Emerson Rosemount 8742C User manual

www.rosemount.com
Reference Manual
00809-0100-4793, Rev CA
August 2004
Rosemount 8742C Magnetic Flowmeter
Transmitter with FOUNDATION™Fieldbus and
8700 Series Magnetic Flowmeter Flowtube
Product Discontinued

Reference Manual
00809-0100-4793, Rev CA
August 2004 Rosemount 8742C
www.rosemount.com
Rosemount 8742C Magnetic
Flowmeter Transmitter with
FOUNDATION
™Fieldbus and 8700
Series Magnetic Flowmeter
Flowtube
Rosemount, the Rosemount logotype, Fisher-Rosemount, Managing the Process Better,
PlantWeb, and SMART FAMILY are registered trademarks of Rosemount Inc.
DeltaV is a trademark of the Fisher-Rosemount group of companies.
HART is a registered trademark of the HART Communication Foundation.
Tefzel and Teflon are registered trademarks of E.I. du Pont de Nemours & Co.
Ryton is a registered trademark of the Phillips Petroleum Co.
Fluoraz is a registered trademark of Greens, Tweed & Co., Inc.
Hastelloy C and Hastelloy C-22 are registered trademarks of Haynes International,
FOUNDATION is a trademark of the Fieldbus Foundation.
Cover photo: 8742h0002
NOTICE
Read this manual before working with the product. For personal and system safety, and for
optimum product performance, make sure you thoroughly understand the contents before
installing, using, or maintaining this product.
Within the United States, Rosemount Inc. has two toll-free assistance numbers:
Customer Central
Technical support, quoting, and order-related questions.
1-800-999-9307 (7:00 am to 7:00 pm CST)
North American Response Center
Equipment service needs.
1-800-654-7768 (24 hours—includes Canada)
Outside of the United States, contact your local Rosemount representative.
The products described in this document are NOT designed for nuclear-qualified
applications. Using non-nuclear qualified products in applications that require
nuclear-qualified hardware or products may cause inaccurate readings.
For information on Rosemount nuclear-qualified products, contact your local Rosemount
Sales Representative.

Reference Manual
00809-0100-4793, Rev CA
August 2004 Rosemount 8742C
www.rosemount.com
Table of Contents
SECTION 1
Introduction
System Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Safety Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
Return of Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
SECTION 2
Installation
Safety Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Transmitter Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Pre-Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Identify Options and Configurations . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Hardware Switches. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Simulate Enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Transmitter Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Changing Hardware
Switch Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Rotate Transmitter Housing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Wiring. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Conduit Ports and Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Conduit Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Conduit Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
Transmitter Coil Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
Installation Category. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Overcurrent Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Transmitter Communication Input . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Power Conditioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Field Wiring. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Transmitter Wiring Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
Transmitter to
Flowtube Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8
Flowtube to Remote Mount Transmitter Connections . . . . . . . . . . 2-9
Flowtube to Integral Mount Transmitter Connections. . . . . . . . . . 2-10

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August 2004
Rosemount 8742C
TOC-2
SECTION 3
Flowtube Installation
Safety Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Flowtube Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
Flowtube Mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
Upstream/Downstream
Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
Flowtube Orientation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
Flow Direction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6
Installation (Flanged Flowtube) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7
Gaskets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7
Flange Bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7
Installation
(Wafer Flowtube) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10
Gaskets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10
Flange Bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11
Installation
(Sanitary Flowtube) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12
Gaskets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12
Alignment and Bolting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12
Grounding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12
Process Leak Protection (Optional) . . . . . . . . . . . . . . . . . . . . . . . . . . 3-15
Standard Housing Configuration . . . . . . . . . . . . . . . . . . . . . . . . . 3-16
Relief Valves. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-16
Process Leak Containment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17
SECTION 4
Configuration
Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
Quick Start-Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2
Flowtube Calibration Number . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2
Assigning Device Tag and Node Address . . . . . . . . . . . . . . . . . . . . . . 4-2
AI Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
Arithmetic Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
Integrator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
PID Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4
Configuring Links and Scheduling Block Execution. . . . . . . . . . . . . . . 4-5
Advanced Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6
Cascade Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7
Resource Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8
FEATURES and FEATURES_SEL . . . . . . . . . . . . . . . . . . . . . . . . 4-8
MAX_NOTIFY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-9
PlantWeb™Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-9

Reference Manual
00809-0100-4793, Rev CA
August 2004
TOC-3
Rosemount 8742C
SECTION 5
Operation and
Maintenance
Safety Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
Software Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
Local Display Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2
Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2
Electronics Trim . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2
Auto Zero Trim . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4
Configuring the Advanced Diagnostics and Empty Pipe . . . . . . . . 5-4
Learning Empty Pipe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4
Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6
Diagnostic Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6
Diagnostic Counter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-9
Hardware Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-9
Replacing the FOUNDATION™Fieldbus Electronics Housing. . . . . . 5-9
Replacing the FOUNDATION™Fieldbus Terminal Block in the Housing5-10
Replacing the FOUNDATION™Fieldbus Electronics Boards. . . . . . 5-10
SECTION 6
Troubleshooting
Step 1: Function Block Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3
Step 2: Diagnostic Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3
Step 3: Wiring Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3
Step 4: Process Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3
Step 5: Installed Flowtube Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3
Step 6: Uninstalled Flowtube Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5
APPENDIX A
Reference Data
Rosemount 8742C Transmitter Specifications . . . . . . . . . . . . . . . . . .A-1
Functional Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1
Foundation Fieldbus Specifications . . . . . . . . . . . . . . . . . . . . . . . . A-3
Performance Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-4
Physical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-5
Rosemount 8705 and 8707 Flowtubes Specifications. . . . . . . . . . . . . A-5
Functional Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-5
Performance Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-8
Physical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-8
Rosemount 8711 Wafer Flowtube Specifications . . . . . . . . . . . . . . . A-11
Functional Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-11
Performance Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-12
Physical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-12
Rosemount 8714D Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . A-14
Functional Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-14
Performance Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-14
Physical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-14
Dimensional Drawings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-15
Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-22
Rosemount 8742C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-22
Rosemount 8705 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-24
Rosemount 8707 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-28
Rosemount 8711 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-30
Rosemount 8714 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-31

Reference Manual
00809-0100-40793, Rev CA
August 2004
Rosemount 8742C
TOC-4
APPENDIX B
Product Certifications
Approved Manufacturing Locations . . . . . . . . . . . . . . . . . . . . . . . . B-1
European Directive Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1
ATEX Directive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1
European Pressure Equipment Directive (PED) (97/23/EC) . . . . . B-1
Electro Magnetic Compatibility (EMC) (89/336/EEC) . . . . . . . . . . . B-2
Low Voltage Directive (93/68/EEC) . . . . . . . . . . . . . . . . . . . . . . . . B-2
Other important guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-2
Hazardous Location Certifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-3
Transmitter Approval Information . . . . . . . . . . . . . . . . . . . . . . . . . B-3
Flowtube Approval Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . B-7
APPENDIX C
Resource Block
Definition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .C-1
Parameters and Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .C-1
Resource Block Errors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .C-5
Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .C-5
Alarm Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .C-6
Status Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .C-6
VCR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .C-6
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .C-6
APPENDIX D
Transducer Block
Definition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .D-1
Parameters and Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .D-2
Flow-Specific Block Configuration Values . . . . . . . . . . . . . . . . . . . . . .D-3
Transducer Block Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .D-4
Transducer Block Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .D-5
Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .D-5
Alarm Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .D-5
Status Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .D-6
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .D-6
APPENDIX E
Field-Removable
Electrodes
Safety Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-1
Remove the Electrode Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-1
Replace the Electrode Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-2

Reference Manual
00809-0100-4793, Rev CA
August 2004 Rosemount 8742C
www.rosemount.com
Section 1 Introduction
System Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 1-1
Safety Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 1-3
Return of Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 1-3
SYSTEM DESCRIPTION The Rosemount®8700 Series Magnetic Flowmeter System combines
separate flowtube and transmitter units, and measures volumetric flow rate by
detecting the velocity of a conductive liquid that passes through a magnetic
field. Magnetic Flowmeter Systems consist of a flowtube and a transmitter.
There are three Rosemount magnetic flowmeter flowtubes:
• Flanged Rosemount 8705
• Flanged High-Signal Rosemount 8707
• Wafer-Style Rosemount 8711
• Sanitary 8721
There are three Rosemount magnetic flowmeter transmitters:
• Rosemount 8712D/H
• Rosemount 8732C
• Rosemount 8742C
The flowtube is installed in-line with process piping — either vertically or
horizontally. Coils located on opposite sides of the flowtube create a magnetic
field. A conductive liquid moving through the magnetic field generates a
voltage at the two electrodes that is proportional to the flow velocity.
The transmitter drives the coils to generate a magnetic field and electronically
conditions the voltage detected by the electrodes. The transmitter then
amplifies and conditions the electrode signal to provide a flow signal. The
transmitter can be integrally mounted or remotely mounted from the flowtube.
This manual is designed to assist in the installation and operation of
Rosemount 8742C Magnetic Flowmeter Transmitter with FOUNDATION™
fieldbus and 8700 Series Magnetic Flowmeter Flowtubes.
Attempting to install and operate the Rosemount 8705, 8707 High-Signal,
or 8711 Magnetic Flowmeter Flowtubes with the Rosemount 8712D/H,
8732, or 8742 Magnetic Flowmeter Transmitter without reviewing the instructions
contained in this manual could result in personal injury or equipment damage.

Reference Manual
00809-0100-4793, Rev CA
August 2004
Rosemount 8742C
1-2
Section 2: Installation
• Transmitter Commissioning
• Wiring Flowmeter to a Flowtube
Section 3: Flowtube Installation
• Handling
• Mounting
• Installation of a Flanged, Wafer, and Sanitary Flowtube
Section 4: Configuration
• Assigning Device Tag
• Configuring Blocks
• Configuring Links and Scheduling Block Execution
Section 5: Operation and Maintenance
• Software Operation
• Hardware Maintenance
• Replacing the FOUNDATION™fieldbus Electronics Housing
Section 6: Troubleshooting
• Troubleshooting Procedures
• Electrical Circuit Diagrams
Appendix A: Reference Data
• Specifications for Rosemount 8742 Transmitter
and 8700 Series Flowtubes
• Ordering Tables
• Dimensional Drawings
Appendix B: Product Certifications
• Transmitter Approval Information
• Flowtube Approval Information
Appendix C: Resource Block
• Parameters and Descriptions
• Modes
Appendix D: Transducer Block
• Parameters and Descriptions
• Modes
Appendix E: Field-Removable Electrodes
• Electrode Assembly

Reference Manual
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August 2004
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Rosemount 8742C
SAFETY MESSAGES Procedures and instructions in this manual may require special precautions to
ensure the safety of the personnel performing the operations. Refer to the
safety messages listed at the beginning of each section before performing
any operations.
RETURN OF MATERIALS To expedite the return process outside the United States, contact the nearest
Rosemount representative.
Within the United States and Canada, call the North American Response
Center using the 800-654-RSMT (7768) toll-free number. The Response
Center, available 24 hours a day, will assist you with any needed information
or materials.
The center will ask for product model and serial numbers, and will provide a
Return Material Authorization (RMA) number. The center will also ask for the
name of the process material to which the product was last exposed.
Mishandling products exposed to a hazardous substance may result in death
or serious injury. If the product being returned was exposed to a hazardous
substance as defined by OSHA, a copy of the required Material Safety Data
Sheet (MSDS) for each hazardous substance identified must be included with
the returned goods.
The North American Response Center will detail the additional information
and procedures necessary to return goods exposed to hazardous
substances.
See “Safety Information” on page 4-1 for complete warning information.

Reference Manual
00809-0100-4793, Rev CA
August 2004
1-4
Rosemount 8742C

Reference Manual
00809-0100-4793, Rev CA
August 2004 Rosemount 8742C
www.rosemount.com
Section 2 Installation
Safety Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 2-1
Transmitter Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 2-2
Pre-Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 2-2
Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 2-4
This section covers the steps required to physically install the magnetic
flowmeter. Instructions and procedures in this section may require special
precautions to ensure the safety of the personnel performing the operations.
Please refer to the following safety messages before performing any
operation in this section.
SAFETY INFORMATION
Failure to follow these installation guidelines could result in death or serious injury:
Installation and servicing instructions are for use by qualified personnel only. Do not
perform any servicing other than that contained in the operating instructions, unless
qualified. Verify that the operating environment of the flowtube and transmitter is
consistent with the appropriate FM or CSA approval.
Do not connect a Rosemount 8742C to a non-Rosemount flowtube that is located in an
explosive atmosphere.
The flowtube liner is vulnerable to handling damage. Never place anything through the
flowtube for the purpose of lifting or gaining leverage. Liner damage can render the
flowtube useless.
To avoid possible damage to the flowtube liner ends, do not use metallic or
spiral-wound gaskets. If frequent removal is anticipated, take precautions to protect the
liner ends. Short spool pieces attached to the flowtube ends are often used for
protection.
Correct flange bolt tightening is crucial for proper flowtube operation and life. All bolts
must be tightened in the proper sequence to the specified torque limits. Failure to
observe these instructions could result in severe damage to the flowtube lining and
possible flowtube replacement.

Reference Manual
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August 2004
Rosemount 8742C
2-2
TRANSMITTER
SYMBOLS
Caution Symbol — Check product documentation for details.
Protective conductor (grounding) terminal.
PRE-INSTALLATION Before installing the Rosemount 8742C Magnetic Flowmeter Transmitter,
there are several pre-installation steps that should be completed to make the
installation process easier. They include identifying the options and
configurations that apply to your application, setting the hardware switches if
necessary, and consideration of physical requirements.
The mounting site for the 8742C should provide enough room for secure
mounting, easy access to the conduit ports, and full opening of the transmitter
covers.
To ensure maximum transmitter life, avoid excessive heat and vibration.
Typical problem areas include high-vibration lines with integrally mounted
transmitters, warm-climate installations in direct sunlight, and outdoor
installations in cold climates. To avoid potential problems, remotely mounted
transmitters may be installed in the control room. This protects the electronics
from the harsh environment and provides easy access for configuration or
service.
The Rosemount 8742C transmitter requires external power regardless of
whether it is mounted remotely or integrally to the flowtube. Access to a
suitable power source must be ensured.
Identify Options and
Configurations
The standard application of the Rosemount 8742C includes a FOUNDATION
fieldbus output. Be sure to identify options and configurations that apply to
your situation, and keep a list of them nearby for consideration during the
installation and configuration procedures.
Hardware Switches The Rosemount 8742C electronics board is equipped with two
user-selectable hardware switches. These switches set Simulate Enable and
Transmitter Security. The standard configurations for these switches when
shipped from the factory are as follows:
Simulate Enable: Off
Transmitter Security: Off
Definitions of these switches and their functions are provided below. The
switches are located on the outerboard of the electronics transmitter stack.
See Figure 2-1 on page 2-3.
Simulate Enable The simulate enable switch is used in conjunction with the Analog Input (AI)
function block. The switch is used to enable flow measurement simulation.
The switch is also used as a lock-out feature for the AI function block. To
enable the simulate enable feature, the switch must transition form OFF to
ON after power is applied to the transmitter, preventing the transmitter from
being accidentally left in simulate mode.
Transmitter Security After you configure the transmitter, you may want to protect the configuration
data from unwarranted changes. Each transmitter is equipped with a security
switch that can be positioned ON to prevent the accidental or deliberate
change of configuration data.

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August 2004
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Rosemount 8742C
Instructions for changing the hardware switches are provided in “Changing
Hardware Switch Settings” on page 2-3.
Figure 2-1. Hardware Switches
Changing Hardware
Switch Settings
In most cases, it is not necessary to change the setting of the hardware
switches. If you need to change the switch settings, complete the steps
outlined below:
NOTE
The hardware switches are located on the electronics board and changing
their settings requires opening of the electronics housing. If possible, carry out
these procedures away from the plant environment in order to protect the
electronics.
1. Disconnect power to the transmitter.
2. Unscrew and remove the electronics cover.
3. Identify the location of the switch.
4. Change the setting of the desired switches with a small screwdriver.
Refer to Figure 2-1.
5. Screw and tighten the electronics cover.
Rotate Transmitter
Housing
The electronics housing can be rotated on the flowtube in 90° increments by
loosening the four mounting bolts on the bottom of the housing, rotating the
housing, and reinstalling the bolts. Refer to Figure 2-2 on page 2-4. When the
housing is returned to its original position, be sure the surface is clean and
there is no gap between the housing and the flowtube.
See “Safety Information” on page 2-1 for complete warning information.
Simulate
Enable
Transmitter
Security
8742-1002H01A

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August 2004
Rosemount 8742C
2-4
Figure 2-2. Rosemount 8742C
Transmitter Dimensional
Drawing
WIRING Correct cable preparation is important for a successful installation. The
conduit connections needed for installation depend on transmitter location. A
conduit run between the flowtube and transmitter is not required if the
transmitter is integrally mounted on the flowtube.
Conduit Ports
and Connections
Both the flowtube and transmitter junction boxes have ports for ¾-inch NPT
conduit connections. These connections should be made in accordance with
local or plant electrical codes. Unused ports should be sealed with metal
plugs. Housing damage will result if metal plugs
are overtightened.
Proper electrical installation is necessary to prevent errors due to electrical
noise and interference. Before making any electrical connections to the
Rosemount 8742C, consider the following standards and be sure to have
proper power supply, conduit, and other accessories. Shielded cable must be
used for best results in electrically noisy environments.
Conduit Connections The transmitter has ports for ¾–inch NPT conduit connections. If the port is
not being used, conduit seals should to be installed. In some cases, conduits
may also require drainage if moisture could build up in the line.
5.10
(130)
6.48 (165)
3.07
(78)
8.81
(224)
3.43
(87)
3/4”-14 NPT Electrical
Conduit Connections
(2 places)
3/4”-14 NPT
Flowtube Conduit
Connections
(2 places)
7.49 (190)
1.94
(49)
3.00
(76)
LOI Cover
10.5
(267)
11.02
(280)

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August 2004
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Rosemount 8742C
Conduit Cables Run the appropriate size cable through the conduit connections in your
magnetic flowmeter system. Run the power cable from the power source to
the transmitter. Run the coil drive and electrode cables between the flowmeter
and transmitter.
Prepare the ends of the coil drive and electrode cables as shown in Figure
2-3. Limit the unshielded wire length to 1-inch on both the electrode and coil
drive cables.
NOTE
Excessive lead length or failure to connect cable shields can create electrical
noise resulting in unstable meter readings.
Figure 2-3. Cable Preparation
Detail
Transmitter Coil Input The Rosemount 8742C Magnetic Flowmeter Transmitter is a four-wire device.
This wiring section covers supplying power to the flowtube coils through the
transmitter. The transmitter coil input power sends a pulsed DC frequency to
the flowtube.
Wire the transmitter according to local electrical requirements. Ground the
transmitter cage via the threaded conduit connection. For ac power
applications, connect ac Neutral to terminal N and connect ac Line to terminal
L1. For dc power applications, properly connect the positive and negative
terminals. Units powered by 15-50 V dc power supply may draw up to 1 amp
of current. In addition, follow the supply wire and disconnect requirements
below:
1.00
(26)
NOTE
Dimensions are in
inches (millimeters).
Cable Shield
8705-0041B
Power Supply (Volts)
1.0
0.75
0.5
0.25
015 50
20 30 40
I = 10/V
I = Supply current requirement (Amps)
V = Power supply voltage (Volts)
Supply Current (Amps)

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Rosemount 8742C
2-6
Supply Wire Requirements
Use 12 to 18 AWG wire rated for the proper temperature application. For
connections in ambient temperatures above 140 °F (60 °C), use a wire
rated for 176 °F (80 °C). For ambients greater than 176 °F (80 °C), use a
wire rated for 230 °F (110 °C).
Disconnects
Connect the device through an external disconnect or circuit breaker.
Clearly label the disconnect or circuit breaker and locate it near
the transmitter and per local electrical control.
Installation Category The installation category for the Rosemount 8742C is
(Overvoltage) Category II.
Overcurrent Protection The Rosemount 8742C Flowmeter Transmitter requires overcurrent
protection of the supply lines. Maximum ratings of overcurrent devices are as
follows:
Transmitter
Communication Input
The FOUNDATION fieldbus communication requires a minimum of
9 V dc and a maximum of 32 V dc at the transmitter communication terminals.
NOTES
•Do not exceed 32 V dc at the transmitter communication terminals.
•Do not apply ac line voltage to the transmitter
communication terminals.
Improper supply voltage can damage the transmitter.
Power Conditioning Each fieldbus power supply requires a power conditioner to decouple the
power supply output from the fieldbus wiring segment.
Field Wiring Power independent of the coil power supply must be supplied for FOUNDATION
fieldbus communications. Use shielded, twisted pair for best results. For new
installations or to get maximum performance, twisted pair cable designed
especially for fieldbus should be used. Table 2-1 details cable characteristics
and ideal specifications.
Table 2-1.
Ideal Cable Specifications
for Fieldbus Wiring
Power System Fuse Rating Manufacturer
110 V ac 250 V; 1 Amp, Quick Acting Bussman AGCI or Equivalent
220 V ac 250 V; 0.5 Amp, Quick Acting Bussman AGCI or Equivalent
See “Safety Messages” on page 2-1 for complete warning information.
Characteristic Ideal Specification
Impedance 100 Ohms ± 20% at 31.25 kHz
Wire Size 18 AWG (0,8 mm2)
Shield Coverage 90%
Attenuation 3 db/km
Capacitive Unbalance 2 nF/km

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August 2004
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Rosemount 8742C
NOTE
The number of devices on a fieldbus segment is limited by the power supply
voltage, the resistance of the cable, and the amount of current drawn by
each device.
Transmitter Wiring
Connection
To make the transmitter communication wiring connection, remove the end
cover on the electronics housing. Connect the power leads to the positive (+)
and negative (–) fieldbus communication terminals. The communication
terminals are polarity insensitive: the polarity of the dc power leads does not
matter when connecting to the power terminals.
When wiring to screw terminals, crimped lugs are recommended. Tighten the
terminals to ensure adequate contact.
Both transmitter covers must be fully engaged to meet explosion proof
requirements. Do not remove the transmitter covers in an explosive
atmosphere when the transmitter is powered(1).
Figure 2-4. Rosemount 8742C
Transmitter Field Wiring
(1) Pending final approval.
8742-8742_01A
Integrated
Power
Conditioner
and Filter Terminators
6234 ft (1900 m) max
(depending upon cable
Fieldbus
Segment
(Spur)
(Trunk)
(The power supply,
filter, first terminator,
and configuration tool
are typically located
in the control room.)
*Intrinsically safe installations may
allow fewer devices per I.S. barrier.
Power
Supply
FOUNDATION
Fieldbus
Configuration
Tool
(Spur)
Devices 1 through 11*

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Rosemount 8742C
2-8
Figure 2-5. Power Connections
Transmitter to
Flowtube Wiring
Flanged and wafer flowtubes have two conduit ports as shown in Figures
3-13, 3-14, 3-15, and 3-16. Either one may be used for both the coil drive and
electrode cables. Use the stainless steel plug that is provided to seal the
unused conduit port.
A single dedicated conduit run for the coil drive and electrode cables is
needed between a flowtube and a remote transmitter. Bundled cables in a
single conduit are likely to create interference and noise problems in your
system. Use one set of cables per conduit run. See Figure 2-6 for proper
conduit installation diagram and Table 2-2 for recommended cable. For
integral and remote wiring diagrams refer to Figure 2-7 and Figure 2-8.
Figure 2-6. Conduit Preparation
8742-1002F01A
Input Power 90–250 V ac
Fieldbus Outputs
Grounding
Lugs
Wrong Correct
Coil Drive
and
Electrode
Cables
Power
Outputs
Power
Outputs
Power Power
Outputs
Outputs
Coil Drive and
Electrode
Cables