Rockwell Automation 1746-NR8 User Manual

SLC 500™ RTD/Resistance Input Module

(Catalog Number 1746-NR8)

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 this control equipment 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.

The illustrations, charts, sample programs and layout examples shown in this guide are intended solely for purposes of example. Since there are many variables and requirements associated with any particular installation, Allen-Bradley 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 Allen-Bradley 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 manual we use notes to make you aware of safety considerations:

ATTENTION

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

Attention statements help you to:

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•

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IMPORTANT

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Preface

Overview

Installation and Wiring

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

Purpose of This Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P-1

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

Common Techniques Used in this Manual. . . . . . . . . . . . . . . . . . . P-3

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

Local Product Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P-3

Technical Product Assistance. . . . . . . . . . . . . . . . . . . . . . . . . . . P-3

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

Chapter 1

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

RTD Compatibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

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

Hardware Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5

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

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

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

Module to Processor Communication. . . . . . . . . . . . . . . . . . . 1-10

Chapter 2

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

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

Safety Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2

Electrostatic Damage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2

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

Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3

Module Location in Chassis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4

Modular Chassis Considerations . . . . . . . . . . . . . . . . . . . . . . . . 2-4

Fixed Expansion Chassis Considerations . . . . . . . . . . . . . . . . . . 2-4

General Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5

Module Installation and Removal . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5

Removing the Terminal Block. . . . . . . . . . . . . . . . . . . . . . . . . . 2-6

Installing the Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7

Removing the Module. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7

Terminal Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8

Wiring Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8

Wiring Resistance Devices (Potentiometers) to the Module . . 2-11

Wiring Input Devices to the Module. . . . . . . . . . . . . . . . . . . . 2-14

Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-15

Factory Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-15

Autocalibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-15

Single-Point Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-16

i Publication 1746-UM003A-EN-P

Table of Contents ii

Preliminary Operating Considerations

Channel Configuration, Data, and Status

Chapter 3

Module ID Code. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

Module Addressing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2

Output Image - Configuration Words. . . . . . . . . . . . . . . . . . . . 3-4

Input Image - Data Words and Status Words . . . . . . . . . . . . . . 3-4

Channel Filter Frequency Selection. . . . . . . . . . . . . . . . . . . . . . . . . 3-5

1746-NR8 Channel Step Response . . . . . . . . . . . . . . . . . . . . . . 3-5

Effective Resolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6

Channel Cut-Off Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7

Channel Autocalibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10

Update Time and Scanning Process . . . . . . . . . . . . . . . . . . . . 3-10

Input Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12

Output Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12

Chapter 4

Channel Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

Channel Configuration Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . 4-3

Configure Each Channel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3

Enter the Configuration Data . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4

Input Type Selection (Bits 0 through 3) . . . . . . . . . . . . . . . . . . 4-6

Data Format Selection (Bits 4 and 5) . . . . . . . . . . . . . . . . . . . . 4-6

Broken Input Selection (Bits 6 and 7) . . . . . . . . . . . . . . . . . . . 4-16

Temperature Units Selection (Bit 8) . . . . . . . . . . . . . . . . . . . . 4-17

Filter Frequency Selection (Bits 9 and 10). . . . . . . . . . . . . . . . 4-17

Channel Enable Selection (Bit 11). . . . . . . . . . . . . . . . . . . . . . 4-17

Excitation Current Selection (Bit 12) . . . . . . . . . . . . . . . . . . . 4-18

Calibration Disable (Bit 13) . . . . . . . . . . . . . . . . . . . . . . . . . . 4-18

Lead Resistance Measurement Enable (Bits 14 and 15) . . . . . . 4-18

Channel Data Word . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-19

Channel Status Checking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-19

Input Type Status (Bits 0 through 3). . . . . . . . . . . . . . . . . . . . 4-22

Data Format Status (Bits 4 and 5) . . . . . . . . . . . . . . . . . . . . . . 4-22

Broken Input Status (Bits 6 and 7) . . . . . . . . . . . . . . . . . . . . . 4-22

Temperature Units Status (Bit 8) . . . . . . . . . . . . . . . . . . . . . . 4-22

Channel Filter Frequency (Bits 9 and 10) . . . . . . . . . . . . . . . . 4-23

Channel Enable Status (Bit 11) . . . . . . . . . . . . . . . . . . . . . . . . 4-23

Calibration Error (Bit 12) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-23

Broken Input Error (Bit 13) . . . . . . . . . . . . . . . . . . . . . . . . . . 4-23

Out-Of-Range Error (Bit 14) . . . . . . . . . . . . . . . . . . . . . . . . . 4-24

Configuration Error (Bit 15) . . . . . . . . . . . . . . . . . . . . . . . . . . 4-24

Publication 1746-UM003A-EN-P

Ladder Programming Examples

Module Diagnostics and Troubleshooting

Table of Contents iii

Chapter 5

Device Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1

Initial Programming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2

Dynamic Programming. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4

Verifying Channel Configuration Changes . . . . . . . . . . . . . . . . . . . 5-4

Interfacing to the PID Instruction. . . . . . . . . . . . . . . . . . . . . . . . . . 5-5

Using the Proportional Counts Data Format

with the User-set Scaling (Class 3). . . . . . . . . . . . . . . . . . . . . . . . . . 5-7

Monitoring Channel Status Bits . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-8

Invoking Autocalibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-10

Chapter 6

Module Operation vs. Channel Operation . . . . . . . . . . . . . . . . . . . 6-1

Power-Up Diagnostics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2

Channel Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2

LED Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2

Error Codes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3

Channel Status LEDs (Green). . . . . . . . . . . . . . . . . . . . . . . . . . 6-4

Module Status LED (Green) . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5

Replacement Parts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7

Contacting Rockwell Automation . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7

Application Examples

Specifications

Chapter 7

Basic Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1

Channel Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1

Program Listing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-2

Supplementary Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3

Channel Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-4

Program Setup and Operation Summary. . . . . . . . . . . . . . . . . . 7-6

Program Listing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-6

Appendix A

Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1

Physical Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1

Environmental Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-2

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

Module Accuracy

RTD Temperature Ranges, Resolution, and Repeatability . . . . . . . A-3

RTD Accuracy and Temperature Drift Specifications . . . . . . . . . . . A-4

Resistance Device Compatibility . . . . . . . . . . . . . . . . . . . . . . . . . . . A-5

Cable Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-5

RTD Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-5

Publication 1746-UM003A-EN-P

Table of Contents iv

Configuration Worksheet for RTD/ Resistance Module

Appendix B

Glossary

Index

Publication 1746-UM003A-EN-P

Preface

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

• who should use this manual

• the purpose of this manual

• terms and abbreviations

• conventions used in this manual

• Allen-Bradley support

Who Should Use This Manual

Purpose of This Manual

Use this manual if you are responsible for designing, installing, programming, or troubleshooting control systems that use Allen-Bradley small logic controllers.

You should have a basic understanding of SLC 500™ products. You should understand programmable controllers and be able to interpret the ladder logic instructions required to control your application. If you do not, contact your local Allen-Bradley representative for information on available training courses before using this product.

This manual is a reference guide for the 1746-NR8 RTD/Resistance Input Module. The manual:

• gives you an overview of system operation

• explains the procedures you need to install and wire the module at the

customer site

• provides ladder programming examples

• provides an application example of how this input module can be used

to control a process

1 Publication 1746-UM003A-EN-P

Preface 2

Common Techniques Used in this Manual

Rockwell Automation Support

The following conventions are used throughout this manual:

• Bulleted lists such as this one provide information, not procedural steps.

• Numbered lists provide sequential steps or hierarchical information.

• Italic type is used for emphasis.

Rockwell Automation offers support services worldwide, with over 75 Sales/ Support Offices, 512 authorized Distributors and 260 authorized Systems Integrators located throughout the United States alone, plus Rockwell Automation representatives in every major country in the world.

Local Product Support

Contact your local Rockwell Automation representative for:

• sales and order support

• product technical training

• warranty support

• support service agreements

Technical Product Assistance

If you need to contact Rockwell Automation for technical assistance, please review the information in the Module Diagnostics and Troubleshooting chapter first. Then call your local Rockwell Automation representative.

Your Questions or Comments on this Manual

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

Publication 1746-UM003A-EN-P

Preface 4

Publication 1746-UM003A-EN-P

Overview

Chapter

Description

This chapter describes the 8-channel 1746-NR8 RTD/Resistance Input Module

Module and explains how the SLC controller gathers RTD (Resistance

Module Module Temperature Detector) temperature or resistance-initiated analog input from the module. Included is:

• a general description of the module’s hardware and software features

• an overview of system operation

For the rest of the manual, the 1746-NR8 RTD/Resistance Input Module referred to as simply the RTD module

The RTD module receives and stores digitally converted analog data from RTDs or other resistance inputs such as potentiometers into its image table for retrieval by all fixed and modular SLC 500 processors. An RTD consists of a temperature-sensing element connected by 2, 3, or 4 wires that provide input to the RTD module. The module supports connections from any combination of up to eight RTDs of various types (for example: platinum, nickel, copper, or nickel-iron) or other resistance inputs.

The RTD module supplies a small current to each RTD connected to the module inputs (up to 8 input channels). The module provides on-board scaling and converts RTD input to temperature ( input in ohms.

RTD module.

RTD moduleRTD module

1746-NR8 RTD/Resistance Input

1746-NR8 RTD/Resistance Input 1746-NR8 RTD/Resistance Input

1746-NR8 RTD/Resistance Input Module is

1746-NR8 RTD/Resistance Input Module1746-NR8 RTD/Resistance Input Module

°C°F



or reports resistance

Each input channel is individually configurable for a specific input device. Broken sensor detection (open- or short-circuit) is provided for each input channel. In addition, the module provides indication if the input signal is out-of-range. For more detail on module functionality, refer to the subsection entitled System Overview

1 Publication 1746-UM003A-EN-P

System Overview later in this chapter.

System OverviewSystem Overview

1-2 Overview

Figure 1.1 Simplified RTD Module Circuit

Constant Current Source

Ic=0.25 or

1.0 mA

RTD

Sense

RTD Module

Backplane

RTD 0

RTD 1

RTD 2

RTD 3

RTD 4

Return

RTD

Sense

Return

RTD Sense

Return

RTD

Sense

Return

RTD

Sense

Return

A/D

Conversion

Digital Data

Digital

µP Circuit

Digital Data

Publication 1746-UM003A-EN-P

RTD 5

RTD 6

RTD 7

RTD

Sense

Return

RTD

Sense

Return

RTD

Sense

Return

Overview 1-3

RTD Compatibility

The following table lists the RTD types used with the RTD module and gives each type’s associated temperature range, resolution, and repeatability specifications. The next table shows the accuracy and temperature drift specifications for the RTDs.

Table 1.1 RTD Temperature Ranges, Resolution, and Repeatability

Input Type Temp. Range

(0.25 mA Excitation)

Platinum (385)

(2)

100Ω -200°C to +850°C

(-328°F to +1562°F)

200Ω -200°C to +850°C

(-328°F to +1562°F)

Ω -200°C to +850°C

500

(-328°F to +1562°F)

Ω -200°C to +850°C

1000

(-328°F to +1562°F)

Platinum (3916)

(2)

100Ω -200°C to +630°C

(-328°F to +1166°F)

Ω -200°C to +630°C

200

(-328°F to +1166°F)

Ω -200°C to +630°C

500

(-328°F to +1166°F)

1000Ω -200°C to +630°C

(-328°F to +1166°F)

Copper (426)

(2) (3)

10Ω -100°C to +260°C

(-328°F to +500°F)

Nickel (618)

(2) (4)

120Ω -100°C to +260°C

(-328°F to +500°F)

Nickel (672)

(2)

120Ω -80°C to +260°C

(-328°F to +500°F)

Nickel Iron (518)

(2)

604Ω -200°C to +200°C

(-328°F to +392°F)

(1) The temperature range for the 1000Ω, 500Ω, and 604Ω RTD is dependent on the excitation current. (2) The digits following the RTD type represent the tem perature 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 ohms/ohm · C or simply 0.00385 / C. (3) Actual value at 0 C is 9.042Ω per SAMA standard RC21-4-1966. (4) Actual value at 0 C is 100Ω per DIN standard.

Temp. Range

(1)

(1.0 mA Excitation)

-200°C to +850°C (-328°F to +1562°F)

-200°C to +390°C (-328°F to +698°F)

-200°C to +50°C (-328°F to +122°F)

-200°C to +630°C (-328°F to +1166°F)

-200°C to +380°C (-328°F to +698°F)

-200°C to +50°C (-328°F to +122°F)

-100°C to +260°C (-328°F to +500°F)

-80°C to +260°C (-328°F to +500°F)

-200°C to +180°C (-328°F to +338°F)

(1)

0.1°C (0.1°F)

(28 Hz, 50/60 Hz)

± 0.2°C (± 0.4°F)

± 0.1°C (± 0.2°F)

Resolution Repeatability

IMPORTANT

The exact signal range valid for each input type is dependent upon the excitation current magnitude that you select when configuring the module. For details on excitation current, refer to Appendix A.

Publication 1746-UM003A-EN-P

1-4 Overview

Table 1.2 RTD Accuracy and Temperature Drift Specifications

Input Type 0.25 mA Excitation 1.0 mA Excitation

Accuracy Temperature Drift Accuracy Temperature Drift

Platinum (385)

Platinum (3916)

Copper (426)

Nickel (618)

Ω ±0.5°C

100

200

Ω ±0.6°C

500

Ω ±0.7°C

1000

Ω ±1.2°C

Ω ±0.4°C

200

Ω ±0.5°C

500

Ω ±0.6°C

1000

Ω ±0.9°C

Ω ±0.5°C

120

Ω ± 0.2°C

(±0.9°F)

(±1.1°F)

(±1.3°F)

(±2.2°F)

(±0.7°F)

(±0.9°F)

(±1.1°F)

(±1.6°F)

(±0.9°F)

(±0.4°F)

±0.012°C/°C (±0.012°F/°F)

±0.015°C/°C (± 0.015°F/°F)

±0.020°C/°C (±0.020°F/°F)

±0.035°C/°C (±0.035°F/°F)

±0.010°C/°C (± 0.010°F/°F)

±0.011°C/°C (±0.011°F/°F)

±0.015°C/°C (± 0.015°F/°F)

±0.026°C/°C (±0.026°F/°F)

±0.008°C/°C (±0.008°F/F)

±0.003°C/°C (±0.003°F/°F)

±0.7°C (±1.3°F)

±0.5°C (± 0.9°F)

±0.4°C (±0.7°F)

±0.6°C (±1.1°F)

±0.4°C (±0.7°F)

±0.3°C (±0.6°F)

±0.8°C (±1.4°F)

±0.2°C (±0.4°F)

±0.020°C/°C (±0.020°F/°F)

±0.012°C/°C (±0.012°F/°F)

±0.010°C/°C (±0.010°F/°F)

±0.015°C/°C (±0.015°F/°F)

±0.012°C/°C (±0.012°F/°F)

±0.010°C/°C (±0.010°F/°F)

±0.008°C/°C (±0.008°F/°F)

±0.005°C/°C (±0.005°F/°F)

Nickel

120

(672)

Nickel Iron

604

(518)

Resistance 150

500

1000Ω ±1.0Ω ±0.025Ω/°C

3000Ω ±1.5Ω ±0.040Ω/°C

Ω ±0.2°C

(±0.4°F)

Ω ±0.3°C

(±0.5°F)

Ω ±0.2Ω ±0.004Ω/°C

Ω ±0.5Ω ±0.012Ω/°C

±0.003°C/°C (±0.003°F/°F)

±0.008°C/°C (±0.008°F/°F)

(±0.002

Ω/°F)

(±0.007

Ω/°F)

(±0.014

Ω/°F)

(±0.023

Ω/°F)

±0.2°C (±0.4°F)

±0.3°C (± 0.5°F)

Ω ±0.003Ω/°C

±0.15

±0.005°C/°C (±0.005°F/°F)

±0.008°C/°C (±0.008°F/°F)

(± 0.002

Ω ±0.012Ω/°C

±0.5

(±0.007

Ω ±0.025Ω/°C

±1.0

(±0.014

Ω ±0.040Ω/°C

±1.2

(±0.023

Ω/°F)

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Resistance Device Compatibility

The table below lists the resistance input types you can use with the RTD module and gives each type’s associated specifications.

Table 1.3 Resistance Input Specifications

Input Type Resistance Range

(0.25 mA Excitation)

Resistance 150

(1) The accuracy values assume that the module was calibrated within the specified temperature range of 0°C to 60°C (32°F to 140°F). (2) The accuracy for 150

(3) The temperature drift for 150

Ω 0Ω to 150Ω 0Ω to 150Ω

500Ω 0Ω to 500Ω 0Ω to 500Ω  0.5Ω ± 0.012Ω/°C

1000Ω 0Ω to 1000Ω 0Ω to 1000Ω  1.0Ω  0.025Ω/ C

3000Ω 0Ω to 3000Ω 0Ω to 1200Ω

Ω is dependent on the excitation current: 0.2 Ω at 0.25 mA and 0.15Ω at 1.0 mA

Ω is dependent on the excitation current: 0.006Ω/°C at 0.25 mA and 0.004Ω at 1.0 mA

Resistance Range (1.0 mA Excitation)

Accuracy

(2)

1.5Ω



(1)

Temperature Drift

±0.004Ω/°C

(±0.002

(± 0.007

(

 0.014Ω/ F)



(

 0.023Ω/ F)

Ω/°F)

0.040Ω/ C

(3)

Overview 1-5

Resolution Repeatability

0.01Ω  0.04Ω

Ω  0.2Ω

0.1

Ω  0.2Ω

0.1

Ω  0.2Ω

0.1

Hardware Overview

The RTD module occupies one slot in an SLC 500:

• modular system, except the processor slot (0)

• fixed system expansion chassis (1746-A2)

The module uses eight input words and eight output words for Class 1 and 16 input words and 24 output words for Class 3.

IMPORTANT

As shown in the illustration below and table that follows, the module contains a removable terminal block (item 3) providing connection for any mix of eight RTD sensors or resistance input devices. There are no output channels on the module. Module configuration is done via the user program. There are no DIP switches.

If the RTD module resides in a remote configuration with a SLC 500 Remote I/O Adapter Module (1747-ASB), use block transfer for configuration and data retrieval. Block transfer requires a 1747-SN Remote I/O Scanner (Series B)

or PLC

processor.

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1-6 Overview

INPUT

CHANNEL ST ATUS

MODULE

RTD / resistance

0 4 1 2 3

5 6 7

Figure 1.2 RTD Module Hardware

RTD 0 Sense 0 Return 0 RTD 1 Sense 1 Return 1 RTD 2 Sense 2 Return 2 RTD 3 Sense 3 Return 3 RTD 4 Sense 4 Return 4 RTD 5 Sense 5 Return 5 RTD 6 Sense 6 Return 6 RTD 7 Sense 7 Return 7

1746-NR8

WIN (21) 1G0AA2ZT

1746-NR8 A 1.00

(21) 1G0AA2ZT

SLC 500

RTD / resistance INPUT MODULE

FRNSERCAT

CL I, DIV2 GP ABCD

IND CONT EQ.

FOR HAZ LOC

LISTED

1P00

55mA @ 24VDC, 100mA @ 5VDC

BACKPLANE REQUIREMENTS:

MADE IN U.S.A

SC P/N: 9060018-01

SC S/N: 167076

SC MFD: 0020

RESISTANCE (OHMS):

150, 500, 1000, 3000

NICKEL, NICKEL - IRON

RTD TYPES:

PLATINUM, COPPER

INPUT SIGNAL RANGES

150

Table 1.4 Hardware Features

Item Description Function

1 Channel Status LED

Indicators (green)

Displays operating and fault status of

channels 0, 1, 2, 3, 4, 5, 6, and 7 2 Module Status LED (green) Displays module operating and fault status 3 Removable Terminal Block Provides physical connection to input devices

(Catalog # 1746-RT35) 4 Cable Tie Slots Secures wiring from module 5 Door Label Provides terminal identification 6 Side Label (Nameplate) Provides module information 7 Self-Locking Tabs Secures module in chassis slot

General Diagnostic Features

The RTD module contains diagnostic features that can be used to help you identify the source of problems that may occur during power up or during normal channel operation. These power-up and channel diagnostics are explained in Chapter 6, Module Diagnostics and Troubleshooting.

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The RTD module communicates to the SLC 500 processor through the parallel backplane interface and receives +5V dc and +24V dc power from the SLC 500 power supply through the backplane. No external power supply is required. You may install as many RTD modules in your system as the power supply can support, as shown in the illustration below.

Overview 1-7

System Overview

Figure 1.3 RTD Configuration

RTD Modules

SLC Processor

Each individual channel on the RTD module can receive input signals from 2, 3 or 4-wire RTD sensors or from resistance input devices. You configure each channel to accept either input. When configured for RTD input types, the module converts the RTD readings into linearized, digital temperature readings in °C or °F. When configured for resistance inputs, the module provides a linear resistance value in ohms.

IMPORTANT

The RTD module is designed to accept input from RTD sensors with up to 3 wires. When using 4-wire RTD sensors, one of the 2 lead compensation wires is not used and the 4-wire sensor is treated like a 3-wire sensor. Lead wire compensation is provided via the third wire. Refer to Wiring Considerations on page 2-8 for more information.

System Operation

The RTD module has 3 operational states:

• power-up

• module operation

• error (module error and channel error)

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1-8 Overview

Power-up

At power-up, the RTD module checks its internal circuits, memory, and basic functions via hardware and software diagnostics. During this time, the module status LED remains off, and the channel status LEDs are turned on. If no faults are found during the power-up diagnostics, the module status LED is turned on, and the channel status LEDs are turned off.

After power-up checks are complete, the RTD module waits for valid channel configuration data from your SLC ladder logic program (channel status LEDs off). After configuration data is written to one or more channel configuration words and their channel enable bits are set by the user program, the channel status LEDs go on and the module continuously converts the RTD or resistance input to a value within the range you selected for the enabled channels. The module is now operating in its normal state.

Each time a channel is read by the module, that data value is tested by the module for a fault condition, for example, open-circuit, short-circuit, overrange, and under range. If such a condition is detected, a unique bit is set in the channel status word and the channel status LED flashes, indicating a channel error condition.

The SLC processor reads the converted RTD or resistance data from the module at the end of the program scan or when commanded by the ladder program. The processor and RTD module determine that the backplane data transfer was made without error and the data is used in your ladder program.

Module Operation

Each input channel consists of an RTD connection, which provides:

• excitation current

• a sense connection, which detects lead-wire resistance

• a return connection, which reads the RTD or resistance value

Each of these analog inputs are multiplexed to an analog converter.

The A/D converter cycles between reading the RTD or resistance value, the lead wire resistance, and the excitation current. From these readings, an accurate temperature or resistance is returned to the user program.

The RTD module is isolated from the chassis backplane and chassis ground. The isolation is limited to 500V ac. Optocouplers are used to communicate across the isolation barrier. Channel-to-channel common-mode isolation is limited to ± 5 volts.

LED Status

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The illustration below shows the RTD module LED panel consisting of nine LEDs. The state of the LEDs (for example, off, on, or flashing) depends on the operational state of the module (see table on page 1-9).

Overview 1-9

Figure 1.4 LED Indicators

INPUT

RTD Module

CHANNEL ST ATUS

MODULE

RTD / resistance

0 4 1 2 3

5 6 7

The purpose of the LEDs is as follows:

• Channel Status - One LED for each of the 8 input channels indicates if the

channel is enabled, disabled, or is not operating as configured, due to an error.

• Module Status - If OFF or flashing at any time, other than at powerup, this

LED indicates that non-recoverable module errors (for example, diagnostic or operating errors) have occurred. The LED is ON if there are no module errors.

The status of each LED, during each of the operational states (for example, powerup, module operation and error), is depicted in the following table.

LED

Power-up

Ch 0 to 7 Status On On/Off

Mod. Status Off On Flashes/Off On

(1) Module is disabled during powerup. (2) Channel status LED is On if the respective channel is enabled and Off if the channel is disabled. (3) Error if channel is enabled.

(1)

Module Operation (No Error)

(2)

(3)

Off

Error

Flashes

Module Error Channel

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1-10 Overview

Module to Processor Communication

As shown in the following illustration, the RTD module communicates with the SLC processor through the backplane of the chassis. The RTD module transfers data to/receives data from the processor by means of an image table. The image table consists of eight input words and eight output words when configured for Class 1 operation; 16 input words and 24 output words when configured for Class 3 operation. Data transmitted from the module to the processor is called the input image (for example, Channel Data Words and Channel Status Words). Conversely, data transmitted from the processor to the module is called the output image (for example, Channel Configuration Words and Scaling Limit Words). Details about the input and output images are found in “Module Addressing” on page 3-2.

Figure 1.5 Communication Flow

Channel Data Words

RTD/Resistance Analog Signals

1746-NR8

Input

Module

Channel Status Words

Scaling Limit Words

SLC 500

Processor

Channel Configuration Words

Chassis Backplane

The Channel Configuration Words (output image) contain user-defined configuration information for the specified input channel. This information is used by the module to configure and operate each channel. The Channel Status Words (input image) contain status information about the channel’s current configuration and operational state. The input data values of the analog input channel are contained in the Channel Data Word (input image), which is valid only when the channel is enabled and there are no channel errors (for example, broken sensor or overrange.)

The user-set Scaling Limit Words (output image) provide a user-definable scaling range for the temperature resistance data when using the proportional counts data type.

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Chapter

Installation and Wiring

This chapter tells you how to:

• comply to European union directives

• avoid electrostatic damage

• determine the RTD module’s chassis power requirement

• choose a location for the RTD module in the SLC chassis

• install the RTD module

• wire the RTD module’s terminal block

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

Compliance to Europe Union Directives

EMC Directive

This product 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.

1 Publication 1746-UM003A-EN-P

2-2 Installation and Wiring

Safety Considerations

Electrostatic Damage

Electrostatic discharge can damage semiconductor devices inside this module if you touch backplane connector pins or other sensitive areas. Guard against electrostatic damage by observing the precautions listed next.

ATTENTION

!!!!

Electrostatic discharge can degrade performance or cause permanent damage. Handle the module as stated below.

• Wear an approved wrist strap grounding device when

handling the module.

• Touch a grounded object to rid yourself of electrostatic

charge before handling the module.

• Handle the module from the front, away from the

backplane connector. Do not touch backplane connector pins.

• Keep the module in its static-shield bag when not in use, or

during shipment.

Hazardous Location Considerations

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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.

• Do not connect or disconnect components unless power

has been switched off.

• All wiring must comply with N.E.C. article 501-4(b).

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Installation and Wiring 2-3

Power Requirements

The RTD module receives its power through the SLC500 chassis backplane from the fixed or modular +5V dc/+24V dc chassis power supply. The maximum current drawn by the module is shown in the table below.

5V dc 24V dc

0.100A 0.055A

When you are using a modular system configuration, add the values shown in the table above to the requirements of all other modules in the SLC chassis to prevent overloading the chassis power supply.

When you are using a fixed system controller, refer to the Important note about module compatibility in a 2-slot expansion chassis on page 2-4.

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2-4 Installation and Wiring

Module Location in Chassis

Fixed Controller Compatibility Table

NR8 5V dc 24V dc

IA4 • 0.035 IA8 • 0.050 IA16 • 0.085 IM4 • 0.035 IM8 • 0.050 IM16 • 0.085 OA8 • 0.185 OA16 0.370 OAP12 0.370 IB8 • 0.050 IB16 • 0.085 IB32 • 0.050 ITB16 • 0.085 IV8 • 0.050 IV16 • 0.085 IV32 • 0.085 ITV16 • 0.085 IC16 • 0.085 IG16 • 0.140 IH16 • 0.085 OB8 • 0.135 OB16 • 0.280 OB32 Series D or later • 0.190 OB16E • 0.135 OBP8 • 0.135 OBP16 • 0.250 OG16 • 0.180 OVP16 • 0.250 OV8 • 0.135 OV16 • 0.270 OV32 Series D or later • 0.190 IN16 • 0.085 OW4 • 0.045 0.045 OW8 • 0.085 0.090 OW16 0.170 0.180 OX8 • 0.085 0.090 IO4 • 0.030 0.025 IO8 • 0.060 0.045 IO12 • 0.090 0.070 NI4 • 0.025 0.085 NI8 0.200 0.100 NI16I • 0.125 0.075 NI16V • 0.125 0.075 NIO4I 0.055 0.145 NIO4V • 0.055 0.115 FIO4I • 0.055 0.150 FIO4V • 0.055 0.120 NO4I 0.055 0.195 NO4V 0.055 0.195 NT4 • 0.060 0.040 NT8 • 0.120 0.070 INT4 • 0.110 0.085 NR4 • 0.050 0.050 HSCE • 0.320 HSCE2 • 0.250 BAS • 0.150 0.040 BASn • 0.150 0.125 KE • 0.150 0.040 KEn • 0.150 0.145 HS • 0.300 HSTP1 • 0.200 -

Modular Chassis Considerations

Place your RTD module in any slot of an SLC 500 modular chassis (except slot

0) or a modular expansion chassis. Slot 0 is reserved for the modular processor or adapter modules.

Fixed Expansion Chassis Considerations

IMPORTANT

The 2-slot, SLC 500 fixed I/O expansion chassis (1746-A2) supports only specific combinations of modules. If you are using the RTD module in a 2-slot expansion chassis with another SLC I/O or communication module, refer to the table at the left to determine whether the combination can be supported.

When using the table, be aware that there are certain conditions that affect the compatibility characteristics of the BASIC module (BAS) and the DH-485/RS-232C module (KE). When you use the BAS module or the KE module to supply power to a 1747-AIC Link Coupler, the link coupler draws its power through the module. The higher current drawn by the AIC at 24V dc is calculated and recorded in the table for the modules identified as BASn (BAS networked) or KEn (KE networked). Make sure to refer to these modules if your application uses the BAS or KE module in this way.

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Installation and Wiring 2-5

General Considerations

Most applications require installation in an industrial enclosure to reduce the effects of electrical interference. RTD inputs are susceptible to electrical noises due to the small amplitudes of their signal.

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

• away from power lines, load lines and other sources of electrical noise such

as hard-contact switches, relays, and AC motor drives

• away from modules which generate significant radiated heat, such as the

32-point I/O modules

Module Installation and Removal

When installing the module in a chassis, it is not necessary to remove the terminal block from the module. However, if the terminal block is removed, use the write-on label located on the side of the terminal block, as shown below, to identify the module location and type.

SLOT

____

MODULE

RACK

____

_______________

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2-6 Installation and Wiring

Removing the Terminal Block

ATTENTION

Never install, remove, or wire modules with power applied to the chassis or devices wired to the module. To avoid cracking the removable terminal block, alternate the removal of the slotted terminal block release screws.

!!!!

1. Loosen the two terminal block release screws.

1.1.

Ter m inal B l ock Release Screw (Requires a 0.100 in slot screwdriver.)

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Maximum Torque = 0.25 Nm (2.25 in-lbs)

2. Grasp the terminal block at the top and bottom and pull outward and

2.2. down.

Installation and Wiring 2-7

Installing the Module

1. Align the circuit board of the RTD module with the card guides located at

1.1. the top and bottom of the chassis, as shown in the following illustration.

Top and Bottom Module Releases

Card Guide

2. Slide the module into the chassis until both top and bottom retaining clips

2.2. are secured. Apply firm even pressure on the module to attach it to its backplane connector. Never force the module into the slot.

3. Cover all unused slots with the Card Slot Filler, Catalog Number 1746-N2.

3.3.

Removing the Module

1. Press the releases at the top and bottom of the module and slide the module

1.1. out of the chassis slot.

2. Cover all unused slots with the Card Slot Filler, Catalog Number 1746-N2.

2.2.

The RTD module contains an 24-position, removable terminal block. The terminal pin-out is shown in the illustration on page 2-8.

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2-8 Installation and Wiring

Terminal Wiring

ATTENTION

Disconnect power to the SLC before attempting to install, remove, or wire the removable terminal wiring block. To avoid cracking the removable terminal block, alternate the removal of the terminal block release screws.

!!!!

Figure 2.1 Terminal Block

(Terminal Block Spare Part Number 1746-RT35)

RTD 0 Sense 0 Return 0 RTD 1 Sense 1 Return 1 RTD 2 Sense 2 Return 2 RTD 3 Sense 3 Return 3 RTD 4 Sense 4 Return 4 RTD 5 Sense 5 Return 5 RTD 6 Sense 6 Return 6 RTD 7 Sense 7 Return 7

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Release Screw Maximum Torque = 0.25 Nm (2.25 lbs-in)

Wiring Considerations

Follow the guidelines below when planning your system wiring.

Since the operating principle of the RTD module is based on the measurement of resistance, take special care in selecting your input cable. For 2-wire or 3-wire configuration, select a cable that has a consistent impedance throughout its entire length.

Configuration Recommended Cable

2-wire Belden™ #9501 or equivalent 3-wire

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

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

Belden #9533 or equivalent

Belden #83503 or equivalent

Installation and Wiring 2-9

For a 3-wire configuration, the module can compensate for a maximum cable length associated with an overall cable impedance of 25 ohms.

IMPORTANT

Details of cable specifications are shown on page A-5.

Three configurations of RTDs can be connected to the RTD module, namely:

• 2-wire RTD, which is composed of 2 RTD lead wires (RTD and Return)

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

Return)

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

and Return). The second sense wire of a 4-wire RTD is left open. It does not matter which sense wire is left open.

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 2-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). Also, use cable that has a lower resistance per foot of wire. The module’s terminal block accepts one AWG #14 gauge wire.

(  $ $ )

•

To limit overall cable impedance, keep input cables as short as possible. Locate your I/O chassis as near the RTD sensors as your application permits.

• Ground the shield drain wire at one end only. The preferred location is at

the chassis mounting tab of the rack, under the RTD module. Refer to IEEE Std. 518, Section 6.4.2.7 or contact your sensor manufacturer for additional details.

• Route RTD/resistance input wiring away from any high-voltage I/O wiring,

power lines, and load lines.

• Tighten terminal screws using a flat-head screwdriver. Each screw should be

turned tight enough to immobilize the wire’s end. Excessive tightening can strip the terminal screw. The torque applied to each screw should not exceed

0.25 Nm (2.25 in-lbs) for each terminal.

• Follow system grounding and wiring guidelines found in your SLC 500

Installation and Operation Manual, publication 1747-6.2.

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2-10 Installation and Wiring

Figure 2.2 RTD Connections to Terminal Block

2-Wire Interconnection

RTD

Return

Belden #9501 Shielded Cable

3-Wire Interconnection

RTD

Sense

Return

Belden #9533 Shielded Cable or Belden #83503 Shielded Cable

4-Wire Interconnection

RTD

Sense

Return

Leave One Sensor Wire Open

Belden #9533 Shielded Cable or Belden #83503 Shielded Cable

Cable Shield (Frame Ground)

Add jumper

RTD 0 Sense 0 Return 0 RTD 1 Sense 1 Return 1 RTD 2 Sense 2 Return2

RTD 0 Sense 0 Return 0 RTD 1 Sense 1 Return 1 RTD 2 Sense 2 Return2 RTD 3 Sense 3 Return 3 RTD 4 Sense 4 Return 4 RTD 5 Sense 5 Return 5 RTD 6 Sense 6 Return 6 RTD 7 Sense 7 Return 7

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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.

+ 88 hidden pages