1764 UM001B EN P, MicroLogix™ 1500 Programmable Controllers Allen Bradley Micrologix User Manual

User Manual: Allen-Bradley Micrologix 1500 User Manual

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MicroLogix™ 1500
Programmable
Controllers
Bulletin 1764

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

!
ATTENTION

!
IMPORTANT

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.

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

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

MicroLogix, Compact I/O, and RSLogix are trademarks of Rockwell Automation.

Summary of Changes
The information below summarizes the changes to this manual since
the last printing.
To help you find new and updated information in this release of the
manual, we have included change bars as shown to the right of this
paragraph.
The table below lists the sections that document new features and
additional or updated information on existing features.

iii

For this information:

See

Series C support for up to 16 expansion I/O
modules

Chapter 1

List of controller series, OS FRN numbers,
and RSLogix versions

Page 1-5

Updated list of recommended surge
suppressors

Page 3-6

Ethernet Connectivity

Page 4-23

Typical CPU hold-up time

Page A-1

Updated system loading and heat
dissipation worksheets

Appendix F

System loading graphs for 1769 power
supplies, including 1769-PA4 and 1769-PB4

pages F-5 through F-7

Publication 1764-UM001B-EN-P - March 2002

Summary of Changes

Publication 1764-UM001B-EN-P - March 2002

Table of Contents
Preface
Who Should Use this Manual. . . . . . . . . . . . . . . .
Purpose of this Manual . . . . . . . . . . . . . . . . . . . .
Related Documentation . . . . . . . . . . . . . . . . . . . .
Common Techniques Used in this Manual . . . . . .
Rockwell Automation Support . . . . . . . . . . . . . . .
Local Product Support . . . . . . . . . . . . . . . . . .
Technical Product Assistance . . . . . . . . . . . . .
Your Questions or Comments on this Manual .

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P-1
P-1
P-1
P-3
P-3
P-3
P-3
P-4

Hardware Features . . . . . . . . . . . . . . . . . . . . . . . . . . .
MicroLogix 1500 Component Descriptions . . . . . . . . . .
Base Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Processors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Data Access Tool (Catalog Number 1764-DAT) . . . .
Memory Modules/Real-Time Clock . . . . . . . . . . . . .
Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Programming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Communication Options . . . . . . . . . . . . . . . . . . . . . . .
Compact™ Expansion I/O . . . . . . . . . . . . . . . . . . . . . .
End Cap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Expansion Power Supply and Cables . . . . . . . . . . .
System Requirements for Using Expansion Modules
Adding an I/O Bank . . . . . . . . . . . . . . . . . . . . . . .
Addressing Expansion I/O . . . . . . . . . . . . . . . . . . .
Expansion I/O Power Failure . . . . . . . . . . . . . . . . .

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1-2
1-3
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1-4
1-4
1-5
1-6
1-6
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1-7
1-7
1-9
1-11
1-11

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2-2
2-2
2-3
2-3
2-4
2-4
2-5
2-5
2-5
2-5
2-6
2-6

Chapter 1
Hardware Overview

Chapter 2
Installing Your Controller

Agency Certifications. . . . . . . . . . . . . . . . . . . . . .
Compliance to European Union Directives . . . . . .
EMC Directive . . . . . . . . . . . . . . . . . . . . . . . .
Low Voltage Directive . . . . . . . . . . . . . . . . . .
Installation Considerations. . . . . . . . . . . . . . . . . .
Safety Considerations . . . . . . . . . . . . . . . . . . . . .
Hazardous Location Considerations . . . . . . . .
Disconnecting Main Power. . . . . . . . . . . . . . .
Safety Circuits . . . . . . . . . . . . . . . . . . . . . . . .
Power Distribution. . . . . . . . . . . . . . . . . . . . .
Periodic Tests of Master Control Relay Circuit .
Power Considerations . . . . . . . . . . . . . . . . . . . . .
Isolation Transformers . . . . . . . . . . . . . . . . . .
Power Supply Inrush . . . . . . . . . . . . . . . . . . .
Loss of Power Source. . . . . . . . . . . . . . . . . . .

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Publication 1764-UM001B-EN-P - April 2002

Table of Contents

Input States on Power Down . . . . . . .
Other Types of Line Conditions . . . . .
Preventing Excessive Heat . . . . . . . . . . . .
Master Control Relay . . . . . . . . . . . . . . . .
Using Emergency-Stop Switches . . . . .
Schematic (Using IEC Symbols) . . . . .
Schematic (Using ANSI/CSA Symbols).
Base Unit Mounting Dimensions . . . . . . .
Controller Spacing. . . . . . . . . . . . . . . . . .
Mounting the Controller . . . . . . . . . . . . .
Using a DIN Rail . . . . . . . . . . . . . . . .
Base Unit Panel Mounting . . . . . . . . .
Installing Controller Components. . . . . . .
Prevent Electrostatic Discharge . . . . . .
Processor. . . . . . . . . . . . . . . . . . . . . .
Data Access Tool (DAT). . . . . . . . . . .
Memory Module/Real-Time Clock. . . .
Compact I/O . . . . . . . . . . . . . . . . . . .

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2-6
2-7
2-7
2-8
2-9
2-10
2-11
2-12
2-12
2-13
2-14
2-16
2-17
2-17
2-17
2-19
2-20
2-22

Wiring Requirements. . . . . . . . . . . . . . . . . . . . . . . . . .
Wiring Recommendation . . . . . . . . . . . . . . . . . . . .
Using Surge Suppressors . . . . . . . . . . . . . . . . . . . . . . .
Recommended Surge Suppressors . . . . . . . . . . . . .
Grounding the Controller . . . . . . . . . . . . . . . . . . . . . .
Wiring Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Miswiring - 1764-28BXB Only. . . . . . . . . . . . . . . . .
Terminal Block Layouts . . . . . . . . . . . . . . . . . . . . .
Terminal Groupings . . . . . . . . . . . . . . . . . . . . . . . .
Sinking and Sourcing Input Circuits . . . . . . . . . . . . . . .
1764-24AWA Wiring Diagram . . . . . . . . . . . . . . . . .
1764-24BWA Wiring Diagram with Sinking Inputs . .
1764-24BWA Wiring Diagram with Sourcing Inputs .
1764-28BXB Wiring Diagram with Sinking Inputs . .
1764-28BXB Wiring Diagram with Sourcing Outputs
Controller I/O Wiring . . . . . . . . . . . . . . . . . . . . . . . . .
Minimizing Electrical Noise. . . . . . . . . . . . . . . . . . .
Transistor Output Transient Pulses . . . . . . . . . . . . .

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3-1
3-2
3-4
3-6
3-6
3-8
3-8
3-9
3-10
3-10
3-11
3-12
3-13
3-14
3-15
3-16
3-16
3-16

Default Communication Configuration . . . . . . . . . . . . . .
Communications Toggle Push Button. . . . . . . . . . . . . . .
Connecting to the RS-232 Port . . . . . . . . . . . . . . . . . . . .
DF1 Full-Duplex Communication Parameters . . . . . .
Making a DF1 Full-Duplex Point-to-Point Connection

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4-1
4-2
4-3
4-3
4-3

Chapter 3
Wiring Your Controller

Chapter 4
Communication Connections

Publication 1764-UM001B-EN-P - April 2002

Table of Contents

Using a Modem . . . . . . . . . . . . . . . . . . . . .
Isolated Modem Connection. . . . . . . . . . . .
Connecting to a DF1 Half-Duplex Network .
Connecting to a DH-485 Network . . . . . . . . . .
DH-485 Configuration Parameters. . . . . . . .
Recommended Tools . . . . . . . . . . . . . . . . .
DH-485 Communication Cable . . . . . . . . . .
Communication Cable Connection to the
DH-485 Connector . . . . . . . . . . . . . . . . . . .
Connecting the AIC+ . . . . . . . . . . . . . . . . .
Connecting to DeviceNet . . . . . . . . . . . . . . . .
Cable Selection Guide . . . . . . . . . . . . . . . .
Connecting to Ethernet . . . . . . . . . . . . . . . . . .
Ethernet Connections . . . . . . . . . . . . . . . . .
RS-232 Connections . . . . . . . . . . . . . . . . . .

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4-5
4-5
4-7
4-10
4-12
4-12
4-12

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4-13
4-15
4-22
4-22
4-23
4-23
4-24

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5-1
5-2
5-2
5-2
5-2
5-3
5-4
5-4
5-5
5-6
5-6
5-6
5-7
5-7
5-8
5-8
5-9

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6-1
6-1
6-1
6-2
6-2
6-2
6-3
6-3
6-4

Chapter 5
Using Trim Pots and the Data
Access Tool (DAT)

Trim Pot Operation . . . . . . . . . . . . . . . . . . . . .
Trim Pot Information Function File . . . . . . .
Error Conditions . . . . . . . . . . . . . . . . . . . .
Data Access Tool (DAT) . . . . . . . . . . . . . . . . .
DAT Keypad and Indicator Light Functions .
Power-Up Operation . . . . . . . . . . . . . . . . .
DAT Function File . . . . . . . . . . . . . . . . . . .
Power Save Timeout (PST) Parameter . . . . .
Understanding the DAT Display . . . . . . . . .
Entering Bit Mode . . . . . . . . . . . . . . . . . . .
Entering Integer Mode . . . . . . . . . . . . . . . .
Monitoring and Editing. . . . . . . . . . . . . . . .
F1 and F2 Functions. . . . . . . . . . . . . . . . . .
Working Screen Operation . . . . . . . . . . . . .
Non-Existent Elements . . . . . . . . . . . . . . . .
Controller Faults . . . . . . . . . . . . . . . . . . . .
Error Conditions . . . . . . . . . . . . . . . . . . . .

Chapter 6
Using Real-Time Clock and
Memory Modules

Real-Time Clock Operation . . . . . . . . . .
Removal/Insertion Under Power. . . .
Real-Time Clock Function File . . . . .
Accuracy . . . . . . . . . . . . . . . . . . . . .
Writing Data to the Real-Time Clock.
RTC Battery Operation . . . . . . . . . . .
Memory Module Operation . . . . . . . . . .
User Program and Data Back-Up . . .
Program Compare . . . . . . . . . . . . . .

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Publication 1764-UM001B-EN-P - April 2002

Table of Contents

viii

Data File Download Protection. . .
Memory Module Write Protection .
Removal/Insertion Under Power. .
Memory Module Information File .

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6-4
6-5
6-5
6-5

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A-1
A-2
A-8
A-9
A-9
A-9
A-10

MicroLogix 1500 Replacement Kits. . . . . . . .
Lithium Battery (1747-BA) . . . . . . . . . . . . .
Installing . . . . . . . . . . . . . . . . . . . . . . . .
Battery Handling . . . . . . . . . . . . . . . . . .
Storing . . . . . . . . . . . . . . . . . . . . . . . . .
Transporting . . . . . . . . . . . . . . . . . . . . .
Disposing . . . . . . . . . . . . . . . . . . . . . . .
Replacement Terminal Blocks . . . . . . . . . . .
Replacement Doors . . . . . . . . . . . . . . . . . . .
Base Terminal Door (1764-RPL-TDR1) . .
Processor Access Door (1764-RPL-CDR1)
Base Comms Door
(included in 1764-RPL-DR) . . . . . . . . . . .
Trim Pots/Mode Switch Cover Door
(included in 1764-RPL-DR) . . . . . . . . . . .

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B-1
B-2
B-2
B-3
B-3
B-3
B-4
B-5
B-6
B-6
B-6

Appendix A
Specifications

Controller Specifications . . . . . . . . . .
Choosing a Power Supply . . . . . .
Transistor Output Transient Pulses
Controller Dimensions. . . . . . . . . . . .
Compact I/O Dimensions . . . . . . . . .
Panel Mounting . . . . . . . . . . . . . .
End Cap . . . . . . . . . . . . . . . . . . .

Appendix B
Replacement Parts

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Appendix C
Troubleshooting Your System

Publication 1764-UM001B-EN-P - April 2002

Understanding Controller LEDs . . . . . . . . . . . . . . . .
When Operating Normally . . . . . . . . . . . . . . . . .
When an Error Exists . . . . . . . . . . . . . . . . . . . . .
Controller Error Recovery Model . . . . . . . . . . . . . . .
Identifying Controller Faults . . . . . . . . . . . . . . . . . .
Automatically Clearing Faults . . . . . . . . . . . . . . .
Manually Clearing Faults Using the Fault Routine
Fault Messages. . . . . . . . . . . . . . . . . . . . . . . . . .
Calling Rockwell Automation for Assistance . . . . . . .

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C-1
C-2
C-2
C-3
C-4
C-4
C-4
C-5
C-5

Table of Contents

Appendix D
Upgrading Your Operating System Preparing for Upgrade. . . . . . . . . . . . . . . . . . . . . . . . . . . . D-1
Performing the Upgrade . . . . . . . . . . . . . . . . . . . . . . . . . . D-2
Missing/Corrupt OS LED Pattern . . . . . . . . . . . . . . . . . . . . D-2

Appendix E
Understanding Communication
Protocols

RS-232 Communication Interface . . . . . . . . . . . . . . . . . .
DF1 Full-Duplex Protocol . . . . . . . . . . . . . . . . . . . . . . .
DF1 Half-Duplex Protocol . . . . . . . . . . . . . . . . . . . . . . .
DF1 Half-Duplex Operation . . . . . . . . . . . . . . . . . . .
Considerations When Communicating as a DF1 Slave
on a Multi-drop Link . . . . . . . . . . . . . . . . . . . . . . . .
Using Modems with MicroLogix 1500
Programmable Controllers . . . . . . . . . . . . . . . . . . . . . . .
Dial-Up Phone Modems . . . . . . . . . . . . . . . . . . . . . .
Leased-Line Modems . . . . . . . . . . . . . . . . . . . . . . . .
Radio Modems. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Line Drivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DH-485 Communication Protocol. . . . . . . . . . . . . . . . . .
DH-485 Network Description . . . . . . . . . . . . . . . . . .
DH-485 Token Rotation . . . . . . . . . . . . . . . . . . . . . .
DH-485 Configuration Parameters. . . . . . . . . . . . . . .
Devices that Use the DH-485 Network . . . . . . . . . . .
Important DH-485 Network Planning Considerations .
Modbus RTU Slave Communication Protocol
(MicroLogix 1764-LSP and 1764-LRP Series B and
later processors only) . . . . . . . . . . . . . . . . . . . . . . . . . .
ASCII Protocol (MicroLogix 1500 1764-LSP
and 1764-LRP Series B and later Processors only) . . . . . .

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E-1
E-2
E-2

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E-3
E-4
E-4
E-5
E-5
E-5
E-5
E-6
E-6
E-7
E-8

. E-13
. E-13

Appendix F
System Loading and Heat
Dissipation

System Loading Limitations . . . . .
System Expansion Calculations . .
Selecting System Devices . . . .
Verifying the System Loading .
Calculating Heat Dissipation . . . .

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F-1
F-1
F-2
F-4
F-9

Glossary
Index

Publication 1764-UM001B-EN-P - April 2002

Table of Contents

Publication 1764-UM001B-EN-P - April 2002

Preface
Read this preface to familiarize yourself with the rest of the manual. It
provides information concerning:
•
•
•
•
•

Who Should Use this
Manual

who should use this manual
the purpose of this manual
related documentation
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
MicroLogix 1500 controllers.
You should have a basic understanding of electrical circuitry and
familiarity with relay logic. If you do not, obtain the proper training
before using this product.

Purpose of this Manual

This manual is a reference guide for MicroLogix 1500 controllers. It
describes the procedures you use to install, wire, and troubleshoot
your controller. This manual:
• explains how to install and wire your controllers
• gives you an overview of the MicroLogix 1500 controller system
Refer to publication 1762-RM001, MicroLogix 1200 and MicroLogix
1500 Programmable Controllers Instruction Set Reference Manual for
the MicroLogix 1200 and 1500 instruction set and for application
examples to show the instruction set in use. Refer to your
programming software user documentation for more information on
programming your MicroLogix 1500 controller.

Related Documentation

The documents listed on page P-2 contain additional information
concerning Rockwell Automation products. If you would like a copy,
you can:
• download a free electronic version from the internet:
www.ab.com/micrologix or www.theautomationbookstore.com
• purchase a printed manual by:
– contacting your local distributor or Rockwell Automation
representative
– visiting www.theautomationbookstore.com and placing your
order
– calling 1.800.963.9548 (USA/Canada)
or 001.330.725.1574 (Outside USA/Canada)

P-1

Publication 1764-UM001B-EN-P - April 2002

Preface

P-2

For

Read this Document

Document Number

A technical overview of the MicroLogix 1500 and related
products

MicroLogix 1500 Programmable Controllers
Technical Data

1764-TD001

Information on the MicroLogix 1500 Controllers instruction set

MicroLogix 1200 and 1500 Programmable
1762-RM001
Controllers Instruction Set Reference Manual

Information on mounting and wiring the MicroLogix 1500 Base
Units, including a mounting template for easy installation

MicroLogix 1500 Programmable Controllers
Base Unit Installation Instructions

1764-IN001

An overview of Compact I/O

Compact I/O System Overview

1769-SO001

More information on Compact I/O Power Supplies and Cables

1769 Compact I/O Power Supplies and
Communication Bus Expansion Cables
Technical Data

1769-TD001

More information on Compact Analog I/O and Temperature Input
Modules

Compact Analog I/O and Temperature Input
Modules Technical Data

1769-TD004

Detailed information on using Compact I/O Analog Modules

Compact I/O Analog Modules User Manual

1769-UM002

Detailed information on installing, configuring, and using
1769-IT6 Thermocouple/mV Input Modules

Compact I/O 1769-IT6 Thermocouple/mV
Input Module User Manual

1769-UM004

Detailed information on installing, configuring, and using
1769-IR6 RTD/Resistance Input Modules

Compact I/O 1769-IR6 RTD/Resistance Input
Module User Manual

1769-UM005

Detailed information on installing, configuring, and using
1769-HSC High Speed Counter Modules

Compact 1769-HSC High Speed Counter
Module User Manual

1769-UM006

A description on how to install and connect an AIC+. This
manual also contains information on network wiring.

Advanced Interface Converter (AIC+) User
Manual

1761-6.4

Information on how to install, configure, and commission a DNI

DeviceNet™ Interface User Manual

1761-6.5

Information on installing, connecting, and configuring an ENI

Ethernet Interface User Manual

1761-UM001

Information on installing, configuring, and using a DeviceNet
Scanner

Compact™ I/O 1769-SDN DeviceNet Scanner
User Manual

1761-UM009

Information on DF1 open protocol.

DF1 Protocol and Command Set Reference
Manual

1770-6.5.16

In-depth information on grounding and wiring Allen-Bradley
programmable controllers

Allen-Bradley Programmable Controller
Grounding and Wiring Guidelines

1770-4.1

A description of important differences between solid-state
programmable controller products and hard-wired
electromechanical devices

Application Considerations for Solid-State
Controls

SGI-1.1

An article on wire sizes and types for grounding electrical
equipment

National Electrical Code - Published by the National Fire Protection
Association of Boston, MA.

A complete listing of current documentation, including ordering Allen-Bradley Publication Index
instructions. Also indicates whether the documents are available
on CD-ROM or in multi-languages.
A glossary of industrial automation terms and abbreviations

Publication 1764-UM001B-EN-P - April 2002

SD499

Allen-Bradley Industrial Automation Glossary AG-7.1

Preface

P-3

Common Techniques Used
in this Manual

The following conventions are used throughout this manual:

Rockwell Automation
Support

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.

• 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.

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
Before you contact Rockwell Automation for technical assistance, we
suggest you please review the troubleshooting information contained
in this publication first.

Publication 1764-UM001B-EN-P - April 2002

Preface

P-4

If the problem persists, call your local Rockwell Automation
representative or contact Rockwell Automation in one of the following
ways:
Phone

Internet

United
States/Canada

1.440.646.5800

Outside United
States/Canada

You can access the phone number for your
country via the Internet:
1. Go to http://www.ab.com
2. Click on Product Support
(http://support.automation.rockwell.com)
3. Under Support Centers, click on Contact
Information

⇒

1. Go to http://www.ab.com
2. Click on Product Support
(http://support.automation.rockwell.com)

Your Questions or Comments on this Manual
If you find a problem with this manual, or you have any suggestions
for how this manual could be made more useful to you, please
contact us at the address below:
Rockwell Automation
Automation Control and Information Group
Technical Communication, Dept. A602V
P.O. Box 2086
Milwaukee, WI 53201-2086
or visit our internet page at:
http://www.rockwellautomation.com
For the latest information on MicroLogix controllers, visit
www.ab.com/micrologix

Publication 1764-UM001B-EN-P - April 2002

Chapter

Hardware Overview

Hardware Features

The MicroLogix 1500 programmable controller is composed of a base
unit, which contains a power supply, input and output circuits, and a
processor. The controller is available with 24 or 28 points of
embedded I/O. Additional I/O may be added using Compact™ I/O.
The hardware features of the controller are:

2
RUN

REM

PROG

4
5

11
10 9 8 1 7

Feature

Description

Feature

Description

Removable Terminal Blocks

Memory Module/Real-Time Clock(1)

Interface to Expansion I/O,
Removable ESD Barrier

Replacement Battery(1)

Input LEDs

Battery

Output LEDs

Terminal Doors and Label

Communication Port

Data Access Tool(1)

Status LEDs

Mode Switch, Trim Pots

(1) Optional.

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1-2

Hardware Overview

MicroLogix 1500
Component Descriptions

A controller is composed of a processor (1764-LSP or enhanced
1764-LRP with RS-232 port) and one of the base units listed below.
The FET transistor outputs are available on the 1764-28BXB base only.

Base Units

Catalog
Number

Publication 1764-UM001B-EN-P - April 2002

Line Power Inputs

Outputs

High Speed I/O

1764-24AWA 120/240V ac (12) 120V ac

(12) Relay, 2 isolated relays n/a
per unit

1764-24BWA 120/240V ac (8) Standard 24V dc
(4) Fast 24V dc

(12) Relay, 2 isolated relays (4) 20 kHz input
per unit

1764-28BXB

(6) Relay, 2 isolated relays
per unit
(4) Standard 24V dc FET
(2) Fast 24V dc FET

24V dc

(8) Standard 24V dc
(8) Fast 24V dc

(8) 20 kHz input
(2) 20 kHz output

Hardware Overview

1-3

Processors
Processor (Catalog Number 1764-LSP)

Processor (Catalog Number 1764-LRP)

Communications Port
• DTE (male) 9-pin D-shell
connector
• 30V dc isolation

Data Access Tool (Catalog Number 1764-DAT)
1764-DAT
mounted on
1764-LSP
processor.

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1-4

Hardware Overview

Memory Modules/Real-Time Clock
Memory module
mounted on
1764-LSP
processor.

The following memory modules and real-time clock modules are
available:

Catalog Number

Function

Memory Size

1764-RTC

Real-Time Clock

not applicable

1764-MM1

Memory Module

1764-MM1RTC

Memory Module and Real-Time Clock

1764-MM2(1)

Memory Module

16K

1764-MM2RTC(1)

Memory Module and Real-Time Clock

16K

(1) For 1764-LRP programs greater than 8k, use the 1764-MM2 or 1764-MM2RTC.

Cables
Use only the following communication cables in Class I, Division 2
hazardous locations.
Table 1.1 Cables for Use in Class I, Division 2 Hazardous Environment

Publication 1764-UM001B-EN-P - April 2002

1761-CBL-PM02 Series C or later

2707-NC8 Series B or later

1761-CBL-HM02 Series C or later

2707-NC9 Series B or later

1761-CBL-AM00 Series C or later

2707-NC10 Series B or later

1761-CBL-AP00 Series C or later

2707-NC11 Series B or later

Hardware Overview

Programming

1-5

Programming the MicroLogix 1500 programmable controller is done
using RSLogix™ 500, Rev. 4.0 or later. Certain features are only
available when using the most current version of the software, as
noted in System Requirements for Using Expansion Modules on page
1-7.
The following table lists the firmware release numbers, feature and
functionality enhancements, and the required version of RSLogix 500
and RSLogix 500 Starter software.

Table 1.B Required Software Version by FRN Number
Available
for Sale
Date

Catalog
Number
Series

Catalog
Number
Revision

OS FRN
Number

Initial
Release

February
1999

Initial Release

3.01.00

Enhancement

October
1999

Power Supply and Expansion Cable
Compatibility

3.01.00

Series B
Release

March
2000

String Data File Type,
ASCII Instruction Set,
Modbus RTU Slave Protocol,
Ramping (when using PWM outputs),
Static Data File Protection,
RTC Messaging

4.00.00

Enhancement

October
2000

PTO Controlled Stop,
4.50.00
Memory Module Program Compare Bit
Enhancement

Series C
Release

September
2001

Floating Point Data File Support,
Programmable Limit Switch (PLS),
Real Time Clock Adjust (Copy Word),
Absolute Value,
Gray Code,
Recipe,
Message Instruction Support for
1769-SDN

5.10.00

Initial
Release

March
2000

Initial Release - Same Functionality as
1764-LSP

4.00.00

Enhancement

October
2000

PTO Controlled Stop,
4.50.00
Memory Module Program Compare Bit
Enhancement

September
2001

Floating Point Data File Support,
Programmable Limit Switch (PLS),
Real Time Clock Adjust (Copy Word),
Absolute Value,
Gray Code,
Recipe,
Message Instruction Support for
1769-SDN

Controller Firmware
Release

1764-LSP

1764-LRP

Series C
Release

Feature and Functionality
Changes

Required
Version of
RSLogix
500/RSLogix
500 Starter
Software

5.10.00

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1-6

Hardware Overview

Communication Options

The MicroLogix 1500 can be connected to a personal computer. It can
also be connected to the DH-485 network using an Advanced
Interface Converter (1761-NET-AIC), to an Ethernet network using an
Ethernet Interface (1761-NET-ENI), or to a DeviceNet™ network using
a DeviceNet Interface (1761-NET-DNI) or through the DeviceNet
Scanner module (1769-SDN). The controller can also be connected to
Modbus™ SCADA networks as an RTU slave. See Communication
Connections on page 4-1 for more information on connecting to the
available communication options.
The 1764-LRP processor provides an additional communication port.
Each of the communications ports can be independently configured
for any supported communication protocol. (Channel 0 is on the base
unit and Channel 1 is on the 1764-LRP processor.)

Compact™ Expansion I/O

Compact expansion I/O (Bulletin 1769) can be connected to the
MicroLogix 1500 Controller. A maximum of either 8 or 16 expansion
I/O modules can be used, depending upon your system. See System
Requirements for Using Expansion Modules on page 1-7.
See System Loading and Heat Dissipation on page F-1 for more
information on system configurations.

End Cap
An end cap terminator (catalog number 1769-ECR or 1769-ECL) must
be used at the end of the group of I/O modules attached to the
MicroLogix 1500 Controller. The end cap terminator is not provided
with the base or processor units. It is required when using expansion
I/O.

This illustration shows the right end cap (1769-ECR ). The left end cap
(1769-ECL) is shown on page 1-10.
Publication 1764-UM001B-EN-P - April 2002

Hardware Overview

1-7

Expansion Power Supply and Cables
With Operating System Revision Number (FRN) 3 or higher, you can
connect an additional bank of I/O to your controller. Using an
expansion power supply increases the system’s capacity for adding
expansion I/O modules. The additional I/O bank is connected to the
controller via a specially designed cable. The additional I/O bank
must include a power supply and an end cap.
TIP

Depending on the system configuration, each
controller can support up to 16 expansion I/O
modules. See the System Requirements for Using
Expansion Modules below. Also see System
Guidelines on page 1-9 for system limitations and
illustrations of expansion I/O banks.

System Requirements for Using Expansion Modules
To support a maximum of 8 I/O modules in an additional I/O bank,
you must have the following:
Table 1.3 Requirements to Support a Maximum of 8 I/O Modules
Product

Catalog Number

MicroLogix 1500
Processor

1764-LSP, Series A, Revision C or higher
1764-LSP, Series B or higher
1764-LRP, Series B or higher

MicroLogix 1500
Base Unit

1764-24AWA, Series A or higher
1764-24BWA, Series A or higher
1764-28BXB, Series A or higher

Operating System
Version

Firmware Revision Number (FRN) 3 or higher(1)

Programming
Software

1764-LSP, Series A

RSLogix 500, Version 3.01.09 or higher,

1764-LSP, Series B
1764-LRP, Series B

RSLogix 500, Version 4.00.00 or higher.

1764-LSP, Series C
1764-LRP, Series C

RSLogix 500, Version 5.00.00 or higher.

1 Power Supply
(optional)

1769-PA2, 1769-PA4
1769-PB2, 1769-PB4

1 Cable (optional)

1769-CRL1, 1769-CRL3, 1769-CRR1, 1769-CRR3

1 End Cap (required)

1769-ECL, 1769-ECR

(1) You can check the FRN by looking at word S:59 (Operating System FRN) in the Status File.

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1-8

Hardware Overview

To support a maximum of 16 I/O modules in an additional I/O bank,
you must have the following:
Table 1.4 Requirements to Support a Maximum of 16 I/O Modules
Product

Catalog Number

MicroLogix 1500 Processor

1764-LSP, Series C or higher
1764-LRP, Series C or higher

MicroLogix 1500 Base Unit

1764-24AWA, Series B or higher
1764-24BWA, Series B or higher
1764-28BXB, Series B or higher

Operating System Version

Firmware Revision Number (FRN) 6 or higher(1)

Programming Software

RSLogix 500, Version 5.10.00 or higher.

1 Power Supply (optional)

1769-PA2, 1769-PA4, 1769-PB2, 1769-PB4

1 Cable (optional)

1769-CRL1, 1769-CRL3, 1769-CRR1, 1769-CRR3

1 End Cap (required)

1769-ECL, 1769-ECR

(1) You can check the FRN by looking at word S:59 (Operating System FRN) in the Status File.

IMPORTANT

If your processor is at an older revision, you must
upgrade the operating system to FRN 3 or higher
to use an expansion cable and power supply (or to
FRN 6 or higher to allow up to 16 expansion
modules). On the Internet, go to
http://www.ab.com/micrologix to download the
operating system upgrade. Navigate to MicroLogix
1500 for further instructions and downloads.
MicroLogix 1500 base units are not field upgradeable
from Series A to Series B.

Publication 1764-UM001B-EN-P - April 2002

Hardware Overview

1-9

Adding an I/O Bank
System Guidelines
A maximum of one 1769 Expansion Cable can be used in a
MicroLogix 1500 system, allowing for two banks of I/O modules (one
connected directly to the controller, and the other connected via the
cable). Each I/O bank requires its own power supply (Bank 1 uses the
controller’s embedded power supply).

ATTENTION

!
ATTENTION

LIMIT OF ONE EXPANSION POWER SUPPLY
The expansion power supply cannot be connected
directly to the controller. It must be connected using
an expansion cable. Only one power supply
(embedded in the base unit or an expansion power
supply) may be used on an I/O bank. Exceeding
these limitations may damage the power supply and
result in unexpected operation.

REMOVE POWER
Remove system power before making or breaking
cable connections. When you remove or insert a
cable connector 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 operation
• causing an explosion in a hazardous environment
Electrical arcing causes excessive wear to contacts on
both the module and its mating connector.
Refer to your power supply and I/O module’s
documentation for instructions on how to set up
your system.

IMPORTANT

See the System Requirements for Using Expansion
Modules on page 1-7 to determine the maximum
number of expansion I/O modules you can use in
your MicroLogix system.
Also see System Loading and Heat Dissipation on
page F-1 for more information on system
configurations.

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1-10

Hardware Overview

The following illustrations show a MicroLogix 1500 with an expansion
I/O bank.

Vertical Orientation

Expansion
I/O Bank 1

1769-CRRx(1)
Expansion Cable

Expansion
I/O Bank 2
1769-ECL
End Cap

(1) The x in this catalog number can be either a 1 or a 3 representing the length of the cable:
1 = 1 foot (305 mm) and 3 = 3.28 feet (1 meter).

Horizontal Orientation

1769-ECR
End Cap

Expansion
I/O Bank 1

1769-CRLx(1)
Expansion Cable

Expansion
I/O Bank 2

(1) The x in this catalog number can be either a 1 or a 3 representing the length of the cable:
1 = 1 foot (305 mm) and 3 = 3.28 feet (1 meter).

Publication 1764-UM001B-EN-P - April 2002

Hardware Overview

1-11

Addressing Expansion I/O
The expansion I/O is addressed as slots 1 through 16 (the controller’s
embedded I/O is addressed as slot 0). Power supplies and cables are
not counted as slots. Modules are counted from left to right on each
bank as shown in the illustrations below. For more information on
addressing, refer to the MicroLogix 1200 and MicroLogix 1500
Programmable Controllers Instruction Set Reference Manual,
publication 1762-RM001.

Slot 2
Slot 5

Slot 4

Slot 3

Embedded
I/O = Slot 0

Slot 1

Vertical Orientation

Expansion
I/O Bank 1

Expansion
I/O Bank 2

Expansion I/O Bank 1

Slot 5

Slot 4

Slot 3

Slot 2

Embedded
I/O = Slot 0

Slot 1

Horizontal Orientation

Expansion I/O Bank 2

Expansion I/O Power Failure
Expansion I/O errors represent failures of the I/O bus or the modules
themselves. The error codes are listed in the MicroLogix 1200 and
MicroLogix 1500 Programmable Controllers Instruction Set Reference
Manual, publication 1762-RM001.

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1-12

Hardware Overview

Publication 1764-UM001B-EN-P - April 2002

Chapter

Installing Your Controller
This chapter shows you how to install your controller system. The
only tools you require are a Flat or Phillips head screwdriver and drill.
Topics include:
•
•
•
•
•
•
•
•

Agency Certifications

Compliance to European
Union Directives

agency certifications
compliance to European Union Directives
using in hazardous locations
master control relay
power considerations
preventing excessive heat
controller spacing
mounting the controller

• UL 508
• C-UL under CSA C22.2 no. 142
• Class I, Division 2, Groups A, B, C, D
(UL 1604, C-UL under CSA C22.2 no. 213)
• CE compliant for all applicable directives

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

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Installing Your Controller

Low Voltage Directive
This product is tested to meet Council Directive 73/23/EEC Low
Voltage, by applying the safety requirements of EN 61131-2
Programmable Controllers, Part 2 - Equipment Requirements and
Tests.
For specific information required by EN 61131-2, see the appropriate
sections in this publication, as well as the following Allen-Bradley
publications:
• Industrial Automation Wiring and Grounding Guidelines for
Noise Immunity, publication 1770-4.1
• Guidelines for Handling Lithium Batteries, publication AG-5.4
• Automation Systems Catalog, publication B111

Installation Considerations

Most applications require installation in an industrial enclosure
(Pollution Degree 2(1)) to reduce the effects of electrical interference
(Over Voltage Category II(2)) and environmental exposure. Locate
your controller as far as possible from power lines, load lines, and
other sources of electrical noise such as hard-contact switches, relays,
and AC motor drives. For more information on proper grounding
guidelines, see the Industrial Automation Wiring and Grounding
Guidelines publication 1770-4.1.

ATTENTION

Vertical mounting of the controller is not
recommended due to heat build-up considerations.

!
ATTENTION

Be careful of metal chips when drilling mounting
holes for your controller or other equipment within
the enclosure or panel. Drilled fragments that fall into
the base or processor unit could cause damage. Do
not drill holes above a mounted controller if the
protective debris strips are removed or the processor
is installed.

(1) Pollution Degree 2 is an environment where normally only non-conductive pollution occurs except that
occasionally temporary conductivity caused by condensation shall be expected.
(2) Overvoltage 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 products insulation.

Publication 1764-UM001B-EN-P - April 2002

Installing Your Controller

Safety Considerations

2-3

Safety considerations are an important element of proper system
installation. Actively thinking about the safety of yourself and others,
as well as the condition of your equipment, is of primary importance.
We recommend reviewing the following safety considerations.

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

WARNING

EXPLOSION HAZARD
• Substitution of components may impair suitability
for Class I, Division 2.
• Do not replace components or disconnect
equipment unless power has been switched off.
• 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
cables connected to the product must remain in
the enclosure or be protected by conduit or other
means.
• All wiring must comply with N.E.C. article
501-4(b).

When installing any peripheral device (for example,
push buttons, lamps) into a hazardous environment,
ensure that they are Class I, Division 2 certified, or
determined to be safe for the environment.

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Installing Your Controller

Use only the following communication cables in Class I, Division 2
hazardous locations.
Table 2.1 Cables for Use in Class I, Division 2 Hazardous Environment
1761-CBL-PM02 Series C or later

2707-NC8 Series B or later

1761-CBL-HM02 Series C or later

2707-NC9 Series B or later

1761-CBL-AM00 Series C or later

2707-NC10 Series B or later

1761-CBL-AP00 Series C or later

2707-NC11 Series B or later

Disconnecting Main Power
WARNING

EXPLOSION HAZARD
Do not replace components or disconnect
equipment unless power has been switched off.

The main power disconnect switch should be located where operators
and maintenance personnel have quick and easy access to it. In
addition to disconnecting electrical power, all other sources of power
(pneumatic and hydraulic) should be de-energized before working on
a machine or process controlled by a controller.

Safety Circuits
WARNING

EXPLOSION HAZARD
Do not connect or disconnect connectors while
circuit is live.

Circuits installed on the machine for safety reasons, like overtravel
limit switches, stop push buttons, and interlocks, should always be
hard-wired directly to the master control relay. These devices must be
wired in series so that when any one device opens, the master control
relay is de-energized, thereby removing power to the machine. Never
alter these circuits to defeat their function. Serious injury or machine
damage could result.
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Installing Your Controller

2-5

Power Distribution
There are some points about power distribution that you should
know:
• The master control relay must be able to inhibit all machine
motion by removing power to the machine I/O devices when
the relay is de-energized. It is recommended that the controller
remain powered even when the master control relay is
de-energized.
• If you are using a dc power supply, interrupt the load side rather
than the ac line power. This avoids the additional delay of
power supply turn-off. The dc power supply should be powered
directly from the fused secondary of the transformer. Power to
the dc input and output circuits should be connected through a
set of master control relay contacts.

Periodic Tests of Master Control Relay Circuit
Any part can fail, including the switches in a master control relay
circuit. The failure of one of these switches would most likely cause
an open circuit, which would be a safe power-off failure. However, if
one of these switches shorts out, it no longer provides any safety
protection. These switches should be tested periodically to assure they
will stop machine motion when needed.

Power Considerations

The following explains power considerations for the micro controllers.

Isolation Transformers
You may want to use an isolation transformer in the ac line to the
controller. This type of transformer provides isolation from your
power distribution system to reduce the electrical noise that enters the
controller and is often used as a step-down transformer to reduce line
voltage. Any transformer used with the controller must have a
sufficient power rating for its load. The power rating is expressed in
volt-amperes (VA).

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Installing Your Controller

Power Supply Inrush
During power-up, the MicroLogix 1500 power supply allows a brief
inrush current to charge internal capacitors. Many power lines and
control transformers can supply inrush current for a brief time. If the
power source cannot supply this inrush current, the source voltage
may sag momentarily.
The only effect of limited inrush current and voltage sag on the
MicroLogix 1500 is that the power supply capacitors charge more
slowly. However, the effect of a voltage sag on other equipment
should be considered. For example, a deep voltage sag may reset a
computer connected to the same power source. The following
considerations determine whether the power source must be required
to supply high inrush current:
• The power-up sequence of devices in a system.
• The amount of the power source voltage sag if the inrush
current cannot be supplied.
• The effect of voltage sag on other equipment in the system.
If the entire system is powered-up at the same time, a brief sag in the
power source voltage typically will not affect any equipment.

Loss of Power Source
The power supply is designed to withstand brief power losses without
affecting the operation of the system. The time the system is
operational during power loss is called “program scan hold-up time
after loss of power.” The duration of the power supply hold-up time
depends on the type and state of the I/O, but is typically between 10
milliseconds and 3 seconds. When the duration of power loss reaches
this limit, the power supply signals the processor that it can no longer
provide adequate dc power to the system. This is referred to as a
power supply shutdown. The processor then performs an orderly
shutdown of the controller.

Input States on Power Down
The power supply hold-up time as described above is generally
longer than the turn-on and turn-off times of the inputs. Because of
this, the input state change from “On” to “Off” that occurs when
power is removed may be recorded by the processor before the

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Installing Your Controller

2-7

power supply shuts down the system. Understanding this concept is
important. Write the user program, taking this effect into account.

Other Types of Line Conditions
Occasionally the power source to the system can be temporarily
interrupted. It is also possible that the voltage level may drop
substantially below the normal line voltage range for a period of time.
Both of these conditions are considered to be a loss of power for the
system.

Preventing Excessive Heat

For most applications, normal convective cooling keeps the controller
within the specified operating range. Ensure that the specified
temperature range is maintained. Proper spacing of components
within an enclosure is usually sufficient for heat dissipation.
In some applications, a substantial amount of heat is produced by
other equipment inside or outside the enclosure. In this case, place
blower fans inside the enclosure to assist in air circulation and to
reduce “hot spots” near the controller.
Additional cooling provisions might be necessary when high ambient
temperatures are encountered.

TIP

Do not bring in unfiltered outside air. Place the
controller in an enclosure to protect it from a
corrosive atmosphere. Harmful contaminants or dirt
could cause improper operation or damage to
components. In extreme cases, you may need to use
air conditioning to protect against heat build-up
within the enclosure.

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Installing Your Controller

Master Control Relay

A hard-wired master control relay (MCR) provides a reliable means for
emergency machine shutdown. Since the master control relay allows
the placement of several emergency-stop switches in different
locations, its installation is important from a safety standpoint.
Overtravel limit switches or mushroom-head push buttons are wired
in series so that when any of them opens, the master control relay is
de-energized. This removes power to input and output device circuits.
Refer to the figures on pages 2-10 and 2-11.

ATTENTION

!
TIP

Never alter these circuits to defeat their function
since serious injury and/or machine damage could
result.

If you are using an external dc power supply,
interrupt the dc output side rather than the ac line
side of the supply to avoid the additional delay of
power supply turn-off.
The ac line of the dc output power supply should be
fused.
Connect a set of master control relays in series with
the dc power supplying the input and output
circuits.

Place the main power disconnect switch where operators and
maintenance personnel have quick and easy access to it. If you mount
a disconnect switch inside the controller enclosure, place the switch
operating handle on the outside of the enclosure, so that you can
disconnect power without opening the enclosure.
Whenever any of the emergency-stop switches are opened, power to
input and output devices should be removed.
When you use the master control relay to remove power from the
external I/O circuits, power continues to be provided to the
controller’s power supply so that diagnostic indicators on the
processor can still be observed.
The master control relay is not a substitute for a disconnect to the
controller. It is intended for any situation where the operator must
quickly de-energize I/O devices only. When inspecting or installing
terminal connections, replacing output fuses, or working on

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Installing Your Controller

2-9

equipment within the enclosure, use the disconnect to shut off power
to the rest of the system.

TIP

Do not control the master control relay with the
controller. Provide the operator with the safety of a
direct connection between an emergency-stop switch
and the master control relay.

Using Emergency-Stop Switches
When using emergency-stop switches, adhere to the following points:
• Do not program emergency-stop switches in the controller
program. Any emergency-stop switch should turn off all
machine power by turning off the master control relay.
• Observe all applicable local codes concerning the placement
and labeling of emergency-stop switches.
• Install emergency-stop switches and the master control relay in
your system. Make certain that relay contacts have a sufficient
rating for your application. Emergency-stop switches must be
easy to reach.
• In the following illustration, input and output circuits are shown
with MCR protection. However, in most applications, only
output circuits require MCR protection.
The following illustrations show the Master Control Relay wired in a
grounded system.
TIP

In most applications input circuits do not require
MCR protection; however, if you need to remove
power from all field devices, you must include MCR
contacts in series with input power wiring.

Publication 1764-UM001B-EN-P - April 2002

2-10

Installing Your Controller

Schematic (Using IEC Symbols)
L1

L2
230V ac

Disconnect
Fuse

Isolation
Transformer
X1

115V ac X2
or 230V ac

MCR

230V ac
I/O
Circuits

Operation of either ofthese contacts will
remove power from the external I/O
circuits, stopping machine motion.
Emergency-Stop
Push Button

Fuse

Overtravel
Limit Switch

Stop

Master Control Relay (MCR)
Cat. No. 700-PK400A1

Start

MCR

Suppr.

MCR

115V ac or
230V ac
I/O Circuits

MCR

dc Power Supply.
Use IEC 950/EN 60950
_
+
(Lo)

(Hi)

Line Terminals:
Connect to terminals of Power Supply
(1764-24AWA and 1764-24BWA).

Publication 1764-UM001B-EN-P - April 2002

Suppressor
Cat. No.
700-N24

MCR
Line Terminals: Connect to 24V dc
terminals of Power Supply.

24V dc
I/O
Circuits

Installing Your Controller

2-11

Schematic (Using ANSI/CSA Symbols)
L1

L2
230V ac

Disconnect
MCR

Fuse

230V ac
Output
Circuits
Isolation
Transformer
X1

115V ac or
230V ac

Operation of either ofthese contacts will
remove power from the external I/O
X2

Emergency-Stop
Push Button

Fuse

Overtravel
Limit Switch

Stop

Master Control Relay (MCR)
Cat. No. 700-PK400A1

Start

MCR

Suppressor
Cat. No.
700-N24

MCR
Suppr.

MCR
115V ac or
230V ac
I/O Circuits
dc Power Supply.
Use NEC Class 2
_
(Lo)

MCR

24 V dc
I/O
Circuits

(Hi)

Line Terminals:
Connect to 1764-24AWA or
1764-24BWA terminals.

Line Terminals: Connect to 24V
dc terminals of Power Supply.

Publication 1764-UM001B-EN-P - April 2002

2-12

Installing Your Controller

Base Unit Mounting
Dimensions
A

Dimension(1)

1764-24AWA

1764-24BWA

1764-28BXB

Height (A)

DIN latch open: 138 mm (5.43 in.), DIN latch closed: 118 mm (4.65 in.)

Width (B)

168 mm (6.62 in.)

Depth (C)

87 mm (3.43 in.)

(1) See Controller Dimensions on page A-9 for more dimensional information.

Controller Spacing

The base unit is designed to be mounted horizontally, with the
Compact™ expansion I/O extending to the right of the base unit.
Allow 50 mm (2 in.) minimum of space on all sides for adequate
ventilation, as shown below.

Bottom

Publication 1764-UM001B-EN-P - April 2002

End Cap

Compact I/O

Controller
Side

Compact I/O

Top

Side

Installing Your Controller

2-13

Mounting the Controller
ATTENTION

Do not remove protective debris strips until after the
base and all other equipment in the panel near the
base is mounted and wiring is complete. The debris
strips are there to prevent drill fragments, wire
strands and other dirt from getting into the controller.
Once wiring is complete, remove protective debris
strips and install processor unit. Failure to remove
strips before operating can cause overheating.

Protective
Debris Strips

ESD Barrier

ATTENTION

!
ATTENTION

Be careful of metal chips when drilling mounting
holes for your controller or other equipment within
the enclosure or panel. Drilled fragments that fall
into the controller could cause damage. Do not drill
holes above a mounted controller if the protective
debris strips have been removed.

Electrostatic discharge can damage semiconductor
devices inside the base unit. Do not touch the
connector pins or other sensitive areas.

Publication 1764-UM001B-EN-P - April 2002

2-14

Installing Your Controller

TIP

If additional I/O modules are required for the
application, remove the ESD barrier to install
expansion I/O modules. A maximum of 16 I/O
modules may be connected to the base. (See page
1-7 for system requirements.) The I/O module’s
current requirements and power consumption may
further limit the number of modules connected to
the base. See System Loading and Heat Dissipation
on page F-1. An end cap terminator (catalog number
1769-ECR or 1769-ECL) is required at the end of the
group of I/O modules attached to the base.

Using a DIN Rail
The base unit and expansion I/O DIN rail latches lock in the open
position so that an entire system can be easily attached to or removed
from the DIN rail. The maximum extension of the latch is 15 mm (0.67
in.) in the open position. A flat-blade screw driver is required for
removal of the base unit. The base can be mounted to
EN50022-35x7.5 or EN50022-35x15 DIN rails. DIN rail mounting
dimensions are shown below.

A
DIN Rail Latch

Dimension

Publication 1764-UM001B-EN-P - April 2002

Height

DIN latch open: 138 mm (5.43 in.), DIN latch closed: 118 mm (4.65 in.)

47.6 mm (1.875 in.)

47.6 mm (1.875 in) DIN latch closed
54.7 mm (2.16 in.) DIN latch open

Installing Your Controller

2-15

To install your base unit on the DIN rail:
1. Mount your DIN rail. (Make sure that the placement of the base
unit on the DIN rail meets the recommended spacing
requirements, see Controller Spacing on page 2-12. Refer to the
mounting template from the inside back cover of the MicroLogix
1500 Programmable Controller Base Units Installation
Instructions, publication 1764-IN001.
2. Hook the top slot over the DIN rail.
3. While pressing the base unit down against the top of the rail,
snap the bottom of the base unit into position. Ensure DIN
latches are in the up (secured) position.
4. Leave the protective debris strip attached until you are finished
wiring the base unit and any other devices.
To remove your base unit from the DIN rail:
1. Place a flat-blade screwdriver in the DIN rail latch at the bottom
of the base unit.
2. Holding the base unit, pry downward on the latch until the latch
locks in the open position. Repeat this procedure with the
second latch. This releases the base unit from the DIN rail.

DIN Rail Latch

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2-16

Installing Your Controller

Base Unit Panel Mounting
Mount to panel using #8 or M4 screws.

Mounting Template

To install your base unit using mounting screws:
1. Remove the mounting template from the inside back cover of
the MicroLogix 1500 Programmable Controller Base Units
Installation Instruction, publication 1764-IN001.
2. Secure the template to the mounting surface. (Make sure your
base unit is spaced properly, see Controller Spacing on page
2-12).
3. Drill holes through the template.
4. Remove the mounting template.
5. Mount the base unit.
6. Leave the protective debris strips attached until you are finished
wiring the base unit and any other devices.

Publication 1764-UM001B-EN-P - April 2002

Installing Your Controller

Installing Controller
Components

2-17

Prevent Electrostatic Discharge

ATTENTION

Electrostatic discharge can damage integrated circuits
or semiconductors if you touch bus connector pins.
Follow these guidelines when you handle any
module:
• Touch a grounded object to discharge static
potential.
• Wear an approved wrist-strap grounding device.
• Do not touch the bus connector or connector
pins.
• Do not touch circuit components inside the
module.
• If available, use a static-safe work station.
When not in use, keep the module in its static-shield
bag.

Be sure the base unit is free of all metal fragments
before removing protective debris strips and
installing the processor unit. Failure to remove strips
before operating can cause overheating.

Processor

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2-18

Installing Your Controller

1. Be sure base unit power is off.
2. Slide the processor into the base unit using the guide rails for
alignment.
3. Push until a click is heard. Be careful not to push on the
connector when installing the 1764-LRP processor.
IMPORTANT

It is critical that the processor is fully engaged
and locked into place.

4. Make sure the actuator is pushed closed.

5. To remove the processor from the base unit, make sure base
unit power is off. Push the actuator to the open position until
the processor is ejected slightly. Once the processor has been
ejected, it can be removed from the base unit.

Publication 1764-UM001B-EN-P - April 2002

Installing Your Controller

2-19

Data Access Tool (DAT)
1. Remove cover from processor.

2. Holding the DAT in the proper orientation (as shown), place the
DAT onto processor. Align DAT port on the processor with the
plug on the DAT.

3. Firmly seat DAT on processor; make sure it seats into place.

Publication 1764-UM001B-EN-P - April 2002

2-20

Installing Your Controller

4. To remove DAT, grasp using finger areas and pull upward.

Memory Module/Real-Time Clock
1. Remove the cover (or DAT if installed) from the processor as
shown below.

ATTENTION

Publication 1764-UM001B-EN-P - April 2002

Electrostatic discharge can damage semiconductor
devices inside the base and processor units. Do not
touch the connector pins or other sensitive areas.

Installing Your Controller

2-21

2. Align connector on the memory module with the connector pins
on the processor.

3. Firmly seat the memory module in the processor making sure
the locking tabs click into place.

4. Replace the cover (or DAT if used).

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2-22

Installing Your Controller

Compact I/O
Attach and Lock Module (Module-to-Controller or Module-to-Module)
A Compact I/O module can be attached to the controller or an
adjacent I/O module before or after mounting to the panel or DIN rail.
The module can be detached and replaced while the system is
mounted to a panel or DIN rail.

ATTENTION

Publication 1764-UM001B-EN-P - April 2002

Remove power before removing or inserting an I/O
module. When you remove or insert a module with
power applied, an electrical arc may occur. An
electrical arc can cause personal injury or property
damage by:
• sending an erroneous signal to your system’s field
devices, causing the controller to fault
• causing an explosion in a hazardous environment
Electrical arcing causes excessive wear to contacts on
both the module and its mating connector. Worn
contacts may create electrical resistance, reducing
product reliability.

When attaching I/O modules, it is very important that
they are securely locked together to ensure proper
electrical connection.

Installing Your Controller

2-23

3
4

2
6
5

To attach and lock modules:

Remove ESD barrier when attaching I/O modules to
a MicroLogix 1500 base unit.

TIP

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 screw driver.
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.

ATTENTION

When attaching I/O modules, it is very important
that the bus connectors are securely locked
together to ensure proper electrical connection.

Publication 1764-UM001B-EN-P - April 2002

2-24

Installing Your Controller

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).

IMPORTANT

A 1769-ECR right end cap (or a 1769-ECL left end cap
if I/O bank is located below the controller) must be
used to terminate the end of the serial
communication bus.

See Controller Dimensions on page A-9 for mounting dimensions.

Publication 1764-UM001B-EN-P - April 2002

Chapter

Wiring Your Controller

This chapter describes how to wire your controller. Topics include:
•
•
•
•
•

wiring requirements
using surge suppressors
grounding guidelines
sinking and sourcing circuits
wiring diagrams, input voltage ranges, and output voltage
ranges
• minimizing noise

Wiring Requirements
Wire Type

Wire Size(1)

Wiring Torque
1.13 Nm (10 in-lb) rated
1.3 Nm (12 in-lb) maximum

Solid

Cu-90°C (194°F)

#14 to #22 AWG

Stranded

Cu-90°C (194°F)

#14 to #22 AWG

(1) Two wires maximum per terminal screw.

ATTENTION

Be careful when stripping wires. Wire fragments that
fall into the controller could cause damage. Once
wiring is complete, be sure the base unit is free of all
metal fragments before removing protective debris
strips and installing the processor unit. Failure to
remove strips before operating can cause
overheating.

Publication 1764-UM001B-EN-P - April 2002

3-2

Wiring Your Controller

Wiring Recommendation

ATTENTION

Before you install and wire any device, disconnect
power to the controller system.

!
ATTENTION

Calculate the maximum possible current in each
power and common wire. Observe all electrical
codes dictating the maximum current allowable for
each wire size. Current above the maximum ratings
may cause wiring to overheat, which can cause
damage.
United States Only: If the controller is installed within
a potentially hazardous environment, all wiring must
comply with the requirements stated in the National
Electrical Code 501-4 (b).

• Allow for at least 50 mm. (2 in.) between I/O wiring ducts or
terminal strips and the controller.
• Route incoming power to the controller by a path separate from
the device wiring. Where paths must cross, their intersection
should be perpendicular.

TIP

Do not run signal or communications wiring and
power wiring in the same conduit. Wires with
different signal characteristics should be routed by
separate paths.

• Separate wiring by signal type. Bundle wiring with similar
electrical characteristics together.
• Separate input wiring from output wiring.
• Label wiring to all devices in the system. Use tape,
shrink-tubing, or other dependable means for labeling purposes.
In addition to labeling, use colored insulation to identify wiring
based on signal characteristics. For example, you may use blue
for dc wiring and red for ac wiring.

Publication 1764-UM001B-EN-P - April 2002

Wiring Your Controller

3-3

Wiring without Spade Lugs
When wiring without spade lugs, it is recommended to keep the
finger-safe covers in place. Loosen the terminal screw and route the
wires through the opening in the finger-safe cover. Tighten the
terminal screw making sure the pressure plate secures the wire.

Finger-Safe Cover
terminal screw torque:
1.13 Nm (10 in-lbs) rated
1.3 Nm (12 in-lbs) max.

Wiring with Spade Lugs
The diameter of the terminal screw head is 5.5 mm (0.220 in.). The
input and output terminals of the MicroLogix 1500 base unit are
designed for a 6.35mm (0.25 in.) wide spade (standard for #6 screw
for up to 14 AWG) or a 4 mm (metric #4) fork terminal.
When using spade lugs, use a small, flat-blade screwdriver to pry the
finger-safe cover from the terminal blocks as shown below. Then
loosen the terminal screw.

terminal screw torque:
1.13 Nm (10 in-lbs) rated
1.3 Nm (12 in-lbs) max.

Finger-Safe
Cover

Publication 1764-UM001B-EN-P - April 2002

3-4

Wiring Your Controller

Using Surge Suppressors

Inductive load devices, such as motor starters and solenoids, require
the use of some type of surge suppression to protect and extend the
operating life of the controller’s output contacts. Switching inductive
loads without surge suppression can significantly reduce the life
expectancy of relay contacts. By adding a suppression device directly
across the coil of an inductive device, you prolong the life of the
output or relay contacts. You also reduce the effects of voltage
transients and electrical noise from radiating into adjacent systems.
The following diagram shows an output with a suppression device.
We recommend that you locate the suppression device as close as
possible to the load device.

+dc or L1

ac or dc
Outputs

VAC/D
Out 0
Out 1
Out 2
Out 3
Out 4
Out 5
Out 6
Out 7
COM

Suppression
Device

dc COM or L2

If the outputs are dc, we recommend that you use an 1N4004 diode
for surge suppression, as shown below.

+24V dc

Relay or Solid
State dc Outputs

VAC/D
Out 0
Out 1
Out 2
Out 3
Out 4
Out 5
Out 6
Out 7
COM

IN4004 Diode
24V dc common

Suitable surge suppression methods for inductive ac load devices
include a varistor, an RC network, or an Allen-Bradley surge
suppressor, all shown below. These components must be
appropriately rated to suppress the switching transient characteristic of
the particular inductive device. See the table on page 3-6 for
recommended suppressors.

Publication 1764-UM001B-EN-P - April 2002

Wiring Your Controller

3-5

Surge Suppression for Inductive ac Load Devices

Output Device

Varistor

Output Device

RC Network

Surge
Suppressor

If you connect an expansion I/O triac output to control an inductive
load, we recommend that you use varistors to suppress noise. Choose
a varistor that is appropriate for the application. The suppressors we
recommend for triac outputs when switching 120V ac inductive loads
are a Harris MOV, part number V175 LA10A, or an Allen-Bradley MOV,
catalog number 599-K04 or 599-KA04. Consult the varistor
manufacturer’s data sheet when selecting a varistor for your
application
For inductive dc load devices, a diode is suitable. A 1N4004 diode is
acceptable for most applications. A surge suppressor can also be used.
See the table on page 3-6 for recommended suppressors.
As shown in the illustration below, these surge suppression circuits
connect directly across the load device.

Surge Suppression for Inductive dc Load Devices
_
+
Output Device

Diode
(A surge suppressor can also be used.)

Publication 1764-UM001B-EN-P - April 2002

3-6

Wiring Your Controller

Recommended Surge Suppressors
Use the Allen-Bradley surge suppressors shown in the following table
for use with relays, contactors, and starters.

Suppressor Device

Coil Voltage

Catalog Number

Bulletin 509 Motor Starter
Bulletin 509 Motor Starter

120V ac
240V ac

599-K04(1)
599-KA04(1)

Bulletin 100 Contactor
Bulletin 100 Contactor

120V ac
240V ac

199-FSMA1(2)
199-FSMA2(2)

Bulletin 709 Motor Starter

120V ac

1401-N10

Bulletin 700 Type R, RM Relays

ac coil

None Required

Bulletin 700 Type R Relay
Bulletin 700 Type RM Relay

12V dc
12V dc

199-FSMA9

Bulletin 700 Type R Relay
Bulletin 700 Type RM Relay

24V dc
24V dc

199-FSMA9

Bulletin 700 Type R Relay
Bulletin 700 Type RM Relay

48V dc
48V dc

199-FSMA9

Bulletin 700 Type R Relay
Bulletin 700 Type RM Relay

115-125V dc
115-125V dc

199-FSMA10

Bulletin 700 Type R Relay
Bulletin 700 Type RM Relay

230-250V dc
230-250V dc

199-FSMA11

Bulletin 700 Type N, P, or PK Relay

150V max, ac or DC

700-N24(2)

Miscellaneous electromagnetic
devices limited to 35 sealed VA

150V max, ac or DC

700-N24(2)

(1) Varistor – Not recommended for use on relay outputs.
(2) RC Type – Do not use with triac outputs.

Grounding the Controller

Publication 1764-UM001B-EN-P - April 2002

In solid-state control systems, grounding and wire routing helps limit
the effects of noise due to electromagnetic interference (EMI). Run the
ground connection from the ground screw of the base unit to the
electrical panel’s ground bus prior to connecting any devices. Use
AWG #14 wire. This connection must be made for safety purposes.

Wiring Your Controller

3-7

This product is intended to be mounted to a well grounded mounting
surface such as a metal panel. Refer to the Industrial Automation
Wiring and Grounding Guidelines, publication 1770-4.1, for
additional information. Additional grounding connections from the
mounting tabs or DIN rail, if used, are not required unless the
mounting surface cannot be grounded. You must also provide an
acceptable grounding path for each device in your application.

TIP

It is recommended to use all four mounting positions
for panel mounting installation.

Grounding Stamping

TIP

ATTENTION

This
symbol denotes a protective earth ground
terminal which provides a low impedance path
between electrical circuits and earth for safety
purposes and provides noise immunity
improvement. This connection must be made for
safety purposes

Remove the protective debris strips before applying
power to the controller. Failure to remove the strips
may cause the controller to overheat.

Publication 1764-UM001B-EN-P - April 2002

3-8

Wiring Your Controller

Wiring Diagrams

This section shows the wiring diagrams for the MicroLogix 1500
controllers. Controllers with dc inputs can be wired as either sinking
or sourcing configuration. (Sinking and sourcing does not apply to ac
inputs.) See pages 3-12 through 3-15 for sinking and sourcing wiring
diagrams.

TIP

This
symbol denotes a protective earth ground
terminal which provides a low impedance path
between electrical circuits and earth for safety
purposes and provides noise immunity improvement.
This connection must be made for safety purposes.

Miswiring - 1764-28BXB Only
The following table shows miswiring conditions and the
consequences of improper wiring:

Condition

Result

Operating with Voltage
Less than 20.4V dc

This will not damage the base unit. The base unit may not
power up.
This is not recommended. You must

IMPORTANT verify that the line voltage remains
within specified limits.

Publication 1764-UM001B-EN-P - April 2002

Reverse Wiring of the Line
Terminals (0 to 30V dc)

Reverse wiring will not damage the base unit. The base unit
will not power up.

Applied Voltage Level
Exceeds the Published
Recommended Value
(i.e. applying 120V ac to
240V ac)

Exceeding the published recommended voltage may result
in permanent damage to the base unit.

Wiring Your Controller

3-9

Terminal Block Layouts
The base unit terminal block layouts are shown below. The shading
on the labels indicates how the terminals are grouped. A detail of the
groupings is shown in the table following the terminal block layouts.

Group 0
DC
COM 0

+24V
DC
POWER
OUT

Inputs

1764-24BWA
Outputs

VAC
VDC 0

85-265
VAC

Group 1

I/1

I/3

I/4

COM

I/0

I/2

DC
COM 1

VAC
VDC 1

VAC
VDC 2

VAC
VDC 3

VAC
VDC 4

O/0

O/1

O/3

O/2

85-265
VAC

VAC
VDC 0

VAC
VDC 1

VAC
VDC 2

O/0

O/1

Group 2
AC
COM 2

I/6

I/9

I / 11

I/8

I / 10

VAC
VDC 3

VAC
VDC 4

O/5

O/7

O/8

O / 10

O/3

O/4

O/6

VAC
VDC 5

O/9

Group 2
DC
COM 2

I/6

I/9

I / 11

I / 13

I / 15

I/7

I/8

I / 10

I / 12

I / 14

VAC VDC 2
VDC 1

O/3

O/5

O/7

VAC
VDC 3

O/9

O / 10

O/4

O/6

VDC
COM 2

O/8

VAC
VDC 4

28BXB

O / 11

3
up

1
up

0
up

up
G ro

G ro

O/2

up
G ro

O/1

24AWA

O / 11

I/5

O/0

24AWA

up
G ro

I/4

24BWA

O / 11

DC
COM 1

I/2

G ro

+24V

I/4

VAC
VDC 0

I/3

O/9

I/7

COM
24 VDC

O/6

up
G ro

Outputs

I/0

VAC
VDC 5

Group 1

I/1

NOT
USED

O / 10

I/5

1764-28BXB

O/8

I/2

up
G ro

Inputs

DC
COM 0

O/7

AC
COM 1

O/2

Group 0
NOT
USED

O/5

5
up
G ro

Outputs

I/0

I / 10

4
up
G ro

1764-24AWA

NOT
USED

I/3

24BWA

I/8

Group 1

I/1

I / 11

I/7

3
up
G ro

2
up
G ro

1
up
G ro

0
up
G ro

Inputs

AC
COM 0

I/9

I/5

O/4

Group 0
NOT
USED

Group 2
DC
COM 2

I/6

Publication 1764-UM001B-EN-P - April 2002

3-10

Wiring Your Controller

Terminal Groupings
Controller
1764-24BWA

1764-24AWA

1764-28BXB

Controller
1764-24BWA

1764-24AWA

1764-28BXB

Sinking and Sourcing Input
Circuits

Inputs
Input Group
Group 0
Group 1
Group 2
Group 0
Group 1
Group 2
Group 0
Group 1
Group 2

Common Terminal
DC COM 0
DC COM 1
DC COM 2
AC COM 0
AC COM 1
AC COM 2
DC COM 0
DC COM 1
DC COM 2

Input Terminal
I/0 through I/3
I/4 through I/7
I/8 through I/11
I/0 through I/3
I/4 through I/7
I/8 through I/11
I/0 through I/3
I/4 through I/7
I/8 through I/15

Outputs
Output Group
Group 0
Group 1
Group 2
Group 3
Group 4
Group 5
Group 0
Group 1
Group 2
Group 3
Group 4
Group 5
Group 0
Group 1
Group 2
Group 3
Group 4

Voltage Terminal
VAC/VDC 0
VAC/VDC 1
VAC/VDC 2
VAC/VDC 3
VAC/VDC 4
VAC/VDC 5
VAC/VDC 0
VAC/VDC 1
VAC/VDC 2
VAC/VDC 3
VAC/VDC 4
VAC/VDC 5
VAC/VDC 0
VAC/VDC 1
VDC 2, VDC COM 2
VAC/VDC 3
VAC/VDC 4

Output Terminal
O/0
O/1
O/2
O/3
O/4 through O/7
O/8 through O/11
O/0
O/1
O/2
O/3
O/4 through O/7
O/8 through O/11
O/0
O/1
O/2 through O/7
O/8 and O/9
O/10 and O/11

Any of the MicroLogix 1500 DC embedded input groups can be
configured as sinking or sourcing depending on how the DC COM is
wired on the group. See pages 3-12 through 3-15 for sinking and
sourcing wiring diagrams.

Type

Definition

Sinking Input
The input energizes when high-level voltage is
connection of a PNP sourcing device applied to the input terminal (active high). Connect
the power supply VDC (-) to the DC COM terminal.
Sourcing Input
The input energizes when low-level voltage is
connection of an NPN sinking device applied to the input terminal (active low). Connect
the power supply VDC (+) to the DC COM terminal.

Publication 1764-UM001B-EN-P - April 2002

Wiring Your Controller

3-11

1764-24AWA Wiring Diagram
Input Terminals

L2
NOT AC
IN 1
USED COM 0
NOT
USED

IN 0

IN 3

IN 4

AC
IN 9
COM 2

IN 6

AC
IN 2 COM 1 IN 5

IN 7

IN 8

IN 11

IN 10

L1
L2 L1
“NOT USED” terminals are not intended for use as connection points.

Output Terminals

L2
(Lo)
VAC VAC/ VAC/ VAC/ VAC/ VAC/
NEUT VDC 0 VDC 1 VDC 2 VDC 3 VDC 4 OUT 5 OUT 7 OUT 8 OUT 10
VAC/
120/240 EARTH
OUT 0 OUT 1 OUT 2 OUT 3 OUT 4 OUT 6
OUT 9 OUT 11
VDC 5
VAC GND

(Hi)
L1

Publication 1764-UM001B-EN-P - April 2002

3-12

Wiring Your Controller

1764-24BWA Wiring Diagram with Sinking Inputs
Input Terminals

+24V
DC
IN 1
POWER
COM
0
OUT
COM

IN 0

IN 3

IN 2

IN 4

DC
IN 5
COM 1

-DC

DC
COM 2

IN 6

IN 7

IN 8

IN 9

IN 11

IN 10

+DC

Output Terminals

L2
(Lo)
VAC VAC/ VAC/ VAC/ VAC/ VAC/
OUT 5 OUT 7 OUT 8 OUT 10
NEUT VDC 0 VDC 1 VDC 2 VDC 3 VDC 4
120/240 EARTH
VAC/
VAC GND OUT 0 OUT 1 OUT 2 OUT 3 OUT 4 OUT 6 VDC 5 OUT 9 OUT 11

(Hi)
L1

Publication 1764-UM001B-EN-P - April 2002

Wiring Your Controller

3-13

1764-24BWA Wiring Diagram with Sourcing Inputs
Input Terminals

+24V
POWER DC IN 1
OUT COM 0
COM

IN 0

IN 2

IN 3

IN 4

IN 6

DC
IN 5
COM 1

DC
IN 9
COM 2

IN 7

IN 8

IN 11

IN 10

+DC -DC

Output Terminals

CR
L2

(Lo)
VAC VAC/ VAC/ VAC/ VAC/ VAC/
NEUT VDC 0 VDC 1 VDC 2 VDC 3 VDC 4 OUT 5 OUT 7 OUT 8 OUT 10
120/240 EARTH
VAC/
OUT 0 OUT 1 OUT 2 OUT 3 OUT 4 OUT 6
OUT 9 OUT 11
VAC GND
VDC 5

(Hi)

Publication 1764-UM001B-EN-P - April 2002

3-14

Wiring Your Controller

1764-28BXB Wiring Diagram with Sinking Inputs
Input Terminals

-DC
+DC

NOT DC
IN 1
USED COM 0
NOT
IN 0
USED

IN 3

IN 2

IN 4

IN 6

DC
IN 5
COM 1

DC IN 9
COM 2

IN 7

IN 8

IN 11 IN 13 IN 15

IN 10 IN 12 IN 14

“NOT USED” terminals are not intended for use as connection points.

Output Terminals (FET Outputs Are Sourcing Only)

-DC

COM

VAC/ VAC/ VDC 2 OUT 3 OUT 5 OUT 7 VAC/ OUT 9 OUT 10
VDC 0 VDC 1
VDC 3

+24v EARTH OUT 0 OUT 1 OUT 2 OUT 4 OUT 6 VDC OUT 8 VAC/ OUT 11
COM 2
GND
VDC 4

+DC

Publication 1764-UM001B-EN-P - April 2002

Wiring Your Controller

3-15

1764-28BXB Wiring Diagram with Sourcing Outputs
Input Terminals

+DC
-DC

NOT DC
IN 1
USED COM 0
NOT IN 0
USED

IN 3

IN 2

IN 4

IN 6

DC
IN 5
COM 1

DC IN 9
COM 2

IN 7

IN 8

IN 11 IN 13 IN 15

IN 10 IN 12 IN 14

“NOT USED” terminals are not intended for use as connection points.

Output Terminals (FET Outputs Are Sourcing Only)

-DC

COM
+24V

+DC

VAC/ VAC/
VAC/
VDC 2 OUT 3 OUT 5 OUT 7
OUT 9 OUT 10
VDC 0 VDC 1
VDC 3

VDC
EARTH
VAC/
OUT 0 OUT 1 OUT 2 OUT 4 OUT 6
OUT 8
OUT 11
COM 2
GND
VDC 4

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3-16

Wiring Your Controller

Controller I/O Wiring

Minimizing Electrical Noise
Because of the variety of applications and environments where
controllers are installed and operating, it is impossible to ensure that
all environmental noise will be removed by input filters. To help
reduce the effects of environmental noise, install the MicroLogix 1500
system in a properly rated (i.e. NEMA) enclosure. Make sure that the
MicroLogix 1500 system is properly grounded.
A system may malfunction may occur due to a change in the
operating environment after a period of time. We recommend
periodically checking system operation, particularly when new
machinery or other noise sources are installed near the Micrologix
1500 system.

Transistor Output Transient Pulses

ATTENTION

A brief transient current pulse may flow through
transistor outputs if the external supply voltage is
suddenly applied at the V dc and V dc com terminals
(e.g. via the master control relay). It is a fast
rate-of-change of voltage at the terminals that causes
the pulse. This condition is inherent in transistor
outputs and is common to solid state devices. The
transient pulses may occur regardless of whether the
controller is powered or running.

The transient energy is dissipated in the load, and the pulse duration
is longer for loads with high impedance. The graph below illustrates
the relation between pulse duration and load current. Power-up
transients will not exceed the times shown in the graph. For most
applications the pulse energy is not sufficient to energize the load.
To reduce the possibility of inadvertent operation of devices
connected to transistor outputs, consider adding an external resistor in
parallel to the load to increase the on-state load current. The duration
of the transient pulse is reduced when the on-state load current is
increased or the load impedance is decreased.

Publication 1764-UM001B-EN-P - April 2002

Wiring Your Controller

3-17

1.0
0.9
0.8

Transient Pulse Duration as a
Function of Load Current

Time - Duration of Transient (ms)

0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
1

100

200

300

400

500

600

700

800

900

1000

On-State Load Current (mA)

Publication 1764-UM001B-EN-P - April 2002

3-18

Wiring Your Controller

Publication 1764-UM001B-EN-P - April 2002

Chapter

Communication Connections

This chapter describes how to set up communications for your control
system. The method you use and cabling required depend on your
application. This chapter also describes how the controller establishes
communication with the appropriate network. Topics include:
•
•
•
•
•
•

Default Communication Configuration
Communications Toggle Push Button
Connecting to the RS-232 Port
Connecting to a DH-485 Network
Connecting to DeviceNet
Connecting to Ethernet

ATTENTION

All devices communicating within a network, must
use the same protocol.

!
Default Communication
Configuration

The MicroLogix 1500 has the following default communication
configuration.
Table 4.1 DF1 Full-Duplex Configuration Parameters

Parameter

Default

Baud Rate

19.2K

Parity

none

Source ID (Node Address)

Control Line

no handshaking

Error Detection

CRC

Embedded Responses

auto detect

Duplicate Packet (Message) Detect

enabled

ACK Timeout

50 counts

NAK retries

3 retries

ENQ retries

3 retries

Stop Bits

Publication 1764-UM001B-EN-P - April 2002

4-2

Communication Connections

TIP

The default configuration is present when:
• The controller is powered-up for the first time.
• The communications toggle push button specifies
default communications (the DCOMM LED is on).
• An OS upgrade is completed.

For more information about communications, see Understanding
Communication Protocols on page E-1.

Communications Toggle
Push Button

The Communications Toggle Push Button is located on the processor.
You must remove processor door or DAT to access the
Communications Toggle Push Button.
Use the Communications Toggle Push Button to change from the
user-defined communication configuration to the default
communications configuration and back. The Default
Communications (DCOMM) LED operates to show when the
controller is in the default communications mode (settings shown on
page 4-1).

COMMS

DC INPUTS

24V SINK/SOURCE
DC/RELAY OUT

24V SOURCE

TIP

The Communication Toggle Push Button must be
pressed and held for two seconds to activate.
The Communication Toggle Push Button only affects
the communication configuration of Channel 0.

Publication 1764-UM001B-EN-P - April 2002

Communication Connections

Connecting to the RS-232
Port

4-3

DF1 Full-Duplex Communication Parameters
When a communication channel is configured for DF1 Full-Duplex,
the following parameters can be changed.
Table 4.2 DF1 Full-Duplex Configuration Parameters
Parameter
Options
Baud Rate
300, 600, 1200, 2400, 4800, 9600, 19.2K, 38.4K
Parity
none, even
Source ID (Node
0 to 254 decimal
Address)
Control Line
no handshaking, Full-Duplex modem
handshaking
Error Detection
CRC, BCC
Embedded Responses
auto-detect, enabled
Duplicate Packet
enabled, disabled
(Message) Detect
ACK Timeout
1 to 65535 counts (20 ms increments)
NAK retries
0 to 255
ENQ retries
0 to 255
Stop Bits
not a setting, always 1

Default
19.2K
none
1
no
handshaking
CRC
auto detect
enabled
50 counts
3 retries
3 retries
1

Making a DF1 Full-Duplex Point-to-Point Connection
You can connect the MicroLogix 1500 programmable controller to
your personal computer using a serial cable from your personal
computer’s serial port to the controller, as shown in the illustrations
below.

ATTENTION

Chassis ground, internal 24V ground, user 24V dc
ground, and RS-232 ground are internally connected.
You must connect the chassis ground terminal screw
to ground prior to connecting any devices. It is
important that you understand your personal
computer’s grounding system before connecting to
the controller. An optical isolator, such as the
1761-NET-AIC, is recommended between the
controller and your personal computer when using
Channel 0. An isolator is not required when using
Channel 1 (1764-LRP).

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4-4

Communication Connections

Channel 0
We recommend using an Advanced Interface Converter (AIC+),
catalog number 1761-NET-AIC, or similar optical isolator, as shown
below. See page 4-16 for specific AIC+ cabling information.

MicroLogix 1500 with 1764-LSP
or 1764-LRP processor

Personal Computer

1761-CBL-AM00
or 1761-CBL-HM02

TERM
A
B
COM
SHLD
CHS GND

1747-CP3 or 1761-CBL-AC00

PWR

DC SOURCE
CABLE

EXTERNAL

24V dc
MicroLogix 1500 provides power
to the AIC+ or an external power
supply may be used.

Channel 1

MicroLogix
1500 Controller
with 1764-LRP
processor
Personal Computer

Publication 1764-UM001B-EN-P - April 2002

1747-CP3

Communication Connections

4-5

Using a Modem
You can use modems to connect a personal computer to one
MicroLogix 1500 controller (using DF1 Full-Duplex protocol), or to
multiple controllers (using DF1 Half-Duplex protocol), or Modbus
Slave RTU protocol, as shown in the following illustration. Do not use
DH-485 protocol through modems under any circumstance. (See
Using Modems with MicroLogix 1500 Programmable Controllers on
page E-3 for information on types of modems you can use with the
MicroLogix controllers.)

Personal
Computer

Modem Cable
(straight-through)
MicroLogix1500
Controller with
1764-LRP
Processor

Modem

Protocol
DF1 Full-Duplex protocol (to 1 controller)
DF1 Half-Duplex Slave protocol (to multiple controllers when a
DF1 Half-Duplex Master is present)

Modem

Isolated Modem Connection
We recommend using an AIC+, catalog number 1761-NET-AIC, as
your optical isolator for Channel 0. See page 4-16 for specific AIC+
cabling information. Using an AIC+ to isolate the modem is illustrated
below:

MicroLogix 1500 with 1764-LSP
or 1764-LRP processor
1761-CBL-AM00
or 1761-CBL-HM02

User supplied modem cable

Modem

24V dc
MicroLogix 1500 provides power to the AIC+ or
an external power supply may be used.

Publication 1764-UM001B-EN-P - April 2002

4-6

Communication Connections

Constructing Your Own Modem Cable
If you construct your own modem cable, the maximum cable length is
15.24 m (50 ft) with a 25-pin or 9-pin connector. Refer to the following
typical pinout for constructing a straight-through cable:

AIC+ Optical Isolator
or 1764-LRP Channel 1

Modem

9-Pin

pins 4 and 6
are internally
connected for
1764-LRP only

25-Pin

9-Pin

TXD

RXD

GND

DTR

DSR

CTS

RTS

Constructing Your Own Null Modem Cable
If you construct your own null modem cable, the maximum cable
length is 15.24m (50 ft) with a 25-pin or 9-pin connector. Refer to the
following typical pinout:

Optical Isolator

Modem

9-Pin

Publication 1764-UM001B-EN-P - April 2002

25-Pin

9-Pin

TXD

RXD

GND

DTR

DSR

CTS

RTS

Communication Connections

4-7

Connecting to a DF1 Half-Duplex Network
When a communication port is configured for DF1 Half-Duplex Slave,
available parameters include:

Table 4.3 DF1 Half-Duplex Configuration Parameters
Parameter

Options

Baud Rate

300, 600, 1200, 2400, 4800, 9600, 19.2K, 38.4K

Parity

none, even

Source ID (Node Address)

0 to 254 decimal

Control Line

no handshaking, handshaking

Error Detection

CRC, BCC

EOT Suppression

enabled, disabled
When EOT Suppression is enabled, the slave does not respond when polled if no message is queued. This
saves modem transmission power and time when there is no message to transmit.

Duplicate Packet (Message)
Detect

enabled, disabled
Detects and eliminates duplicate responses to a message. Duplicate packets may be sent under noisy
communication conditions if the sender’s Message Retries are not set to 0.

Poll Timeout (x20 ms)

0 to 65535 (can be set in 20 ms increments)
Poll Timeout only applies when a slave device initiates a MSG instruction. It is the amount of time that the
slave device waits for a poll from the master device. If the slave device does not receive a poll within the
Poll Timeout, a MSG instruction error is generated, and the ladder program needs to requeue the MSG
instruction. If you are using a MSG instruction, it is recommended that a Poll Timeout value of zero not be
used. Poll Timeout is disabled when set to zero.

RTS Off Delay (x20 ms)

0 to 65535 (can be set in 20 ms increments)
Specifies the delay time between when the last serial character is sent to the modem and when RTS is
deactivated. Gives the modem extra time to transmit the last character of a packet.

RTS Send Delay (x20 ms)

0 to 65535 (can be set in 20 ms increments)
Specifies the time delay between setting RTS until checking for the CTS response. For use with modems
that are not ready to respond with CTS immediately upon receipt of RTS.

Message Retries

0 to 255
Specifies the number of times a slave device attempts to resend a message packet when it does not
receive an ACK from the master device. For use in noisy environments where message packets may
become corrupted in transmission.

Pre Transmit Delay
(x1 ms)

0 to 65535 (can be set in 1 ms increments)
• When the Control Line is set to no handshaking, this is the delay time before transmission.
Required for 1761-NET-AIC physical Half-Duplex networks. The 1761-NET-AIC needs delay time to
change from transmit to receive mode.
• When the Control Line is set to DF1 Half-Duplex Modem, this is the minimum time delay between
receiving the last character of a packet and the RTS assertion.

Publication 1764-UM001B-EN-P - April 2002

4-8

Communication Connections

DF1 Half-Duplex Master-Slave Network
Use this diagram for DF1 Half-Duplex Master-Slave protocol without
hardware handshaking.

MicroLogix 1500 (DF1 Slave)

SLC 5/03 (DF1 Master)

CH0
CH0
AIC+

1761-CBL-AM00 or
1761-CBL-HM02

1761-CBL-AP00 or
1761-CBL-PM02

AIC+
straight 9-25
pin cable

straight 9-25 pin cable
radio modem
or lease line

MicroLogix 1500 (DF1 Slave)

MicroLogix 1500 (DF1 Slave)
radio modem
or lease line

CH0 to port 1 or port 2

1761-CBL-AM00 or
1761-CBL-HM02

1761-CBL-AM00 or
1761-CBL-HM02
AIC+

AIC+
1761-CBL-AP00 or
1761-CBL-PM02

REFERENCE: AIC+ Port Identification
Port 3: RS-485
Port 1: DB-9 RS-232

Publication 1764-UM001B-EN-P - April 2002

Port 2: mini-DIN 8 RS-232

1761-CBL-AP00 or
1761-CBL-PM02

Communication Connections

4-9

DF1 Half-Duplex Network (Using PC and Modems)

Rockwell Software RSLinx 2.0 (or
higher), SLC 5/03, SLC 5/04, and
SLC 5/05, or PLC-5 processors
configured for DF1 Half-Duplex
Master.

TERM

Modem

TERM

COM

SHLD

COM

SHLD

CHS GND

DF1 Half-Duplex Protocol

SHLD

CHS GND

PWR

DC SOURCE

CHS GND

PWR

DC SOURCE

CABLE

EXTERNAL

PWR

CABLE

EXTERNAL

MicroLogix
1000 (Slave)

DC SOURCE

CABLE

EXTERNAL

MicroLogix
1200 (Slave)

MicroLogix 1500 with
1764-LSP or 1764-LRP
Processor (Slave)

SLC 5/03 (Slave)

MicroLogix 1500 with
1764-LRP Processor (Slave)

Publication 1764-UM001B-EN-P - April 2002

4-10

Communication Connections

Connecting to a DH-485
Network

The following network diagrams provide examples of how to connect
MicroLogix 1500 controllers to the DH-485 network using the
Advanced Interface Converter (AIC+, catalog number 1761-NET-AIC).
For more information on the AIC+, see the Advanced Interface
Converter and DeviceNet Interface Installation Instructions,
Publication 1761-5.11.

DH-485 Network with a MicroLogix 1500 Controller
MicroLogix 1500

connection from port 1 or port 2
to MicroLogix Channel 1

Personal Computer

1761-CBL-AP00
or 1761-CBL-PM02
1747-CP3
or 1761-CBL-AC00

AIC+
TERM
A
B
COM
SHLD

connection from port 1 or port 2
to MicroLogix Channel 0

CHS GND

PWR

EXTERNAL

24V dc
(user supply
needed if not
connected to
a controller)

1761-CBL-AM00
or 1761-CBL-HM02
AIC+
TERM
A
B
COM
SHLD
CHS GND

PWR

1761-CBL-AP00
or 1761-CBL-PM02

PC to port 1
or port 2

EXTERNAL

1761-CBL-AP00
or 1761-CBL-PM02

24V dc
(user supply needed if not
connected to a controller)
TERM
A
B
COM
SHLD
CHS GND

REFERENCE: AIC+ Port Identification

AIC+

PWR

DC SOURCE
CABLE

EXTERNAL

TERM

Port 2: mini-DIN 8 RS-232

Port 3: RS-485

B
COM
SHLD
CHS GND

Port 1: DB-9 RS-232

PWR

EXTERNAL

Publication 1764-UM001B-EN-P - April 2002

24V dc
(user supplied)

1747-CP3
or 1761-CBL-AC00

Communication Connections

4-11

Typical 3-Node Network (Channel 0 Connection)

PanelView 550
A-B

PanelView

RJ45 port 1761-CBL-AS09
or 1761-CBL-AS03
TERM

MicroLogix 1500 with
1764-LSP or 1764-LRP
Processor

A
B
COM
SHLD
CHS GND

PWR

DC SOURCE
CABLE

EXTERNAL

1747-CP3 or
1761-CBL-AC00

1761-CBL-AM00
or 1761-CBL-HM02

Typical 3-Node Network (Channel 1 Connection)

A-B
A-B

PanelView 550

PanelView
PanelView

1761-CBL-AS09
RJ45 port
or 1761-CBL-AS03

MicroLogix 1500 with
1764-LRP Processor

TERM
TERM
A A
B B
COM
COM
SHLD
SHLD
CHSCHS
GND
GND

TXTX

PWR
PWR

DCDC
SOURCE
SOURCE
CABLE
CABLE

EXTERNAL
EXTERNAL

1747-CP3 or
1761-CBL-AC00

Networked Operator Interface Device and MicroLogix Controllers
AIC+

AIC+
TERM

TERM

COM

SHLD

CHS GND

A-B

PWR

DC SOURCE

PWR

DC SOURCE

CABLE

EXTERNAL

SLC 5/04

PanelView 550

DH-485 Network
AIC+

AIC+

TERM

PWR

DC SOURCE

PWR

CABLE

EXTERNAL

MicroLogix 1200

DC SOURCE

CABLE

EXTERNAL

MicroLogix 1000

CHS GND

DC SOURCE

CABLE

EXTERNAL

SHLD

CHS GND

DC SOURCE

CABLE

COM

SHLD

CHS GND

COM

SHLD

CHS GND

COM

SHLD

TERM

COM

TERM

AIC+

TERM

PanelView

CHS GND

EXTERNAL

Personal
Computer

MicroLogix 1500

Publication 1764-UM001B-EN-P - April 2002

4-12

Communication Connections

DH-485 Configuration Parameters
When MicroLogix communications are configured for DH-485, the
following parameters can be changed:
Table 4.4 DF1 Full-Duplex Configuration Parameters
Parameter

Options

Baud Rate

9600, 19.2K

Node Address

1 to 31 decimal

Token Hold Factor

1 to 4

See Software Considerations on page E-10 for tips on setting the
parameters listed above.

Recommended Tools
To connect a DH-485 network, you need tools to strip and attach the
shielded cable. We recommend the following equipment (or
equivalent):
Table 4.5 Working with Cable for DH-485 Network
Description

Part Number

Manufacturer

Shielded Twisted Pair Cable

#3106A or #9842

Belden

Stripping Tool

45-164

Ideal Industries

1/8” Slotted Screwdriver

Not Applicable

DH-485 Communication Cable
The communication cable consists of a number of cable segments
daisy-chained together. The total length of the cable segments cannot
exceed 1219 m (4000 ft). However, two segments can be used to
extend the DH-485 network to 2438m (8000 ft). For additional
information on connections using the AIC+, refer to the Advanced
Interface Converter (AIC+) User Manual, publication 1761-6.4.

Publication 1764-UM001B-EN-P - April 2002

Communication Connections

4-13

Communication Cable Connection to the DH-485 Connector

TIP

A daisy-chained network is recommended.
We do not recommend the following:

Belden #3106A or #9842

Connector
Connector

Connector
Incorrect

Single Cable Connection
When connecting a single cable to the DH-485 connector, use the
following diagram.

Orange with White Stripes
White with Orange Stripes

Shrink Tubing Recommended Blue (#3106A) or
Blue with White
Stripes (#9842)

6 Termination
5A
4B
3 Common
2 Shield
1 Chassis Ground
Drain/Shield

Publication 1764-UM001B-EN-P - April 2002

4-14

Communication Connections

Multiple Cable Connection
When connecting multiple cables to the DH-485 connector, use the
following diagram.

to Previous Device

to Next Device

Table 4.6 Connections using Belden #3106A Cable
For this Wire/Pair

Connect this Wire

To this Terminal

Shield/Drain

Non-jacketed

Terminal 2 - Shield

Blue

Terminal 3 - (Common)

White/Orange

White with Orange
Stripe

Terminal 4 - (Data B)

Orange with White
Stripe

Terminal 5 - (Data A)

Table 4.7 Connections using Belden #9842 Cable
For this Wire/Pair
Shield/Drain
Blue/White

White/Orange

Connect this Wire
To this Terminal
Non-jacketed
Terminal 2 - Shield
White with Blue Stripe
Cut back - no
connection(1)
Blue with White Stripe
Terminal 3 (Common)
White with Orange
Terminal 4 - (Data B)
Stripe
Orange with White
Terminal 5 - (Data A)
Stripe

(1) To prevent confusion when installing the communication cable, cut back the white with blue stripe wire
immediately after the insulation jacket is removed. This wire is not used by DH-485.

Grounding and Terminating the DH-485 Network
Only one connector at the end of the link must have Terminals 1 and
2 jumpered together. This provides an earth ground connection for
the shield of the communication cable. Both ends of the network must
have Terminals 5 and 6 jumpered together, as shown below. This
connects the termination impedance (of 120Ω) that is built into each
AIC+ as required by the DH-485 specification.

Publication 1764-UM001B-EN-P - April 2002

Communication Connections

4-15

End-of-Line Termination

Jumper

Belden #3106A or #9842 Cable
1219 m (4000 ft) Maximum
Jumper

Connecting the AIC+
The AIC+, catalog number 1761-NET-AIC, enables MicroLogix
controllers to connect to a DH-485 network when they are configured
for DH-485 protocol. The AIC+ has two isolated RS-232 ports and one
RS-485 port. When two MicroLogix controllers are closely positioned,
you can connect a controller to each of the RS-232 ports on the AIC+.
The AIC+ can also be used as an RS-232 isolator, providing an
isolation barrier between the controllers communications port and any
equipment connected to it (i.e. personal computer, modem, etc.)
The following figure shows the connections and specifications of the
AIC+.

Item

Description

Port 1 - DB-9 RS-232, DTE

Port 2 - mini-DIN 8 RS-232 DTE

Port 3 - RS-485 Phoenix plug

DC Power Source selector switch
(cable = port 2 power source, external =
external power source connected to item 5)

3
2

Terminals for external 24V dc power supply
and chassis ground
5

For additional information on connecting the AIC+, refer to the
Advanced Interface Converter (AIC+) User Manual, publication
1761-6.4.

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4-16

Communication Connections

Cable Selection Guide

1761-CBL-PM02

1761-CBL-AP00

Cable

Length

Connections from

to AIC+ External Power
Supply
Required(1)

Power
Selection
Switch
Setting(1)

1761-CBL-AP00
1761-CBL-PM02

45cm (17.7 in)
2m (6.5 ft)

1764-LRP processor, channel 1

port 2

yes

external

SLC 5/03 or SLC 5/04 processors, channel 0

port 2

yes

external

MicroLogix 1000 or 1500

port 1

yes

external

PanelView 550 through NULL modem adapter

port 2

yes

external

DTAM Plus / DTAM Micro

port 2

yes

external

PC COM port

port 2

yes

external

(1) External power supply required unless the AIC+ is powered by the device connected to port 2, then the selection switch should be set to cable.

1761-CBL-HM02

1761-CBL-AM00

Cable

Length

Connections from

to
AIC+

External Power
Supply Required(1)

Power Selection
Switch Setting(1)

1761-CBL-AM00
1761-CBL-HM02

45cm (17.7 in)
2m (6.5 ft)

MicroLogix 1000 or 1500

port 2

cable

to port 2 on another AIC+

port 2

yes

external

(1) External power supply required unless the AIC+ is powered by the device connected to port 2, then the selection switch should be set to cable.

Publication 1764-UM001B-EN-P - April 2002

Communication Connections

4-17

1747-CP3
1761-CBL-AC00

Cable

Length

Connections from

to AIC+

External Power
Power Selection
(1)
Supply Required
Switch Setting(1)

1747-CP3
1761-CBL-AC00

3m (9.8 ft)
45cm (17.7 in)

1764-LRP processor, channel 1

port 1

yes

external

SLC 5/03 or SLC 5/04 processor, channel 0

port 1

yes

external

PC COM port

port 1

yes

external

PanelView 550 through NULL modem adapter port 1

yes

external

DTAM Plus / DTAM Micro™

port 1

yes

external

Port 1 on another AIC+

port 1

yes

external

(1) External power supply required unless the AIC+ is powered by the device connected to port 2, then the selection switch should be set to cable.

user supplied cable

Cable

Length

Connections from

to
AIC+

External Power
Supply Required(1)

Power Selection
Switch Setting(1)

straight
9-25 pin

—

modem or other communication device

port 1

yes

external

(1) External power supply required unless the AIC+ is powered by the device connected to port 2, then the selection switch should be set to cable.

1761-CBL-AS09
1761-CBL-AS03

Cable

Length

Connections from

to AIC+

External Power
Supply
Required(1)

Power
Selection
Switch
Setting(1)

1761-CBL-AS03
1761-CBL-AS09

3m (9.8 ft)
9.5m (31.17 ft)

SLC 500 Fixed,
SLC 5/01, SLC 5/02, and SLC 5/03 processors

port 3

yes

external

PanelView 550 RJ45 port

port 3

yes

external

(1) External power supply required unless the AIC+ is powered by the device connected to port 2, then the selection switch should be set to cable.

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4-18

Communication Connections

1761-CBL-PM02 (or equivalent) Cable Wiring Diagram

5
4
3
2
1

9
8
7
6

6 78
3

5
4

Publication 1764-UM001B-EN-P - April 2002

Programming
Device

Controller

9-Pin D-Shell

8-Pin Mini Din

24V

CTS

GND

RTS

DSR

RXD

GND

DCD

DTR

CTS

TXD

RXD

GND

DCD

1 2

Communication Connections

4-19

Recommended User-Supplied Components
The components in Table 4.8 can be purchased from your local
electronics supplier.
Table 4.8 User Supplied Components
Component

Recommended Model

external power supply and chassis
ground

power supply rated for 20.4-28.8V dc

NULL modem adapter

standard AT

straight 9-25 pin RS-232 cable

see table below for port information if making own
cables

Port 1
DB-9 RS-232

Port 2
8-pin mini-DIN(2)

1
2

3
4

6 78

Port 3
RS-485 connector

5
3

5
4

4
3

1
(2) The 8-pin mini-DIN connector is not commercially available.

Table 4.9 AIC+ Terminals
Pin

Port 1: DB-9 RS-232

Port 2(2)

Port 3: RS-485
Connector

received line signal
detector (DCD)

24V dc

chassis ground

received data (RxD)

ground (GND)

cable shield

transmitted data (TxD)

request to send (RTS)

signal ground

DTE ready (DTR)(1)

received data (RxD)

DH-485 data B

signal common (GND)

received line signal detector (DCD) DH-485 data A

DCE ready (DSR)(2)

clear to send (CTS)

termination

request to send (RTS)

transmitted data (TxD)

not applicable

clear to send (CTS)

ground (GND)

not applicable

(1) On port 1, pin 4 is electronically jumpered to pin 6. Whenever the AIC+ is powered on, pin 4 will match the state
of pin 6.
(2) An 8-pin mini DIN connector is used for making connections to port 2. This connector is not commercially
available.

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4-20

Communication Connections

Safety Considerations
This equipment is suitable for use in Class I, Division 2, Groups A, B,
C, D or non-hazardous locations only.
.
WARNING

EXPLOSION HAZARD
This product must be installed in an enclosure. All
cables connected to the product must remain in the
enclosure or be protected by conduit or other means.

See Safety Considerations on page 2-3 for additional information.

Installing and Attaching the AIC+
1. Take care when installing the AIC+ in an enclosure so that the
cable connecting the MicroLogix 1500 controller to the AIC+
does not interfere with the enclosure door.
2. Carefully plug the terminal block into the RS-485 port on the
AIC+ you are putting on the network. Allow enough cable slack
to prevent stress on the plug.
3. Provide strain relief for the Belden cable after it is wired to the
terminal block. This guards against breakage of the Belden cable
wires.

Powering the AIC+
In normal operation with a MicroLogix programmable controller
connected to port 2 of the AIC+, the controller powers the AIC+. Any
AIC+ not connected to a MicroLogix controller requires a 24V dc
power source. The AIC+ requires 120 mA at 24V dc.
If both the controller and external power are connected to the AIC+,
the power selection switch determines what device powers the AIC+.

ATTENTION

!
Publication 1764-UM001B-EN-P - April 2002

If you use an external power supply, it must be 24V
dc. Permanent damage results if higher voltage is
used.

Communication Connections

4-21

Set the DC Power Source selector switch to EXTERNAL before
connecting the power supply to the AIC+. The following illustration
shows where to connect external power for the AIC+.

Bottom View

24VDC
DC
NEUT
CHS
GND

ATTENTION

Always connect the CHS GND (chassis ground)
terminal to the nearest earth ground. This connection
must be made whether or not an external 24V dc
supply is used.

Power Options
Below are two options for powering the AIC+:
• Use the 24V dc user power supply built into the MicroLogix
1500 controller. The AIC+ is powered through a hard-wired
connection using a communication cable (1761-CBL-HM02, or
equivalent) connected to port 2.
• Use an external DC power supply with the following
specifications:
– operating voltage: 24V dc +20% or -15%
– output current: 150 mA minimum
– rated NEC Class 2
Make a hard-wired connection from the external supply to the
screw terminals on the bottom of the AIC+.

ATTENTION

If you use an external power supply, it must be 24V
dc. Permanent damage results if miswired with the
wrong power source.

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4-22

Communication Connections

Connecting to DeviceNet

You can connect a MicroLogix 1500 using DF1 Full-Duplex protocol to
a DeviceNet network using the DeviceNet Interface (DNI), catalog
number 1761-NET-DNI. For additional information on using the DNI,
refer to the DeviceNet Interface User Manual, publication 1761-6.5.
The following figure shows the external wiring connections of the
DNI.

V–
CAN_L

NET

SHIELD
CAN_H

DeviceNet Node (Port 1)
(Replacement connector
part no. 1761-RPL-0000)

V+

MOD

NODE

DANGER

Use this write-on
area to mark the
DeviceNet node
address.

TX/RX
GND

RS-232 (Port 2)

Cable Selection Guide

1761-CBL-HM02

1761-CBL-AM00

Cable

Length

Connections from

1761-CBL-AM00
1761-CBL-HM02

45 cm (17.7 in) MicroLogix 1000
2m (6.5 ft)
MicroLogix 1500

port 2
port 2

1761-CBL-PM02

1761-CBL-AP00

Publication 1764-UM001B-EN-P - April 2002

to DNI

Cable

Length

Connections from

to DNI

1761-CBL-AP00
1761-CBL-PM02

45 cm (17.7 in)
2m (6.5 ft)

SLC 5/03 or SLC 5/04 processors,
channel 0

port 2

PC COM port

port 2

1764-LRP processor, channel 1

port 2

Communication Connections

Connecting to Ethernet

4-23

You can connect a MicroLogix 1500 to an Ethernet network using the
Ethernet Interface (ENI), catalog number 1761-NET-ENI. For additional
information on using the ENI, refer to the Ethernet Interface User
Manual, publication 1761-UM006. The following figure shows the
external wiring connections of the ENI.
ETHERNET
RS232
FAULT

NET
TX/RX

Ethernet Port (ENI Port 1)

TX/RX

RS-232 Mini-DIN (ENI Port 2)

IP
PWR

CABLE
EXTERNAL

Ethernet Connections
The Ethernet connector, port 1, is an RJ45, 10Base-T connector. The
pin-out for the connector is shown below:
Pin

Pin Name

Tx+

Tx-

Rx+

not used by 10Base-T

Rx-

not used by 10Base-T

When to use straight-through and cross-over cable:
• ENI Ethernet port to 10Base-T Ethernet switch cables utilize a
straight-through pin-out (1-1, 2-2, 3-3, 6-6).
• Direct point-to-point 10Base-T cables connecting the ENI
Ethernet port directly to another ENI Ethernet port (or a
computer 10Base-T port) require a cross-over pin-out (1-3, 2-6,
3-1, 6-2).

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4-24

Communication Connections

RS-232 Connections
Port 2 of the ENI is an 8-pin mini-DIN RS-232 port that provides
connection to DF1 compatible RS-232 devices. The connector pin
assignments are shown below.

7
6

8
8-pin mini-DIN

5
4
2

Port 2

24V dc

ground (GND)

no connection

ENI input data, RxD

no connection

ENI output data, TxD

ground (GND)

The table below describes the RS-232 compatible cables.

ENI Connected to:

Catalog Number

Use Cable

1761-CBL-AM00
1761-CBL-HM02

Mini DIN to Mini DIN
45 cm (17.7 in)
2m (6.5 ft.)

1761-CBL-AP00
1761-CBL-PM02

Mini DIN to D-Shell
45 cm (17.7 in)
2m (6.5 ft.)

1761-CBL-AP00
1761-CBL-PM02

Mini DIN to D-Shell
45 cm (17.7 in)
2m (6.5 ft.)

MicroLogix (all series)

SLC 5/03, SLC 5/04, or
SLC 5/05 Channel 0
PLC-5

Publication 1764-UM001B-EN-P - April 2002

Chapter

Using Trim Pots and the Data Access Tool
(DAT)

Trim Pot Operation

The processor has two trimming potentiometers (trim pots) which
allow modification of data within the controller. Adjustments to the
trim pots change the value in the corresponding Trim Pot Information
(TPI) register. The data value of each trim pot can be used throughout
the control program as timer, counter, or analog presets depending
upon the requirements of the application.
The trim pots are located below the mode switch under the left access
door of the processor.

Trim Pot 0

RUN

REM

PROG

Trim Pot 1

Use a small flathead screwdriver to turn the trim pots. Adjusting their
value causes data to change within a range of 0 to 250 (fully
clockwise). The maximum rotation of each trim pot is three-quarters,
as shown below. Trim pot stability over time and temperature is
typically ±2 counts.

Minimum
(fully counterclockwise)

Maximum
(fully clockwise)

Trim pot data is updated continuously whenever the controller is
powered-up.
1

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5-2

Using Trim Pots and the Data Access Tool (DAT)

Trim Pot Information Function File
The composition of the Trim Pot Information (TPI) Function File is
described in the MicroLogix 1200 and MicroLogix 1500 Instruction Set
Reference Manual, publication 1762-RM001.

Error Conditions
If the controller detects a problem/error with either trim pot, the last
values read remain in the data location, and an error code is put in the
error code byte of the TPI file for whichever trim pot had the
problem. Once the problem/error is corrected, the error code is
cleared. The error codes are described in the MicroLogix 1200 and
MicroLogix 1500 Instruction Set Reference Manual, publication
1762-RM001.

Data Access Tool (DAT)

The DAT is a convenient and simple tool that provides an interface for
editing and monitoring data. The DAT has five primary features:
•
•
•
•
•

provides direct access to 48 bit elements
provides direct access to 48 integer elements
provides two function keys
displays controller faults
allows removal/insertion under power

DAT Keypad and Indicator Light Functions
The DAT has a digital display, 6 keys, an up/down key, and 7
indicator lights. Their functions are described in the table on page 5-3.

PROTECTED

Publication 1764-UM001B-EN-P - April 2002

ESC

BIT

INT

ENTER

Using Trim Pots and the Data Access Tool (DAT)

5-3

Feature

Function

Digital Display

Displays address elements, data values, faults and errors.

Up/Down Key

Selects element numbers and change data values. The up/down key scrolls when held.

F1 Key and Indicator Light

Controls the F1 status bit. When the F1 key is pressed or latched, the F1 indicator LED is lit.

F2 Key and Indicator Light

Controls the F2 status bit. When the F2 key is pressed or latched, the F2 indicator LED is lit.

ESC Key

Cancels a current operation.

BIT Key and Indicator Light

Pressing the BIT key puts the DAT in bit mode. The bit indicator light is on when the DAT is in bit
mode.

INT Key and Indicator Light

Pressing the INT key puts the DAT in integer mode. The integer indicator light is on when the DAT
is in integer mode.

ENTER Key

Press to select the flashing element number or enter data value.

PROTECTED Indicator Light

Indicates element data cannot be changed using the DAT (element is read-only).

The F1, F2, ESC, BIT, INT, and ENTER keys do not
repeat when held. Holding down any one of these
keys results in only one key press. The Up/Down
arrow key is the only key that repeats when held.

TIP

Power-Up Operation
The DAT receives power when it is plugged into the controller. Upon
power-up, the DAT performs a self-test.
If the test fails, the DAT displays an error code, all indicator lights are
deactivated, and the DAT does not respond to any key presses. See
DAT Error Codes on page 5-10.

PROTECTED

ESC

BIT

INT

ENTER

After a successful self-test, the DAT reads the DAT function file to
determine its configuration.

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Using Trim Pots and the Data Access Tool (DAT)

DAT Function File
DAT configuration is stored in the processor in a specialized
configuration file called the DAT Function File. The DAT Function
File, which is part of the user’s control program, is described in the
MicroLogix 1200 and MicroLogix 1500 Instruction Set Reference
Manual, publication 1762-RM001.
Following a successful power-up sequence, the DAT enters the bit
monitoring mode.

PROTECTED

off-0

ESC

BIT

INT

ENTER

Power Save Timeout (PST) Parameter
The power save timeout turns off the DAT display after keypad
activity has stopped for a user-defined period of time. The power-save
(DAT:0.PST) value is set in the DAT Function File. The valid range is 0
to 255 minutes. The power-save feature can be disabled by setting the
PST value to 0, which keeps the display on continuously. The default
value is 0.
In power-save mode, a dash flashes in the left-most segment of the
display. Press any key (except F1 or F2) to return the DAT to its
previous mode. If F1 or F2 is pressed, the DAT will change the value
of the F1 or F2 status bits, but the display remains in power-save
mode.

Publication 1764-UM001B-EN-P - April 2002

Using Trim Pots and the Data Access Tool (DAT)

5-5

Understanding the DAT Display
When the DAT enters either the bit or integer mode, the element
number and its data are displayed, as shown below. The element
number is either the integer or bit location.

Bit Mode Display

Integer Mode Display

PROTECTED

of f -

12 - 3 2768

ESC

BIT

INT

ENTER

BIT

INT

ENTER

bit element
number
• 0 to 47

bit data
• OFF - 0
• ON - 1
• – – – (undefined)

integer
element
number
• 0 to 47

integer data
• -32,768 to 32,767
• – – – (undefined)

If the displayed element is defined in the controller’s data file, and is
not protected, the element number flashes, indicating that it can be
modified. If the displayed element is protected, the PROTECTED
indicator light illuminates, and the element number does not flash,
indicating that the element cannot be modified.
If the element is undefined, the data field displays three dashes. The
element number does not flash because the element does not exist.

PROTECTED

---

05
F1

ESC

BIT

INT

ENTER

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5-6

Using Trim Pots and the Data Access Tool (DAT)

Entering Bit Mode
Bit mode allows you to view and modify up to 48 contiguous bit
locations in the controller. The DAT enters the bit mode automatically
following a successful power-up. The bit mode can also be selected
by pressing the BIT key. If the bit mode was previously active, the
DAT displays the last bit element monitored. If the integer mode was
active, the DAT displays the first bit element in the data file. However,
there may be a brief delay while the DAT requests information from
the controller. During the delay, the working screen will display. See
Working Screen Operation on page 5-7.

Entering Integer Mode
Integer mode allows you to view and modify up to 48 contiguous
16-bit integer data locations in the controller. To initiate integer mode,
press the INT key. If the integer mode was previously active, the DAT
displays the last integer element monitored. If the bit mode was
active, the DAT displays the first integer element in the data file.
However, there may be a brief delay while the DAT requests
information from the controller. If there is a delay, the working screen
is displayed. See Working Screen Operation on page 5-7.

Monitoring and Editing
1. Press the INT or BIT key to enter the desired mode. The element
number flashes (if not protected).
2. Use the up/down key to scroll and select an element (to scroll
rapidly, hold the up/down key).
3. Press ENTER to edit the element. The element number becomes
steady and the data flashes if it is not protected.
4. Use the up/down key to change the data. Bit values toggle
between “ON” and “OFF”. Integer values increment or
decrement. Holding down the up/down key causes the integer
value to increment or decrement quickly.

TIP

Publication 1764-UM001B-EN-P - April 2002

If the data is protected or undefined, pressing
the up/down key scrolls to the next element in
the list.

Using Trim Pots and the Data Access Tool (DAT)

5-7

5. Press ENTER to load the new data. Press ESC or INT/BIT to
discard the new data.

F1 and F2 Functions
The function keys, F1 and F2, correspond to bits and can be used
throughout the control program as desired. They have no effect on bit
or integer monitoring.
Each key has two corresponding bits in the DAT function file. The bits
within the DAT function file are shown in the table below.

Key

Bits

Address

Data Format

Type

User Program
Access

F1 Key

Pressed

DAT:0/F1P

Binary

Status

Read/Write

Latched

DAT:0/F1L

Binary

Status

Read/Write

Pressed

DAT:0/F2P

Binary

Status

Read/Write

Latched

DAT:0/F2L

Binary

Status

Read/Write

F2 Key

F1 or F2 Key Pressed
The pressed bits (DAT:0/F1P and DAT:0/F2P) function as
push-buttons and provide the current state of either the F1 or F2 key
on the keypad. When the F1 or F2 key is pressed, the DAT sets (1) the
corresponding pressed key bit. When the F1 or F2 key is not pressed,
the DAT clears (0) the corresponding pressed key bit.

F1 or F2 Key Latched
The latched bits (DAT:0/F1L and DAT:0/F2L) function as latched
push-buttons and provide latched/toggle key functionality. When the
F1 or F2 key is pressed, the DAT sets (1) the corresponding latched
key bit within the DAT Function File. When the F1 or F2 key is
pressed a second time, the DAT clears (0) the corresponding latched
key bit.

Working Screen Operation
Because the DAT is a communications device, its performance is
affected by the scan time of the controller. Depending on the user
program, if a long scan time is encountered and the DAT waits for
information from the controller, a working screen is displayed. The

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5-8

Using Trim Pots and the Data Access Tool (DAT)

working screen consists of three dashes that move across the display
from left to right. While the working screen is displayed, key presses
are not recognized. Once the DAT receives data from the controller, it
returns to its normal mode of operation.
If you encounter excessive working screen conditions, you can
minimize the effect by adding an SVC instruction to the control
program. Refer to the MicroLogix 1200 and MicroLogix 1500
Programmable Controllers Instruction Set Reference Manual,
publication 1762-RM001, for information on the SVC instruction.

Non-Existent Elements
When the DAT determines that an element number does not exist in
the controller, the element value displays as three dashes.
If the protection bit for an element is undefined, the DAT will assume
that the element is unprotected.

Controller Faults
The DAT checks for controller faults every 10 seconds. When the DAT
detects a controller fault, the display shows “FL” in the element
number field and the value of the controller’s major fault word (S2:6)
is displayed in the value field, as shown below.

PROTECTED

TIP

Publication 1764-UM001B-EN-P - April 2002

0020H

ESC

BIT

INT

ENTER

If an element value is being modified when the
fault is detected, the fault is stored until the
modification is accepted or discarded. Then, the
fault will be displayed.

Using Trim Pots and the Data Access Tool (DAT)

5-9

Pressing ESC while the fault is being displayed returns the DAT to its
previous mode. The fault is not removed from the controller, just from
the DAT display screen. The fault that was on screen will not display
again and cannot be “recalled”. If a new fault is detected, it will be
displayed. If the initial fault is cleared and returns at a later time, the
DAT will display the fault at that time.

Error Conditions
When the DAT detects an error in its own operation, it displays the
error screen. The error screen consists of “Err” and a two-digit error
code, as shown below.

PROTECTED

ESC

BIT

INT

ENTER

The DAT can experience two different types of errors, internal errors
and communication errors.

Internal DAT Errors
Internal DAT errors are non-recoverable. When the DAT experiences
an internal error, it displays the error screen, and does not respond to
any key presses. Remove and re-install the DAT. If this does not clear
the error, the DAT must be replaced.

Communication Errors
The DAT continually monitors the interface between the DAT and the
controller to ensure a good communication path. If the DAT loses
communication with the controller for more than three seconds, it
generates an interface time-out error. The DAT automatically attempts
to re-establish communications. The error screen displays until the
DAT regains communications with the processor. All key presses are
ignored until the display clears.

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5-10

Using Trim Pots and the Data Access Tool (DAT)

DAT Error Codes

Error Code

Description

Caused by

Recommended Action

Interface time-out

Communication traffic

Add SVC instructions to ladder program

01 to 02

Power-up test failure

Internal failure

Remove and re-insert the DAT. If failure
persists, replace the unit.

03 to 07

internal error

Internal failure

Remove and re-insert the DAT. If failure
persists, replace the unit.

processor owned(1)

Another device has ownership of the controller

Release ownership by the other device

access denied

Cannot access that file because another device
has ownership

Release file ownership by the other device

31 to 34

internal error

Internal failure

Remove and re-insert the DAT. If failure
persists, replace the unit.

(1) This error can occur after a download in which communications configurations are changed. This error can be cleared by removing and re-installing the DAT, or by cycling
power to the controller.

Publication 1764-UM001B-EN-P - April 2002

Chapter

Using Real-Time Clock and Memory Modules

Five modules with different levels of functionality are available for use
with the MicroLogix 1500 controller.

Catalog Number

Function

Memory Size

1764-RTC

Real-Time Clock

not applicable

1764-MM1

Memory Module

1764-MM1RTC

Memory Module and Real-Time Clock

1764-MM2(1)

Memory Module

16K

1764-MM2RTC(1)

Memory Module and Real-Time Clock

16K

(1) For 1764-LRP programs greater than 8k, use the 1764-MM2 or 1764-MM2RTC.

Real-Time Clock Operation Removal/Insertion Under Power
The real-time clock module can be installed or removed at any time
without risk of damage to either the module or the controller. If a
module is installed while the MicroLogix 1500 is in an executing mode
(Run or Remote Run), the module is not recognized until either a
power cycle occurs, or until the controller is placed in a
non-executing mode (program mode or fault condition).
Removal of the memory module is detected within one program scan.
Removal of the real-time clock under power causes the controller to
write zeros to the (RTC) Function File.

Real-Time Clock Function File
The real-time clock provides year, month, day of month, day of week,
hour, minute, and second information to the Real-Time Clock (RTC)
Function File in the controller. Refer to the MicroLogix 1200 and
MicroLogix 1500 Instruction Set Reference Manual, publication
1762-RM001 for information about the RTC function file.

Publication 1764-UM001B-EN-P - April 2002

6-2

Using Real-Time Clock and Memory Modules

Accuracy
The following table indicates the expected accuracy of the real-time
clock at various temperatures.

Ambient Temperature

Accuracy(1)

0°C (+32°F)

+34 to -70 seconds/month

+25°C (+77°F)

+36 to -68 seconds/month

+40°C (+104°F)

+29 to -75 seconds/month

+55°C (+131°F)

-133 to -237 seconds/month

(1) These numbers are expected worst case values over a 31 day month.

Writing Data to the Real-Time Clock
When valid data is sent to the real-time clock from the programming
device, the new values take effect immediately.
The real-time clock does not allow you to write invalid date or time
data.

RTC Battery Operation
The real-time clock has an internal battery that is not replaceable. The
RTC Function File features a battery low indicator bit (RTC:0/BL),
which shows the status of the RTC battery. When the battery is low,
the indicator bit is set (1). This means that the battery may fail within
14 days and the real-time clock module needs to be replaced. When
the battery low indicator bit is clear (0), the battery level is acceptable
or a real-time clock is not attached.
If the RTC battery is low and the controller is powered, the RTC
operates normally. If the controller power is removed and the RTC
battery is low, RTC data may be lost.

Publication 1764-UM001B-EN-P - April 2002

Using Real-Time Clock and Memory Modules

6-3

Use the Disable Clock button in your programming device to disable
the real-time clock before storing a module. This decreases the drain
on the battery during storage.
Table 6.1 RTC Battery Life Expectancy
Battery State

Temperature

Time Duration

Operating

0°C to +40°C (+32°F to +104°F)

5 years(1)

Storage

-40°C to +25°C (-40°F to +77°F)

5 years minimum

+26°C to +60°C (+79°F to +140°F)

3 years minimum

(1) The operating life of the battery is based on 6 months of storage time before the real-time clock is used.

ATTENTION

!
Memory Module Operation

Operating with a low battery indication for more
than 14 days may result in invalid RTC data if
controller power is lost.

The memory module supports program back-up as well as the
following features:
•
•
•
•
•

User Program and Data Back-Up
Program Compare
Data File Download Protection
Memory Module Write Protection
Removal/Insertion Under Power

User Program and Data Back-Up
The memory module provides a simple and flexible program/data
transport mechanism, allowing the user to transfer the program and
data to the controller without the use of a personal computer and
programming software.
The memory module can store one user program at a time.
During transfers from a memory module, the controller’s RUN LED
flashes.

Publication 1764-UM001B-EN-P - April 2002

6-4

Using Real-Time Clock and Memory Modules

Program Compare
The memory module can also provide application security, allowing
you to specify that if the program stored in the memory module does
not match the program in the controller, the controller will not enter
an executing (run or remote run) mode. To enable this feature, set the
S:2/9 bit in the system status file. Refer to the MicroLogix 1200 and
MicroLogix 1500 Instruction Set Reference Manual, publication
1762-RM001, for more information.

Data File Download Protection
The memory module allows the user to specify individual data files in
the controller that are protected from the download procedure. This
allows user data to be saved (not overwritten) during a download.

TIP

Publication 1764-UM001B-EN-P - April 2002

Data file download protection is only functional if
the processor does not have a fault and if all
protected data files in the memory module exactly
match the protected data file structure within the
controller. Refer to the MicroLogix 1200 and
MicroLogix 1500 Instruction Set Reference Manual,
publication 1762-RM001, for information on
protecting data files during download.

Using Real-Time Clock and Memory Modules

6-5

Memory Module Write Protection
The memory module supports write-once, read-many behavior. Write
protection is enabled using your programming software.

IMPORTANT

Once set, write protection cannot be removed. A
change cannot be made to the control program or
data stored in a write-protected memory module. If a
change is required, you must use a different memory
module.

Removal/Insertion Under Power
The memory module can be installed or removed at any time without
risk of damage to either the memory module or the controller. If a
memory module is installed while the MicroLogix 1500 is executing,
the memory module will not be recognized until either a power cycle
occurs, or until the controller is placed in a non-executing mode
(program mode or fault condition).

Memory Module Information File
The controller has a Memory Module Information (MMI) File which
provides status from the attached memory module. At power-up or on
detection of a memory module being inserted, the catalog number,
series, revision, and type (memory module and/or real-time clock) are
identified and written to the MMI file. If a memory module and/or
real-time clock is not attached, zeros are written to the MMI file. Refer
to the MicroLogix 1200 and MicroLogix 1500 Instruction Set Reference
Manual, publication 1762-RM001, for more information.

Publication 1764-UM001B-EN-P - April 2002

6-6

Using Real-Time Clock and Memory Modules

Publication 1764-UM001B-EN-P - April 2002

Appendix

Specifications
Controller Specifications

Table A.1 General Specifications
Description

1764-24BWA

1764-24AWA

1764-28BXB

Number of I/O

12 inputs
12 outputs

16 inputs
12 outputs

Line Power

85 to 265V ac
at 47 to 63 Hz

20.4 to 30V dc

Power Supply
Usage

88 VA

70 VA

30W(2)

Power Supply Inrush 120V ac = 25A for 8
ms
240V ac = 40A for 4
ms

120V ac = 25A for 8
ms
240V ac = 40A for 4
ms

24V dc = 4A for 150
ms

User Power Output

24V dc at 400 mA,
400 µF max.

none

Input Circuit Type

24V dc, sink/source

120V ac

24V dc, sink/source

Output Circuit Type

relay

6 relay, 6 FET
transistor
(24V dc source)

Typical CPU Hold-up 10 to 3000 ms
Time
Operating Temp.

+0°C to +55°C (+32°F to +131°F) ambient

Storage Temp.

-40°C to +85°C (-40°F to +185°F) ambient (1)

Operating Humidity

5% to 95% relative humidity (non-condensing)

Vibration

Operating: 10 to 500 Hz, 5G, 0.030 in. max. peak-to-peak
Relay Operation: 2G

Shock (without Data Operating: 30G panel mounted (15G DIN Rail mounted)
Relay operation: 7.5G panel mounted (5G DIN Rail mounted)
Access Tool
Non-Operating: 40G panel mounted (30G DIN Rail mounted)
installed)
Shock (with Data
Access Tool
installed)
Agency Certification

Operating: 20G panel mounted (15G DIN Rail mounted)
Relay operation: 7.5G panel mounted (5G DIN Rail mounted)
Non-Operating: 30G panel mounted (20G DIN Rail mounted)
• UL 508
• C-UL under CSA C22.2 no. 142
• Class I, Div. 2, Groups A, B, C, D
(UL 1604, C-UL under CSA C22.2 no. 213)
• CE compliant for all applicable directives
• C-Tick marked for all applicable acts

Publication 1764-UM001B-EN-P - April 2002

A-2

Specifications

Table A.1 General Specifications
Description

1764-24BWA

1764-24AWA

1764-28BXB

Electrical/EMC

The module has passed testing at the following levels:
• EN61000-4-2: 4 kV contact, 8 kV air, 4 kV indirect
• EN61000-4-3: 10 V/m
• EN61000-4-4: 2 kV, 5 kHz; communications cable: 1 kV, 5 kHz
• EN61000-4-5: communications cable1 kv galvanic gun
-I/O: 2 kV CM, 1 kV DM,
-Power Supply (1764-24AWA/1764-24BWA): 4 kV CM, 2 kV DM
-Power Supply (1764-28BXB): 0.5 kV CM, 0.5 kV DM
• EN61000-4-6: 10V, communications cable 3V

Terminal Screw
Torque

1.13 Nm (10 in-lb) rated; 1.3 Nm (12 in-lb) maximum

Programming
Software

For 1764-LSP Series A Processors: RSLogix 500,
Version 3.01.09 or higher
For 1764-LSP and 1764-LRP Series B Processors: RSLogix 500,
Version 4.00.00 or higher.

(1) Recommended storage temperature for maximum battery life (5 years typical with normal operating/storage
conditions) of the 1764-RTC, 1764-MM1RTC, and 1764-MM2RTC is -40°C to +40°C (-40°F to +104°F). Battery
life is significantly shorter at elevated temperatures.
(2) See Choosing a Power Supply on page A-2.

Choosing a Power Supply
This section contains information for selecting a power supply for
applications using a 1764-28BXB base unit. Use the tables in
Appendix F to calculate the total power (Watts) consumed by the
system. With that information, use the graphs below to chose a power
supply. You can use either current or power, depending on how the
power supply is rated.

Input Current Required at 24V dc (Amperes)

Figure 1.1 Input Current Required
1.4
1.2
1
0.8
0.6
0.4
0.2
0
0

Power Consumption (Watts)

Publication 1764-UM001B-EN-P - April 2002

Specifications

A-3

Figure 1.2 Input Power Required
30

Input Power Required (Watts)

25
20
15
10
5
0
0

Power Consumption (Watts)

Table A.2 Input Specifications
Description

1764-24AWA

1764-24BWA and 1764-28BXB
Inputs 0 thru 7

Inputs 8 and
Higher
10 to 30.0V dc at
30°C (86°F)
10 to 26.4V dc at
55°C (131°F)

On-State Voltage
Range

79 to 132V ac

14 to 30.0V dc at
30°C (86°F)
14 to 26.4V dc at
55°C (131°F)

Off-State Voltage
Range

0 to 20V ac

0 to 5V dc

Operating
Frequency

Not Applicable

1 kHz to 20 kHz

On-State Current:
• minimum
• nominal
• maximum

• 5.0 mA at 79V ac
• 12.0 mA at 120V ac
• 16.0 mA at 132V ac

• 2.5 mA at 14V dc
• 7.3 mA at 24V dc
• 12.0 mA at 30V dc

1 kHz to 500 Hz(1)
• 2.0 mA at 10V dc
• 8.9 mA at 24V dc
• 12.0 mA at 30V dc

Off-State Leakage 2.5 mA minimum
Current

1.5 mA minimum

Nominal
Impedance

12k ohms at 50 Hz
10k ohms at 60 Hz

3.3k ohms

2.7k ohms

Inrush Current
(max.)

250 mA at 120V ac

Not Applicable

(1) Scan-time dependant.

TIP

The 1764-24AWA input circuits (inputs 0-11) do not
support adjustable filter settings. They have
maximum turn-on and maximum turn-off times of
20 milliseconds.

Publication 1764-UM001B-EN-P - April 2002

A-4

Specifications

Table A.3 Response Times for High-Speed dc Inputs 0 Through 7
(applies to 1764-24BWA and 1764-28BXB)
Filter
Maximum
High-Speed Counter Setting
(ms)
Frequency at 50%
Duty Cycle (KHz)

Minimum
ON Delay
(ms)

Maximum Minimum
ON Delay OFF Delay
(ms)
(ms)

Maximum
OFF Delay
(ms)

20.000

0.025

0.005

0.025

0.005

0.025

6.700

0.075

0.040

0.075

0.045

0.075

5.000

0.100

0.050

0.100

0.060

0.100

2.000

0.250

0.170

0.250

0.210

0.250

1.000

0.500

0.370

0.500

0.330

0.500

1.000

0.700

1.000

0.800

1.000

0.250

2.000

1.700

2.000

1.600

2.000

0.125

4.000

3.400

4.000

3.600

4.000

0.063

8.000(1)

6.700

8.000

7.300

8.000

0.031

16.000

14.000

16.000

14.000

16.000

(1) This is the default setting.

Table A.4 Response Times for Normal dc Inputs 8 Through 11 (1764-24BWA)
and 8 Through 15 (1764-28BXB)
Maximum
Frequency at 50%
Duty Cycle (kHz)

Filter
Setting
(ms)

Minimum
ON Delay
(ms)

Maximum
ON Delay
(ms)

Minimum
OFF Delay
(ms)

Maximum
OFF Delay
(ms)

1.000

0.500

0.090

0.500

0.020

0.500

1.000

0.500

1.000

0.400

1.000

0.250

2.000

1.100

2.000

1.300

2.000

0.125

4.000

2.800

4.000

2.700

4.000

0.063

8.000(1)

5.800

8.000

5.300

8.000

0.031

16.000

11.000

16.000

10.000

16.000

(1) This is the default setting.

Publication 1764-UM001B-EN-P - April 2002

Specifications

A-5

The relay current must stay within the limits defined
in Tables A.5 and A.6.

IMPORTANT

Table A.5 Relay Contact Rating Table 1764-24AWA, -24BWA, -28BXB
Maximum
Volts

Amperes
Make

Break

240V ac

7.5A

0.75A

120V ac

15A

Amperes
Continuous

Voltamperes
Make

Break

2.5A

1800VA

180VA(2)

1.5A

125V dc

0.22A

1.0A

28VA

24V dc

1.2A(1)

2.0A

28VA

(1)

(1) For dc voltage applications, the make/break ampere rating for relay contacts can be determined by dividing 28
VA by the applied dc voltage. For example, 28 VA/48V dc = 0.58A. For dc voltage applications less than 14V, the
make/break ratings for relay contacts cannot exceed 2A.
(2) The total load controlled by the 1764-24AWA and 1764-24BWA is limited to 1440VA (break).

Table A.6 Output Specifications - Maximum Continuous Relay Current
Specification

1764-24AWA,
-24BWA

1764-28BXB

Current per Common

at 150V Maximum

24A

18A

at 240V Maximum

20A

18A

Current per
Controller

Table A.7 1764-28BXB FET Output Specifications
Specification

General
Operation
(Outputs 2 thru 7)

High Speed
Operation(1)
(Outputs 2 and 3 Only)

User Supply
Voltage

minimum

20.4V dc

maximum

26.4V dc

On-State
Voltage Drop

at maximum load
current

1V dc

Not Applicable

at maximum surge
current

2.5V dc

Not Applicable

maximum load

1A at 55°C (131°F)
1.5A at 30°C (86°F)

100 mA

minimum load

1.0 mA

10 mA

maximum leakage

1.0 mA

Current Rating
per Point

Publication 1764-UM001B-EN-P - April 2002

A-6

Specifications

Table A.7 1764-28BXB FET Output Specifications
Specification

General
Operation
(Outputs 2 thru 7)

High Speed
Operation(1)
(Outputs 2 and 3 Only)

peak current

4.0A

Not Applicable

maximum surge
duration

10 msec

Not Applicable

maximum rate of
repetition at 30°C
(86°F)

once every second

Not Applicable

maximum rate of
repetition at 55°C
(131°F)

once every 2
seconds

Not Applicable

Current per
Common

maximum total

Not Applicable

On-State
Current

minimum

2.5 mA at 14V dc

2.0 mA at 10V dc

Off-State
Leakage
Current

maximum

1 mA

Turn-On Time

maximum

0.1 msec

6 µsec

Turn-Off Time

maximum

1.0 msec

18 µsec

Repeatability

maximum

n/a

2 µsec

Drift

maximum

n/a

1 µsec per 5°C
(1 µsec per 9°F)

Surge Current
per Point

(1) Outputs 2 and 3 are designed to provide increased functionality over the other FET outputs (4 through 7). They
may be used like the other FET transistor outputs, but in addition, within a limited current range, they may be
operated at a higher speed. Outputs 2 and 3 also provide a pulse train output (PTO) or pulse width modulation
output (PWM) function.

Publication 1764-UM001B-EN-P - April 2002

Specifications

A-7

Table A.8 Working Voltage (1764-24AWA)
Specification

1764-24AWA

Power Supply Input to Backplane
Isolation

Verified by one of the following dielectric tests: 1836V
ac for 1 second or 2596V dc for 1 second
265V Working Voltage (IEC Class 2 reinforced
insulation)

Input Group to Backplane
Isolation and Input Group to
Input Group Isolation

Verified by one of the following dielectric tests: 151V
ac for 1 second or 2145V dc for 1 second

Output Group to Backplane
Isolation

Verified by one of the following dielectric tests: 1836V
ac for 1 second or 2596V dc for 1 second

132V Working Voltage (IEC Class 2 reinforced
insulation)

265V Working Voltage (IEC Class 2 reinforced
insulation)
Output Group to Output Group
Isolation

Verified by one of the following dielectric tests: 1836V
ac for 1 second or 2596V dc for 1 second
265V Working Voltage (basic insulation) 150V Working
Voltage (IEC Class 2 reinforced insulation).

Table A.9 Working Voltage (1764-24BWA)
Specification

1764-24BWA

Power Supply Input to Backplane Verified by one of the following dielectric tests: 1836V
Isolation
ac for 1 second or 2596V dc for 1 second
265V Working Voltage (IEC Class 2 reinforced
insulation)
Power Supply User 24V Output
to Backplane Isolation

Verified by one of the following dielectric tests: 600V
ac for 1 second or 848V dc for 1 second
50V Working Voltage (IEC Class 2 reinforced insulation)

Input Group to Backplane
Isolation and Input Group to
Input Group Isolation

Verified by one of the following dielectric tests: 1200V
ac for 1 second or 1697V dc for 1 second

Output Group to Backplane
Isolation

Verified by one of the following dielectric tests: 1836V
ac for 1 second or 2596V dc for 1 second

75V dc Working Voltage (IEC Class 2 reinforced
insulation)

265V Working Voltage (IEC Class 2 reinforced
insulation).
Output Group to Output Group
Isolation.

Verified by one of the following dielectric tests: 1836V
ac for 1 second or 2596V dc for 1 second
265V Working Voltage (basic insulation) 150V Working
Voltage (IEC Class 2 reinforced insulation)

Publication 1764-UM001B-EN-P - April 2002

A-8

Specifications

Table A.10 Working Voltage (1764-28BXB)
Specification

1764-28BXB

Input Group to Backplane
Isolation and Input Group to
Input Group Isolation

Verified by one of the following dielectric tests: 1200V
ac for 1 second or 1697V dc for 1 second

FET Output Group to Backplane
Isolation and FET Outputs Group
to Group

Verified by one of the following dielectric tests: 1200V
ac for 1 second or 1697V dc for 1 second

Relay Output Group to
Backplane Isolation

Verified by one of the following dielectric tests: 1836V
ac for 1 second or 2596V dc for 1 second

75V dc Working Voltage (IEC Class 2 reinforced
insulation)

265V Working Voltage (IEC Class 2 reinforced
insulation)
Relay Output Group to Relay and Verified by one of the following dielectric tests: 1836V
FET Output Group Isolation
ac for 1 second or 2596V dc for 1 second
265V Working Voltage (basic insulation) 150V Working
Voltage (IEC Class 2 reinforced insulation)

Transistor Output Transient Pulses
Refer to page 3-16 for “Transistor Output Transient Pulses”.

Publication 1764-UM001B-EN-P - April 2002

Specifications

Controller Dimensions

See page 2-12 for Base Unit Mounting Dimensions.

168 mm
(6.62 in)

35 mm
(1.38 in)

147.4 mm (5.81 in)

35 mm
(1.38 in)

118 mm (4.65 in)

59 mm
(2.32 in)
59 mm
(2.32 in)

122.6 mm (4.83 in)

147 mm
(5.79 in)

132 mm (5.19 in)

A-9

13.5 mm
(0.53 in)

Compact I/O Dimensions

14.7 mm
(0.58 in)

Panel Mounting

For more than 2 modules: (number of modules - 1) X 35 mm (1.38 in.)
Refer to host controller for this dimension
.

132
(5.197)
122.6±0.2
(4.826±0.008)

35
(1.38)

28.5
(1.12)

NOTE: All dimensions
are in mm (inches).
Hole spacing
tolerance: ±0.4 mm
(0.016 in.)

Publication 1764-UM001B-EN-P - April 2002

A-10

Specifications

End Cap

32 mm
(1.26 in.)
18 mm
(0.71 in.)

This illustration shows the
1769-ECR right end cap. For
the 1769-ECL left end cap,
the drawing would be
reversed.

118 mm
(4.65 in.)

Dimensions are in mm (inches).

Publication 1764-UM001B-EN-P - April 2002

Appendix

Replacement Parts

This chapter contains the following information:
• a table of MicroLogix 1500 replacement parts
• procedure for replacing the lithium battery
• illustrations of the MicroLogix 1500 replacement doors and
terminal blocks

MicroLogix 1500
Replacement Kits

The table below provides a list of replacement parts and their catalog
number.

Description

Catalog
Number

Lithium Battery (See page B-2.)

1747-BA

ESD Barrier

1764-RPL-TRM1

Base Terminal Doors (See page B-6.)

1764-RPL-TDR1

Processor Access Door (See page B-6.)

1764-RPL-CDR1

Door Combination Kit, includes ESD Barrier, Terminal Door, Access
Door, Base Comms Door (See page B-6.), and Trim Pots/Mode Switch
Cover Door (See page B-6.)

1764-RPL-DR

17-Point Terminal Block (for inputs on 1764-24AWA and -24BWA
bases) (See page B-5.)

1764-RPL-TB1

21-Point Terminal Block (for inputs of 1764-28BXB and outputs for all
base units)(See page B-5.)

1764-RPL-TB2

Publication 1764-UM001B-EN-P - April 2002

B-2

Replacement Parts

Lithium Battery (1747-BA)
IMPORTANT

When the processor’s Battery Low indicator is lit,
install a backup battery immediately. After the
indicator turns on, the battery lasts for at least:
• 14 days for the 1764-LSP
• 7 days for the 1764-LRP

Installing
Follow the procedure below to ensure proper replacement battery
installation.

IMPORTANT

Do not remove the permanent battery when
installing replacement battery.

1. Insert battery into replacement battery pocket with wires facing
up.
2. Insert replacement battery wire connector into connector port.
3. Secure battery wires under wire latch (as shown below).
Replacement Battery Pocket

Replacement Battery

DC INPUTS

Battery Connector Wires

24V SINK/SOURCE
DC/RELAY OUT

24V SOURCE

Permanent Battery
(DO NOT ATTEMPT
TO REMOVE)

Connector Port

Publication 1764-UM001B-EN-P - April 2002

Wire Connector

Wire Latch

Replacement Parts

B-3

Battery Handling
Follow the procedure below to ensure proper battery operation and
reduce personnel hazards.
• Use only for the intended operation.
• Do not ship or dispose of cells except according to
recommended procedures.
• Do not ship on passenger aircraft.

ATTENTION

• Do not charge the batteries. An explosion could
result or the cells could overheat causing burns.
• Do not open, puncture, crush, or otherwise
mutilate the batteries. A possibility of an
explosion exists and/or toxic, corrosive, and
flammable liquids would be exposed.
• Do not incinerate or expose the batteries to high
temperatures. Do not attempt to solder batteries.
An explosion could result.
• Do not short positive and negative terminals
together. Excessive heat can build up and cause
severe burns.

Storing
Store lithium batteries in a cool, dry environment, typically +20°C to
+25°C (+68°F to 77°F) and 40% to 60% humidity. Store the batteries
and a copy of the battery instruction sheet in the original container,
away from flammable materials.

Transporting
One or Two Batteries
Each battery contains 0.23 grams of lithium. Therefore, up to two
batteries can be shipped together within the United States without
restriction. Regulations governing shipment to or within other
countries may differ.

Publication 1764-UM001B-EN-P - April 2002

B-4

Replacement Parts

Three or More Batteries
Procedures for the transportation of three or more batteries shipped
together within the United States are specified by the Department of
Transportation (DOT) in the Code of Federal Regulations, CFR49,
“Transportation.” An exemption to these regulations, DOT - E7052,
covers the transport of certain hazardous materials classified as
flammable solids. This exemption authorizes transport of lithium
batteries by motor vehicle, rail freight, cargo vessel, and cargo-only
aircraft, providing certain conditions are met. Transport by passenger
aircraft is not permitted.
A special provision of DOT-E7052 (11th Rev., October 21, 1982, par.
8-a) provides that:
“Persons that receive cell and batteries covered by this
exemption may reship them pursuant to the provisions of 49
CFR 173.22a in any of these packages authorized in this
exemption including those in which they were received.”
The Code of Federal Regulations, 49 CFR 173.22a, relates to the use of
packaging authorized under exemptions. In part, it requires that you
must maintain a copy of the exemption at each facility where the
packaging is being used in connection with shipment under the
exemption.
Shipment of depleted batteries for disposal may be subject to specific
regulation of the countries involved or to regulations endorsed by
those countries, such as the IATA Articles Regulations of the
International Air Transport Association, Geneva, Switzerland.

IMPORTANT

Regulations for transportation of lithium batteries are
periodically revised.

Disposing

ATTENTION

!
Publication 1764-UM001B-EN-P - April 2002

Do not incinerate or dispose of lithium batteries in
general trash collection. Explosion or violent rupture
is possible. Batteries should be collected for disposal
in a manner to prevent against short-circuiting,
compacting, or destruction of case integrity and
hermetic seal.

Replacement Parts

B-5

For disposal, batteries must be packaged and shipped in accordance
with transportation regulations, to a proper disposal site. The U.S.
Department of Transportation authorizes shipment of “Lithium
batteries for disposal” by motor vehicle only in regulation 173.1015 of
CFR 49 (effective January 5, 1983). For additional information contact:
U.S. Department of Transportation
Research and Special Programs Administration
400 Seventh Street, S.W.
Washington, D.C. 20590
Although the Environmental Protection Agency at this time has no
regulations specific to lithium batteries, the material contained may be
considered toxic, reactive, or corrosive. The person disposing of the
material is responsible for any hazard created in doing so. State and
local regulations may exist regarding the disposal of these materials.
For a lithium battery product safety data sheet, contact the
manufacturer:
Sanyo Energy Corporation
2001 Sanyo Avenue
San Diego, CA 92173
(619) 661-4801

Replacement Terminal
Blocks

Tadarand Electronic Industries
2 Seaview Blvd.
Port Washington, NY 11050
(516) 621-4980

This figure illustrates how to replace
the MicroLogix 1500 terminal blocks.
Catalog Numbers:
• 1764-RPL-TB1: 17-point
terminal block
• 1764-RPL-TB2: 21-point
terminal block

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B-6

Replacement Parts

Replacement Doors

The following figures illustrate the procedure for installing the
MicroLogix 1500 replacement doors.

Base Terminal Door
(1764-RPL-TDR1)

L2
65
85-2
VAC

VAC 1
VDC

VAC 0
VDC

O/0

VAC 2
VDC

O/1

VAC 3
VDC

O/2

VAC 4
VDC

O/3

O/5
O/4

O/7
O/6

O/8
VAC 5
VDC

O / 10
O/9

24BW

O / 11

1
3
2

Processor Access Door
(1764-RPL-CDR1)

Base Comms Door
(included in 1764-RPL-DR)

Trim Pots/Mode Switch
Cover Door
(included in 1764-RPL-DR)

Publication 1764-UM001B-EN-P - April 2002

Appendix

Troubleshooting Your System

This chab
pter describes how to troubleshoot your controller. Topics include:
•
•
•
•

Understanding Controller
LEDs

understanding the controller LED status
controller error recovery model
identifying controller faults
calling Rockwell Automation for assistance

The controller status LEDs provide a mechanism to determine the
current status of the controller if a programming device is not present
or available.

D.C. INPUTS

24V SINK / SOURCE
POWER

LED

Color

Indicates

POWER

off

no input power

green

power on

off

controller is not in Run mode or REM Run

green

controller is in Run mode or REM Run

DC/RELAY OUT

RUN
FAULT
FORCE

RUN

BAT. LO
COMM 0

24V SOURCE

DCOMM

green flashing system is not in Run mode; memory module transfer is
in progress
FAULT

FORCE
BATTERY LOW
COMM 0

off

no fault detected

red flashing

faulted user program

red

processor hardware fault or critical fault

off

no forces installed

amber

forces installed

off

battery OK

red

battery needs replacement (See page B-2.)

off

flashes when communications are active

green
COMM 1
off
(1764-LRP only)
green
DCOMM(1)

flashes when communications are active

off

user configured communications mode is active

green

default communications mode active

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C-2

Troubleshooting Your System

LED

Color

Indicates

INPUTS

off

input is not energized

amber

input is energized (logic status)

off

output is not energized

amber

output is energized (logic status)

OUTPUTS

(1) When using a 1764-LRP processor, the DCOMM LED applies only to Channel 0.

When Operating Normally
The POWER and RUN LEDs are on. If a force condition is active, the
FORCE LED turns on and remains on until all forces are removed.

When an Error Exists
If an error exists within the controller, the controller LEDs operate as
described in the following tables.

If the
LEDS
indicate:

The Following Probable Cause
Error Exists

Recommended Action

All LEDS
off

No input power No Line Power
or power
supply error
Power Supply
Overloaded

Verify proper line voltage and
connections to the controller.

Power and Hardware
FAULT LEDs faulted
on solid

Processor Hardware Cycle power. Contact your local
Error
Rockwell Automation
representative if the error persists.
Loose Wiring

Power LED
on and
FAULT LED
flashing

Publication 1764-UM001B-EN-P - April 2002

Application
fault

This problem can occur
intermittently if power supply is
overloaded when output loading
and temperature varies.

Hardware/Software
Major Fault
Detected

Verify connections to the controller.
1. Monitor Status File Word
S:6 for major error code.
See page C-5 for more
information.
2. Remove hardware/software
condition causing fault.
3. Clear Major Error Halted
flag, bit S2:1/13.
4. Attempt a controller Run
mode entry. If unsuccessful,
repeat recommended action
steps above or contact your
local Rockwell Automation
distributor.

Troubleshooting Your System

Controller Error Recovery
Model

Identify the error code
and description.

C-3

Use the following error recovery model to help you diagnose software
and hardware problems in the micro controller. The model provides
common questions you might ask to help troubleshoot your system.
Refer to the recommended pages within the model for further help.

Is the error
hardware
related?

Start

Yes
Refer to page C-2 for
probable cause and
recommended action.

Are the wire
connections
tight?

Tighten wire
connections.

Yes

Clear fault.

Is the Power
LED on?

Is power supplied
to the controller?

Is the RUN
LED on?

Check power.

Yes

Correct the condition
causing the fault.

Refer to page C-2 for
probable cause and
recommended action.

Yes
Is the Fault LED on?
Return controller to
RUN or any of the
REM test modes.

Yes
See page C-2 for
probable cause and
recommended action.

Is an input LED
accurately showing
status?

Yes
See page C-2 for
probable cause and
recommended action.

Test and verify
system operation.

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C-4

Troubleshooting Your System

Identifying Controller Faults

While a program is executing, a fault may occur within the operating
system or your program. When a fault occurs, you have various
options to determine what the fault is and how to correct it. This
section describes how to clear faults and provides a list of possible
advisory messages with recommended corrective actions.

Automatically Clearing Faults
You can automatically clear a fault by cycling power to the controller
when the Fault Override at Power-up bit (S:1/8) is set in the status file.
You can also configure the controller to clear faults and go to RUN
every time the controller is power cycled. This is a feature that OEMs
can build into their equipment to allow end users to reset the
controller. If the controller faults, it can be reset by simply cycling
power to the machine. To accomplish this, set the following bits in the
status file:
• S2:1/8 - Fault Override at Power-up
• S2:1/12 - Mode Behavior
If the fault condition still exists after cycling power, the controller
re-enters the fault mode. For more information on status bits, refer to
the MicroLogix 1200 and MicroLogix 1500 Instruction Set Reference
Manual, publication 1762-RM001.

TIP

You can declare your own application-specific major
fault by writing your own unique value to S:6 and
then setting bit S:1/13 to prevent reusing system
defined codes. The recommended values for user
defined faults are FF00 to FF0F.

Manually Clearing Faults Using the Fault Routine
The occurrence of recoverable or non-recoverable user faults can
cause the user fault subroutine to be executed. If the fault is
recoverable, the subroutine can be used to correct the problem and
clear the fault bit S:1/13. The controller then continues in the Run or
test mode.
The subroutine does not execute for non-user faults. Refer to the
MicroLogix 1200 and MicroLogix 1500 Instruction Set Reference

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Troubleshooting Your System

C-5

Manual, publication 1762-RM001, for information on creating a user
fault subroutine.

Fault Messages
Refer to the MicroLogix 1200 and 1500 Instruction Set Reference
Manual, publication 1762-RM001, for the controller fault messages
that can occur during operation of the MicroLogix 1500 programmable
controllers. Each fault message includes the error code description,
the probable cause, and the recommended corrective action.

Calling Rockwell
Automation for Assistance

If you need to contact Rockwell Automation or local distributor for
assistance, it is helpful to obtain the following (prior to calling):
• controller type, series letter, and revision letter of the base unit
• series letter, revision letter, and firmware (FRN) number of the
processor (on bottom side of processor unit)
• controller LED status
• controller error codes (found in S2:6 of status file).

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Troubleshooting Your System

Publication 1764-UM001B-EN-P - April 2002

Appendix

Upgrading Your Operating System

The operating system (OS) can be upgraded through the
communication port on the controller. In order to download a new
operating system, you must have the following:
• ControlFLASH™ Upgrade Kit containing the new OS
• a Windows® 95, Windows® 98, Windows NT™, or
Windows® 2000 based computer to run the download software.
The ControlFLASH™ Upgrade Kit includes:
• the operating system upgrade to be downloaded
• the ControlFLASH programming tool, along with its support
drivers and on-line help
• a readme first file explaining how to upgrade the operating
system

Preparing for Upgrade

Before upgrading the controller’s operating system, you must:
• Obtain the operating system upgrade from
http://www.ab.com/micrologix or from your local Allen-Bradley
distributor
IMPORTANT

Installing a new operating system deletes the
controller’s user program.

• Install the ControlFlash Software. Double click the processor
catalog number/firmware revision number to install the
operating system upgrade.
• The controller must be configured for default communications
(use communications toggle push button; DCOMM LED on) and
be in the Program mode to allow the download of a new
operating system.

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D-2

Upgrading Your Operating System

Performing the Upgrade

The following steps occur during the upgrade process.
1. Controller mode and communications parameters are checked.
2. Download begins.
3. During the download, the Force, Battery, and Comms LEDs
perform a walking bit pattern.
4. When the download is complete, the integrity of the new OS is
checked. If the new OS is corrupt, the controller sends an error
message to the computer and flashes the Missing or Corrupt OS
LED pattern. See Missing/Corrupt OS LED Pattern below.
5. Following a successful transfer, the Power, Force, and Battery
LEDs flash on and remain on for five seconds. Then the
controller resets.

Missing/Corrupt OS LED
Pattern

Publication 1764-UM001B-EN-P - April 2002

When an operating system download is not successful or if the
controller does not contain a valid operating system, the controller
flashes the Run, Force, and Fault LEDS on and off.

Appendix

Understanding Communication Protocols

Use the information in this appendix to understand the differences in
communication protocols. The following protocols are supported
from the RS-232 communication channel:
•
•
•
•

DF1 Full-Duplex
DF1 Half-Duplex Slave
DH-485
Modbus RTU Slave (1764-LSP and 1764-LRP Series B Processors
only)
• ASCII (1764-LSP and 1764-LRP Series B Processors only)
See Chapter 4 for information about required network devices and
accessories.

RS-232 Communication
Interface

The communications port on the MicroLogix 1500 utilizes an RS-232
interface. RS-232 is an Electronics Industries Association (EIA)
standard that specifies the electrical characteristics for serial binary
communication. It provides you with a variety of system configuration
possibilities. (RS-232 defines electrical characteristics; it is not a
protocol.)
One of the biggest benefits of an RS-232 interface is that it lets you
easily integrate telephone and radio modems into your control system.

DF1 Full-Duplex Protocol

DF1 Full-Duplex protocol is an open protocol developed by
Allen-Bradley. It provides a point-to-point connection between two
devices. DF1 Full-Duplex protocol combines data transparency
(American National Standards Institute ANSI - X3.28-1976 specification
subcategory D1) and 2-way simultaneous transmission with
embedded responses (subcategory F1). Refer to DF1 Protocol and
Command Set Reference Manual, publication 1770-6.5.16, for more
information.
DF1 Full-Duplex protocol (also referred to as DF1 point-to-point
protocol) is useful where RS-232 point-to-point communication is
required. DF1 protocol controls message flow, detects and signals
errors, and retries if errors are detected.

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Understanding Communication Protocols

MicroLogix 1500 controllers support the DF1 Full-Duplex protocol via
RS-232 connection to external devices such as computers, controllers,
and other interface devices that support DF1 Full-Duplex.
For information about required network connecting equipment and
examples of DF1 Full-Duplex connections, see Chapter 4.

DF1 Half-Duplex Protocol

DF1 Half-Duplex protocol is a multi-drop single master/multiple slave
network. DF1 Half-Duplex protocol supports data transparency
(American National Standards Institute ANSI - X3.28-1976 specification
subcategory D1). In contrast to DF1 Full-Duplex, communication
takes place in one direction at a time. With an active Half-Duplex
Master, you can use the RS-232 port on the MicroLogix 1500 as a
Half-Duplex programming port and a Half-Duplex peer-to-peer
messaging port.

DF1 Half-Duplex Operation
A DF1 Half-Duplex master device initiates all communication by
“polling” each slave device. The slave device may only transmit when
it is polled by the master. It is the master’s responsibility to poll each
slave on a regular and sequential basis to allow slave devices an
opportunity to communicate.
An additional feature of the DF1 Half-Duplex protocol is that it is
possible for a slave device to enable a MSG write or read to/from
another slave. When the initiating slave is polled, the MSG is sent to
the master. The master recognizes that the message is not intended for
it, but for another slave, so the master immediately forwards the
message to the intended slave. The master does this automatically;
you do not need to program the master to move data between slave
nodes. This slave-to-slave transfer can also be used by programming
software to allow slave-to-slave upload and download of programs to
processors (including the master) on the DF1 Half-Duplex link.
The MicroLogix 1500 can only act as a slave device. A device that can
act as a master is required to “run” the network. Several Allen-Bradley
products support DF1 Half-Duplex master protocol. They include the
SLC 5/03™ and higher processors, enhanced PLC-5® processors, and
Rockwell Software RSLinx (version 2.x and higher).
DF1 Half-Duplex supports up to 255 devices (address 0 to 254) with
address 255 reserved for master broadcasts. The MicroLogix 1500
supports broadcast reception.

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Understanding Communication Protocols

E-3

Considerations When Communicating as a DF1 Slave
on a Multi-drop Link
When communication is between either your programming software
and a MicroLogix Programmable Controller or between two
MicroLogix 1500 Programmable Controllers via slave-to-slave
communication on a larger multi-drop link, the devices depend on a
DF1 Half-Duplex Master to give each of them access in a timely
manner. As the number of slave devices increase, the time between
when slave devices are polled also increases. This increase in time
may also be large if you are using low baud rates. As these time
periods grow, you may need to increase the poll timeout and reply
timeout values for slave devices.

IMPORTANT

Using Modems with
MicroLogix 1500
Programmable Controllers

If a program download is started when using DF1
Half-Duplex, but then is interrupted due to
electromagnetic interference or other events,
discontinue communications to the controller for the
ownership timeout period and then restart the
program download. The ownership timeout period is
60 seconds. After the timeout, you can re-establish
communications with the processor and try the
program download again. The only other way to
remove program ownership is to cycle power on the
processor.

The types of modems that you can use with MicroLogix 1500
controllers include dial-up phone modems, leased-line modems, radio
modems and line drivers.
For point-to-point Full-Duplex modem connections that do not
require any modem handshaking signals to operate, use DF1
Full-Duplex protocol with no handshaking. For point-to-point
Full-Duplex modem connections that require RTS/CTS handshaking,
use DF1 Full-Duplex protocol with handshaking.

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Understanding Communication Protocols

For multi-drop modem connections, or for point-to-point modem
connections that require RTS/CTS handshaking, use DF1 Half-Duplex
slave protocol.
IMPORTANT

TIP

Never attempt to use DH-485 protocol through
modems under any circumstance.

All MicroLogix controllers support RTS/CTS modem
handshaking when configured for DF1 Full-Duplex
protocol with the control line parameter set to
Full-Duplex Modem Handshaking or DF1
Half-Duplex slave protocol with the control line
parameter set to “Half-Duplex Modem”. No other
modem handshaking lines (i.e. Data Set Ready,
Carrier Detect and Data Terminal Ready) are
supported by any MicroLogix 1500 controllers.
MicroLogix 1500 1764-LRP processors also support
DCD (Data Carrier Detect)

Dial-Up Phone Modems
Some dial-up phone line modems support point-to-point Full-Duplex
communications. A MicroLogix 1500 controller, on the receiving end
of the dial-up connection, can be configured for DF1 Full-Duplex
protocol with or without handshaking. The modem connected to the
MicroLogix controller should support auto-answer. The MicroLogix
1500 Series B processors (1764-LSP and 1764-LRP) support ASCII out
communications. There fore, they can cause the modem to initiate or
disconnect a phone call.

Leased-Line Modems
Leased-line modems are used with dedicated phone lines that are
typically leased from the local phone company. The dedicated lines
may be in a point-to-point topology supporting Full-Duplex
communications between two modems or in a multi-drop topology
supporting Half-Duplex communications between three or more
modems.

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Understanding Communication Protocols

E-5

Radio Modems
Radio modems may be implemented in a point-to-point topology
supporting either Half-Duplex or Full-Duplex communications, or in a
multi-drop topology supporting Half-Duplex communications
between three or more modems.

Line Drivers
Line drivers, also called short-haul “modems”, do not actually
modulate the serial data, but rather condition the electrical signals to
operate reliably over long transmission distances (up to several miles).
Line drivers are available in Full- and Half-Duplex models.
Allen-Bradley’s AIC+ Advanced Interface Converter is a Half-Duplex
line driver that converts an RS-232 electrical signal into an RS-485
electrical signal, increasing the signal transmission distance from 50 to
4000 feet (8000 feet when bridged).

DH-485 Communication
Protocol

The information in this section describes DH-485 network functions,
network architecture, and performance characteristics. It will also help
you plan and operate the MicroLogix controllers on a DH-485
network.

DH-485 Network Description
The DH-485 protocol defines the communication between multiple
devices that coexist on a single pair of wires. DH-485 protocol uses
RS-485 Half-Duplex as its physical interface. (RS-485 is a definition of
electrical characteristics; it is not a protocol.) RS-485 uses devices that
are capable of co-existing on a common data circuit, thus allowing
data to be easily shared between devices.
The DH-485 network offers:
•
•
•
•

interconnection of 32 devices
multi-master (peer-to-peer) capability
token passing access control
the ability to add or remove nodes without disrupting the
network
• maximum network segment of 1219 m (4000 ft)

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Understanding Communication Protocols

The DH-485 protocol supports two classes of devices: initiators and
responders. All initiators on the network get a chance to initiate
message transfers. To determine which initiator has the right to
transmit, a token passing algorithm is used.
The following section describes the protocol used to control message
transfers on the DH-485 network.

DH-485 Token Rotation
A node holding the token can send a message onto the network. Each
node is allowed a fixed number of transmissions (based on the Token
Hold Factor) each time it receives the token. After a node sends a
message, it passes the token to the next device.
The allowable range of node addresses is 1 to 31. There must be at
least one initiator on the network (such as a MicroLogix controller, or
an SLC 5/02™ or higher processor).

DH-485 Configuration Parameters
When MicroLogix communications are configured for DH-485, the
following parameters can be changed:
Table E.1 DF1 Full-Duplex Configuration Parameters
Parameter

Options

Baud Rate

9600, 19.2K

Node Address

1 to 31 decimal

Token Hold Factor

1 to 4

See Software Considerations on page E-10 for tips on setting the
parameters listed above.

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E-7

Devices that Use the DH-485 Network
In addition to the MicroLogix 1500 controllers, the devices shown in
the following table also support the DH-485 network.

Table E.2 Allen-Bradley Devices that Support DH-485 Communication
Catalog
Number

Description

Installation

Function

Publication

Bulletin
1761
Controllers

MicroLogix
1000

Series C or
higher

These controllers support DH-485 communications.

1761-6.3

Bulletin
1762

MicroLogix
1200

Series A or
higher

These controllers support DH-485 communications.

1762-UM001

Bulletin
1747
Processors

SLC 500
Processors

SLC Chassis

These processors support a variety of I/O requirements and
functionality.

1747-6.2

1746-BAS

BASIC
Module

SLC Chassis

Provides an interface for SLC 500 devices to foreign devices.
Program in BASIC to interface the 3 channels (2 RS232 and 1
DH-485) to printers, modems, or the DH-485 network for data
collection.

1746-6.1
1746-6.2
1746-6.3

1785-KA5

DH+TM/
DH-485
Gateway

(1771) PLC
Chassis

Provides communication between stations on the PLC-5® (DH+) 1785-6.5.5
1785-1.21
and SLC 500 (DH-485) networks. Enables communication and
®
data transfer from PLC to SLC 500 on DH-485 network. Also
enables programming software programming or data acquisition
across DH+ to DH-485.

2760-RB

Flexible
Interface
Module

(1771) PLC
Chassis

Provides an interface for SLC 500 (using protocol cartridge
2760-SFC3) to other A-B PLCs and devices. Three configurable
channels are available to interface with Bar Code, Vision, RF,
Dataliner™, and PLC systems.

1747-KE
2760-ND001

1784-KTX,
-KTXD

PC DH-485
IM

IBM XT/AT
Computer
Bus

Provides DH-485 using RSLinx.

1784-6.5.22

1784-PCMK

PCMCIA IM

PCMCIA slot
in computer
and
Interchange

Provides DH-485 using RSLinx.

1784-6.5.19

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Understanding Communication Protocols

Table E.2 Allen-Bradley Devices that Support DH-485 Communication
Catalog
Number

Description

Installation

Function

Publication

1747-PT1

Hand-Held
Terminal

Provides hand-held programming, monitoring, configuring, and
troubleshooting capabilities for SLC 500 processors.

1747-NP002

1747-DTAM,
2707-L8P1,
-L8P2,
-L40P1,
-L40P2,
-V40P1,
-V40P2,
-V40P2N,
-M232P3,
and
-M485P3

DTAM,
DTAM Plus,
and DTAM
Micro
Operator
Interfaces

Panel Mount

Provides electronic operator interface for SLC 500 processors.

1747-ND013
2707-800,
2707-803

2711-K5A2,
-B5A2,
-K5A5,
-B5A5,
-K5A1,
-B5A1,
-K9A2,
-T9A2,
-K9A5,
-T9A5,
-K9A1, and
-T9A1

PanelView
550 and
PanelView
900 Operator
Terminals

Panel Mount

Provides electronic operator interface for SLC 500 processors.

2711-802, 2711-816

NA = Not Applicable

Important DH-485 Network Planning Considerations
Carefully plan your network configuration before installing any
hardware. Listed below are some of the factors that can affect system
performance:
• amount of electrical noise, temperature, and humidity in the
network environment
• number of devices on the network
• connection and grounding quality in installation
• amount of communication traffic on the network
• type of process being controlled
• network configuration
The major hardware and software issues you need to resolve before
installing a network are discussed in the following sections.

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E-9

Hardware Considerations
You need to decide the length of the communication cable, where
you route it, and how to protect it from the environment where it will
be installed.
When the communication cable is installed, you need to know how
many devices are to be connected during installation and how many
devices will be added in the future. The following sections will help
you understand and plan the network.

Number of Devices and Length of Communication Cable
The maximum length of the communication cable is 1219m (4000 ft).
This is the total cable distance from the first node to the last node in a
segment. However, two segments can be used to extend the DH-485
network to 2438m (8000 ft). for additional information on connections
using the AIC+, refer to the Advanced Interface Converter (AIC+) User
Manual, publication 1761-6.4.

Planning Cable Routes
Follow these guidelines to help protect the communication cable from
electrical interference:
• Keep the communication cable at least 1.52m (5 ft) from any
electric motors, transformers, rectifiers, generators, arc welders,
induction furnaces, or sources of microwave radiation.
• If you must run the cable across power feed lines, run the cable
at right angles to the lines.
• If you do not run the cable through a contiguous metallic
wireway or conduit, keep the communication cable at least
0.15m (6 in.) from ac power lines of less than 20A, 0.30m (1 ft)
from lines greater than 20A, but only up to 100 kVA, and 0.60m
(2 ft) from lines of 100 kVA or more.
• If you run the cable through a contiguous metallic wireway or
conduit, keep the communication cable at least 0.08m (3 in.)
from ac power lines of less than 20A, 0.15m (6 in.) from lines
greater than 20A, but only up to 100 kVA, and 0.30m (1 ft) from
lines of 100 kVA or more.
Running the communication cable through conduit provides
extra protection from physical damage and electrical

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Understanding Communication Protocols

interference. If you route the cable through conduit, follow
these additional recommendations:
– Use ferromagnetic conduit near critical sources of electrical
interference. You can use aluminum conduit in non-critical
areas.
– Use plastic connectors to couple between aluminum and
ferromagnetic conduit. Make an electrical connection around
the plastic connector (use pipe clamps and the heavy gauge
wire or wire braid) to hold both sections at the same
potential.
– Ground the entire length of conduit by attaching it to the
building earth ground.
– Do not let the conduit touch the plug on the cable.
– Arrange the cables loosely within the conduit. The conduit
should contain only serial communication cables.
– Install the conduit so that it meets all applicable codes and
environmental specifications.
For more information on planning cable routes, see Industrial
Automation Wiring and Grounding Guidelines, publication 1770-4.1.

Software Considerations
Software considerations include the configuration of the network and
the parameters that can be set to the specific requirements of the
network. The following are major configuration factors that have a
significant effect on network performance:
• number of nodes on the network
• addresses of those nodes
• baud rate
The following sections explain network considerations and describe
ways to select parameters for optimum network performance (speed).
See your programming software’s user manual for more information.

Number of Nodes
The number of nodes on the network directly affects the data transfer
time between nodes. Unnecessary nodes (such as a second
programming terminal that is not being used) slow the data transfer
rate. The maximum number of nodes on the network is 32.

Publication 1764-UM001B-EN-P - April 2002

Understanding Communication Protocols

E-11

Setting Node Addresses
The best network performance occurs when node addresses are
assigned in sequential order. Initiators, such as personal computers,
should be assigned the lowest numbered addresses to minimize the
time required to initialize the network. The valid range for the
MicroLogix 1500 controllers is 1-31 (controllers cannot be node 0).
The default setting is 1. The node address is stored in the controller
Communications Status file (CS0:5/0 to CS0:5/7).

Setting Controller Baud Rate
The best network performance occurs at the highest baud rate, which
is 19200. This is the default baud rate for a MicroLogix 1500 device on
the DH-485 network. All devices must be at the same baud rate. This
rate is stored in the controller Communications Status file (CS0:5/8 to
CS0:5/15).

Setting Maximum Node Address
Once you have an established network set up and are confident that
you will not be adding more devices, you may enhance performance
by adjusting the maximum node address of your controllers. It should
be set to the highest node address being used.

IMPORTANT

All devices should be set to the same maximum node
address.

MicroLogix Remote Packet Support
MicroLogix 1500 controllers can respond and initiate with device’s
communications (or commands) that do not originate on the local
DH-485 network. This is useful in installations where communication
is needed between the DH-485 and DH+ networks.
The example below shows how to send messages from a PLC device
or a PC on the DH+ network to a MicroLogix controller on the
DH-485 network. This method uses an SLC 5/04 processor bridge
connection.

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E-12

Understanding Communication Protocols

When using this method (as shown in the following illustration):
• PLC-5 devices can send read and write commands to MicroLogix
1500 controllers.
• MicroLogix 1500 controllers can respond to MSG instructions
received.
• The MicroLogix 1500 controllers can initiate MSG instructions to
devices on the DH+ network.
• PC can send read and write commands to MicroLogix 1500
controllers.
• PC can do remote programming of MicroLogix 1500 controllers.
AIC+

AIC+
TERM

TERM

A-B

COM

SHLD

CHS GND

PanelView

CHS GND

TX
TX

PWR
TX

PWR

DC SOURCE
DC SOURCE

CABLE

EXTERNAL
EXTERNAL

SLC 5/04

PanelView 550

DH-485 Network
AIC+

AIC+

TERM

COM

SHLD

CHS GND

SHLD

CHS GND

SHLD

CHS GND

TERM
A

CHS GND

B
COM

SHLD
CHS GND

PWR

DC SOURCE

PWR

DC SOURCE

CABLE

PWR

DC SOURCE

CABLE

PWR

DC SOURCE
CABLE

PWR

DC SOURCE
EXTERNAL

EXTERNAL

CABLE

EXTERNAL

MicroLogix 1000

MicroLogix 1200

DH+ Network

SLC 5/04

Publication 1764-UM001B-EN-P - April 2002

MicroLogix 1500 with
MicroLogix 1500 with 1764-LSP 1764-LRP Processor
or 1764-LRP Processor

PLC-5

SLC 5/04

Understanding Communication Protocols

Modbus RTU Slave
Communication Protocol
(MicroLogix 1764-LSP and
1764-LRP Series B and later
processors only)

E-13

Modbus RTU Slave is a Half-Duplex, master-slave communications
protocol. The Modbus network master initiates and controls all
communications on the network. Modbus protocol allows a single
master to communicate with a maximum of 255 slave devices.
When a MicroLogix 1200 or 1500 Communications port is configured
for Modbus RTU Slave operation, the user must define where Modbus
data (coils, contacts, and registers) is mapped into the MicroLogix data
space.
The Modbus address space is comprised of seven distinct memory
ranges. Four of these ranges can be mapped into MicroLogix data
files. Three Modbus ranges are fixed to MicroLogix file 2, the Status
file. The table below illustrates Modbus to MicroLogix mappings.

Table E.3 Modbus to MicroLogix Memory Map
Modbus Addressing

Description

Valid MicroLogix Addressing
File Type

Data File Number Address

0001 to 4096

Read/Write Modbus Coil Data space

Bit (B) or Integer (N)

3 to 255

bits 0 to 4095

10001 to 14096

Read-Only Modbus Contact Data space

Bit (B) or Integer (N)

3 to 255

bits 0 to 4095

30001 to 30256

Read-Only Modbus Input Register space Bit (B) or Integer (N)

3 to 255

words 0 to 255

30501 to 30532

Modbus Communication Parameters

Communication
Status Files

words 0 to 31

31501 to 31566

Read-Only System Status File space

Status (S)

words 32 to 65

40001 to 40256

Read/Write Modbus Holding Register
space

Bit (B) or Integer (N)

3 to 255

words 0 to 255

41501 to 41566

Read/Write System Status File space

Status (S)

words 0 to 65

For more information on the MicroLogix 1500 configuration
parameters for Modbus Slave RTU (Remote Terminal Unit transmission
mode) protocol, refer to the MicroLogix 1200 and 1500 Programmable
Controllers Instruction Set Reference Manual, publication 1762-RM001.
For more information about the Modbus Slave protocol, see the
Modbus Protocol Specifications (available from
http://www.modicon.com/techpubs/).

ASCII Protocol (MicroLogix
1500 1764-LSP and 1764-LRP
Series B and later
Processors only)

ASCII protocol provides connection to other ASCII devices, such as
bar code readers, weigh scales, serial printers, and other intelligent
devices.
You can use ASCII protocol by configuring the RS-232 port, channel 0
for ASCII driver (For the 1764-LRP only, you can select either Channel
0 or Channel 1).

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E-14

Understanding Communication Protocols

Refer to the MicroLogix 1200 and MicroLogix 1500 Programmable
Controllers Instruction Set Reference Manual, publication 1762-RM001
for detailed configuration information.
When the driver is set to ASCII, the following parameters can be
changed:

Table E.4 ASCII Channel Configuration Parameters
Parameter

Description

Programming
Software Default

Baud Rate

Toggles between the communication rate of 300, 600, 1200, 2400, 4800, 9600, 19.2K, and 38.4K.

1200

Parity

Toggles between None, Odd, and Even.

None

Termination 1 Specifies the first termination character. The termination character defines the one or two character
sequence used to specify the end of an ASCII line received. Setting the first ASCII termination
character to undefined (\ff) indicates no ASCII receiver line termination is used.

Termination 2 Specifies the second termination character. The termination character defines the one or two
character sequence used to specify the end of an ASCII line received. Setting the second ASCII
Termination character to undefined (\ff) and the first ASCII Termination character to a defined value
(\d) indicates a single character termination sequence.

\ff

Control Line

Toggles between No Handshaking, Half-Duplex Modem, and Full-Duplex Modem

No Handshaking

Delete Mode

The Delete Mode allows you to select the mode of the “delete” character. Toggles between Ignore,
CRT, and Printer.
Delete Mode affects the characters echoed back to the remote device. When Delete Mode is
enabled, the previous character is removed from the receive buffer.
• In CRT mode, when a delete character is encountered, the controller echos three characters
to the device: backspace, space, and backspace. This erases the previous character on the
terminal.
• In Printer Mode, when a delete character is encountered, the controller echos the slash
character, then the deleted character.
Enable the Echo parameter to use Delete Mode.

Ignore

Echo

When Echo Mode is enabled, all of the characters received are echoed back to the remote device.
This allows you to view characters on a terminal connected to the controller. Toggles between
Enabled and Disabled.

Disabled

XON/XOFF

Allows you to Enable or Disable XON/ XOFF software handshaking. XON/XOFF software handshaking
involves the XON and XOFF control characters in the ASCII character set.
When the receiver receives the XOFF character, the transmitter stops transmitting until the receiver
receives the XON character. If the receiver does not receive an XON character after 60 seconds, the
transmitter automatically resumes sending characters.
Also, when the receive buffer is more than 80% full, an XOFF character is sent to the remote device
to pause the transmission. Then, when the receive buffer drops to less than 80% full, an XON
character is sent to the remote device to resume the transmission.

Disabled

RTS Off
Delay (x20
ms)

Allows you to select the delay between when a transmission is ended and when RTS is dropped.
Specify the RTS Off Delay value in increments of 20 ms. Valid range is 0 to 65535.

RTS Send
Delay (x20
ms)

Allows you to select the delay between when RTS is raised and the transmission is initiated. Specify
the RTS Send Delay value in increments of 20 ms. Valid range is 0 to 65535.

Publication 1764-UM001B-EN-P - April 2002

Appendix

System Loading and Heat Dissipation

System Loading Limitations

When you connect MicroLogix accessories and expansion I/O, an
electrical load is placed on the base unit power supply. This section
shows how to calculate the load and validate that the system will not
exceed the capacity of the base unit power supply or expansion
power supply.
The following example is provided to illustrate system loading
validation. The system validation procedure accounts for the amount
of 5V dc and 24V dc current consumed by controller, expansion I/O,
and user supplied equipment.
Current consumed by the Base Units, Memory Modules, Real Time
Clock Modules, and the End Cap Terminators (for systems utilizing
Compact I/O expansion) has already been factored into the
calculations. A system is valid if the current and power requirements
are satisfied.

System Expansion
Calculations

TIP

An End Cap Terminator (catalog number 1769-ECR
or -ECL) is needed for any system using Compact
expansion I/O.

IMPORTANT

In a MicroLogix 1500 system, a maximum of one 1769
expansion cable can be used, allowing for two banks
of I/O modules. One bank is connected directly to
the controller and the other is connected via the
expansion cable. The bank connected to the
controller uses the controller’s embedded power
supply. The bank connected via the cable requires its
own power supply.

A download is also available for system validation. On the Internet, go
to http://www.ab.com/micrologix and navigate to MicroLogix 1500.
The procedure in this publication consists of:
• Selecting System Devices
• Verifying the System Loading

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F-2

System Loading and Heat Dissipation

Selecting System Devices
1. Use Table F.1 to select the processor and optional
communications or display devices. Enter a 1 in the “Select
Devices” column.
2. Enter the current draw values in the “Calculated Current for
System” columns. If an external power supply will be used to
power communication devices, do not include their current
draw values in this calculation. Add up the current draw values
to determine the “SUBTOTAL1” values.
Table F.1 Selecting Hardware: Base Unit and Communications/Display Devices
Catalog Number

Select
Device(s)

Choose a Processor, LSP or LRP:
1764-LSP
1764-LRP

Bus Current Draw Specification
at 5V dc (mA)
at 24V dc (mA)
300
380
350

0
0
0

80(2)

Calculated Current for System
at 5V dc (mA)
at 24V dc (mA)

1764-DAT(1) optional
Communications/Display Devices, optional, one only maximum:
0
1761-NET-AIC(1)
120(2)
0
1761-NET-ENI(1)
100(2)
2707-MVH232 or
2707-MVP232(1)

SUBTOTAL1

(A1)

(B1)

(1) These are optional accessories. Current is consumed only if the accessory is installed.
(2) Current for the AIC+ and ENI may be supplied by controller communications port or from an external 24V dc source. No current is consumed from the controller when a
user-supplied, external source is used. If an external source is to be used, do not select the device here. The current for a 2707-MVH232 or 2707-MVP232 MicroView
Operator Interface is supplied from the controller communication port, when directly connected.

3. Use Table F.2 to select the I/O modules. Enter the number of
modules in either the “Base Unit Expansion” or the “Bank 1”
column.

IMPORTANT

When planning the system layout, keep in
mind that each module has a “Power Supply
Distance Rating”. This is the maximum distance
an I/O module may be located from the power
supply. For most modules, the rating is 8. For
the 1769-HSC and 1769-SDN, the rating is 4.

Depending on its configuration, the 1769-SDN may transfer large
amounts of data into and out of the controller I/O image tables.
Care should be taken when using more than three of these
modules to verify that they are optimally configured. This will

Publication 1764-UM001B-EN-P - April 2002

System Loading and Heat Dissipation

F-3

ensure that the maximum available 4K data table size will not be
exceeded. Refer to the 1769-SDN User Manual for more details.
4. Enter the current draw values in the “Calculated Current”
columns. Add up the current draw values to determine the
“SUBTOTAL2” values.
5. Verify that the total number of modules does not exceed the
system limits using the maximum values for the base unit and
Table F.5 for the expansion power supply, if used.
Table F.2 Selecting Hardware: Expansion I/O
Select I/O Modules for Each Bank:
Expansion I/O
Base Unit
Modules
Expansion

Bank 1

(2)

Bus Current Draw
Specification (mA)

(1)

Catalog Number

Number of Modules(4)
1769-HSC(5)
1769-IA16
1769-IA8I
1769-IF4 (Series A)
1769-IF4 (Series B)
1769-IF4XOF2
1769-IM12
1769-IQ16
1769-IQ6XOW4
1769-IR6
1769-IT6
1769-OA8
1769-OA16
1769-OB16
1769-OB16P
1769-OF2 (Series A)
1769-OF2 (Series B)
1769-OV16
1769-OW8
1769-OW8I
1769-OW16
1769-SDN

X
at 5V dc

Y
at 24V dc

425

115
90
120
120
120
100
115
105
100
100
145
225
200
160
120
120
200
125
125
205
440

0
0
150
60
160
0
0
50
45
40
0
0
0
0
200
120
0
100
100
180
0

TOTAL MODULES:

SUBTOTAL2:

Calculate Current Draw:
Calculated Current for
Base Unit Expansion (mA)
2250 mA max 400 mA max
n1 x X
n1 x Y
at 5V dc
at 24V dc

(A2)

(B2)

Calculated Current for
Bank 1 Power Supply
(mA)(3)
n2 x X
at 5V dc

n2 x Y
at 24V dc

(C)

(D)

(1) May not exceed 8 I/O modules.
(2) No more than 8 I/O modules on either sid e of the power supply.
(3) Maximum value depends on the power supply chosen.
(4) Up to 16 modules may be used in a MicroLogix 1500 system when using a Series B Base Unit and Series C processor (up to 8 for Series A Base Units).
A maximum of 8 modules can be connected directly to the Base Unit.
A maximum of 8 modules can be connected to each side of the Expansion Power Supply.
(5) No more than 4 I/O modules may be connected to the base unit or to either side of the expansion power supply when the 1769-HSC or 1769-SDN are used in the system.

Publication 1764-UM001B-EN-P - April 2002

F-4

System Loading and Heat Dissipation

Verifying the System Loading
To have a valid system, both current and power requirements must be
satisfied.

Verifying the Base Unit Loading
1. Enter the SUBTOTAL values from Tables F.1 and F.2. Add the
total current draw for the Base Unit. Verify the values are within
the maximum limits.

Table F.3 Base Unit Power Supply Loading - Verify the Current Limits
Current from:

Calculated Current for System
at 5V dc (mA)

at 24V dc (mA)

For 1764-24BWA only, enter sum of any User 24V dc Sensor Current

(E)

MAXIMUM LIMIT

n/a

400 mA User 24V dc

Values from SUBTOTAL1 (Table F.1)

(A1)

(B1)

Values from SUBTOTAL2 (Table F.2)

(A2)

(B2)

TOTAL BASE UNIT CURRENT LOADING

(F)

(G)

MAXIMUM LIMIT

2250 mA at 5V dc

400 mA at 24V dc

2. Using the table below, verify that the MAXIMUM POWER LIMIT
is not exceeded.
Table F.4 Base Unit Power Supply Loading - Verify the Required Power
Catalog Number:

1764-24AWA, 1764-28BXB Base Units

1764-24BWA Base Unit

5V Power Calculation

(F)

x 5V

(F)

x 5V

24V Power Calculation

(G)

x 24V

(G)

x 24V

(E)

x 24V

Add up Total Watts

MAXIMUM POWER
LIMIT

16W

22W

Verifying the Expansion Power Supply Loading
Using the values from SUBTOTAL2, verify that the system loading and
I/O distribution are within the limits shown in Table F.5. Consider
future expansion when selecting a power supply.

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System Loading and Heat Dissipation

F-5

Table F.5 Bank 1 Power Supply Loading - Verify the Current Limits
Specification

Catalog Number

Calculated Current for System
at 5V dc (mA)

Values from SUBTOTAL2 (Table F.2):

I/O Distribution - Distribute I/O modules
such that the current consumed from either
the left side or the right side of the power
supply never exceeds the following values:

at 24V dc (mA)
(C)

(D)

1769-PA2

2000

800

250 mA

1769-PA4

4000

2000

n/a

1769-PB2

2000

800

1769-PB4

4000

2000

1769-PA2

2000

800

250 mA

1769-PA4

2000

1000

n/a

1769-PB2

2000

800

1769-PB4

2000

1000

System Using a 1769-PA2
To validate your system, the total 5V dc current and 24V dc current
consumed must be considered. The I/O modules must be distributed,
such that the current consumed from the left or right side of the
power supply never exceeds 2A at 5V dc and 1.0A at 24V dc. Use the
current graphs below to determine if the power supply loading in
your system is within the allowable range.
Figure F.1 1769-PA2 Current with +24V dc User Load = 0A
2.0

+5V dc Load (Amps)

MAXIMUM CURRENT LIMIT

24V dc User Output
Capacity

1.5

Valid Operating Range

1.0
0.5
0.0
0.0

0.1

0.2

0.3 0.4 0.5 0.6 0.7
+24V dc Load (Amps)

0.8

0.9

1.0

Publication 1764-UM001B-EN-P - April 2002

F-6

System Loading and Heat Dissipation

Figure F.2 1769-PA2 Current with +24V dc User Load = 0.2A

+5V dc Load (Amps)

2.0
1.5

Valid Operating Range

1.0
0.5
0.0
0.0

0.1

0.2

0.3 0.4 0.5 0.6 0.7
+24V dc Load (Amps)

0.8

0.9

1.0

0.8

0.9

1.0

Figure F.3 1769-PA2 Current with +24V dc User Load = 0.25A

+5V dc Load (Amps)

2.0
1.5

Valid Operating Range

1.0
0.5
0.0
0.0

0.1

0.2

0.3 0.4 0.5 0.6 0.7
+24V dc Load (Amps)

System Using a 1769-PB2
To validate your system, the total 5V dc current and 24V dc current
consumed must be considered. The I/O modules must be distributed,
such that the current consumed from the left or right side of the
power supply never exceeds 2A at 5V dc and 1.0A at 24V dc. Use the
current graph below to determine if the power supply loading in your
system is within the allowable range.
Figure F.4 1769-PB2 Current

+5V dc Load (Amps)

2.0
1.5
1.0
0.5
0.0
0.0

Publication 1764-UM001B-EN-P - April 2002

Valid Operating Range

0.1

0.2

0.3 0.4 0.5 0.6 0.7
+24V dc Load (Amps)

0.8

0.9

1.0

System Loading and Heat Dissipation

F-7

System Using a 1769-PA4
To validate your system, the total 5V dc current and 24V dc current
consumed must be considered. The I/O modules connected to the
PB2 should be distributed, such that the current consumed from the
left and right side of the power supply never exceeds 2A at 5V and
0.8A at 24V dc with an ambient temperature of 0 to 55°C. Use the
current graph below to determine if the power supply loading in your
system is:
• within the allowable range for special load conditions
• above 55° to 60°C.
Figure 7 1769-PA4 5V and 24V dc Current
Total Output: 68W at 55°C or below

1.7

61W at 60°C or below

4.0
+5V Bus Load (Amps)

55˚C
3.0
2.6
2.0
1.0
0.0
0.0

60˚C

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

+24V Bus Load (Amps)

System Using a 1769-PB4
To validate your system, the total 5V dc current and 24V dc current
consumed must be considered. The I/O modules connected to the
PB2 should be distributed, such that the current consumed from the
left and right side of the power supply never exceeds 2A at 5V and
0.8A at 24V dc with an ambient temperature of 0 to 55°C. Use the
current graph below to determine if the power supply loading in your
system is:
• within the allowable range for special load conditions
• above 55° to 60°C.

Publication 1764-UM001B-EN-P - April 2002

F-8

System Loading and Heat Dissipation

Figure 8 1769-PB4 5V and 24V dc Current
Total Output: 68W at 55°C or below
61W at 60°C or below

1.7

4.0
+5V Bus Load (Amps)

55˚C
3.0
2.6
2.0
1.0
0.0
0.0

60˚C

0.2

0.4

0.6

0.8

1.0

+24V Bus Load (Amps)

Publication 1764-UM001B-EN-P - April 2002

1.2

1.4

1.6

1.8

2.0

System Loading and Heat Dissipation

Calculating Heat
Dissipation
Catalog Number

F-9

Use this procedure when you need to determine the heat dissipation
for installation in an enclosure. Use the following table.

Heat Dissipation
Equation or Constant

Calculation

Subtotal

1764-24AWA

18W + (0.3 x System Loading)

18W + (0.3 x ______ W)

1764-24BWA

20W + (0.3 x System Loading)

20W + (0.3 x ______ W)

1764-28BXB

20W + (0.3 x System Loading)

20W + (0.3 x ______ W)

1764-DAT

1.75W

1769-HSC

6.21W x number of modules

6.21W x __________

1769-IA16

3.30W x number of modules

3.30W x __________

1769-IA8I

1.81W x number of modules

1.81W x __________

1769-IF4 (Series A)

3.99W x number of modules

3.99W x __________

1769-IF4 (Series B)

2.63W x number of modules

2.63W x __________

1769-IF4XOF2

3.03W x number of modules

3.03W x __________

1769-IM12

3.65W x number of modules

3.65W x __________

1769-IQ16

3.55W x number of modules

3.55W x __________

1769-IQ6XOW4

2.75W x number of modules

2.75W x __________

1769-IR6

1.50W x number of modules

1.50W x __________

1769-IT6

1.50W x number of modules

1.50W x __________

1764-LSP

1.5W

1764-LRP

1.9W

1764-MM1, -RTC, -MM1/RTC

1769-OA8

2.12W x number of modules

2.12W x __________

1769-OA16

4.9W x number of modules

4.9W x __________

1769-OB16

2.11W x number of modules

2.11W x __________

1769-OB16P

2.69W x number of modules

2.69W x __________

1769-OF2 (Series A)

4.77W x number of modules

4.77W x __________

1769-OF2 (Series B)

2.52W x number of modules

2.52W x __________

1769-OV16

2.06W x number of modules

2.06W x __________

1769-OW8

2.83W x number of modules

2.83W x __________

1769-OW8I

2.83W x number of modules

2.83W x __________

1769-OW16

4.75W x number of modules

4.75W x __________

1769-SDN

3.8W x number of modules

3.8W x __________

Add Subtotals to determine Heat Dissipation

Publication 1764-UM001B-EN-P - April 2002

F-10

System Loading and Heat Dissipation

Publication 1764-UM001B-EN-P - April 2002

Glossary
The following terms are used throughout this manual. Refer to the
Allen-Bradley Industrial Automation Glossary, Publication Number
AG-7.1, for a complete guide to Allen-Bradley technical terms.
address
A character string that uniquely identifies a memory location. For
example, I:1/0 is the memory address for data located in Input file
word 1, bit 0.
AIC+ Advanced Interface Converter
A device that provides RS-232 isolation to an RS-485 Half-Duplex
communication link. (Catalog Number 1761-NET-AIC.)
application
1) A machine or process monitored and controlled by a controller.
2) The use of computer- or processor-based routines for specific
purposes.
baud rate
The speed of communication between devices. Baud rate is typically
displayed in K baud. For example, 19.2K baud = 19,200 bits per
second.
bit
The smallest unit of memory used in discrete or binary logic, where
the value 1 represents ON and 0 represents OFF.
block diagrams
A method used to illustrate logic components or a sequence of events.
Boolean operators
Logical operators such as AND, OR, NAND, NOR, NOT, and
Exclusive-OR that can be used singularly or in combination to form
logic statements or circuits. Can have an output response of T or F.
branch
A parallel logic path within a rung of a ladder program. Its primary
use is to build OR logic.

Publication 1764-UM001B-EN-P - April 2002

Glossary

communication scan
A part of the controller’s operating cycle. Communication with devices
(such as other controllers and operator interface devices) takes place
during this period.
control program
User logic (the application) that defines the controller’s operation.
controller
A device, such as a programmable controller, used to control output
devices.
controller overhead
A portion of the operating cycle used for housekeeping purposes
(memory checks, tests, communications, etc.).
counter
A device that counts the occurrence of an event.
CPU (Central Processing Unit)
The decision-making and data storage section of a programmable
controller.
data table
The part of processor memory that contains I/O status and files where
user data (such as bit, integer, timers, and counters) is monitored,
manipulated, and changed for control purposes.
DIN rail
Manufactured according to Deutsche Industrie Normenausshus (DIN)
standards, a metal railing designed to ease installation and mounting
of your devices.
download
The transfer of program or data files to a device.
DCD
Data Carrier Detect. A signal generated by a modem that represents
traffic (activity) on a communications network.

Publication 1764-UM001B-EN-P - April 2002

Glossary

DTE
Data Terminal Equipment
EMI
Electromagnetic interference.
embedded I/O
Embedded I/O is the controller’s on-board I/O. For MicroLogix
controllers, embedded I/O is all I/O residing at slot 0.
expansion I/O
Expansion I/O is I/O that is connected to the controller via a bus or
cable. MicroLogix 1200 controllers use Bulletin 1762 expansion I/O.
MicroLogix 1500 controllers use Bulletin 1769 expansion I/O. For
MicroLogix controllers, expansion I/O is all I/O residing at slot 1 and
higher.
encoder
A device that detects position, and transmits a signal representing that
position.
executing mode
Any run, remote run, or test mode.
false
The status of an instruction that does not provide a continuous logical
path on a ladder rung.
FIFO (First-In-First-Out)
The order that data is stored and retrieved from a file.
file
A collection of data or logic organized into groups.
full-duplex
A mode of communication where data may be transmitted and
received simultaneously (contrast with half-duplex).

Publication 1764-UM001B-EN-P - April 2002

Glossary

half-duplex
A mode of communication where data transmission is limited to one
direction at a time.
hard disk
A storage device in a personal computer.
high byte
Bits 8 to 15 of a word.
housekeeping
The portion of the scan when the controller performs internal checks
and services communications.
input device
A device, such as a push button or a switch, that supplies an electrical
signal to the controller.
input scan
The controller reads all input devices connected to the input
terminals.
inrush current
The temporary surge of current produced when a device or circuit is
initially energized.
instruction
A mnemonic defining an operation to be performed by the processor.
A rung in a program consists of a set of input and output instructions.
The input instructions are evaluated by the controller as being true or
false. In turn, the controller sets the output instructions to true or false.
instruction set
The set of instructions available within a controller.
I/O
Input and Output

Publication 1764-UM001B-EN-P - April 2002

Glossary

jump
Changes the normal sequence of program execution. In ladder
programs a JUMP (JMP) instruction causes execution to jump to a
specific rung in the user program.
ladder logic
A graphical programming format resembling a ladder-like diagram.
The ladder logic programing language is the most common
programmable controller language.
least significant bit (LSB)
The element (or bit) in a binary word that carries the smallest value of
weight.
LED (Light Emitting Diode)
Used as status indicator for processor functions and inputs and
outputs.
LIFO (Last-In-First-Out)
The order that data is stored and retrieved from a file.
low byte
Bits 0 to 7 of a word.
logic
A general term for digital circuits or programmed instructions to
perform required decision making and computational functions.
Master Control Relay (MCR)
A hard-wired relay that can be de-energized by any series-connected
emergency stop switch.
mnemonic
A simple and easy to remember term that is used to represent a
complex or lengthy set of information.
Modbus™ RTU Slave
A serial communication protocol.

Publication 1764-UM001B-EN-P - April 2002

Glossary

modem
Modulator/demodulator. Equipment that connects data terminal
equipment to a communication line.
modes
Selected methods of operation. Example: run, test, or program.
negative logic
The use of binary logic in such a way that “0” represents the desired
voltage level.
network
A series of stations (nodes) connected by some type of
communication medium. A network may be made up of a single link
or multiple links.
nominal input current
The typical amount of current seen at nominal input voltage.
normally closed
Contacts on a relay or switch that are closed when the relay is
de-energized or deactivated. They are open when the relay is
energized or the switch is activated.
normally open
Contacts on a relay or switch that are open when the relay is
de-energized or the switch is deactivated. They are closed when the
relay is energized or the switch is activated.
off-delay time
The OFF delay time is a measure of the time required for the
controller logic to recognize that a signal has been removed from the
input terminal of the controller. The time is determined by circuit
component delays and by any applied filter.
offline
When a device is not scanning/controlling or when a programming
device is not communicating with the controller.

Publication 1764-UM001B-EN-P - April 2002

Glossary

offset
A continuous deviation of a controlled variable from a fixed point.
off-state leakage current
When a mechanical switch is opened (off-state), no current flows
through the switch. Semiconductor switches and transient suppression
components which are sometimes used to protect switches, have a
small current flow when they are in the off state. This current is
referred to as the off-state leakage current. To ensure reliable
operation, the off-state leakage current rating must be less than the
minimum operating current rating of the device that is connected.
on-delay time
The ON delay time is a measure of the time required for the controller
logic to recognize that a signal has been presented at the input
terminal of the controller.
one shot
A programming technique that sets a bit ON or OFF for one program
scan.
online
When a device is scanning/controlling or when a programming device
is communicating with the controller.
operating voltage
For inputs, the voltage range needed for the input to be in the On
state. For outputs, the allowable range of user-supplied voltage.
output device
A device, such as a pilot light or a motor starter coil, that receives a
signal or command from the controller.
output scan
The controller turns on, off, or modifies the devices connected to the
output terminals.
PCCC
Programmable Controller Communications Commands

Publication 1764-UM001B-EN-P - April 2002

Glossary

processor
A Central Processing Unit. (See CPU.)
processor files
The set of program and data files resident in the controller.
program file
Areas within a processor that contain the logic programs. MicroLogix
controllers support multiple program files.
program mode
When the controller is not scanning the control program.
program scan
A part of the controller’s operating cycle. During the program scan,
the logic program is processed and the Output Image is updated.
programming device
Programming package used to develop ladder logic diagrams.
protocol
The rules of data exchange via communications.
read
To acquire data. For example, the processor reads information from
other devices via a read message.
relay
An electrically operated device that mechanically switches electrical
circuits.
relay logic
A representation of binary or discrete logic.
restore
To transfer a program from a device to a controller.

Publication 1764-UM001B-EN-P - April 2002

Glossary

reserved bit
A location reserved for internal use.
retentive data
Information (data) that is preserved through power cycles.
RS-232
An EIA standard that specifies electrical, mechanical, and functional
characteristics for serial binary communication circuits.
run mode
An executing mode during which the controller scans or executes the
logic program.
rung
A rung contains input and output instructions. During Run mode, the
inputs on a rung are evaluated to be true or false. If a path of true
logic exists, the outputs are made true (energized). If all paths are
false, the outputs are made false (de-energized).
RTU
Remote Terminal Unit
save
To save a program to a computer hard disk.
scan
The scan is made up of four elements: input scan, program scan,
output scan, and housekeeping.
scan time
The time required for the controller to complete one scan.
sinking
A term used to describe current flow between two devices. A sinking
device provides a direct path to ground.

Publication 1764-UM001B-EN-P - April 2002

Glossary

sourcing
A term used to describe current flow between two devices. A sourcing
device or circuit provides a power.
status
The condition of a circuit or system.
terminal
A point on an I/O module that external devices, such as a push button
or pilot light, are wired to.
throughput
The time between when an input turns on and a corresponding
output turns on or off. Throughput consists of input delays, program
scan, output delays, and overhead.
true
The status of an instruction that provides a continuous logical path on
a ladder rung.
upload
Data is transferred from the controller to a programming or storage
device.
watchdog timer
A timer that monitors a cyclical process and is cleared at the
conclusion of each cycle. If the watchdog runs past its programmed
time period, it causes a fault.
write
To send data to another device. For example, the processor writes
data to another device with a message write instruction.

Publication 1764-UM001B-EN-P - April 2002

Index
Numerics
1764-24AWA
features 1-1
1764-24AWA wiring diagram 3-11
1764-24BWA
features 1-1
1764-24BWA sinking wiring diagram

baud rate G-1
bit G-1
bit key 5-3
Bit Mode 5-6
block diagrams G-1
Boolean operators G-1
branch G-1

3-12
1764-24BWA sourcing wiring diagram

3-13
1764-28BXB
features 1-1
1764-28BXB sinking wiring diagram 3-14
1764-28BXB sourcing wiring diagram

3-15
1764-LRP processor 1-3
1764-LSP processor 1-3

A
address G-1
AIC+
applying power to 4-20
attaching to the network 4-20
connecting 4-15

isolated modem 4-5
installing 4-20
recommended user supplied components

4-19
selecting cable 4-17
AIC+ Advanced Interface Converter G-1
Allen-Bradley
contacting for assistance C-5
support P-3
application G-1
ASCII protocol E-13
attach and lock module 2-22

B
base comms door B-6
base terminal door B-6
base unit panel mounting 2-16
base units
hardware overview 1-2
battery
processor battery life expectancy B-2
processor replacement battery B-2
RTC battery life expectancy 6-3

C
Cables 4-23
cables
hardware overview 1-4
planning routes for DH485 connections

E-9
selection guide for the AIC+ 4-17
selection guide for the DeviceNet
network 4-22
calling Allen-Bradley for assistance C-5
CE mark 2-1
certification 2-1
channel configuration
DF1 full-duplex E-1
clearing faults C-4
common techniques used in this manual

P-3
communication
DeviceNet 4-22, 4-23
communication protocols
DF1 fullduplex E-1
DF1 halfduplex E-2
DH485 E-5
Modbus E-13
communication scan G-2
compact I/O
attach and lock module 2-22
installing 2-22
component descriptions 1-2
accessories

cables 1-4
programming 1-5
base units 1-2
data access tool 1-3
end cap 1-6
expansion I/O 1-6
memory modules/real-time clock 1-3
processor 1-3
components
installing 2-17

Publication 1764-UM001B-EN-P - April 2002

Index

connecting the system
AIC+ 4-15
DeviceNet network 4-22, 4-23
DF1 fullduplex protocol 4-3
DH485 network 4-10
contactors (bulletin 100), surge
suppressors for 3-6
control program G-2
ControlFlash
missing/corrupt OS LED pattern D-2
sequence of operation D-2
using D-1
controller
definition G-2
determining faults C-1
fault messages C-5
features 1-1
grounding 3-6
installation 2-1
mounting 2-13
overhead G-2
preventing excessive heat 2-7
troubleshooting C-1
controller error recovery model C-3
controller faults C-1
controller LED status C-1
controller operation
normal C-2
counters
definition G-2
CPU (central processing unit), definition

G-2
CSA certification
see C-UL 2-1
C-UL certification 2-1

D
DAT
Communication Errors 5-9
configuration 5-4
Controller Faults Displayed 5-8
display 5-5
Error Conditions 5-9
Internal Errors 5-9
keypad 5-3
power-up operation 5-3
DAT Function File 5-4

Publication 1764-UM001B-EN-P - April 2002

data access tool
hardware overview 1-3
installing 2-19
data table G-2
DCD, definition G-2
DeviceNet Communications 4-22, 4-23
DeviceNet network
connecting 4-22, 4-23
selecting cable 4-22
DF1 fullduplex protocol
configuration parameters E-1
connecting 4-3
description E-1
using a modem 4-5, E-3
DF1 halfduplex protocol
description E-2
DH485 communication protocol
configuration parameters 4-12, E-6
DH485 network
configuration parameters E-10
connecting 4-10
description E-5
devices that use the network E-7
installation 4-12
planning considerations E-8
protocol E-6
token rotation E-6
DIN rail G-2
mounting 2-14
removing your base unit 2-15
disconnecting main power 2-4
download G-2
DTE, definition G-3

E
Electronics Industries Association (EIA)

E-1
electrostatic discharge
preventing 2-17
EMC 2-1
EMC Directive 2-1
emergency-stop switches 2-9
EMI G-3
encoder
definition G-3
end cap
hardware overview 1-6
ENTER key 5-3
error recovery model C-3

Index

errors
controller C-2
hardware C-2
identifying C-4
ESC key 5-3
European Union Directive compliance

2-1
executing mode G-3
expansion I/O
hardware overview 1-6

F
F1 Functions 5-7
F1 key 5-3
F2 Functions 5-7
F2 key 5-3
false G-3
fault recovery procedure C-4
fault routine C-4
faults
automatically clearing C-4
identifying C-4
manually clearing using the fault routine

C-4
FET output specifications
1764-28BXB A-5
FIFO (First-In-First-Out) G-3
file G-3
full-duplex G-3

G
grounding the controller 3-6

H
half-duplex G-4
hard disk G-4
hardware
features 1-1
hardware overview 1-1
hazardous location 2-3
heat protection 2-7
high byte G-4
housekeeping G-4

I
I/O G-4
identifying controller faults C-4
input device G-4
input scan G-4
input specifications A-3
input states on power down 2-6
inrush current G-4
installing
ControlFlash software D-1
your controller 2-1
installing controller components
compact I/O 2-22
data access tool 2-19
memory module/real-time clock 2-20
processor 2-17
installing your base unit
on DIN rail 2-15
using mounting screws 2-16
installion 2-17
instruction G-4
instruction set
definition G-4
integer key 5-3
Integer Mode 5-6
isolated link coupler
installing 4-12
isolation transformers
power considerations 2-5

J
jump G-5

K
keypad 5-3

L
ladder logic G-5
least significant bit (LSB) G-5
LED (light emitting diode) G-5
LEDs
error with controller C-2
normal controller operation C-1
status C-1
LIFO (Last-In-First-Out) G-5

Publication 1764-UM001B-EN-P - April 2002

Index

lithium battery (1747-BA)
disposing B-4
handling B-3
installing B-2
manufacturer B-4
storing B-3
transporting B-3
logic G-5
low byte G-5

M
manuals, related P-2
master control relay 2-8
master control relay (MCR) G-5
master control relay circuit
periodic tests 2-5
memory module
data file protection 6-4
program compare 6-4
program/data backup 6-3
removal/installation under power 6-1,

6-5
Memory Module Information File 6-5
memory module/real-time clock
installing 2-20
mnemonic G-5
Modbus communication protocol E-13
Modbus definition G-5
modem G-6
modem cable
constructing your own 4-6
modems
dialup phone E-4
leasedline E-4
line drivers E-5
radio E-5
using with MicroLogix controllers E-3
modes G-6
monitoring
controller operation

fault recovery procedure C-4
motor starters (bulletin 509)
surge suppressors 3-6
motor starters (bulletin 709)
surge suppressors 3-6
mounting
dimensions 2-12
the controller 2-13
using DIN rail 2-14
Publication 1764-UM001B-EN-P - April 2002

N
negative logic G-6
network G-6
nominal input current G-6
normally closed G-6
normally open G-6
null modem cable 4-6

O
offline G-6
offset G-7
off-state leakage current G-7
one shot G-7
online G-7
operating voltage G-7
output device G-7
output scan G-7
output specifications A-5
1764-28BXB FET A-5

P
panel mounting
base unit 2-16
PCCC G-7
planning considerations for a network

E-8
power considerations
input states on power down 2-6
isolation transformers 2-5
loss of power source 2-6
other line conditions 2-7
overview 2-5
power supply inrush 2-6
power distribution 2-5
Power Save Timeout 5-4
power source
loss of 2-6
power supply inrush
power considerations 2-6
preparing for upgrade D-1
preventing excessive heat 2-7
proceessor
hardware overview 1-3
processor G-8
installing 2-17
processor access door B-6
processor files G-8

Index

program faults
determining C-1
program file
definition G-8
program mode G-8
program scan
definition G-8
programming device G-8
programming the controller
required software 1-5
PROTECTED indicator light 5-3, 5-5
protocol G-8
publications, related P-2
Purpose of this Manual P-1

R
read G-8
real time clock
battery low indicator bit 6-2
disabling 6-3
Real Time Clock Function File 6-1
related publications P-2
relay G-8
relay contact rating table A-5
relay logic G-8
relays
surge suppressors for 3-6
remote packet support E-11
replacement battery B-2
disposing B-4
handling B-3
installing B-2
storing B-3
transporting B-3
replacement doors B-6
base comms door B-6
base terminal door B-6
processor access door B-6
trim pots/mode switch cover door B-6
replacement kits B-1
replacement parts B-1
base comms door B-6
base terminal door B-6
processor access door B-6
terminal blocks B-5
trim pots/mode switch cover door B-6
replacement terminal blocks B-5
reserved bit G-9

response times for high-speed dc inputs

A-4
response times for normal dc inputs A-4
restore G-8
retentive data G-9
RS-232 communication interface E-1
RS-232, definition G-9
RTU, definition G-9
run mode G-9
rung G-9

S
safety circuits 2-4
safety considerations
disconnecting main power 2-4
periodic tests of master control relay
circuit 2-5
power distribution 2-5
safety circuits 2-4
save G-9
scan G-9
scan time G-9
sinking G-9
sinking and sourcing circuits 3-10
sinking wiring diagram
1764-28BXB 3-14
sourcing G-10
sourcing wiring diagram
1764-28BXB 3-15
spade lug wiring 3-3
specifications
input A-3
output A-5
relay contact rating table A-5
response times for high-speed dc inputs

A-4
response times for normal dc inputs A-4
working voltage (1764-24AWA) A-7
working voltage (1764-24BWA) A-7
working voltage (1764-28BXB) A-8
status G-10
surge suppressors
for contactor 3-6
for motor starters 3-6
for relays 3-6
recommended 3-6
using 3-4

Publication 1764-UM001B-EN-P - April 2002

Index

terminal G-10
throughput G-10
Trim Pot Information Function File 5-2
trim pots
adjustment 5-1
error conditions 5-2
location 5-1
trim pots/mode switch cover door B-6
troubleshooting
automatically clearing faults C-4
contacting Allen-Bradley for assistance

C-5
controller error recovery model C-3
determining controller faults C-1
identifying controller faults C-4
manually clearing faults C-4
understanding the controller LED status

C-1
using the fault routine C-4
true G-10

Publication 1764-UM001B-EN-P - April 2002

UL certification 2-1
upload G-10

W
wire requirements 3-1
wiring
spade lug 3-3
wiring diagrams 3-8
wiring recommendation 3-2
wiring your controller 3-1
Working Screen Operation 5-7
working voltage (1764-24AWA)
specifications A-7
working voltage (1764-24BWA)
specifications A-7
working voltage (1764-28BXB)
specifications A-8
write G-10

Publication 1764-UM001B-EN-P - April 2002 9
Supersedes Publication 1764-UM001A-US-P - April 2000

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