Rosemount 248DX User Manual

Reference Manual

00809-0300-4248, Rev AA

July 2014

Rosemount 248 Wireless Temperature

Transmitter

Reference Manual

00809-0300-4248, Rev AA

Rosemount 248 Wireless

Temperature Transmitter

Rosemount 248 Hardware Revision	1
HART® Device Revision	1
Field Communicator Field Device Revision	Dev 1, DD v1

NOTICE

Read this manual before working with the product. For personal and system safety, and for optimum product performance, make sure to thoroughly understand the contents before installing, using or maintaining this product.

For technical assistance, contacts are listed below:

Customer Central

Technical support, quoting, and order-related questions.

United States - 1-800-999-9307 (7:00 am to 7:00 pm CST) Asia Pacific65 777 8211

Europe/ Middle East/ Africa - 49 (8153) 9390 North American Response Center

Equipment service needs

1-800-654-7768 (24 hours—includes Canada)

Outside of these areas, contact your local Emerson Process Management 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 a Emerson Process Management Sales Representative.

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Failure to follow these installation guidelines could result in death or serious injury:

Make sure only qualified personnel perform the installation.

Explosions could result in death or serious injury:

Installation of this transmitter in an explosive environment must be in accordance with the appropriate local, national, and international standards, codes, and practices. Please review the approvals section of the 248 reference manual for any restrictions associated with a safe installation.

Before connecting a Field Communicator in an explosive atmosphere, ensure the instruments are installed in accordance with intrinsically safe or non-incendive field wiring practices.

Verify that the operating atmosphere of the transmitter is consistent with the appropriate hazardous locations certifications.

Process leaks may cause harm or result in death.

Do not remove the thermowell while in operation.

Install and tighten thermowells and sensors before applying pressure.

Electrical shock can result in death or serious injury.

Avoid contact with the leads and terminals. High voltage that may be present on leads can cause electrical shock.

This device complies with Part 15 of the FCC Rules. Operation is subject to the following conditions:

This device may not cause harmful interference.

This device must accept any interference received, including interference that may cause undesired operation.

This device must be installed to ensure a minimum antenna separation distance of 20 cm from all persons.

The Power Module may be replaced in a hazardous area. The Power Module has surface resistivity greater than one gigaohm and must be properly installed in the wireless device enclosure. Care must be taken during transportation to and from the point of installation to prevent electrostatic charge build-up.

NOTICE

The Rosemount 248 Wireless and all other wireless devices should be installed only after the Smart Wireless Gateway has been installed and is functioning properly. Wireless devices should also be powered up in order of proximity from the Smart Wireless Gateway, beginning with the closest. This will result in a simpler and faster network installation.

Reference Manual

00809-0300-4248, Rev AA

NOTICE

Shipping considerations for wireless products (Lithium Batteries: Green Power Module, model number 701PGNKF):

The unit was shipped to you without the Power Module installed. Please remove the Power Module prior to shipping the unit.

Each Power Module contains one “D” size primary lithium-thionyl chloride battery. Primary lithium batteries are regulated in transportation by the U. S. Department of Transportation, and are also covered by IATA (International Air Transport Association), ICAO (International Civil Aviation Organization), and ARD (European Ground Transportation of Dangerous Goods). It is the responsibility of the shipper to ensure compliance with these or any other local requirements. Please consult current regulations and requirements before shipping.

NOTICE

Power Module Considerations:

The power module with the wireless unit contains one “D” size primary lithium-thionyl chloride battery (Green Power Module, model number 701PGNKF). Each battery contains approximately 5.0 grams of lithium. Under normal conditions, the battery materials are self-contained and are not reactive as long as the batteries and the pack integrity are maintained. Care should be taken to prevent thermal, electrical or mechanical damage. Contacts should be protected to prevent premature discharge.

Battery hazards remain when cells are discharged.

Power Modules should be stored in a clean and dry area. For maximum Power Module life, storage temperature should not exceed 30 °C.

Reference Manual	Table of Contents
00809-0300-4248, Rev AA	July 2014

Contents

Section 1: Introduction

1.1 Using this manual. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 1.2 Safety messages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 1.2.1 Warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 1.3 Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 1.3.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 1.3.2 Commissioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 1.3.3 Mechanical. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 1.3.4 Electrical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 1.3.5 Environmental. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 1.4 Service support. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 1.5 Product recycling/disposal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

Section 2: Configuration

2.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 2.2 Safety messages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 2.2.1 Warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 2.3 Sensor connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9 2.4 Bench top configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12 2.5 Device network configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 2.5.1 Join to network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 2.5.2 Configure update rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 2.5.3 HART menu tree . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 2.5.4 Fast Key sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18 2.5.5 Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18 2.6 Remove power module. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

Section 3: Installation

3.1 Safety messages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21 3.1.1 Warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21 3.2 Wireless consideration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22 3.2.1 Power up sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22 3.2.2 Internal antenna position . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22 3.3 Field Communicator connections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22 3.4 Mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23

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3.5 Physical installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23 3.5.1 Direct mount . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24 3.5.2 Remote mount . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24

Section 4: Commissioning

4.1 Safety messages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25 4.1.1 Warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25 4.2 Verify operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26 4.2.1 Field Communicator. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26 4.2.2 Emerson Smart Wireless Gateway. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26 4.3 AMS™ Wireless Configurator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27 4.4 Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28 4.5 Reference information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28

Section 5: Operation and Maintenance

5.1 Safety messages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29 5.1.1 Warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29 5.2 Power module replacement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30 5.3 LCD screen messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31 5.3.1 Startup screen sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31

Section 6: Troubleshooting

6.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33 6.2 Safety messages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33 6.2.1 Warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34

Appendix A: Specifications and Reference Data

A.1 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37

A.1.1 Functional specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37

A.1.2 Physical specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38

A.1.3 Performance specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39

A.1.4 Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40

A.1.5 Ambient temperature effect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41

A.1.6 Lead wire resistance effect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43

A.2 Dimensional drawings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44

A.3 Ordering information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45

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Appendix B: Product Certifications

B.1 Approved Manufacturing Locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47

B.2 European Directive Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47

B.3 Ordinary Location Certification from FM Approvals . . . . . . . . . . . . . . . . . . . . . . . .47

Appendix C: Mapping for non-DD based Integration with Host Systems

C.1 Mapping of alert messages in the HART command 48 additional status . . . . . .49

C.2 Mapping of device variables index numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50

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Reference Manual	Section 1: Introduction
00809-0300-4248, Rev AA	July 2014

Section 1 Introduction

1.1Using this manual

The sections in this manual provide information on installing, operating, and maintaining the Rosemount 248 Wireless temperature transmitter with WirelessHART® protocol. The sections are organized as follows:

Section 2: Configuration provides instruction on commissioning and operating 248 Wireless transmitters. Information on software functions, configuration parameters, and on line variables is also included.

Section 3: Installation contains mechanical and electrical installation instructions.

Section 4: Commissioning contains techniques for properly commissioning the device.

Section 5: Operation and Maintenance contains operation and maintenance techniques.

Section 6: Troubleshooting provides troubleshooting techniques for the most common operating problems.

Appendix A: Specifications and Reference Data supplies reference and specification data, as well as ordering information.

Appendix B: Product Certifications contains approval information.

Appendix C: Mapping for non-DD based Integration with Host Systems

Rosemount 248 Wireless Transmitter

Features of the Rosemount 248 Wireless include:

An installation-ready solution that provides a variety of mounting options, transmitter configurations, and sensors/thermowells

Flexibility to meet your most demanding applications

Wireless output with >99% data reliability delivers rich HART data, protected by industry leading security

Simple and easy installation practices already used today for robust installations

Refer to the following literatures for a full range of compatible connection heads, sensors, and thermowells provided by Emerson Process Management.

English Temperature Sensors and Assemblies Product Data Sheet, Volume 1 (document number 00813-0100-2654)

Temperature Sensors and Accessories (Metric Sensors) Product Data Sheet, Volume 2 (document number 00813-0200-2654)

Introduction

Section 1: Introduction	Reference Manual
July 2014	00809-0300-4248, Rev AA

1.2Safety messages

Instructions and procedures in this section may require special precautions to ensure the safety of the personnel performing the operations. Information that potentially raises safety issues is indicated by a warning symbol (). Please refer to the following safety messages before performing an operation preceded by this symbol.

1.2.1Warnings

Failure to follow these installation guidelines could result in death or serious injury.

Make sure only qualified personnel perform the installation.

Explosions could result in death or serious injury.

Before connecting a Field Communicator in an explosive atmosphere, make sure the instruments are installed in accordance with intrinsically safe or non-incendive field wiring practices.

Verify that the operating atmosphere of the transmitter is consistent with the appropriate hazardous locations certifications.

Process leaks could result in death or serious injury.

Do not remove the thermowell while in operation.

Install and tighten thermowells and sensors before applying pressure

Electrical shock could cause death or serious injury.

Avoid contact with the leads and terminals. High voltage that may be present on leads can cause electrical shock.

This device complies with Part 15 of the FCC Rules. Operation is subject to the following conditions.

This device may not cause harmful interference.

This device must accept any interference received, including interference that may cause undesired operations.

This device must be installed to ensure a minimum antenna separation distance of 20 cm from all person.

2	Introduction

Reference Manual	Section 1: Introduction
00809-0300-4248, Rev AA	July 2014

1.3Considerations

1.3.1General

Electrical temperature sensors such as RTDs and thermocouples produce low-level signals proportional to their sensed temperature. With simple HART configuration, the Rosemount 248 Wireless converts the low-level sensor signal to a wireless-enabled signal.

1.3.2Commissioning

The transmitter can be commissioned before or after installation. It may be useful to commission it on the bench, before installation, to ensure proper operation and to become familiar with its functionality. When applicable, make sure the instruments are installed in accordance with intrinsically safe or non-incendive field wiring practices. The device will be powered whenever the power module is installed. To avoid depleting the Power Module, make sure it is removed when the device is not in use.

Power up sequence

The Power Module should not be installed on any wireless device until the Smart Wireless Gateway is installed and functioning properly. This transmitter uses the Green Power Module (order model number 701PGNKF). Wireless devices should also be powered up in order of proximity from the Smart Wireless Gateway, beginning with the closest. This will result in a simpler and faster network installation. Enable Active Advertising on the Gateway to ensure that new devices join the network faster. For more information, see the Smart Wireless Gateway Manual (Doc. No. 00809-0200-4420).

Internal antenna position

The internal antenna is designed for multiple mounting orientations. The transmitter should be mounted according to best practices for your temperature measurement application. The antenna should be approximately 3 ft (1 m) from any large structure or building to allow clear communication to other devices.

Network design best practices

When mounting the device, recommended practices should be considered to achieve the best wireless performance. See “Mounting” on page 23 for more information on recommended practices.

Field Communicator connections

The Power Module needs to be installed in the device for the Field Communicator to interface with the Rosemount 248 Wireless Temperature Transmitter. The Field Communicator connections are located on the Power Module. To communicate to the transmitter, connect the Field Communicator to the COMM port connections on the Power Module. This transmitter uses the Green Power Module; please order model number 701PGNKF. Field communication with this device requires a HART-based Field Communicator using the correct Rosemount 248 Wireless DD. The Power Module is keyed and can only be inserted in one orientation. Refer to Figure 3-1 for instructions on connecting the Field Communicator to the 248.

Introduction

Section 1: Introduction	Reference Manual
July 2014	00809-0300-4248, Rev AA

1.3.3Mechanical

Location

When choosing an installation location and position, take into account the need for access to the mesh network, access to the transmitter and to the power module compartment for ease power module replacement.

Electronics cover

The electronics cover is tightened so that polymer contacts polymer. When removing the electronics cover, ensure that there is no damage done to the o-ring. If damaged replace before reattaching cover, ensuring polymer contacts polymer (i.e. no o-ring visible).

1.3.4Electrical

Power Module

The Rosemount 248 Wireless Temperature transmitter is self-powered. The Power Module contains a primary lithium-thionyl chloride battery (Green Power Module, model number 701PGNKF). Each battery contains approximately 5 grams of lithium. Under normal conditions, the battery materials are self-contained and are not reactive as long as the battery and the Power Module are maintained. Care should be taken to prevent thermal, electrical, or mechanical damage. Contacts should be protected to prevent premature discharge.

Use caution when handling the power module, it may be damaged if dropped from heights in excess of 20 feet.

Battery hazards remain when cells are discharged.

Power Modules should be stored in a clean and dry area. For maximum Power Module life, storage temperature should not exceed 30 °C.

Sensor

Make sensor connections with the threaded 1/2-inch. NPT connection sensor adapter.

1.3.5Environmental

Verify that the operating atmosphere of the transmitter is consistent with the appropriate hazardous locations certifications.

Temperature effects

The transmitter will operate within specifications for ambient temperatures between –40 and 185 °F (–40 and 85 °C). Heat from the process is transferred from the thermowell to the transmitter housing. If the expected process temperature is near or beyond specification limits, consider the use of additional thermowell and extension, or remote mounting the transmitter to thermally isolate it from the process.

4	Introduction

Reference Manual	Section 1: Introduction
00809-0300-4248, Rev AA	July 2014

Temperature limits

Operating limit	Storage limit

–40 to 185 °F	–40 to 185 °F
–40 to 85 °C	–40 to 85 °C

1.4Service support

To expedite the return process outside of the United States, contact the nearest Emerson Process Management representative.

Within the United States, call the Emerson Process Management Instrument and Valves Response Center using the 1-800-654-RSMT (7768) toll-free number. This center, available 24 hours a day, will assist you with any needed information or materials.

The center will ask for the following information:



Product model

Serial numbers

The last process material to which the product was exposed

The center will provide:

A Return Material Authorization (RMA) number

Instructions and procedures that are necessary to return goods that were exposed to hazardous substances

Individuals who handle products exposed to a hazardous substance can avoid injury if they are informed of and understand the hazard. 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.

Note

If the device has been exposed to a hazardous substance, a Material Safety Data Sheet (MSDS) must be included with the returned materials. An MSDS is required by law to be available to people exposed to specific hazardous substances.

Introduction

Section 1: Introduction	Reference Manual
July 2014	00809-0300-4248, Rev AA

NOTICE

Shipping considerations for wireless products (Lithium Batteries: Green Power Module, model number 701PGNKF):

The unit was shipped to you without the Power Module installed. Please remove the Power Module prior to shipping the unit.

Each power module contains a primary lithium-thionyl chloride battery. Primary lithium batteries are regulated in transportation by the U. S. Department of Transportation, and are also covered by IATA (International Air Transport Association), ICAO (International Civil Aviation Organization), and ARD (European Ground Transportation of Dangerous Goods). It is the responsibility of the shipper to ensure compliance with these or any other local requirements. Please consult current regulations and requirements before shipping.

1.5Product recycling/disposal

Recycling of equipment and packaging should be taken into consideration and disposed of in accordance with local and national legislation/regulations.

6	Introduction

Reference Manual	Section 2: Configuration
00809-0300-4248, Rev AA	July 2014

Section 2 Configuration

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 7 Safety messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 7 Warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 8 Sensor connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 9 Bench top configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 12 Device network configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 14 HART menu tree . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 15

2.1Overview

This section contains information on configuration and verification that should be performed prior to installation.

Field Communicator and AMS instructions are given to perform configuration functions. For convenience, Field Communicator fast key sequences are labeled “Fast Keys” for each software function below the appropriate headings.

Sensor Input Trim example

Fast Key sequence 1, 2, 3, etc.

2.2Safety messages

Electrical grounds are indicated on drawings by a ground symbol (). Always follow proper grounding practices.

Configuration

Section 2: Configuration	Reference Manual
July 2014	00809-0300-4248, Rev AA

2.2.1Warnings

Failure to follow these installation guidelines could result in death or serious injury.

Make sure only qualified personnel perform the installation.

Explosions could result in death or serious injury.

Before connecting a Field Communicator in an explosive atmosphere, make sure the instruments are installed in accordance with intrinsically safe or non-incendive field wiring practices.

Verify that the operating atmosphere of the transmitter is consistent with the appropriate hazardous locations certifications.

Process leaks could result in death or serious injury.

Do not remove the thermowell while in operation.

Install and tighten thermowells and sensors before applying pressure

Electrical shock could cause death or serious injury.

Avoid contact with the leads and terminals. High voltage that may be present on leads can cause electrical shock.

This device complies with Part 15 of the FCC Rules. Operation is subject to the following conditions:

This device may not cause harmful interference.

This device must accept any interference received, including interference that may cause undesired operation.

This device must be installed to ensure a minimum antenna separation distance of 20 cm from all persons.

The Power Module may be replaced in a hazardous area. The Power Module has surface resistivity greater than one gigaohm and must be properly installed in the wireless device enclosure. Care must be taken during transportation to and from the point of installation to prevent electrostatic charge build-up.

8	Configuration

Reference Manual	Section 2: Configuration
00809-0300-4248, Rev AA	July 2014

2.3Sensor connections

The 248 Wireless is compatible with a number of RTD and thermocouple sensor types. Figure 2-1 shows the correct input connections to the sensor terminals on the transmitter. To ensure a proper sensor connection, anchor the sensor lead wires into the appropriate compression terminals and tighten the screws.

Thermocouple or Millivolts inputs

The thermocouple can be connected directly to the transmitter. Use appropriate thermocouple extension wire if mounting the transmitter remotely from the sensor.

RTD or Ohm inputs

The transmitters will accept a variety of RTD or ohmic configurations, including 2-wire, 3-wire or 4-wire connections. If the transmitter is mounted remotely from a 3-wire or 4-wire RTD, it will operate within specifications, without recalibration, for lead wire resistances of up to 5 ohms per lead (equivalent to 500 feet of 20 AWG wire). In this case, the leads between the RTD and transmitter should be shielded. If using a 2-wire connection, both RTD leads are in series with the sensor element, so significant errors can occur if the lead lengths exceed three feet of 20 AWG wire (approximately 0.05 C/ft.). For longer runs, attach a third or fourth lead to achieve a 3-wire or 4-wire connection as described above.

Effect-RTD input

Since the lead wires are part of the RTD circuit, the lead wire resistance needs to be compensated for to achieve the best accuracy. This becomes especially critical in applications where long sensor and/or lead wires are used. There are three lead wire configurations commonly available. In a two-wire configuration there can be no compensation for lead wire resistance since the lead wires are in series with the element and appear to the transmitter as part of the sensor's resistance causing inherent accuracy degradation. In a three-wire configuration, compensation is accomplished using the third wire with the assumption that it will be the same resistance as the other two wires and the same compensation is applied to all three wires. A four-wire design is ideal because the lead wire resistance is inconsequential to the measurement. It uses a measurement technique where a very small constant current of about 150 micro amps is applied to the sensor through two leads and the voltage developed across the sensor is measured over the other two wires with a high-impedance and high resolution measuring circuit. In accordance with Ohm's Law, the high impedance virtually eliminates any current flow in the voltage measurement leads and therefore the resistance of the leads is not a factor.

Table 2-1. Examples of Approximate Basic Error

Sensor input	Approximate basic error

4-wire RTD	Negligible(1)
3-wire RTD	Error in reading is equivalent to unbalanced lead wire resistance(2)
2-wire RTD	Error in reading is equivalent to total lead wire resistance

(1)Independent of lead wire resistance up to 5 per lead.

(2)Unbalanced lead wire resistance is the maximum resistance differences between any two leads.

Configuration

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