Rockwell Automation 1762-IR4 User Manual

MicroLogix™ 1200 RTD/Resistance Input Module

(Catalog Number 1762-IR4)

User Manual

Important User Information

Because of the variety of uses for the products described in this publication, those responsible for the application and use of these products must satisfy themselves that all necessary steps have been taken to assure that each application and use meets all performance and safety requirements, including any applicable laws, regulations, codes and standards. In no event will Rockwell Automation be responsible or liable for indirect or consequential damage resulting from the use or application of these products.

Any illustrations, charts, sample programs, and layout examples shown in this publication are intended solely for purposes of example. Since there are many variables and requirements associated with any particular installation, Rockwell Automation does not assume responsibility or liability (to include intellectual property liability) for actual use based upon the examples shown in this publication.

Allen-Bradley publication SGI-1.1, Safety Guidelines for the

Application, Installation and Maintenance of Solid-State Control

(available from your local Rockwell Automation office), describes some important differences between solid-state equipment and electromechanical devices that should be taken into consideration when applying products such as those described in this publication.

Reproduction of the contents of this copyrighted publication, in whole or part, without written permission of Rockwell Automation, is prohibited.

Throughout this publication, notes may be used to make you aware of safety considerations. The following annotations and their accompanying statements help you to identify a potential hazard, avoid a potential hazard, and recognize the consequences of a potential hazard:

WARNING

Identifies information about practices or circumstances that can cause an explosion in a hazardous environment, which may lead to personal injury or death, property damage, or economic loss.

ATTENTION

Identifies information about practices or circumstances that can lead to personal injury or death, property damage, or economic loss.

IMPORTANT

Identifies information that is critical for successful application and understanding of the product.

Allen-Bradley, MicroLogix, RSLogix, and RSLinx are trademarks of Rockwell Automation.

Overview

Preface

Who Should Use This Manual . . . . . . . . . . . . . . . . . . . . . . P-1

How to Use This Manual. . . . . . . . . . . . . . . . . . . . . . . . . . P-1

Manual Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P-1

Related Documentation . . . . . . . . . . . . . . . . . . . . . . . . P-2

Conventions Used in This Manual . . . . . . . . . . . . . . . . . . . P-2

Rockwell Automation Support . . . . . . . . . . . . . . . . . . . . . . P-3

Your Questions or Comments on the Manual . . . . . . . . P-3

Chapter 1

General Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

RTD Compatibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

Resistance Device Compatibility . . . . . . . . . . . . . . . . . . 1-5

Hardware Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6

General Diagnostic Features . . . . . . . . . . . . . . . . . . . . . 1-6

System Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7

System Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7

Module Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8

Module Field Calibration . . . . . . . . . . . . . . . . . . . . . . . 1-8

Installation and Wiring

Chapter 2

Compliance to European Union Directives . . . . . . . . . . . . . 2-1

EMC Directive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

Low Voltage Directive . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2

General Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2

Hazardous Location Considerations . . . . . . . . . . . . . . . 2-3

Prevent Electrostatic Discharge . . . . . . . . . . . . . . . . . . . 2-3

Remove Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4

Selecting a Location . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4

Mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5

Minimum Spacing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5

DIN Rail Mounting. . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6

Panel Mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6

System Assembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7

Field Wiring Connections . . . . . . . . . . . . . . . . . . . . . . . . . 2-8

System Wiring Guidelines. . . . . . . . . . . . . . . . . . . . . . . 2-8

RTD Wiring Considerations . . . . . . . . . . . . . . . . . . . . . 2-9

Wiring the Finger-Safe Terminal Block . . . . . . . . . . . . . 2-10

Wire Size and Terminal Screw Torque . . . . . . . . . . . . . 2-11

Wiring Input Devices to the Module . . . . . . . . . . . . . . . 2-11

Wiring RTDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-12

Wiring Resistance Devices (Potentiometers) . . . . . . . . . 2-14

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2 Table of Contents

Module Data, Status, and Channel Configuration

Chapter 3

Module Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

Input Image. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2

Configuration File . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2

Accessing Input Image File Data . . . . . . . . . . . . . . . . . . . . 3-2

Input Data File. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3

Input Data Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3

General Status Flag Bits (S0 to S3) . . . . . . . . . . . . . . . . 3-3

Open-Circuit Flag Bits (OC0 to OC3) . . . . . . . . . . . . . . 3-4

Over-Range Flag Bits (O0 to O3) . . . . . . . . . . . . . . . . . 3-5

Under-Range Flag Bits (U0 to U3). . . . . . . . . . . . . . . . . 3-5

Configuring Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5

Configuration Data File . . . . . . . . . . . . . . . . . . . . . . . . 3-6

Channel Configuration . . . . . . . . . . . . . . . . . . . . . . . . . 3-7

Enabling or Disabling a Channel (Bit 15) . . . . . . . . . . . 3-9

Selecting Data Format (Bits 12 to 14) . . . . . . . . . . . . . . 3-9

Selecting Input/Sensor Type (Bits 8 to 11) . . . . . . . . . . 3-14

Selecting Temperature Units/Mode (Bit 7). . . . . . . . . . . 3-15

Selecting Open-Circuit Response (Bits 5 and 6) . . . . . . . 3-15

Selecting Cyclic Lead Compensation (Bit 4). . . . . . . . . . 3-16

Selecting Excitation Current (Bit 3) . . . . . . . . . . . . . . . . 3-16

Setting Filter Frequency (Bits 0 to 2) . . . . . . . . . . . . . . . 3-16

Selecting Enable/Disable Cyclic Autocalibration

(Word 4, Bit 0) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-20

Determining Effective Resolution and Range . . . . . . . . . . . 3-20

Determining Module Update Time. . . . . . . . . . . . . . . . . . . 3-27

Effects of Autocalibration on Module Update Time . . . . 3-28

Calculating Module Update Time with Autocalibration

Enabled. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-29

Effects of Cyclic Lead Wire Compensation on

Module Update Time . . . . . . . . . . . . . . . . . . . . . . . . . . 3-30

Calculating Module Update Time with Cyclic Lead Wire

Compensation Enabled . . . . . . . . . . . . . . . . . . . . . . . . 3-31

Impact of Autocalibration and Lead Wire Compensation

on Module Startup . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-32

Effects of Autocalibration on Accuracy . . . . . . . . . . . . . . . . 3-33

Diagnostics and Troubleshooting

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Chapter 4

Safety Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

Indicator Lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

Activating Devices When Troubleshooting . . . . . . . . . . 4-2

Stand Clear of the Equipment. . . . . . . . . . . . . . . . . . . . 4-2

Program Alteration. . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2

Safety Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2

Module Operation vs. Channel Operation . . . . . . . . . . . . . 4-2

Specifications

Table of Contents 3

Power-up Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3

Channel Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3

Invalid Channel Configuration Detection. . . . . . . . . . . . 4-3

Out-of-Range Detection . . . . . . . . . . . . . . . . . . . . . . . . 4-3

Open-Wire or Short-Circuit Detection . . . . . . . . . . . . . . 4-4

Non-critical vs. Critical Module Errors . . . . . . . . . . . . . . . . 4-4

Module Error Definition Table . . . . . . . . . . . . . . . . . . . . . . 4-5

Module Error Field. . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5

Extended Error Information Field . . . . . . . . . . . . . . . . . 4-6

Error Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7

Module Inhibit Function . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8

Contacting Rockwell Automation . . . . . . . . . . . . . . . . . . . . 4-8

Appendix A

General Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1

Input Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-2

Cable Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-4

RTD Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-4

Configuring the 1762-IR4 Module Using RSLogix 500

Two’s Complement Binary Numbers

Appendix B

Module Addressing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1

1762-IR4 Configuration File . . . . . . . . . . . . . . . . . . . . . . . . B-1

Configuration Using RSLogix 500 Version 5.50 or Higher . . B-2

Configuration Using RSLogix 500 Version 5.2 or Lower. . . . B-6

Appendix C

Positive Decimal Values . . . . . . . . . . . . . . . . . . . . . . . . . . C-1

Negative Decimal Values. . . . . . . . . . . . . . . . . . . . . . . . . . C-2

Glossary

Index

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4 Table of Contents

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Preface

Read this preface to familiarize yourself with the rest of the manual. This preface covers the following topics:

• who should use this manual

• how to use this manual

• related publications

• conventions used in this manual

• Rockwell Automation support

Who Should Use This Manual

How to Use This Manual

Use this manual if you are responsible for designing, installing, programming, or troubleshooting control systems that use MicroLogix 1200 controllers and 1762 Expansion I/O.

As much as possible, we organized this manual to explain, in a task-by-task manner, how to install, configure, program, operate and troubleshoot a control system using the 1762-IR4.

Manual Contents

If you want... See

An overview of the RTD/resistance input module Chapter 1 Installation and wiring guidelines Chapter 2 Module addressing, configuration and status information Chapter 3 Information on module diagnostics and troubleshooting Chapter 4 Specifications for the module Appendix A Information on programming the module using MicroLogix 1200 and

RSLogix 500 Information on understanding two’s complement binary numbers Appendix C

Appendix B

Definitions of terms used in this manual Glossary

1 Publication 1762-UM003A-EN-P - February 2003

2 Preface

Conventions Used in This Manual

Publication 1762-UM003A-EN-P - February 2003

The following conventions are used throughout this manual:

• Bulleted lists (like this one) provide information not procedural

steps.

• Numbered lists provide sequential steps or hierarchical

information.

• Italic type is used for emphasis.

Preface 3

Rockwell Automation Support

Rockwell Automation tests all of our products to ensure that they are fully operational when shipped from the manufacturing facility.

If you are experiencing installation or startup problems, please review the troubleshooting information contained in this publication first. If you need technical assistance to get your module up and running, please contact Customer Support (see the table below); our trained technical specialists are available to help.

If the product is not functioning and needs to be returned, contact your distributor. You must provide a Customer Support case number to your distributor in order to complete the return process.

Phone United

States/Canada Outside United

States/Canada

Internet Worldwide Go to http://support.rockwellautomation.com/

1.440.646.5800

You can access the phone number for your country via the Internet:

1. Go to http://support.rockwellautomation.com/

2. Under Contacting Customer Support and Other Countries, click on Click here

Your Questions or Comments on the Manual

If you find a problem with this manual, please notify us. If you have any suggestions for how this manual could be made more useful to you, please contact us at the address below:

Rockwell Automation Automation Control and Information Group Technical Communication, Dept. A602V P.O. Box 2086 Milwaukee, WI 53201-2086

Publication 1762-UM003A-EN-P - February 2003

4 Preface

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Chapter

Overview

This chapter describes the four-channel 1762-IR4 RTD/resistance Input module and explains how the controller reads resistance temperature detector (RTD) or direct resistance-initiated analog input data from the module. Included is:

• a general description of hardware features

• an overview of module and system operation

• compatibility

General Description

The 1762-IR4 module supports RTD and direct resistance signal measurement applications that require up to four channels. The module digitally converts analog data and then stores the converted data in its image table.

The module supports connections from any combination of up to four input devices. Each channel is individually configurable via software for 2- or 3-wire RTD or direct resistance input devices. Channels are compatible with 4-wire sensors, but the fourth sense wire is not used. Two programmable excitation current values (0.5mA and 1.0mA) are provided, to limit RTD self-heating. When configured for RTD inputs, the module can convert the RTD readings into linearized digital temperature readings in °C or °F. When configured for resistance analog inputs, the module can convert voltages into linearized resistance values in ohms. The module assumes that the direct resistance input signal is linear prior to input to the module.

Each channel provides open-circuit (all wires), short-circuit (excitation and return wires only), and over- and under-range detection and indication.

IMPORTANT

1 Publication 1762-UM003A-EN-P - February 2003

The module accepts input from RTDs with up to 3 wires. If your application requires a 4-wire RTD, one of the two lead compensation wires is not used, and the RTD is treated like a 3-wire sensor. The third wire provides lead wire compensation. See Chapter 2, Installation and Wiring, for more information.

1-2 Overview

The following data formats are supported by the module.:

• raw/proportional

• engineering units x 1

• engineering units x 10

• scaled-for-PID

• percent full scale

Available filter frequencies are:

• 10 Hz

• 50 Hz

• 60 Hz

• 250 Hz

• 500 Hz

• 1 kHz

The module uses six input words for data and status bits and five configuration words. Module configuration is stored in the controller memory. Normally configuration is done via the controller’s programming software. In addition, some controllers support configuration via the user program. Refer to your controller manual for additional information. See Chapter 3, Module Data, Status, and Channel Configuration, for details on module configuration.

RTD Compatibility

An RTD consists of a temperature-sensing element connected by two, three, or four wires that provide input to the module. The following table lists the RTD types that you can use with the module, including their temperature range, effective resolution, and repeatability for both excitation currents, 0.5 and 1.0 mA.

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Table 1.1 RTD Specifications

Overview 1-3

RTD Type

(1)

Temperature Range Using

0.5 mA Excitation

Temperature Range Using

1.0 mA Excitation

Maximum Scaled Resolution

Maximum Scaled Repeatability

Copper 426 10Ω Not allowed -100 to 260°C (-148 to 500°F) 0.1°C (0.1°F) ±0.2°C (±0.4°F)

(2)

Nickel 618

120Ω -100 to 260°C (-148 to 500°F) -100 to 260°C (-148 to 500°F) 0.1°C (0.1°F) ±0.1°C (±0.2°F)

Nickel 672 120Ω -80 to 260°C (-112 to 500°F) -80 to 260°C (-112 to 500°F) 0.1°C (0.1°F) ±0.1°C (±0.2°F)

Nickel-Iron

604Ω -100 to 200°C (-148 to 392°F) -100 to +200°C (-148 to 392°F) 0.1°C (0.1°F) ±0.1°C (±0.2°F)

518 Platinum 385 100Ω -200 to 850°C (-328 to 1562°F) -200 to 850°C (-328 to 1562°F) 0.1°C (0.1°F) ±0.2°C (±0.4°F)

200Ω -200 to 850°C (-328 to 1562°F) -200 to 850°C (-328 to 1562°F) 0.1°C (0.1°F) ±0.2°C (±0.4°F) 500Ω -200 to 850°C (-328 to 1562°F) -200 to 850°C (-328 to 1562°F) 0.1 °C (0.1 °F) ±0.2°C (±0.4°F) 1000Ω -200 to 850°C (-328 to 1562°F) Not Allowed 0.1°C (0.1°F) ±0.2°C (±0.4°F)

Platinum 3916 100Ω -200C to 630°C (-328 to

-200 to 630°C (-328 to 1166°F) 0.1°C (0.1°F) ±0.2°C (±0.4°F)

1166°F)

200Ω -200 to 630°C (-328 to 1166°F) -200 to 630°C (-328 to 1166°F) 0.1°C (0.1°F) ±0.2°C (±0.4°F) 500Ω -200 to 630°C (-328 to 1166°F) -200 to 630°C (-328 to 1166°F) 0.1°C (0.1°F) ±0.2°C (±0.4°F) 1000Ω -200 to 630°C (-328 to 1166°F) Not Allowed 0.1°C (0.1°F) ±0.2°C (±0.4°F)

(1) Digits following the RTD type represent the temperature coefficient of resistance (α) , which is defined as the resistance change per ohm per °C. For instance,

platinum 385 refers to a platinum RTD with α = 0.00385 ohm/ohm -°C, or simply 0.00385/°C.

(2) Actual value at 0°C is 100

Ω per DIN standard.

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1-4 Overview

The tables below provide specifications for RTD accuracy and temperature drift.

Table 1.2 RTD Accuracy and Temperature Drift

RTD Type Maximum Scaled Accuracy

(25°C with Calibration)

Copper 426 10Ω ±0.6°C (1.08°F) ±1.1°C (1.98°F) ±0.032°C/°C (0.032°F/°F) Nickel 618 120Ω ±0.2°C (±0.36°F) ±0.4°C (±0.72°F) ±0.012°C/°C (±0.012°F/°F) Nickel 672 120Ω ±0.2°C (±0.36°F) ±0.4°C (±0.72°F) ±0.012°C/°C (±0.012°F/°F) Nickel-Iron 518 604Ω ±0.3°C (±0.54°F) ±0.5° C (±0.9°F) ±0.015°C/°C (±0.015°F/°F) Platinum 385 100Ω ±0.5°C (±0.9°F) ±0.9°C (±1.62°F) ±0.026°C/°C (±0.026°F/°F)

200Ω ±0.5°C (±0.9°F) ±0.9°C (±1.62°F) ±0.026°C/°C (±0.026°F/°F) 500Ω ±0.5°C (±0.9°F) ±0.9°C (±1.62°F) ±0.026°C/°C (±0.026°F/°F) 1000Ω ±0.5°C (±0.9°F) ±0.9°C (±1.62°F) ±0.026°C/°C (±0.026°F/°F)

Platinum 3916 100Ω ±0.4°C (±0.72°F) ±0.8°C (±1.44°F) ±0.023°C/°C (±0.023°F/°F)

200Ω ±0.4°C (±0.72°F) ±0.8°C (±1.44°F) ±0.023°C/°C (±0.023°F/°F) 500Ω ±0.4°C (±0.72°F) ±0.8°C (±1.44°F) ±0.023°C/°C (±0.023°F/°F) 1000Ω ±0.4°C (±0.72°F) ±0.8°C (±1.44°F) ±0.023°C/°C (±0.023°F/°F)

Maximum Scaled Accuracy

(0 to 55°C with Calibration)

Maximum Temperature Drift

(from 25°C without

Calibration)

IMPORTANT

Using Table 1.2 to Calculate Module Accuracy:

For example, when you are using any platinum (385) RTDs with 0.5 mA excitation current, the module’s accuracy is:

• ±0.5°C (0.9°F) after you apply power to the

module or perform an autocalibration at 25°C (77°F) ambient, with module operating temperature at 25°C (77°F).

• ±[0.5°C (0.9°F) ± DT x 0.026 deg./°C

(0.026 deg./°F)] after you apply power to the module or perform an autocalibration at 25°C (77°F) ambient, with module operating temperature between 0 (32°F) and 55°C (131°F). DT is the temperature difference between the actual module operating temperature and 25°C (77°F). The value 0.026 deg./°C (0.026 deg./°F) is the temperature drift shown in the table above.

• ±0.9°C after you apply power to the module or

perform an autocalibration at 55°C (131°F) ambient, with module operating temperature at 55°C (131°F).

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Table 1.3 Resistance Device Specifications

Overview 1-5

Resistance Device Compatibility

The following table lists the specifications for the resistance devices that you can use with the module.

Resistance Device Ty pe

150Ω 0 to 150Ω 0 to 150Ω ±0.15Ω ±0.007Ω/°C

500Ω 0 to 500Ω 0 to 500Ω ±0.5Ω ±0.023Ω/°C

1000Ω 0 to 1000Ω 0 to 1000Ω ±1.0Ω ±0.043Ω/°C

3000Ω 0 to 3000Ω Not allowed ±1.5Ω ±0.072Ω/°C

(1) Accuracy values are based on the assumption that the module has been calibrated to the temperature range of 0 to 55°C (32 to 131°F).

Resistance Range (0.5 mA Excitation)

Resistance Range (1.0 mA Excitation)

Accuracy

(1)

Temperature Drift Resolution Repeatability

0.01Ω ±0.04Ω

(±0.012Ω/°F)

0.1Ω ±0.2Ω

(±0.041Ω/°F)

0.1Ω ±0.2Ω

(±0.077Ω/°F)

0.1Ω ±0.2Ω

(±0.130Ω/°F)

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1-6 Overview

Hardware Features

The RTD/resistance module provides connections for four 3-wire inputs for any combination of RTD and resistance input devices. Channels are wired as differential inputs. The illustration below shows the hardware features of the module.

Item Description

1a upper panel mounting tab 1b lower panel mounting tab

2 power diagnostic LED 3 module door with terminal identification label 4 bus connector with male pins 5 bus connector cover 6 flat ribbon cable with bus connector (female) 7 terminal block 8 DIN rail latch 9 pull loop

General Diagnostic Features

A single diagnostic LED helps you identify the source of problems that may occur during power-up or during normal channel operation. The LED indicates both status and power. See Chapter 4, Diagnostics and Troubleshooting, for details on power-up and channel diagnostics.

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Overview 1-7

System Overview

The modules communicate to the local controller or communication adapter through the 1762 bus interface. The modules also receive 5 and 24V dc power through the bus interface.

System Operation

At power-up, the module performs a check of its internal circuits, memory, and basic functions. During this time, the module status LED remains off. If no faults are found during power-up diagnostics, the module status LED is turned on.

After power-up checks are complete, the module waits for valid channel configuration data. If an invalid configuration is detected, the module generates a configuration error. Once a channel is properly configured and enabled, the module continuously converts the RTD or resistance input to a value within the range selected for that channel.

Each time the module reads an input channel, it tests the data for a fault (over- or under-range, short-circuit, or open-circuit condition). If it detects a fault, the module sets a unique bit in the channel status word. See Input Data File on page 3-3.

Using the module image table, the controller reads the two’s compliment binary converted input data from the module. This typically occurs at the end of the program scan or when commanded by the control program. If the controller and the module determine that the data transfer has been made without error, the data is used in the control program.

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1-8 Overview

Input

EXC

Module Operation

As shown in the block diagram below, each input channel of the module consists of an RTD/resistance connection that accepts excitation current; a sense connection that detects lead wire resistance; and a return connection. The signals are multiplexed to an A/D converter that reads the RTD or resistance value and the lead wire resistance.

Current

Source

A/D

Converter

MCU

ASIC

SENSE

RTN

Multiplexer

Te rm in al

+15V

+5V

A-GND

-15V

Opto-coupler

BUS

+24V dc

Isolation

Power Supply

S-GND

From the readings taken by the converter, the module returns an accurate temperature or resistance to the controller user program through the microprocessor. The module uses two bidirectional serial ports for communication, each using an optocoupler for isolation. A third optocoupler is used to reset the microprocessor if the module detects a loss of communication.

Module Field Calibration

The input module performs autocalibration when a channel is initially enabled. Autocalibration compensates for offset and gain drift of the A/D converter caused by temperature change within the module. An internal, high-precision, low drift voltage and system ground reference is used for this purpose. In addition, you can program the module to perform a calibration cycle once every 5 minutes. See Selecting Enable/Disable Cyclic Autocalibration (Word 4, Bit 0) on page 3-20 for information on configuring the module to perform periodic calibration.

Publication 1762-UM003A-EN-P - February 2003

Installation and Wiring

This chapter tells you how to:

• determine the power requirements for the modules

• avoid electrostatic damage

• install the module

• wire the module’s terminal block

• wire input devices

Chapter

Compliance to European Union Directives

This product is approved for installation within the European Union and EEA regions. It has been designed and tested to meet the following directives.

EMC Directive

The 1762-IR4 module is tested to meet Council Directive 89/336/EEC Electromagnetic Compatibility (EMC) and the following standards, in whole or in part, documented in a technical construction file:

• EN 50081-2

EMC – Generic Emission Standard, Part 2 - Industrial Environment

• EN 50082-2

EMC – Generic Immunity Standard, Part 2 - Industrial Environment

This product is intended for use in an industrial environment.

Low Voltage Directive

This product is tested to meet Council Directive 73/23/EEC Low Voltage, by applying the safety requirements of EN 61131-2 Programmable Controllers, Part 2 – Equipment Requirements and Tests.

1 Publication 1762-UM003A-EN-P - February 2003

2-2 Installation and Wiring

For specific information required by EN61131-2, see the appropriate sections in this publication, as well as the following Allen-Bradley publications:

• Industrial Automation, Wiring and Grounding Guidelines for

Noise Immunity, publication 1770-4.1

• Automation Systems Catalog, publication B113

Power Requirements

General Considerations

The module receives +5V dc and 24V dc power from the system power supply through the bus interface.

The maximum current drawn by the module is shown in the table below.

5V dc 24V dc

40 mA 50 mA

TIP

When you configure your system, ensure that the total current draw of all the modules does not exceed the maximum current output of the system power supply.

1762 I/O is suitable for use in an industrial environment when installed in accordance with these instructions. Specifically, this equipment is intended for use in clean, dry environments (Pollution

(1)

degree 2

) and to circuits not exceeding Over Voltage Category II

(IEC 60664-1).

(3)

(2)

Publication 1762-UM003A-EN-P - February 2003

(1) Pollution Degree 2 is an environment where, normally, only non-conductive pollution occurs except that

occasionally a temporary conductivity caused by condensation shall be expected.

(2) Over Voltage Category II is the load level section of the electrical distribution system. At this level transient

voltages are controlled and do not exceed the impulse voltage capability of the product’s insulation.

(3) Pollution Degree 2 and Over Voltage Category II are International Electrotechnical Commission (IEC)

designations.

Installation and Wiring 2-3

Hazardous Location Considerations

This equipment is suitable for use in Class I, Division 2, Groups A, B, C, D or non-hazardous locations only. The following WARNING statement applies to use in hazardous locations.

WARNING

EXPLOSION HAZARD

• Substitution of components may impair

suitability for Class I, Division 2.

• Do not replace components or disconnect

equipment unless power has been switched off or the area is known to be non-hazardous.

• Do not connect or disconnect components

unless power has been switched off or the area is known to be non-hazardous.

• This product must be installed in an enclosure.

• All wiring must comply with N.E.C. article

501-4(b).

Prevent Electrostatic Discharge

ATTENTION

Electrostatic discharge can damage integrated circuits or semiconductors if you touch I/O module bus connector pins or the terminal block on the input module. Follow these guidelines when you handle the module:

• Touch a grounded object to discharge static

potential.

• Wear an approved wrist-strap grounding device.

• Do not touch the bus connector or connector

pins.

• Do not touch circuit components inside the

module.

• If available, use a static-safe work station.

• When it is not in use, keep the module in its

static-shield box.

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2-4 Installation and Wiring

Remove Power

ATTENTION

Remove power before removing or inserting this module. When you remove or insert a module with power applied, an electrical arc may occur. An electrical arc can cause personal injury or property damage by:

• sending an erroneous signal to your system’s

field devices, causing unintended machine motion

• causing an explosion in a hazardous

environment

Electrical arcing causes excessive wear to contacts on both the module and its mating connector and may lead to premature failure.

Selecting a Location

Reducing Noise

Most applications require installation in an industrial enclosure to reduce the effects of electrical interference. RTD inputs are highly susceptible to electrical noise. Electrical noise coupled to the RTD inputs will reduce the performance (accuracy) of the module.

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Group your modules to minimize adverse effects from radiated electrical noise and heat. Consider the following conditions when selecting a location for the module. Position the module:

• away from sources of electrical noise such as hard-contact

switches, relays, and AC motor drives

• away from modules which generate significant radiated heat.

Refer to the module’s heat dissipation specification.

In addition, route shielded, twisted-pair wiring away from any high voltage I/O wiring.

Mounting

Installation and Wiring 2-5

ATTENTION

Do not remove protective debris strip until after the module and all other equipment near the module is mounted and wiring is complete. Once wiring is complete and the module is free of debris, carefully remove the protective debris strip. Failure to remove the strip before operating can cause overheating.

Minimum Spacing

Maintain spacing from enclosure walls, wireways, adjacent equipment, etc. Allow 50.8 mm (2 in.) of space on all sides for adequate ventilation, as shown below:

To p

Side Side

TIP

ATTENTION

MicroLogix

1200

1762 I/O may be mounted horizontally only.

During DIN rail or panel mounting of all devices, be sure that all debris (metal chips, wire strands, etc.) is kept from falling into the module. Debris that falls into the module could cause damage at power up.

1762 I/O

Bottom

1762 I/O

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2-6 Installation and Wiring

DIN Rail Mounting

The module can be mounted using the following DIN rails: 35 x 7.5 mm (EN 50 022 - 35 x 7.5) or 35 x 15 mm (EN 50 022 - 35 x 15).

Before mounting the module on a DIN rail, close the DIN rail latch. Press the DIN rail mounting area of the module against the DIN rail. The latch will momentarily open and lock into place.

Use DIN rail end anchors (Allen-Bradley part number 1492-EA35 or 1492-EAH35) for environments with vibration or shock concerns.

End Anchor

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TIP

For environments with extreme vibration and shock concerns, use the panel mounting method described below, instead of DIN rail mounting.

Panel Mounting

Use the dimensional template shown below to mount the module. The preferred mounting method is to use two M4 or #8 panhead screws per module. M3.5 or #6 panhead screws may also be used, but a washer may be needed to ensure a good ground contact. Mounting screws are required on every module.

For more than 2 modules: (number of modules - 1) x 40.4 mm (1.59 in.)

14.5 (0.57)

100

(3.94)

(3.54)

NOTE: Hole spacing tolerance: ±0.4 mm (0.016 in.).

MicroLogix 1200

Installation and Wiring 2-7

40.4 (1.59)

Expansion I/O

MicroLogix 1200

Expansion I/O

40.4 (1.59)

System Assembly

The expansion I/O module is attached to the controller or another I/O module by means of a ribbon cable after mounting as shown below.

IMPORTANT

WARNING

Use the pull loop on the connector to disconnect modules. Do not pull on the ribbon cable.

EXPLOSION HAZARD

• In Class I, Division 2 applications, the bus

connector must be fully seated and the bus connector cover must be snapped in place.

• In Class I, Division 2 applications, all modules

must be mounted in direct contact with each other as shown on page 2-1. If DIN rail mounting is used, an end stop must be installed ahead of the controller and after the last 1762 I/O module.

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2-8 Installation and Wiring

Field Wiring Connections

System Wiring Guidelines

Consider the following when wiring your system:

General

• This product is intended to be mounted to a well-grounded

mounting surface such as a metal panel. Additional grounding connections from the module’s mounting tabs or DIN rail (if used) are not required unless the mounting surface cannot be grounded.

• Channels are isolated from one another by ±10V dc maximum.

• Do not use the modules NC terminals as connection points.

• Route field wiring away from any other wiring and as far as

possible from sources of electrical noise, such as motors, transformers, contactors, and ac devices. As a general rule, allow at least 15.2 cm (6 in.) of separation for every 120V of power.

• Routing field wiring in a grounded conduit can reduce electrical

noise.

• If field wiring must cross ac or power cables, ensure that they

cross at right angles.

• To ensure optimum accuracy, limit overall cable impedance by

keeping your cable as short as possible. Locate the I/O system as close to your sensors or actuators as your application will permit.

• Tighten terminal screws with care. Excessive tightening can strip

a screw.

Publication 1762-UM003A-EN-P - February 2003

Shield Grounding

• Use Belden shielded, twisted-pair wire to ensure proper

operation and high immunity to electrical noise. Refer to the following table and the RTD Wiring Considerations below.

Configuration

2-wire Belden™ 9501 or equivalent 3-wire

less than 30.48 m (100ft.) 3-wire

greater than 30.48 m (100 ft.) or high humidity conditions

(1) For additional information, see page A-4.

• Under normal conditions, the drain wire and shield junction

should be connected to earth ground, via a panel or DIN rail mounting screw at the 1762-IR4 module end.

Recommended Cable

Belden™ 9533 or equivalent

Belden™ 83503 or equivalent

(1)

Installation and Wiring 2-9

• Keep shield connection to ground as short as possible.

• If noise persists for a device, try grounding the opposite end of

the cable. (You can only ground one end at a time.)

• Refer to Industrial Automation Wiring and Grounding

Guidelines, Allen-Bradley publication 1770-4.1, for additional

information.

RTD Wiring Considerations

Since the operating principle of the RTD module is based on the measurement of resistance, take special care when selecting your input cable. For 2-wire or 3-wire configurations, select a cable that has a consistent impedance throughout its entire length. See Cable Specifications on page A-4.

IMPORTANT

The RTD module requires three wires to compensate for lead resistance error. We recommend that you do not use 2-wire RTDs if long cable runs are required, as it reduces the accuracy of the system. However, if a two-wire configuration is required, reduce the effect of the lead wire resistance by using a lower gauge wire for the cable (for example, use AWG #16 instead of AWG #24). The module’s terminal block accepts two AWG #14 gauge wires.

When using a 3-wire configuration, the module compensates for resistance error due to lead wire length. For example, in a 3-wire configuration, the module reads the resistance due to the length of one of the wires and assumes that the resistance of the other wire is equal. If the resistances of the individual lead wires are much different, an error may exist. The closer the resistance values are to each other, the greater the amount of error that is eliminated.

IMPORTANT

To ensure temperature or resistance value accuracy, the resistance difference of the cable lead wires must be equal to or less than 0.01

Ω .

To insure that the lead values match as closely as possible:

• Keep lead resistance as small as possible and less than 25

• Use quality cable that has a small tolerance impedance rating.

• Use a heavy-gauge lead wire which has less resistance per foot.

Publication 1762-UM003A-EN-P - February 2003

Ω .

2-10 Installation and Wiring

Wiring the Finger-Safe Terminal Block

ATTENTION

Be careful when stripping wires. Wire fragments that fall into a module could cause damage when power is applied. Once wiring is complete, ensure the module is free of all metal fragments.

When wiring the terminal block, keep the finger-safe cover in place.

1. Route the wire under the terminal pressure plate. You can use

the stripped end of the wire or a spade lug. The terminals will accept a 6.35 mm (0.25 in.) spade lug.

2. Tighten the terminal screw making sure the pressure plate

secures the wire. Recommended torque when tightening terminal screws is 0.904 Nm (8 in-lbs).

3. After wiring is complete, remove the debris shield.

TIP

If you need to remove the finger-safe cover, insert a screw driver into one of the square wiring holes and gently pry the cover off. If you wire the terminal block with the finger-safe cover removed, you will not be able to put it back on the terminal block because the wires will be in the way.

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Installation and Wiring 2-11

Wire Size and Terminal Screw Torque

Each terminal accepts up to two wires with the following restrictions:

Wire Type Wire Size Terminal Screw Torque

Solid Cu-90°C (194°F) #14 to #22 AWG 0.904 Nm (8 in-lbs) Stranded Cu-90°C (194°F) #16 to #22 AWG 0.904 Nm (8 in-lbs)

Wiring Input Devices to the Module

ATTENTION

To prevent shock hazard, care should be taken when wiring the module to analog signal sources. Before wiring any module, disconnect power from the system power supply and from any other source to the module.

After the module is properly installed, follow the wiring procedure below and the RTD and potentiometer wiring diagrams on pages 2-12 through 2-15. To ensure proper operation and high immunity to electrical noise, always use Belden™ shielded, twisted-pair or equivalent wire.

Cut foil shield and drain wire

signal wire

drain wire

cable

foil shield

signal wire

drain wire

foil shield

cable

Publication 1762-UM003A-EN-P - February 2003

Cut foil shield and drain wire

signal wires (3)

2-12 Installation and Wiring

To wire your module follow these steps:

1. At each end of the cable, strip some casing to expose the

individual wires.

2. Trim the signal wires to 2-inch (5 cm) lengths. Strip about 3/16

inch (5 mm) of insulation away to expose the end of the wire.

ATTENTION

Be careful when stripping wires. Wire fragments that fall into a module could cause damage at power up.

3. At the module end of the cable, twist the drain wire and foil

shield together, bend them away from the cable, and apply shrink wrap. Then earth ground via a panel or DIN rail mounting screw at the end of the module. Keep the length of the drain wire as short at possible.

4. At the other end of the cable, cut the drain wire and foil shield

back to the cable and apply shrink wrap.

5. Connect the signal wires to the terminal block as described for

each type of input. See Wiring RTDs on page 2-12 or Wiring Resistance Devices (Potentiometers) on page 2-14.

6. Connect the other end of the cable to the analog input device.

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7. Repeat steps 1 through 6 for each channel on the module.

Wiring RTDs

Three types of RTDs can be connected to the 1762-IR4 module:

• 2-wire RTD, which is composed of an RTD EXC (excitation) lead

wire and a RTN (return) lead wire

• 3-wire RTD, which is composed of a Sense and 2 RTD lead

wires (RTD EXC and RTN)

• 4-wire RTD, which is composed of a Sense and 2 RTD lead

wires (RTD EXC and RTN). The second sense wire from the 4-wire RTD is left open.

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