard-related.
Do not operate without doors and covers secure. Servicing requires access to
live parts which can cause death or serious injury. Refer servicing to qualified
personnel.
For safety and proper performance this instrument must be connected to a
properly grounded three-wire source of power.
WARNING: ELECTRICAL SHOCK HAZARD

MODEL 755 OXYGEN ANALYZER
Rosemount Analytical 748183-H November 1997
P-2
The general purpose Model 755 Oxygen Analyzer, catalog number 191102, is for
operation in non-hazardous locations. It is of a type capable of analysis of
sample gases which may be flammable. If used for analysis of such gases, the
instrument must be protected by a continuous dilution purge system in
accordance with Standard ANSI/NFPA-496-1086 (Chapter 8) or IEC Publication
79-2-1983 (Section Three).
The explosion-proof Model 755 Oxygen Analyzer, catalog number 632440, is for
operation in hazardous locations. The enclosure must be properly secured with
all flange bolts in place and tightened, lens cover fully engaged, all factory
installed flame arrestor assemblies are properly installed in sample inlet and
outlet and any unused openings plugged with approved threaded plugs properly
secured in place. Installation must be made in accordance with applicable parts
of the NEC, especially Articles 501-4(a) and 501-5(a)(1).
If explosive gases are introduced into this analyzer, the sample containment
system must be carefully leak-checked upon installation and before initial start-
up, during routine maintenance and any time the integrity of the sample
containment system is broken, to ensure the system is in leak-proof condition.
Leak-check instructions are provided in Section 2.7.
Internal leakage of sample resulting from failure to observe these precautions
could result in an explosion causing death, personal injury, or property damage.
Tampering or unauthorized substitution of components may adversely affect
safety of this product. Use only factory documented components for repair.
This analyzer requires periodic calibration with known zero and standard gases.
See General Precautions for Handling and Storing High Pressure Cylinders, in
the rear of this manual.
WARNING: POSSIBLE EXPLOSION HAZARD
WARNING: HIGH PRESSURE GAS CYLINDERS
CAUTION: PARTS INTEGRITY

PREFACE
P-3
748183-H Rosemount Analytical
November 1997
SPECIFICATIONS - GENERAL1
CATALOG NUMBER
191102 General Purpose for operation in non-hazardous locations
632440 Explosion-Proof for operation in hazardous locations
STANDARD RANGE OPTIONS (% OXYGEN FULLSCALE) 2
0 to 1, 2.5, 5, and 10% fullscale
0 to 5, 10, 25, and 50% fullscale
0 to 10, 25, 50, and 100% fullscale
0 to 1, 2.5, 5 and 25% fullscale
0 to 1, 5, 10, and 25% fullscale
50 to 100, 60 to 100, 80 to 100, and 90 to 100% fullscale
RESPONSE TIME (90% OF FULLSCALE)
Factory set for 20 seconds; adjustable from 5 to 25 seconds.
REPRODUCIBILITY
±0.01% Oxygen or ±1% of fullscale, whichever is greater
AMBIENT TEMPERATURE LIMITS
Maximum: 49°C (120°F)
Minimum: -7°C (20°F)
ZERO AND SPAN DRIFT 3
±1% of fullscale per 24 hours, provided that ambient temperature does not
change by more than 11.1°C (20°F).
±2.5% of fullscale per 24 hours with ambient temperature change over entire
range.
1Performance specifications based on recorder output.
2For applications requiring suppressed ranges other than those provided, we recommend the Model 755A Oxygen
Analyzer, Catalog Number 617720. This instrument includes automatic correction for barometric pressure variations and
provides maximum accuracy for suppressed ranges. This particularly important at high level suppressed ranges such as
99 to 100% where a barometric pressure change from standard 29.90 inches Hg (101 kPa) to 31.5 inches Hg (106 kPa)
would result in an actual oxygen change in the order of 5%. The Model 755A provides automatic barometric pressure
correction and optimum accuracy for such suppressed ranges. The Model 755A also provides direct readout from 0.00%
to 100.00% oxygen on a digital display. Optimum resolution of the oxygen reading is provided.
3Zero and span drift specifications based on following conditions: Operating pressure constant; ambient temperature
change from initial calibration temperature, less than 11.1 Celsius degrees (20 Fahrenheit degrees); deviation from set
flow held to within ±10% or ±20 cc/min, whichever is smaller.

MODEL 755 OXYGEN ANALYZER
Rosemount Analytical 748183-H November 1997
P-4
SPECIFICATIONS - SAMPLE
DRYNESS
Sample dewpoint below 43°C (110°F), sample free of entrained liquids.
TEMPERATURE LIMITS
Maximum: 66°C (150°F)
Minimum: 10°C (50°F)
OPERATING PRESSURE
Maximum: 69 kPa (10 psig).
Minimum: 88.1 kPa absolute (660 mm Hg absolute pressure)
FLOW RATE 4
Maximum: 500 cc/min
Minimum: 50 cc/min
Recommended: 250 ±20 cc/min
MATERIALS IN CONTACT WITH SAMPLE GAS
316 stainless steel, glass, titanium, Paliney No. 7, epoxy resin, Viton-A,
platinum, nickel.
SPECIFICATIONS - ELECTRICAL
SUPPLY VOLTAGE AND FREQUENCY (SELECTABLE WHEN ORDERED)
Standard: 115 VAC ±10 VAC, 50/60 Hz
Optional: 230 VAC ±10 VAC, 50/60 Hz
POWER CONSUMPTION
Maximum: 300 watts
OUTPUTS
Standard: Field selectable voltage output of 0 to 10mV, 0 to 100mV, 0 to 1V,
or 0 to 5VDC
Optional: Isolated current output of 0 to 20mA or 4 to 20mA (with Current
Output Board)
ALARM OPTION
High-Low Alarm
Contact Ratings:
5 amperes, 240V AC, resistive 3 amperes, 120 VAC inductive
1 amperes, 24V DC, resistive 5 amperes, 30 VDC resistive
5 amperes, 120V AC, resistive 3 amperes, 30 VDC inductive
SETPOINT
Adjustable from 1% to 100% of fullscale
DEADBAND
Adjustable from 1% to 20% of fullscale (Factory set at 10% of fullscale)
4Deviation from set flow would be held to within ±10% or ±20 cc/min, whichever is smaller. If so, zero and span drift will
be within specifications, provided that operating temperature remains constant.

PREFACE
P-5
748183-H Rosemount Analytical
November 1997
SPECIFICATIONS - PHYSICAL
GENERAL PURPOSE ENCLOSURE
MOUNTING
Standard: Panel mount
Optional: Surface or stanchion mount accessory available
ENCLOSURE CLASSIFICATION
Meets requirements for NEMA 3R
Air Purge Option5: NFPA 496 (1989) Type Z purge
REFER TO INSTALLATION DRAWING 632349 IN THE REAR OF THIS MANUAL.
SPECIFICATIONS - PHYSICAL
EXPLOSION-PROOF ENCLOSURE
MOUNTING
Surface or wall
ENCLOSURE CLASSIFICATION
Class I, Groups B, C, and D, Division 1 hazardous locations (ANSI/NFPA 70)
REFER TO INSTALLATION DRAWING 643127 IN THE REAR OF THIS MANUAL.
5When installed with user supplied components, meets requirements for Class I, Division 2 locations per National
Electrical Code (ANSI/NFPA 70) for analyzers sampling nonflammable gases. Analyzers sampling flammable gases
must be protected by a continuous dilution purge system in accordance with Standard ANSI/NFPA 496-1986, Chapter 8.
Consult factory for recommendations.

MODEL 755 OXYGEN ANALYZER
Rosemount Analytical 748183-H November 1997
P-6
CUSTOMER SERVICE, TECHNICAL ASSISTANCE AND FIELD SERVICE
For order administration, replacement Parts, application assistance, on-site or factory
repair, service or maintenance contract information, contact:
Rosemount Analytical Inc.
Process Analytical Division
Customer Service Center
1-800-433-6076
RETURNING PARTS TO THE FACTORY
Before returning parts, contact the Customer Service Center and request a Returned
Materials Authorization (RMA) number. Please have the following information when
you call: Model Number, Serial Number, and Purchase Order Number or Sales Order
Number.
Prior authorization by the factory must be obtained before returned materials will be
accepted. Unauthorized returns will be returned to the sender, freight collect.
When returning any product or component that has been exposed to a toxic, corrosive
or other hazardous material or used in such a hazardous environment, the user must
attach an appropriate Material Safety Data Sheet (M.S.D.S.) or a written certification
that the material has been decontaminated, disinfected and/or detoxified.
Return to:
Rosemount Analytical Inc.
4125 East La Palma Avenue
Anaheim, California 92807-1802
TRAINING
A comprehensive Factory Training Program of operator and service classes is
available. For a copy of the Current Operator and Service Training Schedule contact
the Technical Services Department at:
Rosemount Analytical Inc.
Phone: [phone]
FAX: [phone]
DOCUMENTATION
The following Model 755 Oxygen Analyzer instruction materials are available.
Contact Customer Service or the local representative to order.
748183 Instruction Manual (this document)

PREFACE
P-7
748183-H Rosemount Analytical
November 1997
COMPLIANCES
MODEL 755 OXYGEN ANALYZER - GENERAL PURPOSE ENCLOSURE
The Model 755 Oxygen Analyzer (general purpose enclosure), catalog number
191102, has been designed to meet the applicable requirements of the U.S.
Occupational Safety and Health Act (OSHA) of 1970 if installed in accordance with the
requirements of the National Electrical Code (NEC) of the United States in non-
hazardous areas and operated and maintained in the recommended manner.
MODEL 755 OXYGEN ANALYZER - EXPLOSION-PROOF ENCLOSURE
The Model 755 Oxygen Analyzer (explosion-proof enclosure), catalog number 632440,
is approved by Factory Mutual (FM) for installation in Class I, Groups B, C, and D,
Division 1, hazardous locations as defined in the National Electrical Code (NEC) of the
United States (ANSI/NFPA 70).
®
APPROVED
FM

MODEL 755 OXYGEN ANALYZER
Rosemount Analytical 748183-H November 1997
P-8
NOTES

1
INTRODUCTION
748183-H 1-1
Rosemount Analytical
November 1997
The Model 755 Oxygen Analyzer provides continuous read-out of the oxygen content
of a flowing gas sample. The determination is based on measurement of the magnetic
susceptibility of the sample gas. Oxygen is strongly paramagnetic, other common
gases are weakly diamagnetic, with few exceptions.
The instrument provides direct read-out of oxygen concentration on a front-panel
meter. In addition a field-selectable voltage output is provided as standard. An isolated
current output of 4 to 20 mA or 0 to 20 mA is obtainable through plug-in of the optional
circuit board. Current and voltage outputs may be utilized simultaneously, if desired.
The basic electronic circuitry is incorporated into two master boards designated the
Control Board and the Case Board, see Figure 1-2. The Control Board has
receptacles that accept optional plug-in circuit boards thus permitting inclusion of such
features as current output and alarms, and facilitating conversion from one range
option to another.
The analyzer is available in a general purpose enclosure or an explosion proof
enclosure. See Figures 1-1.
1.1 RANGE OPTIONS
The Model 755 is supplied, as ordered, with four switch-selectable ranges: an overall
range and three sub-ranges, each covering a portion of the overall range. The
standard range options are of two general types: zero-based (Section 1.1.1) and zero-
suppressed (Section 1.1.2). In addition, special range options incorporating
combinations of zero-based and zero-suppressed ranges are available on factory
special order, refer to Section 1.1.3. All range options utilize a front-panel meter with
left-hand zero. See Figure 1-1 and Table 1-1.
1.1.1 STANDARD ZERO-BASED RANGE OPTIONS
In a zero-based range option, the lower range-limit for all four ranges is 0% oxygen.
There are five standard zero-based range options:
•Range Option
•Sub-Range A
•Sub-Range B
•Sub-Range C
•Overall Range
Refer to Table 1-2.

MODEL 755 OXYGEN ANALYZER
1-2 748183-H
Rosemount Analytical November 1997
Rosemount Analytical Model 755
Oxygen Analyzer
ZERO Control
RANGE Switch SPAN Adjust
Controls have slotted shafts for screwdriver adjustment from outside the enclosure.
Meter
Rosemount Analytical Model 755
Oxygen Analyzer
Meter
ZERO Adjust
SPAN Adjust
RANGE Switch
A. GENERAL PURPOSE ENCLOSURE
B. EXPLOSION-PROOF ENCLOSURE
FIGURE 1-1. MODEL 755 - FRONT VIEW

INTRODUCTION
748183-H 1-3
Rosemount Analytical
November 1997
TABLE 1-1. FRONT PANEL CONTROLS
RANGE
OPTION SUB-RANGE A SUB-RANGE B SUB-RANGE C OVERALL RANGE
01 0 to 1% 0 to 2.5% 0 to 5% 0 to 10%
02 0 to 5% 0 to 10% 0 to 25% 0 to 50%
03 0 to 10% 0 to 25% 0 to 50% 0 to 100%
04 0 to 1% 0 to 2.5% 0 to 5% 0 to 25%
06 90 to 100% 80 to 100% 60 to 100% 50 to 100%
TABLE 1-2. RANGE OPTIONS
1.1.2 STANDARD ZERO-SUPPRESSED RANGE OPTIONS
With any zero-suppressed range the 0% oxygen point lies off-scale below the lower
range-limit. In a zero-suppressed range option the four ranges have the same upper
range-limit, but different lower range-limits. There is a standard zero-suppressed
range option, as shown in Table 1-2.
1.1.3 SPECIAL RANGE OPTIONS
On factory special order, the analyzer may be provided with a special range option
incorporating any desired combination of zero-based and zero-suppressed ranges,
arranged in ascending order according to span.
CONTROL FUNCTION
METER
Indicates oxygen content of sample, provided the analyzer has been
calibrated by appropriate adjustment of % RANGE switch, ZERO control,
and SPAN control. Meter face is calibrated with scales covering the
operating ranges provided.
%RANGE SWITCH
Select percentage oxygen range for meter and recorder
ZERO ADJUST
Used to establish downscale calibration point on meter scale or recorder
chart. With suitable downscale standard gas flowing through the analyzer,
the ZERO Control is adjusted for appropriate reading on meter or recorder.
SPAN ADJUST
Used to establish downscale calibration point on meter scale or recorder
chart. With suitable downscale standard gas flowing through the analyzer,
the ZERO Control is adjusted for appropriate reading on meter or recorder.

MODEL 755 OXYGEN ANALYZER
1-4 748183-H
Rosemount Analytical November 1997
FIGURE 1-2. MODEL 755 - LOCATION OF MAJOR COMPONENTS
+-
+
COM
MA
MV
TB2
NO
COM
NC
RESET
NO
COM
NC
RESET
NO. 1
NO. 2
HOT
GND N
E
U
T
H
O
T
TB1
R2
R
R
R
8
U
IG
U
U
1
2
I
G
C
C
C
U
U
IG
C3
U
J
Alarm Relay
Assembly
(Alarm Option)
Case Board
Transformer, Power
T1
(Behind TB1)
AC Power
TB1
Detector/Magnet
Assembly
Detector/Magnet
Assembly Shock
Mount
Fuse
AC Power
Recorder Output
TB2
Case Heater
Assembly
Fuse
Case
Heater
Current Output
Board (Option)
Control Board
Door
General Purpose enclosure shown. Components mounted in same locations in Explosion-Proof enclosure.