Rockwell Automation 1769-OF4VI User Manual

0 (0)
Rockwell Automation 1769-OF4VI User Manual

User Manual

Compact I/O Isolated Analog Modules

Catalog Numbers 1769-IF4I, 1769-OF4CI, 1769-OF4VI

Important User Information

Solid-state equipment has operational characteristics differing from those of electromechanical equipment. Safety Guidelines for the Application, Installation and Maintenance of Solid State Controls (publication SGI-1.1 available from your local Rockwell Automation sales office or online at http://www.rockwellautomation.com/literature/) describes some important differences between solid-state equipment and hard-wired electromechanical devices. Because of this difference, and also because of the wide variety of uses for solid-state equipment, all persons responsible for applying this equipment must satisfy themselves that each intended application of this equipment is acceptable.

In no event will Rockwell Automation, Inc. be responsible or liable for indirect or consequential damages resulting from the use or application of this equipment.

The examples and diagrams in this manual are included solely for illustrative purposes. Because of the many variables and requirements associated with any particular installation, Rockwell Automation, Inc. cannot assume responsibility or liability for actual use based on the examples and diagrams.

No patent liability is assumed by Rockwell Automation, Inc. with respect to use of information, circuits, equipment, or software described in this manual.

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

Throughout this manual, when necessary, we use notes to make you aware of safety considerations.

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. Attentions help you identify a hazard, avoid a hazard, and recognize the consequence

SHOCK HAZARD: Labels may be on or inside the equipment, for example, a drive or motor, to alert people that dangerous voltage may be present.

BURN HAZARD: Labels may be on or inside the equipment, for example, a drive or motor, to alert people that surfaces may reach dangerous temperatures.

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

Allen-Bradley, Rockwell Software, Rockwell Automation, and TechConnect are trademarks of Rockwell Automation, Inc.

Trademarks not belonging to Rockwell Automation are property of their respective companies.

 

Table of Contents

 

Preface

 

 

Who Should Use This Manual. . . . . . . . . . . . . . . . . . . . . . . . . .

Preface-1

 

How to Use This Manual. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Preface-1

 

Manual Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Preface-1

 

Related Documentation. . . . . . . . . . . . . . . . . . . . . . . . . . . .

Preface-2

 

Conventions Used in This Manual . . . . . . . . . . . . . . . . . . . . . .

Preface-2

 

Chapter 1

 

Overview

How to Use Analog I/O Data . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . 1-1

 

General Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . 1-2

 

Hardware Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . 1-2

 

General Diagnostic Features . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . 1-4

 

System Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . 1-4

 

System Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . 1-5

 

Module Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . 1-6

 

Module Field Calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . 1-8

 

Chapter 2

 

Installation and Wiring

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

 

Reduce Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . 2-4

 

Protect the Circuit Board from Contamination . . . . . . . . . .

. . . . 2-4

 

System Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . 2-5

 

Mount . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . 2-6

 

Minimum Spacing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . 2-6

 

Panel Mount. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . 2-7

 

DIN-rail Mount . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . 2-8

 

Replace a Single Module Within a System . . . . . . . . . . . . . . . . .

. . . . 2-8

 

Field Wiring Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . 2-9

 

Ground. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . 2-9

 

System Wiring Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . 2-10

 

Label the Terminals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . 2-14

 

Remove the Finger-safe Terminal Block . . . . . . . . . . . . . . .

. . . 2-15

 

Wire the Finger-safe Terminal Block . . . . . . . . . . . . . . . . . .

. . . 2-15

 

Wire the Modules. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . 2-16

 

Analog Input Module Wiring . . . . . . . . . . . . . . . . . . . . . . . .

. . . 2-18

 

Analog Output Modules Wiring . . . . . . . . . . . . . . . . . . . . . .

. . . 2-20

Publication 1769-UM014B-EN-P - May 2010

ii Table of Contents

Chapter 3

Module Data, Status, and Channel

1769-IF4I Input Module Addressing . . . . . . . . . . . . . . . . . . . . . . . .

. 3-1

Configuration for the Input Module

1769-IF4I Input Image . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3-2

 

1769-IF4I Output Image . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3-2

 

1769-IF4I Configuration File . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3-2

 

1769-IF4I Input Data File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3-3

 

1769-IF4I Input Data Values . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3-3

 

1769-IF4I Output Data File . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3-5

 

1769-IF4I Configuration Data File . . . . . . . . . . . . . . . . . . . . . . . . . . .

3-6

 

Channel Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3-7

 

Enable/Disable Channel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3-8

 

Input Filter Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3-8

 

Input Type/Range Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3-9

 

Input Data Selection Formats . . . . . . . . . . . . . . . . . . . . . . . . . . .

3-10

 

1769-IF4I Real Time Sampling . . . . . . . . . . . . . . . . . . . . . . . . . .

3-11

 

1769-IF4I Time Stamping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3-12

 

1769-IF4I Process Alarms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3-13

 

Chapter 4

 

Module Data, Status, and Channel

1769-OF4CI Output Module Memory Map. . . . . . . . . . . . . . . . . . . .

4-1

Configuration for the Output

1769-OF4VI Output Module Memory Map. . . . . . . . . . . . . . . . . . . .

4-2

Modules

1769-OF4CI and -OF4VI Output Data File . . . . . . . . . . . . . . . . . . .

4-3

 

Channel Alarm Unlatch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4-3

 

1769-OF4CI and -OF4VI Input Data File . . . . . . . . . . . . . . . . . . . . .

4-4

 

1769-OF4CI and -OF4VI Data Values . . . . . . . . . . . . . . . . . . . .

4-4

 

1769-OF4CI and -OF4VI Output Data Loopback/Echo . . . . .

4-6

 

1769-OF4CI and -OF4VI Configuration Data File . . . . . . . . . . . . . .

4-7

 

1769-OF4CI and -OF4VI Channel Configuration . . . . . . . . . . .

4-8

 

1769-OF4CI and -OF4VI Enable/Disable Channel . . . . . . . . . .

4-9

 

Clamping/Limiting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4-10

 

Clamp/Limit Alarms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4-10

 

Ramping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4-11

 

Hold for Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4-13

 

1769-OF4CI and -OF4VI Fault Mode (FM) . . . . . . . . . . . . . . .

4-13

 

1769-OF4CI and -OF4VI Program/Idle Mode (PM) . . . . . . . .

4-14

 

1769-OF4CI and -OF4VI Program/Idle to Fault Enable (PFE) . . .

 

4-14

 

 

1769-OF4CI and -OF4VI Fault Value . . . . . . . . . . . . . . . . . . . .

4-15

 

1769-OF4CI and -OF4VI Program/Idle Value. . . . . . . . . . . . .

4-16

Publication 1769-UM014B-EN-P - May 2010

Table of Contents

iii

 

 

Module Diagnostics and

Troubleshooting

Specifications

Module Addressing and Configuration with MicroLogix 1500

Configuration Using the RSLogix 5000 Generic Profile for CompactLogix Controllers

Chapter 5

Safety Considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1 Indicator Lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1 Activate Devices When Troubleshooting. . . . . . . . . . . . . . . . . . . 5-1 Stand Clear of the Machine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2 Program Alteration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2 Safety Circuits. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2

Module Operation versus Channel Operation . . . . . . . . . . . . . . . . . . 5-2 Power Cycle Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3 Channel Diagnostics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3 Out-of-range Detection (Input and Output Modules) . . . . . . . . 5-3 Open-circuit Detection (1769-IF4I Module Only) . . . . . . . . . . . 5-4 Non-critical vs. Critical Module Errors. . . . . . . . . . . . . . . . . . . . . . . . 5-4 Module Error Definition Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4 Module Error Field . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5 Extended Error Information Field . . . . . . . . . . . . . . . . . . . . . . . . 5-5 Error Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6 Module Inhibit Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-9 Contacting Rockwell Automation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-9

Appendix A

General Specifications for 1769-IF4I, -OF4CI, and -OF4VI Modules. . A-1

1769-IF4I Input Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-3 1769-OF4CI Output Specifications . . . . . . . . . . . . . . . . . . . . . . . . . A-5 1769-OF4VI Output Specifications . . . . . . . . . . . . . . . . . . . . . . . . . A-7

Appendix B

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

Input Module’s Input Image . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-2

Input Module’s Configuration File . . . . . . . . . . . . . . . . . . . . . . . . B-3

Configure Analog I/O Modules in a MicroLogix 1500 System. . . . . B-4

Appendix C

Configure I/O Modules. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-6

Configure Analog Output Modules . . . . . . . . . . . . . . . . . . . . . . . C-7

Configure Analog Input Modules . . . . . . . . . . . . . . . . . . . . . . . . . C-7

Publication 1769-UM014B-EN-P - May 2010

iv Table of Contents

Configure Modules in a Remote DeviceNet System with a 1769-ADN DeviceNet Adapter

Two’s Complement Binary

Numbers

Index

Appendix D

Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D-1 Add the DeviceNet Adapter to the Scanlist . . . . . . . . . . . . . . . . . . . D-2 Configure the 1769-IF4I Input Module Example . . . . . . . . . . . . . . D-4 1769-IF4I External Power Example. . . . . . . . . . . . . . . . . . . . . . D-8 Configure the 1769-OF4CI Output Module Example. . . . . . . . . . . D-9 1769-OF4CI External Power Example . . . . . . . . . . . . . . . . . . D-10 1769-OF4CI Output Channels Example . . . . . . . . . . . . . . . . . D-11

Appendix E

Positive Decimal Values. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-1

Negative Decimal Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-2

Glossary

Publication 1769-UM014B-EN-P - May 2010

Preface

Who Should Use This

Manual

How to Use This Manual

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

Use this manual if you are responsible for designing, installing, programming, or troubleshooting control systems that use the Allen-Bradley Compact I/O system.

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 1769 isolated analog I/O modules.

Manual Contents

For

See

 

 

An overview of the analog input and output modules

Chapter 1

 

 

Installation and wiring guidelines

Chapter 2

 

 

Input module addressing, configuration, and status information

Chapter 3

 

 

Output module addressing, configuration, and status information

Chapter 4

 

 

Information on module diagnostics and troubleshooting

Chapter 5

 

 

Specifications for the input and output modules

Appendix A

 

 

Information on addressing and configuration using MicroLogix 1500 and

Appendix B

RSLogix 500 software

 

 

 

Information on configuring the module using CompactLogix and RSLogix

Appendix C

5000 software

 

 

 

Information on configuring the module using the 1769-ADN DeviceNet

Appendix D

adapter and RSNetWorx software

 

 

 

Information on understanding two’s complement binary numbers

Appendix E

 

 

Definitions of terms used in this manual

Glossary

 

 

Publication 1769-UM014B-EN-P - May 2010

2 Preface

Related Documentation

The table below provides a listing of publications that contain important information about MicroLogix 1500 systems.

For

Read this document

Document number

 

 

 

A user manual containing information on how to install,

MicroLogix 1500 User Manual

1764-UM001

use and program your MicroLogix 1500 controller.

 

 

 

 

 

A user manual containing information on how to install,

DeviceNet Adapter User Manual

1769-UM001

and use your 1769-ADN DeviceNet adapter.

 

 

 

 

 

A user manual containing information on how to install,

CompactLogix User Manual

1769-UM007

use and program your 1769-L20 and -L30 CompactLogix

 

 

controllers.

 

 

 

 

 

A user manual containing information on how to install,

CompactLogix System User Manual

1769-UM011

use and program your 1769-L31, -L32C, -L32E, -L35CR

 

 

and -L35E CompactLogix controllers.

 

 

 

 

 

An overview of 1769 Compact I/O modules.

Compact I/O Selection Guide

1769-SG002

 

 

 

An overview of the MicroLogix 1500 System, including

MicroLogix 1500 System Overview

1764-SO001

the 1769 Compact I/O system.

 

 

 

 

 

In-depth information on grounding and wiring

Allen-Bradley Programmable Controller Grounding and

1770-4.1

Allen-Bradley programmable controllers.

Wiring Guidelines

 

 

 

 

Conventions Used in This

Manual

If you would like a manual, you can:

download a free electronic version from the internet at www.literature.rockwellautomation.com.

purchase a printed manual by contacting your local distributor or Rockwell Automation representative.

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.

Bold type is used for emphasis.

Publication 1769-UM014B-EN-P - May 2010

Chapter 1

Overview

 

This chapter explains how analog data is used, describes the 1769-IF4I isolated

 

analog input module, and describes the 1769-OF4CI and 1769-OF4VI isolated

 

analog output modules. Included is information about:

 

 

 

the use of analog I/O.

 

 

 

the modules’ hardware and diagnostic features.

 

 

 

an overview of the 1769 analog input system operation.

 

 

 

an overview of the 1769 analog output system operation.

 

How to Use Analog I/O Data

Analog refers to the representation of numerical quantities by the

 

measurement of continuous physical variables. Analog applications are present

 

in many forms. The following application shows a typical use of analog data.

 

In this application, the controller controls the amount of fluid in a holding

 

tank by adjusting the valve opening. The valve is initially open 100%. As the

 

fluid level in the tank approaches the preset point, the controller modifies the

 

output to close the valve 90%, 80%, and so on, continuously adjusting the

 

valve to maintain the fluid level.

 

 

Figure 1.1 Analog I/O Application Example

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Analog Output

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Wired to Valve

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Valve

 

 

 

 

 

 

Analog I/O

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Controller

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Level Sensor

 

 

 

 

 

 

Module

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Analog Input Wired

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

to Tank

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Publication 1769-UM014B-EN-P - May 2010

1-2 Overview

General Description

The 1769-IF4I isolated analog input module converts and digitally stores analog data for retrieval by controllers, such as the CompactLogix controller or the MicroLogix 1500 controller. The module supports connections from any combination of as many as four voltage or current analog sensors. The 1769-IF4I input module provides four, isolated-differential analog input channels.

The 1769-OF4CI and -OF4VI isolated output modules each provide four, isolated differential analog output channels.

The modules provide the following input/output types/ranges:

Table 1.1 Normal and Full Ranges

Normal Operating Input Range

Full Module Range

 

 

±10V dc

± 10.5V dc

 

 

1…5V dc

0.5…5.25V dc

 

 

0…5V dc

-0.5…+5.25V dc

 

 

0…10V dc

-0.5…+10.5V dc

 

 

0…20 mA

0…21 mA

 

 

4…20 mA

3.2…21 mA

 

 

The data can be configured on board each module as:

engineering Units.

scaled-for-PID.

percent.

raw/proportional data.

Hardware Features

The modules contain removable terminal blocks. The modules’ channels are isolated from each other and are normally wired as differential inputs or outputs. Single-ended applications can be supported by wiring the negative terminal of each channel to the other channel’s negative terminals; however, this eliminates the channel-to-channel isolation provided by the modules.

Module configuration is normally done via the controller’s programming software. In addition, some controllers support configuration via the user program. In either case, the module configuration is stored in the memory of the controller. Refer to your controller’s user manual for more information.

Publication 1769-UM014B-EN-P - May 2010

Overview 1-3

Figure 1.2 Isolated Analog Modules’ Hardware Features

1

 

 

2a

 

 

OK

 

3

 

 

Analog

 

 

 

 

 

 

DANGER

 

 

 

 

Do Not Remove RTB Under Power

 

10a

 

 

Unless Area is Non-Hazardous

 

 

 

N/C

 

 

 

 

Ch0+

 

 

 

 

Ch0_iRtn

 

 

 

 

N/C

 

 

 

 

Ch0-

 

 

 

 

Ch1+

 

 

 

 

N/C

 

 

 

 

Ch1_iRtn

 

10

 

 

Ch2+

 

 

 

Ch1-

 

 

 

Ch2_iRtn

 

 

 

 

N/C

 

 

 

 

Ch2-

 

 

 

 

Ch3+

 

10b

 

 

N/C

 

 

 

Ch3_iRtn

 

 

 

Ch3-

 

 

 

 

N/C

 

 

 

 

Ensure Adjacent

 

 

 

Bus Lever is Unlatched/Latched

4

 

 

 

Before/After

 

 

 

Removing/Inserting Module

 

 

 

 

1769-IF4I

 

8a

 

 

 

 

7a

 

7a

2b

 

 

 

 

5a

9

OK

Analog

5b

6

 

 

 

 

 

 

 

 

7b

 

 

 

 

 

 

 

 

 

7b

 

 

 

 

 

 

 

 

 

 

 

8b

Table 1.2 Isolated Modules’ Feature Descriptions

 

 

 

 

 

 

 

 

 

Item

Description

 

 

 

 

 

 

 

 

 

1

Bus lever (with locking function)

 

 

 

 

 

 

 

 

 

2a

Upper-panel mounting tab

 

 

 

 

 

 

 

 

 

2b

Lower-panel mounting tab

 

 

 

 

 

 

 

 

 

3

Module status LEDs

 

 

 

 

 

 

 

 

 

4

Module door with terminal identification label

 

 

 

 

 

 

 

 

 

5a

Movable bus connector with female pins

 

 

 

 

 

 

 

 

 

5b

Stationary bus connector with male pins

 

 

 

 

 

 

 

 

 

6

Nameplate label

 

 

 

 

 

 

 

 

 

7a

Upper tongue-and-groove slots

 

 

 

 

 

 

 

 

 

7b

Lower tongue-and-groove slots

 

 

 

 

 

 

 

 

 

8a

Upper DIN-rail latch

 

 

 

 

 

 

 

 

 

8b

Lower DIN-rail latch

 

 

 

 

 

 

 

 

 

9

Write-on label for user identification tags

 

 

 

 

 

 

 

 

 

10

Removable terminal block (RTB) with finger-safe cover

 

 

 

 

 

 

 

 

 

10a

RTB upper retaining screw

 

 

 

 

 

 

 

 

 

10b

RTB lower retaining screw

 

 

 

 

 

 

 

 

 

Publication 1769-UM014B-EN-P - May 2010

1-4 Overview

General Diagnostic Features

System Overview

The analog modules contain diagnostic features that can help you identify the source of problems that may occur when cycling power or during normal channel operation.

These power cycle and channel diagnostics are explained in chapter 5.

The modules communicate to the controller through the bus interface. The modules also receive 5 and 24V dc power through the bus interface.

You can install as many analog modules as your power supply can support. However, the modules may not be located more than eight modules away from the system power supply.

Figure 1.3 Determine Power Supply Distance

CompactLogix Controller or I/O Communication Adapter

Compact I/O

Compact I/O

Compact I/O

System Power Supply

Compact I/O

Compact I/O

Compact I/O

End Cap

 

4

3

2

1

 

1

2

3 Power Supply Distance

or

MicroLogix 1500 Controller

CompactI/O

CompactI/O

CompactI/O

CompactI/O

CapEnd

 

 

 

 

 

with Integrated System

 

 

 

 

 

Power Supply

 

 

 

 

 

 

 

 

 

 

 

1 2 3 4 Power Supply Distance

Publication 1769-UM014B-EN-P - May 2010

Overview 1-5

System Operation

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

After power-cycle 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, it begins the analog-to-digital or digital-to-analog conversion process.

Input Modules

Each time a channel is read by the input module, that analog data value is tested by the module for an over-range or under-range condition. If any of these conditions are detected, unique bits are set in the channel status word.

The channel status word is described in the 1769-IF4I Input Data File on page 3-3.

The controller reads the two’s complement binary converted analog data from the modules. This typically occurs at the end of the program scan or when commanded by the control program. If the controller and the modules determine that the bus data transfer was made without error, the data is used in your control program.

Output Modules

The output modules monitor channels for over-range and under-range conditions and can also clamp the outputs at designated levels (if enabled by the user program). If such conditions are detected, a unique bit is set in the channel status word.

The channel status word is described in the 1769-OF4CI and -OF4VI Output Data File on page 4-3.

The output modules receive two’s complement binary values from the bus master. 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 bus transfer was completed without error, the output module converts the data to an analog output signal.

Publication 1769-UM014B-EN-P - May 2010

1-6 Overview

Ch0+

Ch0_iRtn

Ch0-

Ch0+

Ch0_iRtn

Ch0-

Module Operation

The following sections describe the input and output modules’ block diagrams.

Input Module Block Diagram

The input module’s input circuitry consists of four isolated-differential analog inputs each with it’s own analog-to-digital (A/D) converter. The A/D converter reads the selected input signal and converts it to a digital value that is presented to the controller.

Figure 1.4 1769-IF4I Block Diagram

LED

High

 

 

 

 

OPTO

 

 

Impendence

ADC

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

OPTO

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

DC / DC

 

 

 

 

 

 

 

Converter

 

 

 

 

 

 

 

 

 

 

CPU

 

ASIC

 

BUS

 

 

 

 

 

 

 

 

 

High

 

 

 

 

OPTO

 

 

Impendence

ADC

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

OPTO

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

DC / DC

 

 

 

 

 

 

 

Converter

 

 

 

 

 

 

 

 

 

 

 

Publication 1769-UM014B-EN-P - May 2010

Overview 1-7

Output Modules Block Diagram

The output modules use one digital-to-analog (D/A) converter per isolated output channel to convert the digital output data from the controller to an analog output signal.

Figure 1.5 1769-OF4CI Block Diagram

LED

OPTO

 

 

 

 

_

 

 

 

 

 

 

DAC

 

+

 

 

 

 

 

 

OPTO

 

 

 

 

 

 

 

 

 

 

 

 

Iout0+

Iout0-

DC / DC

Converter

0

0

BUS

 

ASIC

 

CPU

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

_

 

 

 

 

 

 

 

 

 

 

 

 

 

OPTO

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

DAC

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

+

 

 

 

 

 

 

 

 

 

 

 

 

 

OPTO

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Iout3+

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Iout3-

 

 

DC / DC

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Converter

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Publication 1769-UM014B-EN-P - May 2010

1-8 Overview

Figure 1.6 1769-OF4VI Block Diagram

LED

 

 

OPTO

 

 

 

 

 

 

 

+

 

 

 

 

 

 

 

 

 

 

 

 

 

 

DAC

_

 

 

 

 

 

Vout0+

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

OPTO

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Vout0-

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0

 

 

DC / DC

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Converter

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0

 

 

 

 

 

 

 

 

 

 

 

 

BUS

 

ASIC

 

CPU

 

 

 

 

 

 

 

 

 

 

 

OPTO

 

 

 

 

 

 

 

+

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

DAC

_

 

 

 

 

 

Vout3+

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

OPTO

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Vout3-

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3

 

 

 

DC / DC

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Converter

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3

 

 

 

 

 

 

 

 

 

 

 

 

Module Field Calibration

Each isolated analog modules’s calibration is guaranteed by its design. No field calibration is required.

Publication 1769-UM014B-EN-P - May 2010

Chapter 2

Installation and Wiring

Compliance to European Union Directives

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.

wire output devices.

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 analog modules are tested to meet Council Directive 2004/108/EC Electromagnetic Compatibility (EMC) and the following standards, in whole or in part, documented in a technical construction file:

EN 61000-6-4

EMC – Generic Emission Standard, 6-4 - Industrial Environment

EN 61000-6-2

EMC – Generic Immunity Standard, Part 6-2 - Industrial Environment

This product is intended for use in an industrial environment.

Low Voltage Directive

This product is tested to meet Council Directive 2006/95/ECLow Voltage, by applying the safety requirements of EN 61131-2 Programmable Controllers, Part 2 – Equipment Requirements and Tests.

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

Publication 1769-UM014B-EN-P - May 2010

2-2 Installation and Wiring

Power Requirements

General Considerations

Industrial Automation, Wiring and Grounding Guidelines for Noise Immunity, publication 1770-4.1

Automation Systems Catalog, publication B113

The modules receive power through the bus interface from the +5V dc/+24V dc system power supply.

Table 2.1 Maximum Current Draw

Module

5V dc

24V dc

 

 

 

1769-IF4I (Series A)

145 mA

125 mA

 

 

 

1769-OF4CI (Series A)

145 mA

140 mA

 

 

 

1769-OF4VI (Series A)

145 mA

75 mA

 

 

 

The Compact I/O system 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 degree

2(1)) and to circuits not exceeding Over Voltage Category II(2) (IEC 60664-1).(3)

(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.

Publication 1769-UM014B-EN-P - May 2010

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 attention statement applies to use in hazardous locations.

 

 

 

EXPLOSION HAZARD

ATTENTION

 

 

 

 

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

 

 

 

Electrostatic discharge can damage integrated circuits or

ATTENTION

semiconductors if you touch analog 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.

Use a static-safe work station, if available.

When it is not in use, keep the module in its static-shield box.

Publication 1769-UM014B-EN-P - May 2010

2-4 Installation and Wiring

Remove Power

 

 

 

Remove power before removing or inserting this module.

ATTENTION

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.

Reduce Noise

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

Group your modules to minimize adverse effects from radiated electrical noise and heat. Consider the following conditions when selecting a location for the analog 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, such as the 1769-IA16 module. Refer to the module’s heat dissipation specification.

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

Protect the Circuit Board from Contamination

System Assembly

The printed circuit boards of the analog modules must be protected from dirt, oil, moisture, and other airborne contaminants. To protect these boards, the system must be installed in an enclosure suitable for the environment. The interior of the enclosure should be kept clean and the enclosure door should be kept closed whenever possible.

The module can be attached to the controller or an adjacent I/O module before or after mounting.

Publication 1769-UM014B-EN-P - May 2010

Installation and Wiring

2-5

 

 

For mounting instructions, see Panel Mounting Using the Dimensional Template on page 2-7, or DIN-rail Mount on page 2-8. To work with a system that is already mounted, see Replace a Single Module Within a System on page 2-8.

Figure 2.1 Assemble the Compact I/O System

3

4

2 1

6 1

5

1.Disconnect power.

2.Check that the bus lever of the module to be installed is in the unlocked (fully right) position.

3.Use the upper and lower tongue-and-groove slots (1) to secure the modules together (or to a controller).

4.Move the module back along the tongue-and-groove slots until the bus connectors (2) line up with each other.

5.Push the bus lever back slightly to clear the positioning tab (3). Use your fingers or a small screwdriver.

Publication 1769-UM014B-EN-P - May 2010

2-6 Installation and Wiring

6.To allow communication between the controller and module, move the bus lever fully to the left (4) until it clicks. Ensure it is locked firmly in place.

 

 

 

When attaching I/O modules, it is very important

ATTENTION

that the bus connectors are securely locked together

 

 

 

 

 

 

 

 

 

to be sure of proper electrical connection.

 

 

 

 

 

 

 

 

 

 

 

 

7.Attach an end cap terminator (5) to the last module in the system by using the tongue-and-groove slots as before.

8.Lock the end cap bus terminator (6).

 

A 1769-ECR or 1769-ECL right or left end cap must be

IMPORTANT

used to terminate the end of the bus.

 

 

 

 

Mount

ATTENTION

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

Minimum Spacing

Maintain spacing from enclosure walls, wireways, or adjacent equipment. Allow 50 mm (2 in.) of space on all sides for adequate ventilation.

Figure 2.2 Space Requirements

Side

Host Controller

 

Top

Compact I/O

 

Compact I/O

Compact I/O

Compact I/O

Compact I/O

End Cap

 

 

 

 

 

 

 

 

 

 

Bottom

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Side

Publication 1769-UM014B-EN-P - May 2010

Installation and Wiring

2-7

 

 

Panel Mount

Mount the module to a panel using two screws per module. Use M4 or #8 panhead screws. Mounting screws are required on every module.

Figure 2.3 Panel Mounting Using the Dimensional Template

Spacing for single-wide modules 35 mm (1.378 in.).

Spacing for one-and-a-halfMounting-wide modules 52.5 mm (2.067 in.).

Refer to host controller documentation for this dimension.

Overall hole spacing tolerance: ±0.4 mm (0.016 in.).

Locate holes every 17.5 mm (0.689 in.) to allow for a mix of single-wide and one-and-a-half-wide modules (for example, the 1769-OA16 module).

Host Controller

Panel Mounting Procedure Using Modules as a Template

The following procedure allows you to use the assembled modules as a template for drilling holes in the panel. If you have sophisticated panel-mounting equipment, you can use the dimensional template provided. Due to module mounting hole tolerance, it is important to follow these procedures.

1.On a clean work surface, assemble no more than three modules.

2.Using the assembled modules as a template, carefully mark the center of all module-mounting holes on the panel.

3.Return the assembled modules to the clean work surface, including any previously mounted modules.

4.Drill and tap the mounting holes for the recommended M4 or #8 screw.

5.Place the modules back on the panel, and check for proper hole alignment.

6.Attach the modules to the panel using the mounting screws.

 

If mounting more modules, mount only the last one of this

TIP

group and put the others aside. This reduces remounting

 

 

 

time during drilling and tapping of the next group.

7. Repeat steps 1 to 6 for any remaining modules.

Publication 1769-UM014B-EN-P - May 2010

2-8 Installation and Wiring

Replace a Single Module

Within a System

DIN-rail Mount

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 latches. Press the DIN rail mounting area of the module against the DIN rail. The latches will momentarily open and lock into place.

The module can be replaced while the system is mounted to a panel (or DIN rail). Follow these steps in order:

1. Remove power.

 

 

 

Remove power before removing or inserting this module.

ATTENTION

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.

2.On the module to be removed, remove the upper and lower mounting screws from the module (or open the DIN latches using a flat-blade or Phillips screwdriver).

3.Move the bus lever to the right to disconnect (unlock) the bus.

4.On the right-side adjacent module, move its bus lever to the right (unlock) to disconnect it from the module to be removed.

5.Gently slide the disconnected module forward. If you feel excessive resistance, check that the module has been disconnected from the bus, and that both mounting screws have been removed (or DIN latches opened).

 

It may be necessary to rock the module slightly from front

TIP

to back to remove it, or, in a panel-mounted system, to

 

 

 

loosen the screws of adjacent modules.

Publication 1769-UM014B-EN-P - May 2010

Installation and Wiring

2-9

 

 

6.Before installing the replacement module, be sure that the bus lever on the module to be installed and on the right-side adjacent module are in the unlocked (fully right) position.

7.Slide the replacement module into the open slot.

8.Connect the modules together by locking (fully left) the bus levers on the replacement module and the right-side adjacent module.

9.Replace the mounting screws (or snap the module onto the DIN rail).

Field Wiring Connections

Use the following information to properly make field wiring connections.

Ground

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. Refer to Allen-Bradley Industrial Automation Wiring and Grounding Guidelines, publication 1770-4.1, for additional information.

Publication 1769-UM014B-EN-P - May 2010

2-10 Installation and Wiring

System Wiring Guidelines

Consider the following when wiring your system.

General Guidelines

Channels are isolated from each other.

Do not use the analog module’s NC terminals as connection points.

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.

Use Belden 8761, or equivalent, shielded wire.

Keep shield connection to ground as short as possible.

Under normal conditions, the drain wire and shield junction must be connected to earth ground via a panel or DIN rail mounting screw at the analog I/O module end.(1)

(1)In environments where high-frequency noise may be present, it may be necessary to directly ground cable shields to earth at the module end and via a 0.1µF capacitor at the sensor end.

Publication 1769-UM014B-EN-P - May 2010

Installation and Wiring

2-11

 

 

1769-IF4I Input Module Guidelines

If multiple power supplies are used with analog inputs, the power supply commons must be kept at potentials that do not result in the module’s working voltage rating being exceeded.

The 1769-IF4I module does not provide loop power for analog inputs. Use power supplies that match the input transmitter specifications.

Differential analog inputs are more immune to noise than single-ended analog inputs.

Voltages on Ch+, Ch-, and Ch_IRtn for a single, isolated channel of the 1769-IF4I module must not exceed the module’s maximum overload levels.

1769-IF4I channels used as current inputs require a jumper to be placed between a channel’s CH_IRtn and Chterminals.

1769-OF4CI and -OF4VI Output Modules Guidelines

Voltage outputs (Vout 0+ to Vout 3+ for 1769-OF4VI) of the output module are referenced to each channel’s Voutterminal (channels are isolated from each other). Load resistance for a voltage output channel must be equal to or greater than 2 k .

Current outputs (Iout 0+ to Iout 3+ for 1769-OF4CI) of the output module source current that returns to each channel’s Ioutterminal (channels are isolated from each other). Load resistance for a current output channel must remain between 0 and 500 .

Effect of Transducer/Sensor and Cable Length Impedance on Voltage Input

Accuracy

For voltage inputs, the length of the cable used between the transducer/sensor and the 1769-IF4I module can affect the accuracy of the data provided by the module.

Figure 2.4 Voltage Input Accuracy

 

 

Rs

 

Rc

+

 

 

 

 

 

 

 

 

 

Ri

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Vs

 

 

 

 

V in

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

-

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Rc

Publication 1769-UM014B-EN-P - May 2010

2-12 Installation and Wiring

Where:

Rc = DC resistance of the cable (each conductor) depending on cable length

Rs = Source impedance of analog transducer/sensor input Ri = Impedance of the voltage input (1 M for 1769-IF4I)

Vs = Voltage source (voltage at the transducer/sensor input device) Vin = Measured potential at the module input

%Ai = Percent added inaccuracy in a voltage-based system due to source and cable impedance.

Vin =

Ri Vs

 

------------------------------------------------------

Rs + 2 Rc

+ Ri

For example, for Belden 8761 two conductor, shielded cable:

Rc = 16 /1000 ft

Rs = 0 (ideal source)

Table 2.2 Effect of Cable Length on Input Accuracy

 

 

 

 

 

 

Length of Cable,

DC Resistance of the Cable,

Accuracy Impact at the

 

m (ft)

Rc ( )

Input Module

 

 

 

 

50 (164)

2.625

0.000525%

 

 

 

 

 

100

(328)

5.25

0.00105%

 

 

 

 

200 (656)

10.50

0.0021%

 

 

 

 

300 (984)

15.75

0.00315%

 

 

 

 

 

 

 

Vin

 

%Ai =

1

--------

 

100

Vs

As input source impedance (Rs) and/or resistance (dc) of the cable (Rc) get larger, system accuracy decreases. If you determine that the inaccuracy error is significant, implementing the following equation in the control program can compensate for the added inaccuracy error due to the impedance of the source and cable.

 

Vs = Vin ------------------------------------------------------Rs + 2 Rc + Ri

 

Ri

 

In a current loop system, source and cable impedance do

TIP

not impact system accuracy.

 

 

Publication 1769-UM014B-EN-P - May 2010

Installation and Wiring

2-13

 

 

Effect of Device and Cable Output Impedance on Output Module Accuracy

The maximum value of the output impedance is shown in the example below, because it creates the largest deviation from an ideal voltage source.

Figure 2.5 Output Module Accuracy

 

 

 

Rs

 

 

 

Rc

 

 

+

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Ri

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Vs

 

 

 

 

 

 

 

 

 

V in

 

 

 

 

 

 

 

 

 

 

 

 

 

 

-

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Rc

 

 

Where:

Rc = DC resistance of the cable (each conductor) depending on cable length

Rs = Source impedance (1 for 1769-OF4VI)

Ri = Impedance of the voltage input (220 k for 1769-IF4I) Vs = Voltage at the output of 1769-OF4VI

Vin = Measured potential at the module input

%Ai = Percent added inaccuracy in a voltage-based system due to source and cable impedance.

Vin =

Ri Vs

------------------------------------------------------Rs + 2 Rc + Ri

For example, for Belden 8761 two conductor, shielded cable and a 1769-OF4CI output module:

Rc = 16 /1000 ft

Rs = 15

Ri = 220 k

Table 2.3 Effect of Output Impedance and Cable Length on Accuracy

Length of Cable (m)

dc Resistance of the Cable

Accuracy Impact at the

 

Rc ( )

Input Module

 

 

 

50

2.625

0.00919%

 

 

 

100

5.25

0.01157%

 

 

 

200

10.50

0.01634%

 

 

 

300

15.75

0.02111%

 

 

 

Publication 1769-UM014B-EN-P - May 2010

2-14 Installation and Wiring

 

 

Vin

 

%Ai =

1

--------

 

100

Vs

Publication 1769-UM014B-EN-P - May 2010

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