Rosemount OCX 8800 O2 / Combustibles Transmitter Hazardous Area Owner's manual

Reference Manual

00809-0100-4881, Rev AA

July 2018

Rosemount

™

OCX 8800 Oxygen and

Combustibles Transmitter

Hazardous Location Probe with Integral Electronics

Signal words and symbols

Pay attention to the following signal words, safety alert symbols, and statements.

WARNING!

Indicates a hazardous situation which, if not avoided, could result in death or serious injury.

CAUTION!

Indicates a hazardous situation which, if not avoided, could result in equipment damage.

NOTICE

Used to address messages or practices not related to personal injury or equipment damage.

Symbols

Earth (ground) terminal

Protective conduit terminal

Risk of electrical shock

Warning: Refer to instruction manual

Essential Instructions

Read this page before proceeding!

Emerson designs, manufactures, and tests its products to meet many national and international standards. Because these

instruments are sophisticated technical products, you must properly install, use, and maintain them to ensure they continue to

operate within their normal specifications. The following instructions must be adhered to and integrated into your safety program

when installing, using, and maintaining Emerson's Rosemount products. Failure to follow the proper instructions may cause any one

of the following situations to occur: loss of life, personal injury, property damage, damage to this instrument, and warranty

invalidation.

• Read all instructions prior to installing, operating, and servicing the product.

• If you do not understand any of the instructions, contact your Emerson representative for clarification.

• Follow all warnings, cautions, and instructions marked on and supplied with the product.

• Inform and educate your personnel in the proper installation, operation, and maintenance of the product.

• Install your equipment as specified in the installation instructions of the appropriate instruction manual and per applicable

local and national codes. Connect all products to the proper electrical and pressure sources.

• To ensure proper performance, use qualified personnel to install, operate, update, program, and maintain the product.

• When replacement parts are required, ensure that qualified people use replacement parts specified by Emerson.

Unauthorized parts and procedures can affect the product's performance, place the safe operation of your process at risk,

and VOID YOUR WARRANTY. Look-alike substitutions may result in fire, electrical hazards, or improper operation.

• Ensure that all equipment doors are closed and protective covers are in place, except when maintenance is being performed

by qualified people, to prevent electrical shock and personal injury.

The information contained in this document is subject to change without notice.

NOTICE

If a Model 375 Field Communicator is used with this unit, the software within the Model 375 may require modification. If a software

modification is required, please contact your local Emerson Service Group or National Response Center at 1-800-654-7768.

Preface

The purpose of this manual is to provide a comprehensive understanding of the OCX8800

components, functions, installation, and maintenance.

Emerson recommends that you thoroughly familiarize yourself with Chapter 1 and Chapter 2 before installing your transmitter.

Before contacting Emerson concerning any questions, first consult this manual. It describes most situations encountered in yoru

equipment's operation and details necessary action.

Chapter 1 presents the basic principles of the transmitter along with its performance characteristics and components. The

remaining sections contain detailed procedures and information necessary to install and service the transmitter.

Product operation personnel

• Read and understand all instructions and operating procedures for this product.

• Install this product as specified in Chapter 2 of this manual per applicable local and national codes.

• Follow all warnings, cautions, and notices marked on and supplied with the product.

• Follow all instructions during the installation, operation,and maintenance of this product.

• To prevent personal injury, ensure that all components are in place prior to and during operation of this product.

• Connect all products to the proper electrical and pressure sources when and where applicable.

• Ensure that all connections to pressure and electrical sources are secure prior to and during equipment operation.

• If you do not understand an instruction or do not feel comfortable following the instructions, contact your Rosemount

representative for clarification or assistance.

• If this instruction manual is not the correct manual for you Rosemount product, call Rosemount at 800 854 8257, and

Rosemount will provide you with the requested manual. You may also download the manual from

www.Emerson.com/RosemountGasAnalysis.

• Save this instruction manual for future reference.

Notice

The contents of this publication are presented for informational purposes only, and while

every effort has been made to ensure their accuracy, they are not to be construed as

warranties or guarantees, expressed or implied, regarding the products or services

described herein or their use or applicability. All sales are governed by Rosemount's terms

and conditions, which are available upon request. We reserve the right to modify or

improve the designs or specifications of such products at any time.

Rosemount does not assume responsibility for the selection, use, or maintenance of any product. Responsibility for proper

selection, use, and mainteance of any Rosemount product remains solely with the purchaser and end-user.

To the best of Rosemount's knowledge, the information herein is complete and accurate. Rosemount makes no warranties,

expressed or implied, including implied warranties of merchantability and fitness for a particular purpose, with respect to this

manual and, in no event, shall Rosemount be liable for any incidental, punitive, special, or consequential damages including, but not

limited to, loss of production, loss of profits, loss of revenue or use, and costs incurred, including without limitation for capital, fuel

and power, and claims of third parties.

Product names used herein are for manufacturer or supplier identification only and may be trademarks/registered trademarks of

these companies.

Rosemount and the Rosemount logo are registered trademarks of Rosemount. The Emerson logo is a trademark and service mark of

Emerson Electric Co.

Warranty

1. LIMITED WARRANTY: Subject to the limitations contained in Section 2 herein, Rosemount warrants that the licensed

firmware embodied in the Goods will execute the programming instructions provided by Rosemount and that the Goods

manufacturerd by Rosemount will be free from defects in materials or workmanship under normal use and care and Services

will be performed by trained personnel using proper equipment and instrumentation for the particular Service provided.

The foregoing warranties will apply until the expiration of the applicable warranty period. Goods are warranted for twelve

(12) months from the date of initial installation or eighteen (18) months from the date of shipment by Rosemount,

whichever period expires first. Consumables and Services are warranted for a period of 90 days from the date of shipment or

completion of the Services. Products purchased by Rosemount from a third party for resale to Buyer ("Resale Products") shall

carry only the warranty extended by the original manufacturer. Buyer agrees that Rosemount has no liability for Resale

Products beyond making a reasonable commercial effort to arrange for procurement and shipping of Resale Products. If

Buyer discovers any warranty defects and notifies Rosemount thereof in writing during the applicable warranty period,

Rosemount shall, at its option, correct any errors that are found by Rosemount in the firmware or Services or repair or

replace F.O.B. point of manufacture that portion of the Goods or firmware found by Rosemount to defective, or refund the

purchase price of the defective portion of the Goods/Services. All replacements or repairs necessitated by inadequate

maintenance, normal wear and usage, unsuitable power sources, or environmental conditions, accident, misuse, improper

installation, modifications, repair, use of unauthorized replacement parts, storage or handling, or any other cause not the

fault of Rosemount are not covered by this limited warranty and shall be at Buyer's expense. Rosemount shall not be

obligated to pay any costs or charges incurred by Buyer or any other party except as may be agreed upon in writing in

advance by Rosemount. All costs of dismantling, reinstallation and freight, and the time and expenses of Rosemount's

personnel and representatives for site travel and diagnosis under this warranty clause shall be borne by Buyer unless

accepted in writing by Rosemount. Goods repaired and parts replaced by Rosemount during the warranty period shall be in

warranty for the remainder of the original warranty period or ninety (90) days, whichever is longer. This limited warranty is

the only warranty made by Rosemount and can be amended only in a writing signed by Rosemount. THE WARRANTIES AND

REMEDIES SET FORTH ABOVE ARE EXCLUSIVE. THERE ARE NO REPRESENTATIONS OR WARRANTIES OF ANY KIND,

EXPRESSED OR IMPLIED, AS TO MERCHANTABILITY, FITNESS FOR PARTICULAR PURPOSE, OR ANY OTHER MATTER WITH

RESPECT TO ANY OF THE GOODS OR SERVICES. Buyer acknowledges and agrees that corrosion or erosion of materials is not

covered by this warranty.

2. LIMITATION OF REMEDY AND LIABILITY: ROSEMOUNT SHALL NOT BE LIABLE FOR DAMAGES CAUSED BY DELAY IN

PERFORMANCE. THE REMEDIES OF BUYER SET FORTH IN THIS AGREEMENT ARE EXCLUSIVE. IN NO EVENT, REGARDLESS OF

THE FORM OF THE CLAIM OR CAUSE OF ACTION (WHETHER BASED IN CONTRACT, INFRINGEMENT, NEGLIGENCE, STRICT

LIABILITY, OTHER TORT OR OTHERWISE), SHALL ROSEMOUNT'S LIABILITY TO BUYER AND/OR ITS CUSTOMERS EXCEED THE

PRICE TO BUYER OF THE SPECIFIED GOODS MANUFACTURED OR SERVICES PROVIDED BY ROSEMOUNT GIVING RISE TO THE

CLAIM OR CAUSE OF ACTION. BUYER AGREES THAT IN NO EVENT SHALL ROSEMOUNT'S LIABILITY TO BUYER AND/OR ITS

CUSTOMERS EXTEND TO INCLUDE INCIDENTAL, CONSEQUENTIAL, OR PUNITIVE DAMAGES. THE TERM "CONSEQUENTIAL

DAMAGES" SHALL INCLUDE, BUT NOT BE LIMITED TO, LOSS OF ANTICIPATED PROFITS, REVENUE, OR USE AND COSTS

INCURRED INCLUDING WITHOUT LIMITATION FOR CAPITAL, FUEL AND POWER, AND CLAIMS OF BUYER'S CUSTOMERS.

Contents

Chapter 1 Description and specifications ..........................................................................................1

1.1 Component checklist ..................................................................................................................... 1

1.2 System overview ............................................................................................................................ 3

1.2.1 Scope .............................................................................................................................. 3

1.2.2 System description .......................................................................................................... 3

1.2.3 System configurations .....................................................................................................4

1.2.4 System features ...............................................................................................................5

1.2.5 System operation ............................................................................................................ 5

1.2.6 Handling the OCX 8800 ................................................................................................... 6

1.2.7 System considerations .....................................................................................................6

1.3 Specifications ...............................................................................................................................11

1.3.1 Net O

2

range ..................................................................................................................11

1.3.2 Combustibles ................................................................................................................ 11

1.3.3 Accuracy ........................................................................................................................11

1.3.4 System response to test gas .......................................................................................... 11

1.3.5 Temperature limits ........................................................................................................ 11

1.3.6 Nominal and approximate shipping weights ..................................................................12

1.3.7 Mounting .......................................................................................................................12

1.3.8 Materials ........................................................................................................................12

1.3.9 Calibration .....................................................................................................................13

1.3.10 Calibration gas mixtures recommended (ref. test gas bottles kit #1A9919G04) .............13

1.3.11 Calibration gas flow ....................................................................................................... 13

1.3.12 Reference air ................................................................................................................. 13

1.3.13 Eductor air ..................................................................................................................... 13

1.3.14 Dilution air .....................................................................................................................13

1.3.15 Blowback air (optional) ..................................................................................................13

1.3.16 Certifications ................................................................................................................. 14

1.3.17 Electrical noise ...............................................................................................................14

1.3.18 Line voltage ................................................................................................................... 14

1.3.19 Pollution degree ............................................................................................................ 14

1.3.20 Over voltage category ................................................................................................... 14

1.3.21 Relative humidity ...........................................................................................................15

1.3.22 Isolated output ..............................................................................................................15

1.3.23 Alarm .............................................................................................................................15

1.3.24 Power consumption ...................................................................................................... 15

1.4 Product matrix - OCX 8800 ...........................................................................................................15

Chapter 2 Install .............................................................................................................................19

2.1 Product safety .............................................................................................................................. 19

2.2 Mechanical installation .................................................................................................................20

2.2.1 Selecting a location ....................................................................................................... 20

2.2.2 Installation .....................................................................................................................21

2.3 Electrical installation .................................................................................................................... 26

2.3.1 Electrical connections ....................................................................................................29

2.3.2 Connect line voltage ......................................................................................................29

2.3.3 Connect output signals ..................................................................................................29

2.3.4 O

2

4-20 mA signal ..........................................................................................................29

Contents

Reference Manual i

2.3.5 COe 4-20 mA signal ....................................................................................................... 29

2.3.6 Foundation Fieldbus signal ............................................................................................ 29

2.3.7 Alarm output relay .........................................................................................................29

2.3.8 Remote electronics connections to sensor housing ....................................................... 30

2.3.9 Signal connections .........................................................................................................32

2.3.10 Heater power connections .............................................................................................32

2.4 Pneumatic installation ..................................................................................................................32

2.4.1 Reference air set option (only) ....................................................................................... 32

2.4.2 Reference air set and solenoids option without COe zero function .................................34

2.4.3 Reference air set and solenoids option with COe zero function ...................................... 36

2.4.4 Reference air set, solenoids, and blowback option with COe zero function .................... 38

2.5 Initial startup ................................................................................................................................42

Chapter 3 Configuration and startup .............................................................................................. 43

3.1 Verify installation ......................................................................................................................... 43

3.1.1 Verify configuration - HART electronics ......................................................................... 43

3.1.2 Verify configuration - Fieldbus electronics ..................................................................... 45

3.2 Initial power up ............................................................................................................................ 46

3.3 Set test gas values ........................................................................................................................ 46

3.3.1 Setting test gas values with the Field Communicator .....................................................46

3.3.2 Setting test gas values with Fieldbus communicator ......................................................46

3.3.3 Setting test gas values with the LOI ................................................................................47

3.4 Calibration solenoids ....................................................................................................................47

3.4.1 Configuring the calibration solenoids with the Field Communicator - HART ...................47

3.4.2 Configuring the calibration solenoids with the Field Communicator - Fieldbus .............. 48

3.4.3 Configuring the calibration solenoids with the LOI .........................................................48

3.5 Blowback feature ......................................................................................................................... 48

3.5.1 Configuring blowback with the Field Communicator - HART ..........................................48

3.5.2 Configuring blowback with the Field Communicator - Fieldbus ......................................49

3.5.3 Configuring blowback with the LOI ................................................................................49

3.6 Calibration verify feature ..............................................................................................................50

3.6.1 Performing a calibration verify with the Field Communicator - HART ............................. 50

3.6.2 Performing a calibration verify with the Field Communicator - Fieldbus ......................... 51

3.6.3 Performing a calibration verify with the LOI ................................................................... 51

3.7 Calibration tolerance feature ........................................................................................................52

3.7.1 Configuring the calibration tolerance feature with the Field Communicator -HART ....... 52

3.7.2 Configuring the calibration tolerance feature with the Field Communicator -

Fieldbus .........................................................................................................................52

3.7.3 Configuring the calibration tolerance feature with the LOI .............................................53

3.8 COe purge / zero feature .............................................................................................................. 53

3.8.1 Configuring the COe zero feature with the Field Communicator - HART ........................ 54

3.8.2 Configuring the COe zero feature with the Field Communicator - Fieldbus ....................54

3.8.3 Configuring the COe zero feature with the LOI ...............................................................55

3.9 Reset procedure ...........................................................................................................................55

3.9.1 Reset with the LOI ..........................................................................................................56

3.9.2 Reset with Field Communicator .....................................................................................56

Chapter 4 Using the LOI ..................................................................................................................57

4.1 Display orientation .......................................................................................................................57

4.2 LOI controls ..................................................................................................................................58

4.2.1 Overview ....................................................................................................................... 58

4.2.2 LOI key functions ........................................................................................................... 59

Contents

ii OCX 8800

4.2.3 Lockout ......................................................................................................................... 60

4.2.4 LOI status codes .............................................................................................................62

4.3 LOI menu tree .............................................................................................................................. 62

4.3.1 First column submenus ..................................................................................................66

4.3.2 Second column submenus .............................................................................................66

4.3.3 Third and fourth column submenus ...............................................................................67

Chapter 5 Calibration ..................................................................................................................... 69

5.1 Overview ......................................................................................................................................69

5.2 Fully automatic calibration ........................................................................................................... 69

5.2.1 Autocalibration setup using HART ................................................................................. 69

5.3 Operator-initiated autocalibration ............................................................................................... 70

5.3.1 Autocalibration using HART ...........................................................................................70

5.4 Manual calibration ........................................................................................................................70

5.4.1 Manual calibration using the optional LOI ...................................................................... 71

5.4.2 Manual O

2

calibration using the Field Communicator - HART .........................................72

5.4.3 Manual COe calibration using the Field Communicator - HART ...................................... 73

5.4.4 Manual O

2

and COe calibration using the Field Communicator - Fieldbus ...................... 75

5.5 D/A trim procedures - LOI .............................................................................................................77

5.5.1 O

2

D/A trim procedure using the LOI ............................................................................. 77

5.5.2 COe D/A trim procedure using the LOI ...........................................................................78

5.6 D/A trim procedures - HART ......................................................................................................... 79

5.6.1 O

2

D/A trim procedure using HART ................................................................................79

5.6.2 COe D/A trim procedure using HART ............................................................................. 81

Chapter 6 Field Communicator .......................................................................................................83

6.1 Overview ......................................................................................................................................83

6.2 Field Communicator connections .................................................................................................83

6.2.1 Connecting to a HART loop ............................................................................................83

6.2.2 Connecting to a Fieldbus segment .................................................................................84

6.3 HART menu tree ...........................................................................................................................86

6.4 Fieldbus menu tree .......................................................................................................................90

Chapter 7 Foundation Fieldbus .......................................................................................................95

7.1 Foundation Fieldbus technology .................................................................................................. 95

7.1.1 Overview ....................................................................................................................... 95

7.1.2 Introduction .................................................................................................................. 95

7.1.3 Function blocks ............................................................................................................. 96

7.1.4 Device descriptions ....................................................................................................... 97

7.1.5 Instrument-specific function blocks ...............................................................................97

7.2 Network communication ............................................................................................................. 98

7.2.1 Link active scheduler (LAS) .............................................................................................99

7.2.2 Device addressing ..........................................................................................................99

7.3 OCX function blocks ...................................................................................................................100

7.3.1 Implemented function blocks ......................................................................................100

7.4 Resource block ...........................................................................................................................100

7.4.1 PlantWeb Alerts ...........................................................................................................100

7.4.2 Mapping of PWA ..........................................................................................................101

7.4.3 PWA SIMULATE ............................................................................................................110

7.4.4 Fieldbus/PWA simulate ................................................................................................111

7.4.5 Configure simulation from AMS ...................................................................................111

7.5 Configure simulation with the Model 375 Field Communicator ..................................................112

7.5.1 Support resource block errors ......................................................................................113

Contents

Reference Manual iii

7.6 Transducer block ........................................................................................................................113

7.6.1 Transducer block parameters ...................................................................................... 114

7.7 Transducer block enumerations ................................................................................................. 122

7.7.1 Calibration states .........................................................................................................122

7.7.2 Calibration step command .......................................................................................... 123

7.7.3 Transducer block channel assignments for AI blocks ....................................................128

7.7.4 Transducer block channel status ..................................................................................128

7.7.5 Transducer block simulate ...........................................................................................129

7.7.6 Support transducer block errors .................................................................................. 129

7.8 Analog input (AI) function block .................................................................................................130

7.8.1 Introduction ................................................................................................................ 130

7.8.2 Simulation ................................................................................................................... 135

7.8.3 Filtering ....................................................................................................................... 138

7.8.4 Signal conversion .........................................................................................................138

7.8.5 Direct signal conversion ...............................................................................................138

7.8.6 Indirect signal conversion ............................................................................................ 139

7.8.7 Indirect square root ..................................................................................................... 139

7.8.8 Block errors ................................................................................................................. 139

7.8.9 Modes ......................................................................................................................... 140

7.8.10 Alarm detection ...........................................................................................................140

7.8.11 Status handling ............................................................................................................141

7.8.12 Advanced features .......................................................................................................142

7.8.13 Application information ...............................................................................................142

7.8.14 Application examples .................................................................................................. 143

7.8.15 Pressure transmitter used to measure level in an open tank .........................................143

7.8.16 Differential pressure transmitter to measure flow ........................................................147

7.8.17 Troubleshooting ..........................................................................................................147

7.9 Proportional/integral/derivative (PID) function block ................................................................. 149

7.9.1 Setpoint selection and limiting .................................................................................... 158

7.9.2 PID equation structures ............................................................................................... 160

7.9.3 Reverse and direct action .............................................................................................161

7.9.4 Reset limiting .............................................................................................................. 161

7.9.5 Block errors ................................................................................................................. 161

7.9.6 Modes ......................................................................................................................... 162

7.9.7 Alarm detection ...........................................................................................................162

7.9.8 Status handling ............................................................................................................163

7.9.9 Application information ...............................................................................................164

7.9.10 Application examples .................................................................................................. 165

7.9.11 Cascade control with master and slave loops ............................................................... 167

7.9.12 Cascade control with override ..................................................................................... 169

7.9.13 Troubleshooting ..........................................................................................................170

7.10 Airthmetic (ARTHM) function block ............................................................................................172

7.10.1 Block errors ................................................................................................................. 175

7.10.2 Modes ......................................................................................................................... 176

7.10.3 Alarm detection ...........................................................................................................176

7.10.4 Block execution ........................................................................................................... 177

7.10.5 Compensation input calculations ................................................................................ 177

7.10.6 Application information ...............................................................................................178

7.11 Advanced topics .........................................................................................................................179

7.11.1 Arithmetic types ..........................................................................................................179

7.11.2 Troubleshooting ..........................................................................................................180

Contents

iv OCX 8800

7.12 Input selector (ISEL) function block ............................................................................................ 181

7.12.1 Block errors ................................................................................................................. 185

7.12.2 Modes ......................................................................................................................... 185

7.12.3 Alarm detection ...........................................................................................................186

7.12.4 Block execution ........................................................................................................... 186

7.12.5 Status handling ............................................................................................................187

7.12.6 Application information ...............................................................................................187

7.12.7 Troubleshooting ..........................................................................................................189

7.13 Operation with Emerson DeltaV ................................................................................................. 189

7.13.1 About AMS and DeltaV software ..................................................................................189

Chapter 8 Troubleshooting .......................................................................................................... 193

8.1 Overview ....................................................................................................................................193

8.1.1 Grounding ................................................................................................................... 193

8.1.2 Electrical noise .............................................................................................................193

8.1.3 Electrostatic discharge ................................................................................................ 193

8.1.4 Total power loss ...........................................................................................................194

8.2 Diagnostic alarms .......................................................................................................................196

8.3 Fault isolation .............................................................................................................................196

8.4 Alarm relay events ......................................................................................................................205

Chapter 9 Maintenance and service .............................................................................................. 209

9.1 Overview ....................................................................................................................................209

9.2 Removal and installation ............................................................................................................ 209

9.2.1 OCX with integral electronics ...................................................................................... 209

9.2.2 OCX with remote electronics ....................................................................................... 213

9.2.3 Repair sensor housing ..................................................................................................216

9.2.4 Sensor housing assembly .............................................................................................233

9.3 Repair electronics housing ......................................................................................................... 248

9.3.1 Electronics housing disassembly ..................................................................................248

9.3.2 Electronics housing assembly ...................................................................................... 252

Chapter 10 Replacement parts ....................................................................................................... 255

10.1 Sensor housing ...........................................................................................................................255

10.2 Electronics housing .................................................................................................................... 259

10.3 O

2

cell and heater strut assembly ............................................................................................... 262

Appendices and reference

Appendix A Safety data ................................................................................................................... 265

A.1 Safety Instructions ..................................................................................................................... 265

A.2 Safety data sheet for ceramic fiber products .............................................................................. 266

A.2.1 Identification ............................................................................................................... 266

A.2.2 Physical data ................................................................................................................266

A.2.3 Hazardous ingredients .................................................................................................267

A.2.4 Fire and explosion data ................................................................................................ 267

A.2.5 Health hazard data ...................................................................................................... 267

A.2.6 Reactivity data .............................................................................................................269

A.2.7 Spill or leak procedures ................................................................................................269

A.2.8 Special precautions ......................................................................................................269

Contents

Reference Manual v

A.3 High pressure gas cylinders ........................................................................................................ 271

A.3.1 General precautions for handling and storing high pressure gas cylinders ....................271

A.4 ATEX clarification ....................................................................................................................... 272

A.4.1 ATEX compliant gas analysis performed within a flameproof enclosure ....................... 272

Appendix B SPA with HART Alarm ................................................................................................... 275

B.1 Overview ....................................................................................................................................275

B.2 Description ................................................................................................................................ 275

B.3 Installation ................................................................................................................................. 277

B.4 Setup ......................................................................................................................................... 277

B.4.1 Jumper and switch settings ..........................................................................................278

B.4.2 Configuration/calibration ............................................................................................ 279

Appendix C Returning material ....................................................................................................... 285

Appendix D ......................................................................................................................................287

Contents

vi OCX 8800

1 Description and specifications

1.1 Component checklist

A typical OCX 8800 Oxygen/Combustibles Transmitter package contains the items shown

in Figure 1-1.

Description and specifications

Reference Manual 1

Typical system packageFigure 1-1:

A. Hazardous Area OCX 8800 with integral electronics

B. Field communicator package (optional)

C. Quick Start Guide

D. Blowback hardware (optional)

E. Adapter plate with mounting hardware and gasket

F. Reference air and calibration set (optional)

G. Hazardous Area OCX 8800 with remote electronics

Use the product matrix in Table 1-1 at the end of this section to verify your order number.

The first part of the matrix defines the model. The last part defines the various options and

features of the OCX 8800. Check the model number against the transmitter features and

options, making sure options specified by this number are on or included with the unit.

Use this complete model number for any correspondence with Emerson. A list of

accessories for use with the OCX 8800 is provided in Table 1-2.

Description and specifications

2 OCX 8800

1.2 System overview

1.2.1 Scope

This Instruction Manual supplies details needed to install, start up, operate, and maintain

the OCX 8800. Signal conditioning electronics output a digital signal representing oxygen

(O

2

) and combustibles (COe) values. This information, plus additional details, can be

accessed with the 375 Field communicator or Emerson AMS software..

1.2.2 System description

The OCX 8800 is designed to measure oxygen and combustible concentrations in flue gas

temperatures up to 1427 °C (2600 °F). Electrical connections, power, and communications

are made through two 3/4 NPT ports in the flameproof electronics enclosure using fittings

and cables provided by you. Cable installation must meet NEC, IEC, and/or other applicable

national or local codes for Class I, Zone 1, Group IIB +H2 T3/T6 permanently mounted

equipment. The transmitter is close coupled to the process and requires minimum sample

conditioning requirements.

The equipment measures oxygen percentage by reading the voltage developed across a

heated electrochemical cell, which consists of a small yttria-stabilized, zirconia disc. Both

sides of the disc are coated with porous metal electrodes. When operating at the proper

temperature, the following Nernst equation gives the millivolt output of the cell.

EMF = KT log10 (P

1

/P

2

) + C

where:

1. P

2

is the partial pressure of the oxygen in the measured gas on one side of the cell.

2. P

1

is the partial pressure of the oxygen in the reference air on the opposite side of

the cell.

3. T is the absolute temperature.

4. C is the cell constant.

5. K is an arithmetic constant.

Note

For best results, use clean, dry instrument air (20.95% oxygen) as the reference air.

When the cell is at operating temperature and there are unequal oxygen concentrations

across the cell, oxygen ions travel from the high oxygen partial pressure side to the low

oxygen partial pressure side of the cell. The resulting logarithmic output voltage is

approximately 50 mV per decade. The output is proportional to the inverse lograrithm of

the oxygen concentration. Therefore, the output signal increases as the oxygen

concentration of the sample decreases. This characteristic enables the transmitter to

provide exceptional sensitivity at low oxygen concentrations.

Description and specifications

Reference Manual 3

The transmitter measures net oxygen concentration in the presence of all the products of

combustion, including water vapor. Therefore, it may be considered an analysis on a wet

basis. In comparison with older methods, such as the portable apparatus, which provides

an analysis on a dry gas basis, the wet analysis will, in general, indicate a lower percentage

of oxygen.

The combustibles sensor is a catalytic sensor consisting of two resistance devices (RTD).

One RTD is the reference element covered with an inert coating. The other RTD element is

active, coated with a catalyst. As the sample gases flow by the sensor, the combustible

gases oxidize on the surface of the active element. The temperature difference produces a

resistance relationship between the two elements that is directly proportional to the

concentration of combustibles in the sample gases.

The catalyst is specifically designed to detect carbon monoxide (CO), but the sensor

responds to other combustible gases. The sensor is calibrated using CO; thus the output

should be expressed in terms of CO. However, as the sensor detects other combustible

gases, the output cannot just be labeled CO. The response of the sensor to other

combustible gases gives an output that is equivalent to the sensor detecting CO.

The term COe is used in this manual to describe the sensor output. This term indicates that

the sensor is calibrated in terms of CO and that the sensor output is equivalent to CO but

not specific to CO.

Dilution air is provided by the COe sensors to ensure that there is adequate oxygen to fully

oxidize any combustible gases regardless of the concentration of oxygen in the process.

1.2.3

System configurations

Transmitters are available in four lengths, giving you flexibility to use a penetration

appropriate to the size of the stack or duct. The length options are 18 in. (457 mm), 3 ft

(0.91 m), 6 ft (1.83 m), or 9 ft (2.7 m). Probes are available in three material options: 316L

stainless steel, Inconel 600, and ceramic to accommodate higher temperatures.

The electronics are contained in a separate housing from the sensors. When the

transmitter is configured with the integral electronics option, the electronics and sensor

housings are mounted as a unit at the stack mounting flange. When the transmitter is

configured with the remote electronics option, the electronics are contained in a separate

housing from the sensors. The electronics housing may be mounted up to 150 feet from

the sensor housing.

The electronics control both sensor temperatures and provide output signals in one of two

ways:

1. Individual 4-20 mA isolated outputs that are proporational to the measured oxygen

and combustibles concentrations. The oxygen output also contains HART

communication.

2. Single Foundation Feldbus output.

The power supply can accept voltages of 100 to 240 Vac and 50 to 60 Hz. The electronics

accepts millivolt signals generated by the snesors and produces the outputs to be used by

remotely connected devices. Refer to Chapter 3 for specific instructions upon intial power

up.

Description and specifications

4 OCX 8800

1.2.4 System features

1. The O

2

cell output voltage and sensitivity increase as the oxygen concentration

decreases.

2. HART or Foundation Fieldbus communication is standard. To use this capability, you

must have either:

a. Model 375 Field Communicator

b. Asset Management Solutions (AMS) software for the PC

3. Oxygen cell and heater/thermocouple assembly are field replaceable.

4. Electronics are automatically configured for line voltages from 100 to 240 Vac.

5. You can calibrate and diagnostically troubleshoot the transmitter in one of two

ways:

a. LOI: The LOI is mounted to the end of the electronics module and allows local

communications with the electronics. Refer to Chapter 4 for more information.

b. HART or Foundation Fieldbus interface: The transmitter's output line transmits a

digital signal with the detected oxygen or combustible levels encoded in a digital

format. This information can be accessed through the following:

• Model 375 Field Communicator - The handheld field communicator requires

Device Description (DD) software specific to the OCX 8800. The DD software

is supplied with many Model 375 units, but can also be programmed into

existing units at most Emerson service offices. Refer to Chapter 6Section for

additional information.

• Personal computer (PC) - The use of a personal computer requires AMS

software available from Emerson.

• Selected distributed control systems - The use of distributed control systems

requires input/output (I/O) hardware and AMS software which permit HART

communications.

6. When the transmitter is configured without the LOI, you must calibrate and

diagnostically troubleshoot the transmitter using the HART of Foundation Fieldbus

interface.

7. Optional blowback system: The blowback system periodically blows instrument air

back through the sample line filter and out the sample tube. This clears out

particulate and keeps the sample line filter from clogging.

1.2.5

System operation

Figure 1-2 shows the relationship between the components of the OCX 8800. The sensors

and the electronics are contained in separate housings. The sensor housing and probe

mount to a duct or process wall so that the probe protrudes into the flue gas stream. An air

powered eductor continuously pulls samples of the process flue gas through the probe to a

chamber in front of the sensor housing where the sample passes the O

2

sensor and

continues on the COe sensor. Dilution air is provided to the COe sensor and reference air to

the O

2

sensor. After the gas sample flows past the O

2

sensor and through the COe sensor,

it is drawn through the eductor where it mixes with the eductor air and exits through

exhaust back into the system. The electronics housing contains the CPU and

communication boards which convert the sensor inputs into digital output signals. The

Description and specifications

Reference Manual 5

CPU can also initiate and perform calibrations. Three test gases and instrument air can be

turned on and off by solenoids. Test gas flow to the sensors is regulated by a flow meter

between the electronics and sensor housings. Instrument air is separated into eductor air,

reference air, and dilution air. The instrument air solenoid does not allow air flow until the

heaters are up to temperature. This minimizes the amount of sampled process flue gas

being pulled into the cold sensors causing condensation.

System operation diagramFigure 1-2:

1.2.6 Handling the OCX 8800

CAUTION!

EQUIPMENT DAMAGE

Only handle printed circuit boards and integrated circuits when adequate anti-static

precautions have been taken to prevent possible equipment damage.

The OCX 8800 is designed for industrial application. Treat each component of the system with

care to avoid physical damage. The probe may contain components made from ceramics,

which are susceptible to shock when mishandled.

1.2.7

System considerations

Prior to installing your OCX 8800, make sure you have all the components necessary to

make the system installation. Ensure that all components are properly integrated to make

the system functional.

After verifying that you have all the components, select mounting locations and determine

how each component will be placed in terms of available line voltage, ambient

temperatures, environmental considerations, convenience and serviceability. Figure 1-4

shows a typical system wiring for a system with integral electronics. Figure 1-5 shows

Description and specifications

6 OCX 8800

simplified installations for the OCX 8800.Figure 1-5 shows the dimensions for the optional

sample tube support. Figure 1-6 shows the dimensions for the optional in-situ filters.

Figure 1-7 shows the optional panel mounted blowback.

A source of instrument air is required at the OCX 8800 for reference air, dilution air, and

eductor air. As the OCX 8800 is equipped with an in-place calibration feature, make

provisions for connecting test gas tanks to the OCX 8800 when it is to be calibrated.

Note

The electronics module is designed to meet Type 4X and IP66, and the electronic components are

rated to temperatures up to 85 °C (185 °F ).

Retain packaging in which the unit arrived from the factory in case any components are to be

shipped to another site. This packaging has been designed to protect the product.

Communications Connections and AMS application - Hazardous Area OCX

8800 with Integral Electronics

Figure 1-3:

Description and specifications

Reference Manual 7

Typical System Installation - Integral ElectronicsFigure 1-4:

A. Adapter plate

B. Signal outputs (twisted pairs)

C. Line voltage

D. Instrument air supply (reference gas)

E. High O

2

test gas

F. Low O

2

test gas

G. CO test gas

Description and specifications

8 OCX 8800

Optional Sample Tube SupportFigure 1-5:

C. 0.75 (19) dia. on 7.5 (190) dia. B.C. 8 places

D. 0.75 (19) dia. on 4.75 (121) dia. B.C. 4 places

Description and specifications

Reference Manual 9

Probe length L

18 in. 24.5 (621)

3 ft 42.5 (1078)

6 ft 78.5 (1993)

9 ft 114.5 (2907)

Optional In-Situ FiltersFigure 1-6:

Optional Panel Mounted Blowback and Calibration/Reference Air Set (19

in. Rack or Wall Mount)

Figure 1-7:

Description and specifications

10 OCX 8800

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Rosemount OCX 8800 O2 / Combustibles Transmitter Hazardous Area Owner's manual

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