Allen AB SCADA Diagram

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Allen-Bradley

SCADA System

(Publication AG-6.5.8)

Application Guide

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 eq uipment 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 int ellectual 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 in part, without written permission of Allen-Bradley Company, Inc., is prohibited.

Throughout this manual we use notes to make you aware of safety considerations:

ATTENTION: Identifies information about practices

Attention statements help you to:

• identify a hazard

• avoid the hazard

• recognize the consequences

Important: Identifies information that is critical for su ccessful

or circumstances that can lead to personal injury or death, property damage or economic loss.

application and understanding of the product.

Publication AG-6.5.8 - October 1998

Summary of Changes

Introduction This document has been revised since the June 1996 printing.

Changes to this document are so extensive, that it is impractical to mark every change with a revision bar in the margin of the page. The purpose of this section is to outline the changes in the SCADA Application Guide.

Scope of Changes This SCADA Application Guide represents the latest developments

in Allen-Bradley hardwar e and software, and i ncludes the most rece nt third-party supplier information as it relates to SCADA applications.

Changes incorporated in this document include:

• The updating of the enhanced PLC-5 chapter (Chapter 2), including new screen captures from RSLogix 5 and messaging details.

• The restructuring of the SLC 5/03, 5/04 chapter (Chapter 4) to include the SLC 5/05, new screen captures from RSLogix 500 and messaging details.

• The addition of a MicroLogix chapter, (Chapter 6) which details the use of MicroLogix controllers in SCADA applications.

• The addition of a Logix5550 chapter, (Chapter 7) which details the use of the Logix5550 controller in SCADA applications.

• Updated third-party modem documentation (Chapter 8).

• The addition of a RSLinx c hapter, which details the conf iguration of the RSLinx DF1 Polling Ma st er a nd DF1 Slave drivers for use in SCADA applications.

• The addition of an appendix (Appendix E) which provides detailed examples of messaging ladder logic that is typical to SCADA applications.

Publication AG-6.5.8 - October 1998

Preface

What SCADA Information

Two principle SCADA documents are available:

Is Available?

Flexible Solutions for Your SCADA Needs SCADA System Selection Guide

SCADA System Selection Guide

Publication AG-2.1

• Presents A-B capabilities for SCADA applications

• Guides you through choosing SCADA system components

SCADA System Application Guide

Publication AG-6.5.8 (this manual)

• Describes how to configure A-B products and third-party modems

• Describes how to send messages

• Gives application samples

Audience We designed this document for individuals who are configuring a

SCADA system or are answering configuration questions. This document assumes you know how to:

• handle, install, and operate the produc ts referenced in this document

• install, navigate through, and use the software products referenced in this document

• prepare cables, if necessary

Publication AG-6.5.8 - October 1998

Book Overview

Design

chapter 1

Designing Communication

Configure

Apply

chapter 2

Configuring Enhanced PLC-5

Processors

chapter 5

Configuring SLC 500

Processors with 1747-KE

Interface Modules

chapter 8

Configuring Modems

chapter 10

Using Dial-up Telephone

Communication

chapter 3

Configuring Classic PLC-5

Processors with 1785-KE

Modules

chapter 6

Configuring MicroLogix

Controllers

Configuring RSLinx 2.0

Software for DF1 Half-duplex

Communications

Remotely Programming

PLC-5 and SLC 500

chapter 4

Configuring SLC-5/03,5/04

and 5/05 Processors

chapter 7

Configuring Logix5550

Processors

chapter 9

chapter 11

Processors

Modem Cable Reference

Reference

Publication AG-6.5.8 - October 1998

appendix A

appendix D

Worksheets

appendix B

Basic DF1 Protocol

Troubleshooting

appendix E

Sample Ladder Logic

appendix C

Third-Party Supplier Contact

Information

Glossary

Terms We use these terms frequently in this book:

Term: Definition:

Classic PLC–5 processor A collective name used to refer to PLC–5/10, –5/12,

–5/15, and –5/25 processors.

Enhanced PLC–5 processor A collective name used to refer to PLC–5/11, –5/20,

–5/30, –5/40, –5/60, and PLC–5/80 processors.

Ethernet PLC–5 processor A collective name used to refer to PLC–5/20E, –5/40E, and

–5/80E processors.

master station A device (programmable controller with I/O modules or a

workstation) that sends data to and collects data from devices connected on a point-to-multipoint, half-duplex network.

slave station A device (programmable controller with I/O modules) that

is located in a remote site away from the master station and that controls I/O points at the remote site. A slave station accepts commands from and can send data (if capable) to a master station via a telemetry network.

See the Glossary for other definitions.

Conventions This section explains the following conventions:

iii

• addresses

• identifying where you are within the manual

Addresses

These values: Are represented like:

octal decimal

Publication AG-6.5.8 - October 1998

Related Publications Use these manuals as necessary::

Title: Publication Number:

Automation Systems Catalog

Enhanced and Ethernet PLC–5 Programmable Controllers User Manual

Classic PLC–5™ Family Programmable Controllers Hardware Installation Manual

1785 PLC–5 Family Programmable Controllers Quick Reference

PLC–5 Instruction Set Reference Manual 1785–6.1 1785–KE DH+ Communications Interface Module User Manual 1785–6.5.2 SLC 500™ and MicroLogix™ 1000 Instruction Set Reference

Manual SLC 500 Modular Hardware Style Installation and Operation

Manual DH–485/RS232C Interface Module User Manual 1747–6.12 MicroLogix™ 1000 Programmable Controllers Users Manual 1761-6.3 Logix5550 Controller User Manual 1756-6.5.12 Logix5550 Controller Programming Manual 1756-6.4.1

1785–6.5.12

1785–6.6.1

1785–7.1

1747–6.15

1747–6.2

Publication AG-6.5.8 - October 1998

Chapter 1

Designing Communication Use This Chapter . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

Choosing a Polling Mode for DF1 Half-Duplex Master. . . . . . . . . . . . . 1-2

Message-Based Polling Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

Standard Polling Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

About Slave-to-Slave Messaging . . . . . . . . . . . . . . . . . . . . . . . . . 1-5

Addressing Tips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5

Communication Scheme Design Using Standard-Mode . . . . . . . . . . . 1-6

Designing a Polling Scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-10

Planning for Timing Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-12

Design Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-12

Communication Scheme Design Using Message-based Mode . . . . . 1-14

Designing Communication

for Full-Duplex Protocol. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-14

What to Do Next?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-16

Chapter 2

Configuring Enhanced PLC-5 Processors

Use This Chapter... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1

Installing the Processor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2

Configuring a DF1 Half-Duplex Standard Mode Master Station. . . . . . 2-3

Define the Communication Driver Characteristics . . . . . . . . . . . . . 2-4

Displaying System (Master) Channel Status . . . . . . . . . . . . . . . . . . 2-6

Create Station Lists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7

Monitor Active Stations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8

Configuring a DF1 Half-Duplex Message-based Mode

Master Station. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9

Configuring the Processor

as a Slave Station . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-13

Displaying Slave System Channel Status . . . . . . . . . . . . . . . . . . . 2-16

Configuring the Processor as a Station on a Point-to-Point Link. . . . 2-18

Displaying Point-to-Point System Channel Status. . . . . . . . . . . . . 2-20

Messaging. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-21

Master Station to Slave Station . . . . . . . . . . . . . . . . . . . . . . . . . 2-21

Polled Report-by-Exception . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-21

Processor-to-Processor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-22

Considerations When Configuring MSG Control Blocks . . . . . . . . 2-23

Example MSG Control Blocks . . . . . . . . . . . . . . . . . . . . . . . . . . 2-24

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ii Table of Contents – SCADA System Selection Guide

Chapter 3

Configuring Classic PLC-5 Processors with 1785-KE Modules

Configuring SLC 5/03, 5/04 and 5/05 Processors

Use This Chapter. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1

Installing the Processor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2

Configuring and Installing

the 1785-KE Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3

Connecting the Processor

and 1785-KE Module. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4

Messaging. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5

Polled Report-by-Exception . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5

Processor-to-Processor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5

Considerations When Configuring MSG Control Blocks . . . . . . . . . 3-6

Example MSG Control Blocks . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6

Chapter 4

Use This Chapter.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1

Installing the Processor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2

Using Modems that Support DF1 Communication Protocols . . . . . . . . 4-2

Dial-up Phone Modems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2

Leased-Line Modems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3

Radio Modems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3

Line Drivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3

Modem Control Line Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4

DF1 Full-Duplex. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4

No Handshaking Selected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4

Full-Duplex Modem Selected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4

DF1 Half-Duplex Slave. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4

No Handshaking Selected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4

Half-Duplex Modem with Continuous Carrier Selected . . . . . . . . . . 4-5

Half-Duplex Modem without Continuous Carrier Selected. . . . . . . . 4-5

DF1 Half Duplex Master. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5

No Handshaking Selected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5

Full-Duplex Modem Selected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5

Half-Duplex Modem without Continuous Carrier Selected. . . . . . . . 4-5

Configuring DF1 Half-Duplex Channel 0 Parameters . . . . . . . . . . . . . 4-6

RTS Send Delay and RTS Off Delay . . . . . . . . . . . . . . . . . . . . . . . . 4-6

Configuring a Standard-Mode DF1 Half-Duplex Master Station . . . . . 4-7

Minimum DF1 Half-Duplex Master Channel 0 ACK Timeout . . . . . 4-10

Determining Minimum Master ACK Timeout. . . . . . . . . . . . . . . . . 4-10

DF1 Half-Duplex Master Channel Status. . . . . . . . . . . . . . . . . . . . 4-12

Monitor Active Stations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13

Configuring a Message-based Mode DF1 Half-Duplex

Master Station. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-14

Configuring a Slave Station . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-17

Configuring Channel 0 Poll Timeout . . . . . . . . . . . . . . . . . . . . . . . . . 4-19

DF1 Half-Duplex Slave Channel Status. . . . . . . . . . . . . . . . . . . . . 4-20

Configuring a Station on a Point-to-Point Link . . . . . . . . . . . . . . . . . 4-21

DF1 Full-Duplex Channel Status. . . . . . . . . . . . . . . . . . . . . . . . . . 4-23

Messaging. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-25

Publication AG-6.5.8 - October 1998

Table of Contents – SCADA System Appl ication Guide iii

Master Station to Slave Station . . . . . . . . . . . . . . . . . . . . . . . . . . 4-25

Polled Report-by-Exception . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-25

Processor-to-Processor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-25

Considerations When Configuring MSG Control Blocks . . . . . 4-26

For both Point-to-Multipoint and Point-to-Point Link Configurations . 4-

Minimum Master MSG Block Message Timeout . . . . . . . . . . . . . . 4-26

Message-based Polling Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-27

Standard Polling Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-28

Standard Polling Mode With Single Message Transfer . . . . . . . . . 4-28

Standard Polling Mode With Multiple Message Transfer. . . . . . . . 4-28

Minimum Slave MSG Block Message Timeout . . . . . . . . . . . . . . . 4-30

Minimum Point-to-Point MSG Block Message Timeout. . . . . . . . . 4-30

Example MSG Control Blocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-30

Chapter 5

Configuring SLC 500™ Processors with 1747-KE Interface Modules

Configuring MicroLogix Controllers

Use This Chapter.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1

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

Installing the Processor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1

Installing the 1747-KE

Interface Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2

Configuring the Processor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3

Configuring the 1747-KE

Interface Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3

Prepare to Configure the Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3

Configure the DF1 Protocol Driver . . . . . . . . . . . . . . . . . . . . . . . . . 5-6

Save the Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-11

Messaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-11

Polled Report-by-Exception . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-11

Processor-to-Processor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-12

Considerations When Configuring MSG Control Blocks . . . . . . . . 5-12

Point-to-Multipoint and Point-to-Point Link Configurations. . . . . . 5-12

Point-to-Multipoint Link Configurations . . . . . . . . . . . . . . . . . . . . 5-13

Point-to-Point Link Configurations . . . . . . . . . . . . . . . . . . . . . . . . 5-13

Example MSG Control Blocks . . . . . . . . . . . . . . . . . . . . . . . . . 5-13

Chapter 6

Use This Chapter.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1

Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1

Installing the Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2

Isolated Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3

Automatic Protocol Switching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3

Using Modems that Support DF1 Communication Protocols . . . . . . . . 6-4

Dial-up Phone Modems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4

Leased-Line Modems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5

Radio Modems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5

Line Drivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5

Modem Control Line Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6

DF1 Full-Duplex Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6

DF1 Half-Duplex Slave Operation. . . . . . . . . . . . . . . . . . . . . . . . . . 6-6

Publication AG-6.5.8 - October 1998

iv Table of Contents – SCADA System Selection Guide

DF1 Slave on a Multi-drop Link . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7

Ownership Timeout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7

Configuring a Slave Station . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-8

Configuring RTS Send Delay and RTS Off Delay . . . . . . . . . . . . . . . . . 6-9

Configuring Poll Timeout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-10

Configuring a Point-to-Point Station. . . . . . . . . . . . . . . . . . . . . . . . . 6-11

Messaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-13

Polled Report-by-Exception . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-13

Processor-to-Processor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-13

Considerations When Configuring MSG Control Blocks . . . . . . . . 6-14

Configuring MSG Block Message Timeout . . . . . . . . . . . . . . . . . . 6-15

Example MSG Control Blocks . . . . . . . . . . . . . . . . . . . . . . . . . 6-16

Chapter 7

Configuring Logix5550 Controllers Use This Chapter... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1

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

Installing the Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-2

Using Modems that Support DF1 Communication Protocols . . . . . . . . 7-2

Dial-up Phone Modems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-2

Leased-Line Modems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3

Radio Modems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3

Line Drivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3

Configuring the Controller to use the Serial Port. . . . . . . . . . . . . . . . . 7-4

Modem Control Line Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-5

Configuration Considerations for RTS Send and Off Delays. . . . . . . . . 7-6

Configuring a Standard-Mode DF1 Half-Duplex Master Station . . . . . 7-7

Configuring a Master Station for Standard Polling Mode. . . . . . . . . . . 7-8

Minimum DF1 Half-Duplex Master ACK Timeout. . . . . . . . . . . . . . 7-10

Determining Minimum Master Serial Port ACK Timeout . . . . . . . . 7-10

DF1 Half-Duplex Master Diagnostic Counter . . . . . . . . . . . . . . . . . . 7-12

Create Polling List(s) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-14

Monitor Active Stations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-15

Configuring a Message-based Mode DF1 Half-DuplexMaster Station 7-16

Configuring a Master Station for Message-based Polling Mode . . . . 7-16

Configuring the Controller as a Slave Station . . . . . . . . . . . . . . . . . . 7-18

Configuring Slave Poll Timeout . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-19

DF1 Half-Duplex Slave Diagnostic Counters. . . . . . . . . . . . . . . . . . . 7-19

Configuring the Controller as a Station on a Point-to-Point Link . . . . 7-22

DF1 Point-to-Point Diagnostic Counters. . . . . . . . . . . . . . . . . . . . . . 7-24

Accessing DF1 Diagnostic Counters. . . . . . . . . . . . . . . . . . . . . . . . . 7-26

Messaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-29

Master Station to Slave Station . . . . . . . . . . . . . . . . . . . . . . . . . . 7-29

Polled Report-by-Exception . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-29

Controller-to-Controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-29

Considerations When Configuring MSG Control Blocks. . . . . . . . . 7-30

Example MSG Control Blocks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-31

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Table of Contents – SCADA System Appl ication Guide v

Chapter 8

Configuring Modems Use This Chapter.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1

Installing a Modem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1

Configuration Tips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-2

Telephone Modem

Configurations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-2

DATA-LINC Group . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-3

DLM4300. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-3

LLM1000-2 and LLM1000-4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-4

DLM4000. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-7

DLM4100-SLC and DLM4100-PLC. . . . . . . . . . . . . . . . . . . . . . . . . 8-8

Miille Applied Research

Company, Inc. (MARC). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-9

MARC Model 166-101 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-10

MARC Model 137-001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-12

MARC Model 148-001 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-14

MARC Model 166-100 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-16

MARC Model 166-010 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-17

Radio Modem Configurations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-18

DATA-LINC Group . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-20

SRM6000/6100/6200E . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-20

SRM6000/6100/6200E-SLC. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-22

SRM6000/6100/6200E-PLC. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-23

Electronic Systems Technology (ESTeem) . . . . . . . . . . . . . . . . . . . . 8-26

Microwave Data Systems (MDS) . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-31

MDS Model 2100 and 4100 Master Stations . . . . . . . . . . . . . . . . 8-31

MDS Model 2310 and 4310 Remote Stations. . . . . . . . . . . . . . . . 8-32

MDS Model 9810 Spread Spectrum. . . . . . . . . . . . . . . . . . . . . . . 8-33

Power Line Modem Configurations. . . . . . . . . . . . . . . . . . . . . . . . . . 8-35

DATA-LINC Group . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-35

LCM100 Line Carrier Modem. . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-35

Configuring RSLinx Software for DF1Half-Duplex Communications

Using Dial-up Telephone Communication

Chapter 9

Use This Chapter.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-1

Configuring RSLinx Version 2.0 as a Master Station . . . . . . . . . . . . . 9-1

Configuring RSLinx Version 2.1 as a Slave Station . . . . . . . . . . . . . 9-10

Chapter 10

Use This Chapter.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-1

Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-2

Setting up the System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-3

Install the Processor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-3

Configure the Processor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-3

Configure the Modems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-4

Communicating over the Telephone Line . . . . . . . . . . . . . . . . . . . . . 10-5

Initiate Modem Dialing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-5

Verify Connection to the Remote Modem . . . . . . . . . . . . . . . . . . . 10-6

Transfer Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-6

Disconnect the Telephone Link . . . . . . . . . . . . . . . . . . . . . . . . 10-7

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vi Table of Contents – SCADA System Selection Guide

Peer-to-Peer Communication. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-8

Report-by-Exception and/or Master Station-initiated Communication10-8

Chapter 11

Remotely Programming PLC-5, SLC 500 and MicroLogix 1000 Processors

Use This Chapter.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-1

Remote Programming

Hardware Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-2

RS-232 Splitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-3

Configure RSLogix Programming Software for

Remote Communications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-4

Appendix A

Modem Cable Reference ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1

Appendix B

Basic DF1 Protocol Troubleshooting

... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1

Appendix C

Third-Party Supplier Contact Information

... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C-1

Appendix D

Worksheets .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D-1

Appendix E

Sample Ladder Logic ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E-1

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Chapter

Designing Communication

Use This Chapter . . . ... to choose a communication method and design a communication

scheme for getting information to and from slave stations. Use this chapter along with the configuration chapters of the devices in your SCADA system to help you make design and configuration choices.

While designing your communication scheme, consider these application requirements:

• responsiveness

• determinism

•cost

• efficiency Keep in mind the factors that af fect communic ation are a re sult of the

protocol you are using, whether half-duplex or full-duplex.

For information about: See page:

choosing a communication method for the half-duplex protocol 1-2 designing a communication scheme using

standard-communication mode designing a communication scheme using message-based

communication mode designing communication for full-duplex protocol 1-14 what to do next 1-16

1-6

1-14

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1-2 Designing Communication

Choosing a Polling Mode for DF1 Half-Duplex Master

A master station can be configured to communicate with slave stations in either Message-based polling mode or Standard polling mode. The pros and cons of each polling mode are described below.

Message-Based Polling Mode

Message-based polling mode is best used in networks when communication with the slave stations is not time critical and where the user needs to be able to limit when and how often the master station communicates wit h each sl ave sta tion. It is no t recommended for larger systems that require time critical communication between the master and all the slave stations, or for systems where slave station-initiated messages are going to be used.

With Message-Based polling mode, the only time a master station communicates with a slave station is when a message (MSG)

instruction in l adder l ogic i s tri ggere d to that pa rtic ular s la ve sta tion’s address. This polling mode gives the user complete control (through ladder logic) over when and how often to communicate with each slave station.

If multiple MSG instructions are trigge red “simultaneously,” they will be executed in order, one at a time, to completion (i.e., the first MSG queued up will be transmitted and completed to done or error before the next queued up MSG is transmitted). Any time a message is triggered to a slave station that can’t respond (for instance, if its modem fails), the message will go through retries and timeouts that will slow down the execution of all the other queued up messages. The minimum time to message to every responding slave station increases linearly with the number of slave stations that can’t respond.

Publication AG-6.5.8 - October 1998

If the Message-based se lection is “don’t allow slaves to initiate messages,” then even if a s la ve s ta ti on t ri gge rs and queues up a MSG instruction in its ladder logic, the master station will not process it. This mode is similar to how a mas ter/sl ave network based on Modbus protocol would work, since Mo dbus slave statio ns cannot ever ini tiate a message.

If the Message-based selection is “allow slaves to initiate messages,” when a slave station initiates a message to the master station (polled

report by exception messaging) or to another slave station (slave-to-slav e messagi ng) , t he MSG c ommand packet will remain in

that slave station’s transmit queue until the master station triggers its own MSG command packet to i t (whi ch coul d be s econds, minu tes or hours later, depending on the master’s ladder logic).

Designing Communication 1-3

Standard Polling Mode

Standard polling mode is strongly recommended for larger systems that require time critical communication between the master and all the slave stations, or for any system where slave station-initiated messages are going to be use d (this includes slave programming over the network, since this uses the same mechanism that slave-to-slave

messaging uses). The Acti ve Node Table “automat ically ” keeps track of which slaves are (and are not) communicating. Standard polling mode should not be used in cases where the user needs to be able to limit when and how often t he ma ste r s ta ti on communicates with each slave station.

Standard polling mode cau ses the mast er sta tion t o conti nuousl y send one or more 4-byte poll packets to each slave station address configured by the user in the poll list(s) in round robin fashion – as soon as the end of the polling list is reached, the master station immediately goes back and starts polling slave stations from the top of the polling list over again. This is independent and asynchronous to any MSG instructions that might be triggered in the master station ladder logic. In fact, this polling continues even while the master station is in program mode!

When a MSG instruction is triggered while the master station is in run mode, the master station wi ll transmit the message packet just after it finishes polling the current slave station in the poll list and before it starts polling the next slave station in the pol l li st (no matter where in the poll list it is currently at). If multiple MSG instructions have been triggered “simultane ously,” at least four message packet s may be sent out between two slave stat ion polls. Each o f these messages will have an opportunity to complete when the master polls the slave station that was addressed in the message packet as it comes to it in the poll list.

If each of the transmitted message packets is addressed to a different slave station, the order of completion will be based upon which slave station address comes up next in the poll list, not the order that the MSG instructions were executed and transmitted in.

When a slave station recei ves a poll pa cket from the mast er stat ion, if it has one or more message packets queued up to transmit (either replies to a command received earlier or MSG commands triggered locally in ladder logic), the slave station will transmit the first message packet in the transmit queue.

If the standard mode sel ec ti on i s “ single message per poll scan,” then the master station will then go to the next station in the poll list. If the standard mode selection is “multiple messages per poll scan,” the master station will conti nue to poll this slave station until its transmit queue is empty.

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1-4 Designing Communication

The master station “knows” the slave station has no message packets queued up to transmit when the slave station responds to the master poll packet with a 2-byte poll response.

Every time a slave station responds or doesn’t respond to its poll packet, the master station “automatically” updates its active node list (again, even if it’s in program mode). In this list, one bit is assigned to each possible slave station address (0-254). If a slave station doesn’t res pond wh en i t i s polled, its active node list bi t i s cl eared. If it does respond when it is polled, its active node bit is set. Besides being an excellent online troubleshooting tool, two common uses of the active node list are to report good/bad communication status for all slave stations to an operator interface connected to the master station for monitoring, alarming and logging purposes, and to precondition MSG instructions to each particular slave.

This second use is based on the supposition that if a slave station didn’t respond the last time it was polled (which was just a few seconds ago, if that long ), then cha nces ar e it won’ t be able to recei ve and respond to a MSG instruction now, and so it would most likely just end up going through the maximum number of retries and timeouts before completing in error (which slows down both the poll scan and any other messaging going on). Using this technique, the minimum time to message to every responding slave station actually decreases as the number of slave stati ons that can’ t respo nd increase s.

Important: In order to remotely monitor and program the slave

stations over the half-duplex network while the master station is configured for Standard polling mode, the programming computer DF1 slave driver (typically Rockwell Software WINLINX or RSLinx) station address must be included in the master station pol l list.

Standard polling mode should not be used in cases where the user needs to be able to limit when and how often the master station communicates with each slave station.

About Polled Report-by-Exception Polled report-by-exception lets a slave station i nitiate data transfer to

its master station , freeing the maste r station f rom having t o constan tly read blocks of data from each slave station to determine if any slave input or data changes have occurred. Instead, through user programming, the slave station monitors its own inputs for a change of state or data, which triggers a block of data to be written to the master sta tion when the m aster station polls the slave.

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Designing Communication 1-5

If your SCADA application is time-critical and any two or more of the following apply, then you can benefit from polled report-by-exception messaging:

• communication channel is slow (2400 bps or less)

• average number of words of data to monitor in each slave station is greater than five

• number of slave stations is greater than ten

About Slave-to-Slave Messaging

Most SCADA half-duplex proto col s do not allow one slave station to talk to another slave station, except through special application-specific code, which requires processing overhead in the master station. However, Allen-Bradley’s DF1 half-duplex protocol implements slave-to-slave commun ications as a feature of the protocol within the master st at ion, without any additional application code or extra processing overhead.

If one slave station has a message to send to another, it simply includes the destination slave station’s address in the message instruction’s destination field in place of the master station’s address when responding to a poll. The master station checks the destination station address in every packet header it receives from any slave station. If the address does not match its own station address, the entire message is forwarded back onto the telemetry network to the appropriate slave station, without any further processing.

Addressing Tips

Each station on the network including the master station must have a unique address. Th e a ddr ess r ange is 0-254

a maximum of 254 address 255

stations on a single telemetry network. Station

(3778) is the broadcast address, which you cannot

select as a station’s individual address. A remote programming terminal station address should be reserved,

even if remote programmi ng is no t consi dered a requi rement init iall y. This address will need to be periodically polled, even though it will remain on the inactive poll list unless a remote programming terminal is online. See chapter 11 for more info rmation.

SLC 500™ and MicroLogix 1000 Processor Addressing Considerations

When a SLC 5/02™ or MicroLogix 1000 slave station issues a

PLC-2

-type message to a PLC-5® master station, the message’s

destination in the PLC-5 processor’s data table is an integer file with the file number equal to the SLC 500 or MicroLogix 1000 processor station add ress.

(3768), so you can h ave

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1-6 Designing Communication

An address lower than 9 may int erfere with a PLC-5 process or master station since files 0-8 are usually left in their default configuration; file 9 is often used by programmers for the I/O list. Station address

is the broadcast address. So, assign addresses between

255

-25410.

When using a SLC 5/03, 5/04 or 5/05 processor as a master station, the poll list config urati on cons is ts of a cont iguous block of addres ses. Therefore, assign slave station addresses in a contiguous block in order to avoid polling for nonexistent slave stations.

SLC 500 Processors with a 1747-KE Module Addressing Considerations

Since you can have up to 254 devices on a half-duplex network and 31 devices on a DH-485 network, to allow 255 DH-485 nodes requires using a group number. This parameter defines the address group of the SLC 500 half-duplex address. Each address group can consist of 32 addresses.

The address of the SLC 500 processor is determined with the following formula: (32*G)+A, where G is the “group number” (0-7)

and A is the DH-485 node address of the SLC 500 processor.

Communication Scheme Design Using Standard-Mode

One station address wi thin e ach gro up of si ze 32 must be re served for any 1747-KE modules configured with that group number. A second address within each group should also be reserved for local DH-485 programming terminals. These 16 addresses (two per group) should never have to be polled by the master station.

Standard-communication mode for an Allen-Bradley master station uses centralized polling to gather data from slave stations. A master station using this communication technique asks (polls) individual slave stations if they have any information to send. All stations on the link “hear” the master station’s requests, but only the slave station to which a request is addressed replies. PLC-5, Logix5550 and RSLinx master st ations poll sl ave station s based on an ordered list (polling list) configured by the system designer. SLC 5/03, 5/04 and 5/05 master stations poll slave stations sequentially in a range of addresses configured by the system designer. Figure 1.1 shows how a slave station gets polled and how it responds.

Publication AG-6.5.8 - October 1998

Figure 1.1 A master station polls the slave stations in the order the slave stations appear on the list. slave stations send either a data packet or a packet indicating that the station has no data to send.

Polling List

Stn 1 Stn 2

Master Station

Modem

Stn 3

1. Master station polls a slave station for data.

Return Data Packet or DLE EOT to Master

Designing Communication 1-7

Poll to slave

2. If the slave station has data to send, then it sends a data packet. If there is no data to send then it sends an end of tr ansmission packet (DLE EOT).

Polling List

Stn 1 Stn 2

Master Station

Stn 3

3. Master station polls the next slave station for data.

4. If the slave station has data to send, then it sends a data packet. If there is no data to send then it sends an end of transmission packet (DLE EOT).

5. Master station continues to poll each slave station in the polling list. When the end of the list is reached, the master station then moves back to the beginning of the list and starts the polling sequence over again.

Modem

slave

station 1

Return Data Packet or DLE EOT to Master

Modem

slave

station 1

Modem

slave

station 2

Modem

slave

station 2

Poll to slave

Modem

slave

station 3

Modem

slave

station 3

41180

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1-8 Designing Communication

When the master station is configured for standard-communication mode, you do not need to program any master-station message instructions to communi cate with sl ave stations. Communi cation with slave stations occurs by the master station sending polling packets to slave stations. You only need mess age instruct ions when you want the master station to write data to or read data from a location within a

slave station’s data table.

To help you understand: See:

standard-communication mode Figure 1.2 how a master station requests data Figure 1.3

Figure 1.2 Use this machine state diagram to help you understand

communication

mode.

standard-

timeout received and station active and tries < or = “DF1 message retries”

MSG received and multiple mode

forward data to or return data from data table

• Check for and send outgoing MSG

• Select next station to poll

timeout received and station inactive

•Send poll

• Start ACK timeout

• Wait for EOT or MS G (or timeout)

timeout received and station active and tries > “DF1 message retries”

make station inactive

EOT received indicating no MSG to send make station

active (if inactive)

MSG received and single poll mode

forward data to or return data from data table

41181

Publication AG-6.5.8 - October 1998

Master data table

reply packet received

return data

Figure 1.3 Use this machine state diagram to help you understand how a device requests data transfer (read or write request) via DF1 half-duplex protocol.

ACK timeout received and tries > “DF1 message retries”

return error indication

Designing Communication 1-9

• Ladder logic triggers MSG

• Master driver formats command packet

ACK timeout received and station active and tries < or = “DF1 message retries”

• Send command packet

• Start ACK t imer

• Wait for ACK (or timeout)

application timeout received return

error indicaton

• Start application timer

• Resume polling

• Wait for reply (or timeout)

To design a communication scheme using standard-communication mode, you must do the following:

• design a polling scheme

• plan for timing issues

ACK received

41182

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1-10 Designing Communication

Designing a Polling Scheme

Each master station in a SCADA application must have a polling scheme configured. To design a polling scheme, do the following:

• choose the type of scheme best suited for your application

• optimize your polling scheme to obtain the best efficiency The master station you are using determines the type of polling

choices you have; ho wever, A-B master stations of fer si milar ch oices, such as:

• normal and priority polling lists

• ability to poll a slave sta tion: – once per occurrence in the poll list (single)

– until it has no more messages to send (multiple)

Choosing Normal or Priority Polling Lists

slave stations listed in a pr iority poll list are polled more frequently than those listed in the normal poll list. Place the slave stations that you need information from more frequently in a priority poll list.

Within each poll list, slave stations are assigned a status, which is either active or inactive. A slave station becomes inactive when it does not respond to a master stati on’s poll packet after the co nfigur ed number of retries.

If your master station is a Logix5550 or PLC-5, you can use application logic to reorder the polling lists and priority while the application logic is executing.

Figure 1.4 and Figure 1.5 show h ow normal and pri orit y list s rel ate to one another.

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Designing Communication 1-11

Figure 1.4 The master station scans slave stations in a set sequence.

1. Scans all stations in the active priority

poll file

2. Scans one station in the inactive priority poll file

3. Scans stations in the active normal poll file based on the normal poll group size, which you specify during configuration. For example, if the group size were 3, then three stations would be polled in the normal file before the master continues to the next step in the sequence

4. Scans one station in the inactive normal poll file after all stations in the active normal list have been polled.

Active Priority

Poll List STN1 STN7

Poll List STN2

Inactive Priority

STN6

Poll List

Active Normal

STN3 STN4

Group size = 1

Active Priority Poll List

Inactive Priority Poll List

Active Normal Poll List

aa bb

Inactive Normal Poll List

Figure 1.5 Here is how the polling sequence applies to an application.

Master

Station

Modem

41183

STN1 STN7 STN2 STN3

STN1 STN7 STN6 STN4 STN5

Inactive Normal

Beginning of new scan

Poll List STN5

Modem

7Polling Sequen c e:

41184

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1-12 Designing Communication

Choosing Single or Multiple Message Transfer

Depending on your application’s requirement, you can choose the number of messages you want to receive from a slave station during its turn.

If you want to receive: Choose:

only one message from a slave station per poll per a

station’s turn Choose this method only if it is critical to keep the poll

list scan time to a minimum. as many messages from the slave station as it has in

its queue

single transfer

multiple transfer

Planning for Timing Issues

Two types of timing categories exist:

• protocol timers, which sp ecify how long a master station will wait to “he ar” from a slave station

• Request to send (RTS) timers, which you can use to make sure the modem is ready to accept data or has passed on the data

Set and adjust these timing values as necessary for your application. Set your RTS times based on the communication media and modem you are using.

Design Considerations

• Define a polling list type to use (normal or priority).

• Define a station list.

• Use Figure 1.6 to help understand how the MSGs are handled using standard communication.

Publication AG-6.5.8 - October 1998

. Polled station 1; ready to poll station 2. . MSG sent to station 3 (MSG was waiting in queue).

Polling List

Stn 1 Stn 2

Master Station

Stn 3

Designing Communication 1-13

Figure 1.6 Use this figure to help you understand the effect sending MSGs has on Logix5550, PLC-5 and SLC 500 polling.

MSG to slave

Modem

3. Master station continues polling where it left off in the polling sequence, e.g., station 2.

Polling List

Stn 1

Master

Stn 2

Station

Stn 3

. Master station polls station 3. . Station 3 replies with data.

Polling List

Stn 1 Stn 2

Master Station

Modem

Stn 3

Modem

slave

station 1

Return Data Packet or DLE EOT to Master

Modem

slave

station 1

Modem

slave

station 2

Poll to slave

Modem

slave

station 2

Return Data Packet to Master

Modem

slave

station 3

Modem

slave

station 3

Poll to slave

6. Master station returns to beginning of the poll list.

Modem

slave

station 1

Modem

slave

station 2

Modem

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station 3

slave

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1-14 Designing Communication

Communication Scheme Design Using Message-based Mode

1. Message (via MSG instruction) sent to

Master Station

3. Master station waits a user-defined time “Reply Message Wait” parameter before polling the station for a reply.

Modem

a specific slave station. (eg., slave station 1)

2. Slave station receives message and sends an acknowledgment back (ACK)

In message-based communication mode, the master station sends solicited messages (messages programmed via ladder logic) to a specific slave station when the master requires information. In this mode, the communication link is inactive until the master station has a message to send to a slave station. Figure 1.7 explains the communication sequence that occurs.

Figure 1.7 Use this figure to help you understand message-based communication.

Modem

Slave Station 1

3. Slave station forms a reply message to the master station’s enquiry.

Modem

Slave Station 2

Designing Communication for Full-Duplex Protocol

4. Master station polls slave station for its reply

5. slave station sends its reply message

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6. Master station receives reply and sends an acknowledgement back (ACK)

When designing communic at io n us ing DF1 full-duplex protocol, you must specify some timers and counters that control the communication betwee n a tran smitting st ation and a receiving station. Consider the type of link media you are using to help you determine the best values for the timer and counters. For example, you can expect a message being sent over a satellite link to take longer than one being sent over a te lephon e leas ed-li ne li nk. Figur e 1.8 shows th e communication sequence for DF1 full-duplex protocol.

Publication AG-6.5.8 - October 1998

Data table

reply packet received return data

Figure 1.8 Use this machine state diagram to help you understand a device requests data transfer (read or write request) via DF1 full-duplex protocol.

NAK received and retries > “NAK retries”

or ACK timeout received and

tries > “ENQ retries”

return error indication

• Ladder logic triggers MSG

• DF1 driver formats command packet

• Send command packet

• Start ACK timer

• Wait for ACK (or timeout)

Designing Communication 1-15

NAK received and retries < or = “NAK retries”

or ACK timeout received

and tries < or = “ENQ retries” send enquiry

application timeout received return error

indication

•Start application timer

•Wait for reply (or timeout)

ACK received

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1-16 Designing Communication

What to Do Next? Make sure you:

• choose the communication method best suited for your application

• make initial confi guration choices for the communicati on method you have chosen

• use this chapter as a reference as you configure the devices in your SCADA system

Publication AG-6.5.8 - October 1998

Chapter

Configuring Enhanced PLC-5 Processors

Use This Chapter... ... to help you set up an Enhanced PLC-5 processor as a master

station, as a slave station, or as a station on a point-to-point link.

For information about: See page:

an overview of the tasks required to configure a PLC-5 processor 2-1 installing the processor 2-2 configuring the processor as a DF1 half-duplex master station using

standard-communication mode configuring the processor as a DF1 half-duplex master station using

message-based communication mode configuring the processor as a slave station 2-13 configuring the processor as a station on a point-to-point link 2-16 the types of mes sages you can se nd from a PLC-5 processo r to an other

processor, how to configure the MSG instruction, and some configuration characteristics

2-3

2-9

2-20

Overview To configure an Enhanced PLC-5 processor, perform these tasks:

3. Install and configure the modem

for communication with the

1. Install the processor; connect the serial cable to channel 0.

2. Define the processor’s communication characteristics using your PLC-5 programming software.

processor; connect the modem to

the processor’s serial channel.

Modem

PLC-5 programming software

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2-2 Configuring Enhanced PLC-5 Processors

Installing the Processor Before install ing the p rocessor, set the processor s witch ass emblies.

Define: By setting switch assembly:

DH+ and DF1 point-to-point station address S1 RS-232 as the electrical interface for the serial port S2

For details about installing the processor, see the Enhanced PLC-5 Programmable Controllers Quick Start, publication 1785-10.4.

For cable pinouts, see Figure 2.1 or Appendix A-2.

Figure 2.1 Enhanced PLC-5 Serial Port Pin Assignments and S2 Settings.

25-pin male 25-pin 9-pin

C. GND 1 1 NC

TXD.OUT 2 2 3

RXD.IN 3 3 2

44 7 55 8 66 6 77 5 88 1 20 20 4

to modem

25-pin male cable connector

RTS.OUT

CTS.IN

DSR.IN

SIG.GND

DCD.IN

DTR.OUT

S2 (set for RS-232) Bottom of processor

o Specify:

RS-232C

Publication AG-6.5.8 - October 1998

12345678910

ON ON ON OFF OFF ON ON OFF ON OFF

Set Switches:

Note: The DF1 Point-to-Point Station Address of the processor is the same as the DH+ address defined by S1

Toggle pushed toward TOP

OFF

Toggle pushed toward BOTTOM

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Configuring Enhanced PLC-5 Proces sors 2-3

Configuring a DF1 Half-Duplex Standard Mode Master Station

Double-click on the Channel Configuration file to bring up the Edit Channel Configuration interface.

Choose standard-communication mode if you want to query slave stations for in formation bas ed upon user -config ured poll ing lists. This mode is used most often in point-to-multipoint configurations because it allows polled report-by-exception (page 1-4), slave-to-slave messaging (page 1-5) and slave programming over the telemetry network (chapt er 1 1) to be impl emented. In add ition, in th is mode the master station maintains an active node table which allows an MMI or programming terminal to immediately identify which slave nodes can currently communicate and which nodes cannot.

To configure the processor for a master station using standard communication, place the processor into program mode and do the following using your RSLogix 5 software:

1. On the Channel 0 tab, choose System (Master) for your Communication Mode.

2. Configure the Serial Port, Options, and Polling parameters according to Table 2.A.

3. Configure Options parameters according to Table 2.A .

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2-4 Configuring Enhanced PLC-5 Processors

4. Configure the Polling parameters

according to Table 2.A.

5. When all parameters are set, click OK.

6. Create station lists (page 2-7).

Define the Communication Driver Characteristics

Use Table 2.A to help you understand the c ommu nic at ion parameters you need to specify on the Channel Configuration screen for standard-communication mode.

Use Worksheet 2.1 (Appendix D-4) for an example confi gurati on and

to record your station’s configuration.

Table 2.A Define these communication parameters for a PLC-5 master station using standard-communication mode to talk to slave stations.

RSLogix 5 Tab: Parameter: Selections:

Channel 0 Diagnostic File Select an unused integer file to store channel status information. You must define a diagnostic file in

order to be able to view channel 0 status. See Table 2.B on page 2-6 for description of what is in this file.

Remote Mode Change

Mode Attention Character

System Mode Character

User Mode Character

Serial Port Baud Rate Select a communication rate that all devices in your system support. Configure all devices in the

Bits Per Character Match the number of bits per character to the devices with which you are communicating Stop Bits Match the number of stop bits to the devices with which you are communicating. Control Line This parameter defines the mode in which the master driver operates. Choose a method appropriate

Check enable remote mode change if you want to switch the configuration of the channel during runtime. Leave the parameter set at the default (unchecked) if you are not using this feature.

Select a ch ara cter th at will sig na l a r emot e mo de c han ge. Leav e the par amet er s et at the d ef ault i f yo u are not using remote mode change.

Select a character that will signal the channel to switch into system mode. Leave the parameter set at the default if you are not using remote mode change.

Select a character that will signal the channel to switch into user mode. Leave the parameter set at the default if you are not using remote mode change.

system for the same communication rate.

for your system’s configuration:

• If you are not using a modem, choose NO HANDSHAKING.

• If the master modem is full duplex and the slave modem is full-duplex, choose FULL-DUPLEX MODEM.

• If all the modems in the system are half-duplex, choose HALF-DUPLEX MODEM WITHOUT CONTINUOUS CARRIER.

Publication AG-6.5.8 - October 1998

RSLogix 5 Tab: Parameter: Selections:

Configuring Enhanced PLC-5 Proces sors 2-5

Serial Port Error Detect With this selection, you choose how the processor checks the accuracy of each DF1 packet

transmission. BCC: This algorithm provides a medium level of data security. It cannot detect:

• transposition of bytes during transmission of a packet

• the insertion or deletion of data values of zero within a packet

CRC: This algorithm provides a higher level of data security. Select an error detection method that all devices in your system support. When possible, choose CRC.

Options Station Address Define the octal address of the processor on the DF1 half-duplex link. Each station on a link must have

a unique address. Choose an address between 0 and 376 Station address 377

is the broadcast address, which you cannot select as a station’s individual

address.

DF1 Retries Defines the number of times a master station retries either a message before the master station

declares the message undeliverable, or poll packet to an active station before the master station declares that station to now be inactive.

RTS Send Delay RTS send delay is the amount of time in 20 millisecond increments that elapses between the assertion

of the RTS signal and the beginning of the message transmission. This time allows the modem to prepare to transmit the message.

The Clear to Send (CTS) signal must be high for transmission to occur.

RTS Off Delay RTS off delay is the amount of time in 20 millisecond increments that elapses between the end of the

message transmission and the de-assertion of the RTS signal. This time delay is a buffer to make sure that the modem has transmitted the message but should normally be left at zero.

ACK Timeout Define the amount of time in 20 millisecond increments that you want the processor to wait for an

acknowledgment from a slave station to its transmitted message before the processor retries the message or the message errors out.

Reply Message Wait Define the amount of time in 20 millisecond increments that the master station will wait after receiving

an ACK (to a master-initiated message) before polling the slave station for a reply. Choose a time that is, at minimum, equal to the longest time that a slave station needs to format a

reply packet. This is typically the maximum scan time of the slave station Note: This field is only valid if the polling mode field is configured to be MESSAGE BASED.

MSG Application Timeout

Define the number of 30 second increments within which the reply message must be received before the error bit is set on the message. The timer starts when the ACK is received.

Polling Polling Mode If you want to receive:

• only one message from a slave station per its turn, choose STANDARD (SINGLE MESSAGE TRANSFER PER NODE SCAN)

Choose this method only if it is critical to keep the poll list scan time to a minimum.

• as many messages from a slave station as it has, choose STANDARD (MULTIPLE MESSAGE TRANSFER PER NODE SCAN)

Master Message Transmit

If you want the master station to:

• send all of the master station-initiated MSG instructions to the slave stations before polling the next slave station in the poll list, choose Between Station Polls

This method makes certain that master station-initiated messages are sent in a timely and regular manner (after every slave station poll).

• only send master station-initiated MSG instructions when the master’s station number appears in the polling sequence; choose In Poll Sequence

With this method, sending master station-initiated messages are dependent upon where and how often the master station appears in the poll list. To achieve the same goal as the Between Station Polls method, the master-station’s address would have to appear after every slave-station’s address.

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2-6 Configuring Enhanced PLC-5 Processors

RSLogix 5 Tab: Parameter: Selections:

Polling Normal Poll Node

File Normal Poll Group

Size Priority Poll Node

File Active Station File Enter an unused binary file that will store the status of all the stations in your network configuration.

To display Channel Status, double click on Channel Status, which is located within Channel Configuration.

Enter an unused integer file that will store the addresses of the slave stations you want in the normal poll list.

Enter the quantity of active stations located in the normal poll list that you want polled during a scan through the normal poll list before returning to the priority poll list.

Enter an unused integer file that will store the addresses of the slave stations you want in the priority poll list.

The file stores one station address per bit. 0 = inactive; 1 = active.

Displaying System (Master) Channel Status

To access the various channels from the Channel status screen, click on the tabs. Descriptions of the status screen fields can be found in Table 2.B.

Table 2.B Descriptions of System Mode DF1 Master Channel Status Fields

Status Field: Location Description

Clear Clear counters for all channels by clicking on Clear button DCD Recover word 11 Displays the number o f tim es the pr o ces sor dete ct s t he DCD ha nd sh ak ing l ine ha s

gone low to high.

Lost Modem word 12 Displays the number of times that the modem lost bit (S:17/5) has gone low to

high.

Messages Sent word 1 Displays the number of messages sent by the processor (including message retry).

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Configuring Enhanced PLC-5 Proces sors 2-7

Status Field: Location Description

Messages Received word 2 Displays the number of messages the processor received with no error. Undelivered Messages word 3 Displays the number of messages that were sent by the processor but not received

Messages Retry word 4 Displays the number of messages resent. Duplicate Mesages Received word 9 Displays the number of times the processor received a message packet identical to

EOT Received on First Poll word 8 Displays the number of times the Master received an EOT in response to the first

Bad Packet / No ACK word 7 Displays the number of incorrect data packets that the processor has received. Last Normal Poll List Scan (100 ms) word 5 The time it took to complete the previous scan of the normal station poll list. Max Normal Poll List Scan (100 ms) word 6 The maximum time taken to complete a scan of the normal station poll list. Last Priority Poll List Scan (100 ms) word 10 The time it took to complete the previous scan of the priority station poll list. Max Priority Poll List Scan (100 ms) word 13 The maximum time taken to complete a scan of the priority station poll list. DTR (Data Terminal Read) word 0; bit 4 Displays the status of the DTR handshaking line (asserted by the processor). DCD (Data Carrier Detect) word 0; bit 3 Displays the status of the DCD handshaking line (received by the processor). DSR (Data Set Ready) word 0; bit 2 Displays the status of the DSR handshaking line (received by the processor). RTS (Request to Send) word 0; bit 1 Displays the status of the RTS handshaking line (asserted by the processor). CTS (Clear to Send) word 0; bit 0 Displays the status of the CTS handshaking line (received by the processor).

by the destination device.

the previous message packet.

poll of a station.

Create Station Lists

After defining your pol ling fi les an d group si ze, cre ate st ation list s by entering the station address of each slave station into either the normal poll file or priority poll file of the PLC-5 data table. Place each station address in an individual word in a poll file (normal and priority) starting at wo rd 2.

The normal and priority poll file layout is as follows:

This word in a poll file: Contains this information:

word 0 total number of stations to be polled (for a list) word 1 the address location (poll offset) of the station currently

word 2 through word

being polled (as long as all configured stations are active) For example: a value of 1 means the station address stored

in word 2 is being polled, 2 means the address stored in word 3 is being polled, etc.

This word is automatically updated by the master station as a new slave station is polled.

the slave station address in the order that the stations should be polled

Store one station address in each word.

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2-8 Configuring Enhanced PLC-5 Processors

To place a station address in a poll file, do the following:

1. Access the PLC-5 data table.

2. Specify the address of the integer file that i s either the no rmal poll

3. Enter the station addresses of the slave stations you want in the

Important: PLC-5 station addresses are octal addresses. The poll

Figure 2.2 is an example of a station list containing three stations: octal addresses 10, 3, and 12. Station 12 is being polled.

Figure 2.2 Example Station List

file or priority poll file (e.g., If the normal poll file is N11, then you specify N11:0).

poll list starting at word 2. Put them in the order you want them polled.

files are integer files. To properly enter PLC-5 station addresses in a poll file, you must either:

•change the radix of the file to octal

•convert the PLC-5 octal station addresses to decimal

total number of stations

pointer showing the station address being polled

address of first station in list

address of second station in list

address of third station in list

Monitor Active Stations

T o see wha t stati ons are ac tive, vie w the acti ve station f ile. Each bit in the file represents a station on the link. The stations are numbered in order as a continuous bit-stream file starting with the first bit in the first word (F igure 2.3).

Figure 2.3 Example Active Station File

Address 15 Data 0 B11:0 1111 1111 1111 1111 Remote station 0

B11:1 1111 1111 1111 1111 Remote station 16 B11:2 1111 1111 1111 1111

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Configuring Enhanced PLC-5 Proces sors 2-9

For PLC-5 pro cessors, note the following:

Starting with these PLC-5 firmware revisions: This is what you will see:

Series E/Revision B Series D/Revision C Series C/Revision L Series B/Revision M Series A/Revision M

For all prior firmware revisions At power-up or after reconfiguration, the master station

Configuring a DF1 Half-Duplex Message-based Mode Master Station

At power-up or after reconfiguration, the master station assumes that all slave stations are inactive (bit=0).

assumes that all slave stations are active (bit=1) and the station displays inactive only after it fails to respond to a poll packet.

Choose message-based commu nication mode i f you want to use MSG instructions in user programming to communicate with one station at a time. If your application uses satellite transmission or public switched telephone network transmission, consider choosing message-based. Communication to a slave station can be initiated on an as-need ed basis.

Also choose message -based mode whe n a r edundant PLC-5 system is being used as a master station. Connect both PLC-5 processor serial ports to the master s ta ti on mode m through an RS-232 modem splitter and precondition all MSG instructions with the Primary Processor status bit.

With messa ge- based mode, you do not have an active station file that you can use to monitor station status. Also, you cannot implement slave-to-slave messaging or slave programming over the telemetry network.

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2-10 Configuring Enhanced PLC-5 Processors

To configure the processor for a master station using message-based communication, place the processor in program mode and do the following using RSLogix 5:

Double-click on the Channel Configuration file to bring up the Edit Channel Configuration interface.

1. On the Channel 0 tab, choose System (Master) for your Communication Mode.

2. Configure the Serial Port, Options, and Polling parameters according to Table 2.C.

3. Configure Options parameters according to Table 2.C.

4. Configure the Polling parameters according to Table 2.C.

5. When all parameters are set, click OK.

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Configuring Enhanced PLC-5 Proces sors 2-11

Use Table 2.C to help you understand the communication para me te rs you need to specify on the Channel Configuration screen.

Use Worksheet 2.2 (Appendix D-5) for an example confi gurati on and

to record your station’s configuration.

Table 2.C Define these communication parameters for a PLC-5 master station using message-based communication mode to talk to slave stations.

RSLogix 5 Tab: Parameter: Selections:

Channel 0 Diagnostic File Select an unused integer file to store channel status information. You must define a diagnostic

file in order to be able to view channel 0 status. See Table 2.B on page 2-6 for description of

what’s in this file.

Remote Mode Change Check enable remote mode change if you want to switch the configuration of the channel

during runtime. Leave the parameter set at the default (uncheck) if you are not using this feature.

Mode Attention Character Select a character that will signal a remote mode change. Leave the parameter set at the

default if you are not using remote mode change.

System Mode Character Select a character that will signal the channel to switch into system mode. Leave the parameter

User Mode Character Select a character that will signal the channel to switch into user mode. Leave the parameter

Serial Port Baud Rate Select a communication rate that all devices in your system support. Configure all devices in the

Bits Per Character Match the numbers of bits per character to the devices with which you are communicating. Stop Bits Match the number of stop bits to the devices with which you are communicating.

Serial Port Control Line This parameter defines the mode in which the master driver operates. Choose a method

Parity Parity provides additional message packet error detection. To implement even parity checking,

Error Detect With this selection, you choose how the processor checks the accuracy of each DF1 packet

set at the default if you are not using remote mode change.

system for the same communication rate.

appropriate for your system’s configuration:

• If you are not using a modem, choose NO HANDSHAKING.

• If the master modem is full duplex and the slave modem is full-duplex, choose FULL-DUPLEX MODEM.

• If all the modems in the system are half-duplex, choose HALF-DUPLEX MODEM WITHOUT CONTINUOUS CARRIER.

choose Even. To implement no parity checking, choose None.

transmission. BCC: This algorithm provides a medium level of data security. It cannot detect:

• transposition of bytes during transmission of a packet

• the insertion or deletion of data values of zero within a packet

CRC: This algorithm provides a higher level of data security. Select an error detection method that all devices in your system support. When possible, choose CRC.

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2-12 Configuring Enhanced PLC-5 Processors

RSLogix 5 Tab: Parameter: Selections:

Options Station Address Define the octal address of the processor on the DF1 half-duplex link. Each station on a link

must have a unique address. Choose an address between 0 and 376

Station addr ess 3 778 is the broadcast address, which you cannot select as a station’s individual

address.

DF1 Retries Define the number of times a master station retries either a message before the master station

declares the message undeliverable, or a poll packet to an active station before the master station declares tht station to be inactive.

RTS Send Delay RTS send delay is the amount of time in 20 millisecond increments that elapses between the

assertion of the RTS signal and the beginning of the message transmission. This time allows the modem to prepare to transmit the message. The Clear to Send (CTS) signal must be high for transmission to occur.

RTS Off Delay RTS off delay is the amount of time in 20 millisecond increments that elapses between the end

of the message transmission and the de-assertion of the RTS signal. This time delay is a buffer to ensure that the modem has transmitted the message but should normally be left at zero.

ACK Timeout Define the amount of time in 20 millisecond increments that you want the processor to wait for

an acknowledgment from a slave station to its transmitted message before retrying. This timeout value is also used for the poll response timeout.

Reply Message Wait Define the amount of time in 20 millisecond increments that the master station will wait after

receiving an ACK (to a master-initiated message) before polling the slave station for a reply. Choose a time that is, at minimum, equal to the longest time that a slave station needs to

format a reply packet. This is typically the maximum scan time of the slave station.

MSG Application Timeout The application timeout of the message is the number of 30 second increments within which

the reply message must be received before the error bit is set on the message. The timer starts when the ACK is received.

Polling Polling Mode If you want to:

• accept unsolicited messages from slave stations, choose MESSAGE BASED (ALLOW SLAVE TO INITIATE MESSAGES)

Slave station-initiated messages are acknowledged and processed after all master station-initiated (solicited) messages.

Note: Slave stations can only send messages when they are polled. If the message-based master st atio n n e ve r s en d s a slave station a messag e , t he m a st er st ati o n w i ll n e ve r s en d t he slave station a poll. Therefore, to regularly obtain a slave station-initiated message from a slave station, you should choose to use standard communications mode instead.

• ignore unsolicited messages from slave stations, choose MESSAGE BASED (DO NOT ALLOW SLAVES TO INITIATE MESSAGES)

Slave station-initiated messages are acknowledged and discarded. The master station acknowledges the slave station-initiated message so that the slave station removes the message from its transmit queue, which allows the next packet slated for transmission into the transmit queue.

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Configuring Enhanced PLC-5 Proces sors 2-13

Configuring the Processor as a Slave Station

Double-click on the Channel Configuration file to bring up the Edit Channel Configuration interface.

1. On the Channel 0 tab, choose System (Slave) for your Communication Mode

2. Configure the Serial Port parameters according to Table 2.D.

To configure the processor as a slave station, place the processor in program mode and do the following using your programming software:

3. Configure the Options parameters according to Table 2.D.

4. When all parameters are set, click OK.

Use Table 2.D to help you understand the c ommu nic at ion parameters you need to specify on the Channel Configuration screen.

Use Worksheet 2.3 (Appendix D-6) for an example confi gurati on and

to record your station’s configuration.

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2-14 Configuring Enhanced PLC-5 Processors

Table 2.D Define these communication parameters when configuring a PLC-5 slave station.

RSLogix 5 Tab: Parameter: Selections:

Channel 0 Diagnostic File Select an unused integer file to store channel status information. You must define a

Remote Mode Change Enable

Mode Attention Character Select a character that will signal a remote mode change. Leave the parameter set at the

System Mode Character Select a character that will signal the channel to switch into system mode. Leave the

User Mode Character Select a character that will signal the channel to switch into user mode. Leave the

Serial Port Baud Rate Select a communication rate that all devices in your system support. Configure all devices

Bits Per Character Match the number of bits per character to the devices with which you are communicating. Stop Bits Match the number of stop bits to the devices with which you are communicating. Control Line This parameter defines the mode in which the slave station driver operates. Choose a

diagnostic file in order to be able to view channel 0 status. See Table 2.E on page 2-16 for a description of what this file contains.

Check enable remote mode change if you want to switch the configuration of the channel during runtime. Leave th e parame ter set at th e defaul t (unche cked ) if you are not using this feature.

default if you are not using remote mode change.

parameter set at the default (unchecked) if you are not using remote mode change.

parameter set at the default if you are not using remote mode change.

in the system for the same communication rate.

method appropriate for your system’s configuration:

• If you are not using a modem, choose NO HANDSHAKING.

• If the master modem is full duplex and transmits a constant carrier and the slave modem is half-duplex, choose HALF-DUPLEX MODEM WITH CONTINUOUS CARRIER.

• If all the modems in the system are half-duplex, choose HALF-DUPLEX MODEM WITHOUT CONTINUOUS CARRIER.

Parity Parity provides additional message packet error detection. To implement even parity

checking, choose Even. To implement no parity checking, choose None.

Serial Port Error Detect With this selection, you choose how the processor checks the accuracy of each DF1 packet

Publication AG-6.5.8 - October 1998

transmission. BCC: This algorithm provides a medium level of data security. It cannot detect:

• transposition of bytes during transmission of a packet

• the insertion or deletion of data values of zero within a packet

CRC: This algorithm provides a higher level of data security. Select an error detection method that all devices in your system support. When possible, choose CRC.

RSLogix 5 Tab: Parameter: Selections:

Configuring Enhanced PLC-5 Proces sors 2-15

Options Station Address Define the octal address of the the processor on the DF1 half-duplex link. Each station on a

link must have a unique address. Choose an address between 0 and 376

Station address 3778 is the broadcast address, which you cannot select as a station’s

individual address.

DF1 Retries The number of times a slave station retries a message before the slave station declares the

message undeliverable.

RTS Send Delay RTS send delay is the amount of time in 20 millisecond increments that elapses between

the assertion of the RTS signal and the beginning of the message transmission. This time allows the modem to prepare to transmit the message.

The CTS (Clear-to-Send) signal must be high for transmission to occur.

RTS Off Delay RTS off delay is the amount of time in 20 millisecond increments that elapses between the

end of the message transmission and the de-assertion of the RTS signal. This time delay is a buffer to make sure that the modem has transmitted the message but should normally be left at zero.

ACK Timeout Define the amount of time in 20 millisecond increments that you want the processor to wait

for an acknowledgment from the master station to its transmitted message.

Detect Duplicate Messages Duplicate packet detection lets the PLC-5 processor detect if it has received a message

that is a duplicate of its most recent message from the master station. If you choose detect duplicate mes sag es, the p roc es sor wi ll a ckn owl edge (AC K) th e me ss age b ut will no t a ct o n it since it has already performed the message’s task when it received the command from the first message.

If you want to detect du plicate pack ets and di scard them , check this par ameter. If you want to accept duplicate packets and execute them, leave this parameter unchecked.

MSG Application Timeout Define the number of 30 second increments within which the reply message must be

received before the error bit is set on the message. The timer starts when the ACK is received.

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2-16 Configuring Enhanced PLC-5 Processors

Displaying Slave System Channel Status

To display Channel Status, double click on Channel Status, which is located within Channel Configuration.

To access the various channels from the Channel status screen, click on the tabs. Descriptions of the status screen fields can be found in Table 2.E.

Table 2.E Descriptions of System Mode DF1 Slave Channel Status Fields

Status Field Diagnostic File Location Definition

DCD Recover word 11 The number of times the processor detects the DCD handshaking line has

Messages Sent word 1 The total number of DF1 messages sent by the processor (including message

Messages Received word 2 The number of messages received with no errors Polling Received word 6 The number of master poll packets received by the processor Received NAK word 5 The number of NAKs received by the processor Lack of Memory/No ACK Sent word 8 The number of times the processor could not receive a message because it did

Lost Modem word 12 The number of times the lost modem bit has gone low to high Messages Retry word 4 The number of message retries sent by the processor Undelivered Messages word 3 The number of messages that were sent by the processor but not

Duplicate Messages Received word 9 The number of times the processor received a message packet identical to the

gone low to high

retries)

not have available memory

acknowledged by the destination device

previous message packet

Publication AG-6.5.8 - October 1998

Status Field Diagnostic File Location Definition

Configuring Enhanced PLC-5 Proces sors 2-17

Bad Packet/No ACK word 7 The number of incorrect data packets received by the processor for which a no

DTR (Data Terminal Ready) word 0;bit 4 The status of the DTR handshaking line (asserted by the processor) DSR (Data Set Ready) word 0;bit 2 The status of the DSR handshaking line (received by the processor) RTS (Request to Send) word 0;bit 1 The status of the RTS handshaking line (asserted by the processor) CTS (Clear to Send) word 0;bit 0 The status of the CTS handshaking line (received by the processor) DCD (Carrier Detect) word 0;bit 3 The status of the DCD handshaking line (received by the processor)

ACK was returned

Publication AG-6.5.8 - October 1998

2-18 Configuring Enhanced PLC-5 Processors

Configuring the Processor as a Station on a Point-to-Point Link

Double-click on the Channel Configuration file to bring up the Edit Channel Configuration interface.

1. On the Channel 0 tab, choose System (Point-to-Point) for your Communication Mode.

2. Configure the Serial Port parameters according to Table 2.F.

To configure the processor as a station on a point-to-point link, place the processor in program mode and do the following using your programming software:

3. Configure the Options parameters according to Table 2.F.

4. When all parameters are set, click OK.

Publication AG-6.5.8 - October 1998

Use Table 2.F to help you unders tan d t he screen parameters you need to specify on the Channel Configuration screen.

Use Worksheet 2.4 (Appendix D-7) for an example confi gurati on and

to record your station’s configuration.

Table 2.F Define these parameters when using the PLC-5 processor as a device on a point-to-point link.

Configuring Enhanced PLC-5 Proces sors 2-19

RSLogix 5 Tab:

Channel 0 Diagnostic File Select an unused integer file that you want to use to store channel status information. You must

Serial Port Baud Rate Select a communication rate that all devices in your system support. Configure all devices in the

Parameter: Selections:

define a diagnostic file in order to be able to view channel 0 status. See Table 2.G on page 2-20 for a description of what this file contains

Remote Mode Change Enable remote mode change if you want to switch the configuration of the channel during runtime.

Leave the parameter set at the default if you are not using remote mode change.

Mode Attention Character Select a character that will signal a remote mode change. Leave the parameter set at the default if

you are not using remote mode change.

System Mode Character Select a character that will signal the channel to switch into system mode. Leave the parameter

set at the default if you are not using remote mode change.

User Mode Character Select a character that will signal the channel to switch into user mode. Leave the parameter set

at the default if you are not using remote mode change.

system for the same communication rate. Bits Per Character Match the number of bits per character to the device with which you are communicating. Stop Bits Match the number of stop bits to the device with which you are communicating. Control Line This parameter defines the mode in which the driver operates. Choose a method appropriate for

your system’s configuration:

• If you are not using a modem, choose NO HANDSHAKING.

• If you are using a full-duplex modem, choose FULL-DUPLEX.

Parity Parity provides additional message packet error detection. To implement even parity checking,

choose Even. To implement no parity checking, choose None.

Options NAK Receive Define the number of NAKs the processor can receive in response to a transmitted message before

DF1 ENQs Define the number of enquiries (ENQs) that you want the processor to send after an ACK timeout

ACK Timeout Define the amount of time in 20 millisecond increments you want the processor to wait for an

Options Detect Duplicate

Messages

MSG Application Timeout Define the number of 30 second increments within which the reply message must be received

Error Detect With this selection you choose how the processor checks the accuracy of each DF1 packet

the station declares the message undeliverable.

occurs before the station declares the message undeliverable.

acknowledgment from a station to its transmitted message.

Duplicate Packet Detection lets the PLC-5 processor detect if it has received a message that is a

duplicate of its most recent message from another station. If you choose detect duplicate

messages, the processor will acknowledge (ACK) the message but will not act on it since it has

already performed the message’s task when it received the command from the first message.

If you want to detect duplicate packets and discard them, check this parameter. If you want to

accept duplicate packets, and execute them, leave this parameter unchecked.

before the error bit is set on the message. The timer starts when the ladder program first initiates

the message and is restarted if/when the ACK is received.

transmission.

BCC: This algorithm provides a medium level of data security. It cannot detect:

• transposition of bytes during transmission of a packet

• the insertion or deletion of data values of zero within a packet

CRC: This algorithm provides a higher level of data security.

Select an error detection method that all devices in your system support.

When possible, choose CRC.

Important: The station address in the point-to-point driver is determined by the DH+ address defined by switch assembly S1.

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2-20 Configuring Enhanced PLC-5 Processors

Displaying Point-to-Point System Channel Status

To display Channel Status, double click on Channel Status, which is located within Channel Configuration.

To access the various channels from the Channel status screen, click on the tabs. Descriptions of the status screen fields can be found in Table 2.G.

Table 2.G Descriptions of System (Point-to-Point) Channel Status Fields

Status Field Diagnostic File Location Definition

DCD Recover word 11 The number of times the processor detects the DCD handshaking line has

Messages Sent word 1 The total number of DF1 messages sent by the processor (including message

Messages Received word 2 The number of messages received with no errors Inquiry Received word 6 The number of master poll packets received by the processor Received NAK word 5 The number of NAKs received by the processor Lack of Memory/Sent NAK word 8 The number of times the processor could no t receive a message be cause it did

Lost Modem word 12 The number of times the lost modem bit has gone low to high Undelivered Messages word 3 The number of messages that were sent by the processor but not

Duplicate Messages Received word 9 The number of times the processor received a message packet identical to the

Inquiry Sent word 4 The number of ENQs sent by the processor

gone low to high

retries)

not have available memory

acknowledged by the destination device

previous message packet

Publication AG-6.5.8 - October 1998

Status Field Diagnostic File Location Definition

Configuring Enhanced PLC-5 Proces sors 2-21

Bad Packet/No ACK word 7 The number of incorrect data packets received by the processor for which a

NAK was returned

Messaging Messaging can occur between:

• a master station and a slave station

• a slave station and its master station (See “Polled Report-by-Exception”)

• slave stations or between two processors connected via a point-to-point li nk

For: See Page:

examples 2-21 list of considerations 2-23

Master Station to Slave Station

A PLC-5 master station communi cates with t he slav e stat ions t hat ar e connected to it via modems in a point-to-multipoint configuration. A master station send s a slav e stati on messages to rece ive status or issue commands. For sample messaging ladder logic, see Appendix E-8.

Polled Report-by-Exception

Slave stations can gather information from the I/O points they are responsible for and can send any anomalous readings to the master station. To do this, write ladder logic in the slave station to monitor certain conditions and send the data in a MSG instruction to the master station. Figure 2.5 i s an exa mp le MSG instruct ion and control block that a PLC-5 processor in a slave station can send to a PLC-5 master station. For sample messsaging ladder logic when using a PLC-5 as a slave, see Appendix E-12.

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2-22 Configuring Enhanced PLC-5 Processors

Processor-to-Processor

A processor-to-processor message can be two types:

• In a point-to-multipoint configuration, the messaging would be between slave st ations; th e master st ation au tomatically routes the message.

Master Station

MSG from Slave Station 1 to Slave Station 2

Modem

Slave Station 1

Master Station routes MSG to Slave Station 2

Modem

Slave Station 2

• In a point-to-point configuration, the messaging would be between the two connected peer devices.

MSG

Modem

Station 1

Modem

Station 2

The configuration of the network (point-to-multipoint vs. point-topoint) and the configuration of the station (master, slave, or peer) does not af fect how you c onfig ure a MSG ins truct ion. Th at i s, a MSG instruction being sent be tween two PLC-5 slave stat ions is configured the same as a MSG instruction between two PLC-5 processors connected point-to-point, which is configured the same as a MSG instruction between a PLC-5 master st ation and a PLC- 5 slave statio n. See Figure 2.4 through Figure 2.7 for example MSG control blocks.

Publication AG-6.5.8 - October 1998

Configuring Enhanced PLC-5 Proces sors 2-23

Considerations When Configuring MSG Control Blocks

Keep these considerations in mind when configuring messages between a PLC-5 and SLC 500 or MicroLogix 1000 processors.

The following table lists which PLC-5 processors (series and revision) you can use with the MSG instruction to transfer data from/to a PLC-5 processor to/from any SLC 500 processor or MicroLogix 1000 in SLC native mode.

Processor

Series/Revision:

Series A / revision M PLC-5/40, -5/40L, -5,60, -5/60L Series A / revision J PLC-5/30 Series A / revision H PLC-5/11, -5/20 Series B / revision J PLC-5/40, -5/40L, -5/60, -5/60L Series C / revision G PLC-5/11, -5/20, -5/20E, -5/30, -5/40, -5/40L, -5/V40,

-5/V40L, -5/40E, -5/60, -5/60L, -5/80, -5/80E, -5/V80,

-5/20C, -5/40C, -5/80C

Series D / all PLC-5/11, -5/20, -5/20E, -5/30, -5/40, -5/40L, -5/V40,

-5/V40L, -5/40E, -5/60, -5/60L, -5/80, -5/80E, -5/V80,

-5/20C, -5/40C, -5/80C

Series E / all PLC-5/11, -5/20, -5/20E, -5/30, -5/40, -5/40L, -5/V40,

-5/V40L, -5/40E, -5/60, -5/60L, -5/80, -5/80E, -5/V80,

-5/20C, -5/40C, -5/80C

Processors:

• Since all SLC 5/05, 5/04 and 5/03 processors with operating system 301 or higher can respond to (and initiate) PLC-5 native mode message commands, al l PLC- 5 proce ssors can t ransfer data between their data tables and the data table of these particular SLC processors (except fo r the I/O image table) as if they we re messaging with another PLC-5 processor.

• In a single instruction, the maximum amount of words you can read from or write to through channel 0 is as follows:

• SLC 500, 5/01, 5/02, and MicroLogix 1000 processor, 41

words

• SLC 5/03, 5/04, and 5/05 processor, 103 words

When configuring messages between a PLC-5 and Logix5550 processor , use the PLC-5 typed read and write commands and e nclose the name of the Logix5550 tag in doub le quotes. Thi s is calle d logical ASCII addressing.

Publication AG-6.5.8 - October 1998

2-24 Configuring Enhanced PLC-5 Processors

Example MSG Control Blocks

Application: See: Page:

PLC-5 read message to another PLC-5 processor Figure 2.4 2-24 PLC-5 write message to another PLC-5 processor Figure 2.5 2-25

Ladder Rung

Control Block

PLC-5 read message to a SLC 500 or MicroLogix 1000 processor

PLC-5 write message to a SLC 500 or MicroLogix 1000 processor

Figure 2.4 This is an example of a PLC-5 read MSG to another PLC-5 (or SLC 5/03, 5/04, 5/05, or Logix5550) processor.

Figure 2.6 2-26

Figure 2.7 2-27

MSG being sent to anoth er PLC-5 processor.

MSG being sent out channel 0 (must use MG file type).

If the destination were a Logix5550 processor, then the address could also be

entered as “tagname”.

This MSG example tells this (master) PLC-5 to read the information from PLC-5 (slave) station 13 information in file N19:0 (master).

Publication AG-6.5.8 - October 1998

’s, location N7:0 and place the

Ladder Rung

Control Block

MSG being sent to anot her PLC-5 processor.

Configuring Enhanced PLC-5 Proces sors 2-25

Figure 2.5 This is an example of a PLC-5 write MSG to another PLC-5 (or SLC 5/03, 5/04, 5/05, or Logix5550) processor.

MSG being sent out channel 0 (must use MG file type).

If the destination were a Logix5550 processor, then the address could also be entered as “tagname”.

This MSG example tells this (master) PLC-5 to write the information from its file N19:0 through its serial port (channel 0) to the PLC-5 (slave) station 13

. The data’s destination is N7:0 of the PLC-5 (slave) station.

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2-26 Configuring Enhanced PLC-5 Processors

Figure 2.6 This is an example of a PLC-5 read MSG to a SLC 500 processor.

Ladder Rung

Control Block

MSG being sent to an SLC 500 or MicroLogix 1000 processor.

MSG being sent out channel 0 (must use MG file type).

This MSG example tells this PLC-5 (master) to read the information from SLC 500 (slave) 13 its N15:0 file.

(158) S:1 and place the information in

Publication AG-6.5.8 - October 1998

Ladder Rung

Control Block

MSG being sent to an S L C 500 or MicroLogix 1000 processor.

Configuring Enhanced PLC-5 Proces sors 2-27

Figure 2.7 This is an example of a PLC-5 Write MSG to a SLC 500 processor.

MSG being sent out channel 0 (must use MG file type).

This MSG example tells the PLC-5 master station to write the information from its N15:1 through its serial port (channel 0) to the SLC 500 slave station 13

(158). The data’s destination is N7:0 of the SLC 500 slave station.

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2-28 Configuring Enhanced PLC-5 Processors

Notes

Publication AG-6.5.8 - October 1998

Chapter

Configuring Classic PLC-5 Processors with 1785-KE Modules

Use This Chapter. .. ... to help you set up a Classic PLC-5 processor, with the 1785-KE

Data Highway Plus™ Communicati on I nt erf ac e Mo dul e, as a remot e station.

For information about: See page:

an overview of the tasks required to configure a Classic PLC-5 processor as a remote station

installing the processor 3-2 configuring and installing the 1785-KE module 3-3 connecting the processor and the 1785-KE module 3-4 the types of messages you can send from a Classic PLC-5

processor; how to configure the MSG instruction and some configuration considerations

Overview To configure a Classic PLC-5 remote station, perform these tasks:

3-1

3-5

1. Install the processor

4. Install and configure the modem for communication with the 1785-KE module; connect

the modem to the 1785-KE module’s serial channel. See

modem

2. Configure and install the 1785-KE module

3. Connect the processor and the 1785-KE module

41194

Publication AG-6.5.8 - October 1998

3-2 Configuring Classic PLC-5 Processors with 1785-KE Modules

Installing the Processor Before installing the processor, set the switch assemblies.

Specify: By setting switch assembly:

DH+ station address of the processor scanner as the processor mode

terminating resistors for remote I/O and DH+ links SW3

For more information:

About: See:

setting switches 1785 PLC-5 Family Programmable

Controllers Hardware Installation Manual, publication 1785-6.6.1

installing the processor 1785 PLC-5 Family Programmable

Controllers Hardware Installation Manual, publication 1785-6.6.1

Top View of Module Bottom View of Module

SW1

Set switches to define:

• the station address

• scanner as the mode of operation

Switch Assembly SW1

Switch Assembly SW3

See the 1785 PLC-5 Family Programmable Controllers Hardware Installation Manual, publication 1785-6.6.1, for the settings.

Set switches for terminating resistors

Publication AG-6.5.8 - October 1998

Configuring Classic PLC-5 Processors with 1785-KE Modules 3-3

Configuring and Installing the 1785-KE Module

Configure each 1785-KE being used with a Classic PLC-5 processor in the network according to the following:

Configuration Selections Switch Settings For: Choose: Set switch To:

Switch Assembly SW1 Protocol half-duplex 1 on

Error check CRC 2 on Parity none 3 on Embedded responses no 4 on Duplicate message ignore 5 on Handshaking signals use 6 on Diagnostic command execute

Switch Assembly SW2 Station address

When the module is in remote mode, do not poll this address.

7 (Set all 1785-KE modules for the same address (if on different DH+s). The address should be one that is not used by any remote station.)

7 in this example

10 2on 3on 4on 5on 6off 7off 8off

Switch Assembly SW3 DH+

Communication Rate RS-232

Communication Rate

Addressing mode remote 6 off

Switch Assembly SW4 Reserved 1-4 off

57.6 K 1 on

9600 (must match the

modem’s rate)

9600 in this example

2on

3off 4on 5on

Record your configurations on Worksheet 3.1 (page 9-9).

You can reconfigure the module’s parameters if additional requirements are necessary.

Publication AG-6.5.8 - October 1998

3-4 Configuring Classic PLC-5 Processors with 1785-KE Modules

For more information about: See:

Connecting the Processor and 1785-KE Module

1785-KE

COMM CONTROL

DH+

setting switches installing the module

1785-KE DH+ Communications Interface Module User Manual, publication 1785-6.5.2

module to modem cable Connecting the Processor and 1785-KE

Module (page 3-4) appendix A

The processor and 1785-KE module communicate with each other over a DH+ link. Use a length of Belden 9463 cable to connect the processor and the 1785-KE module.

15-pin male

C. GND 1

TXD.OUT 2

RXD.IN 3

RTS.OUT 4

CTS.IN 5

DSR.IN 6

SIG.GND 7

DCD.IN 8

DTR.OUT 11

25-pin male

1 2 3 4 5 6 7 8 20

DH+ connection via Belden 9463 cable

DH+

RS-232

to modem

Publication AG-6.5.8 - October 1998

Configuring Classic PLC-5 Processors with 1785-KE Modules 3-5

Messaging Messaging can occur between:

• a remote station and its master station (See “Polled Report-by-Exception”)

• remote stations or between two processors connected via a point-to-point li nk

Polled Report-by-Exception

Remote stations can gather information from the I/O points they are

For: See page:

list of considerations 3-6 examples 3-6

responsible for and send any anomalous readings to the master station. To do this, write logic in the remote station’s processor to monitor certain conditions and send the data in a MSG instruction to the master station. Figure 3.2 is an example MSG instruction and control block that a Classic PLC-5 processor in a remote station can send to a PLC-5 master station.

Processor-to-Processor

A processor-to-processor message can be two types:

• In a point-to-multipoint configuration, the messaging is between remote stations; the master station routes the message.

Master Station

MSG from Remote Station 1 to Remote Station 2

modem

Remote

Station 1

Master Station rout es MSG to Remote Station 2

modem

Remote

Station 2

• In a point-to-point configuration, the messaging would be between the two devices connected together.

MSG

modem

Station 1

modem

Station 2

The 1785-KE module acts as bridge between the Classic PLC-5 processor and the other stations on the telemetry network. Generally, use remote MSGs to read data from and write data to another processor.

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3-6 Configuring Classic PLC-5 Processors with 1785-KE Modules

Considerations When Configuring MSG Control Blocks

Keep these considerations in mind when configuring messages between a Classic PLC-5 and a SLC 5/02, 5/03, 5/04 or 5/05 processor.

• If you are sending mess ages betwee n a PLC-5 pro cessor and SLC 5/02 processor, then set S:2/8 in the SLC 5/02 status file to 1. This bit is the CIF (Common Interface File) Addressing Mode selection bit and lets the SLC 5/02 processor accept “byte-offsets” from a PLC-5 processor.

• You cannot access words 0-7

-7110) in a SLC 5/02 C ommon Interface File from a PL C-5

(64

or directly access 1008-1078

processor.

• Since all SLC 5/04 and 5/05 processors and SLC 5/03 processors with operating system 301 or higher can respond to (and initiate) PLC-5 native mode message commands, all PLC-5 processors can transfer data between their data tables and the data table of these particular SLC processors (except for the I/O image table) as if they were messaging with another PLC-5 processor.

• In a single instruction, the maximum amount of words you can read from or write to as fo llows:

– SLC 5/02 processor: 41 words – SLC 5/03, 5/04, 5/05 processor: 103 words

Example MSG Control Blocks

Application: See: Page:

Classic PLC-5 read message to another PLC-5 processor Figure 3.1 3-8 Classic PLC-5 write message to another PLC-5 processor Figure 3.2 3-9 Classic PLC-5 read message to a SLC 5/02 processor Figure 3.3 3-10 Classic PLC-5 write message to a SLC 5/02 processor Figure 3.4 3-11

Publication AG-6.5.8 - October 1998

ladder rung

setup screen (remote message)

Configuring Classic PLC-5 Processors with 1785-KE Modules 3-7

Figure 3.1 This is an example of a Classic PLC-5 read MSG to another PLC-5 processor.

MSG being sent to a PLC-5 processor

address of the 1785-KE module

address of the target processor

This MSG example tells the Classic PLC-5 remote station to read the information from the PLC-5 master station’s (13 place the information in remote station file N19:0.

.) S:23 and

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3-8 Configuring Classic PLC-5 Processors with 1785-KE Modules

Figure 3.2 This is an example of a Classic PLC-5 write MSG to another PLC-5 processor.

ladder rung

setup screen (remote message)

MSG being sent to a PLC-5 processor

address of the 1785-KE module

address of the target processor

This MSG example tells the Classic PLC-5 remote station to write the information from its S:23 to PLC-5 master station (13 N19:0.

.) file

Publication AG-6.5.8 - October 1998

ladder rung

setup screen (remote message)

MSG being sent to a PLC-2-like device

Configuring Classic PLC-5 Processors with 1785-KE Modules 3-9

Figure 3.3 This is an example of a Classic PLC-5 read MSG to a SLC 5/02 processor.

Word offset (in octal) of SLC 500 file N9

Address of the 1785-KE module

Enter octal equivalent of the SLC 500 decimal station address

This MSG example tells the Classic PLC-5 processor to read the information from SLC 500 remote station 13 interface file N9, offset 77

(6310) and place the information in its N15:0 file.

(158) common

Set S:2/8 in SLC 5/02 status file to 1. This bit is the Common Interface File (CIF) Addressing Mode selection bit that allows the SLC

5/02 processor to accept “byte-offsets” from a PLC-5 processor.

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3-10 Configuring Classic PLC-5 Processors with 1785-KE Modules

Figure 3.4 This is an example of a Classic PLC-5 wr ite MSG to a SLC 5/ 02 pr oce ssor.

ladder rung

setup screen (remote message)

MSG being sent to a PLC-2-like device

Word offset (in octal) of SLC 500 file N9

Address of the 1785-KE module

Enter octal equivalent of the SLC 500 decimal station address

This MSG example tells the Classic PLC-5 processor to write th e information from its N15:0 to SLC 500 remot e station 13 The information is to be written to offset 77

(6310) in the SLC common interface file N9.

(158).,

Set S:2/8 in SLC 5/02 status file to 1. This bit is the Common Interface File (CIF) Addressing Mode selection bit that allows the SLC

5/02 processor to accept “byte-offsets” from a PLC-5 processor.

Publication AG-6.5.8 - October 1998

Chapter

Configuring SLC 5/03, 5/04, and 5/05 Processors

Use This Chapter... ...to help you set up a SLC 5/03, 5/04, or 5/05 processor as a master

station, as a slave station, or as a station on a point-to-point link.

For information about: See page:

an overview of the tasks required to configure a SLC 5/03, 5/04, or 5/05 processor

installing the processor 4-2 configuring the processor as a DF1 half-duplex master station using standard

communication configuring the processor as a DF1 half-duplex master station using

message-based communication configuring the processor as a slave station 4-17 configuring the processor for point-to-point communication 4-20 the types of messages you can send from a SLC 5/03, 5/04, or 5/05

processor to another processor; how to configure the MSG instruction and some configuration characteristics

4-1

4-7

4-14

4-23

Overview To configure a SLC 5/03, 5/04, or 5/05 processor, perform these

tasks:

1. Install the processor; connect the serial cable to channel 0.

modem

2. Define the processor’s communication characteristics using RSLogix 500 programming software.

RSLogix 500 programming software

3. Install and configure the modem for communication with the processor; connect

the modem to the processor’s serial channel.

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Publication AG-6.5.8 - October 1998

4-2 Configuring SLC 5/03, 5/04, and 5/05 Processors

Installing the Processor For details about installing the processor into an I/O chassis, see the

SLC 500 Modular Hardware S tyle Inst allation a nd Operation Man ual, publication 1747-6.2. Cable pinouts are shown in each example configuration as well as in Appendix A.

9-pin female 25-pin 9-pin

DCD.IN 1 8 1

RXD.IN 2 3 2

SLC 5/03CPU

RUN

FORCE

FLT

DH485

BATT RS232

RUN REM PROG

9-pin female cable connector

TXD.OUT 3 2 3

DTR.OUT

SIG.GND

DSR.IN

RTS.OUT

CTS.IN

420 4 57 5 66 6 74 7 85 8

to modem

Using Modems that Support DF1 Communication Protocols

41191

The types of modems that you can use with SLC processors include dial-up phone modems, leased-line modems, radio modems and line drivers. For point-to-point full-duplex modem connections, use DF1 full-duplex protocol . For point -to-multipoint modem connecti ons, use DF1 half-duplex master and slave protocols. In this case, one (and only one) of the other devices must be configured for DF1 half-duplex master protocol.

Important: Do not attempt to use DH-485 protocol through

modems under any circumstance.

Dial-up Phone Modems

Dial-up phone line modems support point-to-point full-duplex communications. Normally, an SLC processor on the initiating or receiving end of the dial-up connection, will be configured for DF1 full-duplex protocol with the control line parameter set for

“Full-Duplex Modem.” See page 4-4 for details on the operation of the RS-232 modem control signals when “Full-Duplex Modem” is selected. See chapter 1 1 for further detai ls on using SLC process ors in dial-up modem applications.

Publication AG-6.5.8 - October 1998

Configuring SLC 5/03, 5/04, and 5/05 Processors 4-3

When an SLC processor is the initia tor of the dial-up connection, use

one of the ASCII write instructions to send out the “AT” dial-up string (for example ATDT 555-1212). The status file modem lost bit (S:5/14) provides the feedback that the connection has been successfully made. To hang up the connection, use the ASCII AHL instruction to temporarily lo wer the DTR signal.

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 point-to-point topology supporting full-duplex communications between two modems or in a point-to-multipoint topology supporting half-duplex communications between three or more modems. In the point-to-point topology, configure the SLC processor for DF1 full-duplex protocol with the control line parameter set to “Full-Duplex Modem.” In the point-to-multipoint topology, configure the SLC processors for DF1 half-duplex master or slave protocol with the control parameter set to “Half-Duplex Modem without Continuous Carrier.” See page 4-5 for details on the operation of the RS-232 modem control signals when “Half-Duplex Modem without Continuous Carrier” is selected.

Radio Modems

Radio modems may be implemented in a point-to-point topology supporting either half-duplex or full-duplex communications, or in a point-to-multip oint t opolog y suppor ting half- duplex commun icati ons between three or more modems. In the point-to-point topology using full-duplex radio modems, configure the SLC processors for DF1 full-duplex protocol. In the point-to-multipoint topology using half-duplex radio modems, configure the SLC processors for DF1 half-duplex master or slave protocol. If these radio modems require RTS/CTS handshaking, c onfigure the control line parameter to “Half-Duplex Modem without Continuous Carrier.”

Line Drivers

Line drivers, also called short-h aul modems , do not actuall y modulate the serial data, but rather condition the electrical signals to operate reliably over long transmission distances (up to several miles). Allen-Bradley’s AIC+ Advanced Interface Converter is a 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. In a point-to-point line driver topology, configure the SLC processor for DF1 full-duplex protocol. In a point-to-multipoint line driver topology, configure the SLC processors for DF1 half-duplex master or slave protocol. If these line drivers require RTS/CTS handshaking, configure the control line parameter to “Half-Duplex Modem without Continuous Carrier.”

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4-4 Configuring SLC 5/03, 5/04, and 5/05 Processors

Modem Control Line Operation The following explains the operation of the SLC 5/03, 5/04 and 5/05

processors when you configure the RS-232 channel for the following applications.

DF1 Full-Duplex

When configured for DF1 full-duplex, the following control line operation takes effect:

No Handshaking Selected

DTR is always active (high) and RTS is always inactive (low).

Receptions and transmissions take place regardless of the states of DSR, CTS, or DCD inputs. Only make this selection when the SLC

5/03, 5/04 and 5/05 processors are directly connected to another device that does not require handshaking signals.

Full-Duplex Modem Selected

DTR and RTS are always active except:

• If DSR goes inactive, both DTR and RTS are dropped for 1 to 2 seconds, then reactivated. The modem lost bit (S:5/14) is turned on immediately. While DSR is inactive, the state of DCD is ignored. Neither receptions nor transmissions are performed.

• If DCD goes inactive while DSR i s active, t hen recept ions are no t allowed. If DCD remains inactive fo r 9 to 10 seconds , DTR is set inactive. At this point, the modem lost bit is also set. If DSR remains active, DTR is raised again in 5 to 6 seconds.

Reception r equir es DSR and DCD to be active. Transmission require s all three inputs (CTS, DCD, and DSR) to be active. Whenever DSR

and DCD are both active, the modem lost bit is reset.

DF1 Half-Duplex Slave

When configured for DF1 half-duplex slave, the following control line operation takes effect:

No Handshaking Selected

DTR is always active and RTS is always inactive. Receptions and transmissions take place regardless of the states of DSR, CTS, or DCD inputs. Only make this selection when the processor is directly

connected to another device that does not require handshaking signals.

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Configuring SLC 5/03, 5/04, and 5/05 Processors 4-5

Half-Duplex Modem with Continuous Carrier Selected

DTR is always active and RTS is only activated during transmis si ons (and any programmed delays before or after transmissions). The handling of DCD and DSR are exactly the same as with Full-Duplex Modem. Reception requires DSR and DCD to be active. Transmissions require CTS, DCD and DSR to be active. Whenever DSR and DCD are both active, the modem lost bit is reset.

Half-Duplex Modem without Continuous Carrier Selected

This is exactly the same as Half-Duplex Modem with Continuous Carrier except monitoring of DCD is not performed. DCD is still

required for receptions, but is not required for transmissions. Transmissions still require CTS and DSR. Whenever DSR is active,

the modem lost bit is reset.

DF1 Half Duplex Master

When configuring for DF1 half-duplex master, the following control line operation takes effect:

No Handshaking Selected

DTR is always active and RTS is always inactive. Receptions and transmissions take place regardless of the states of DSR, CTS, or DCD inputs. Only make this selection when the processor is directly

connected to another device that does not require handshaking signals.

Full-Duplex Modem Selected

DTR and RTS are always active except at the following times:

• If DSR goes inactive, both DTR and RTS are dropped for 1 to 2 seconds then reactivated. The modem lost bit (S:5/14) is turned on immediately. While DSR is inactive, the state of DCD is ignored. Neither receptions nor transmissions are performed.

• If DCD goes inactive while DSR i s active, t hen recept ions are no t allowed. If DCD remains inactive for 9 to 10 seconds, then DTR is set inactive. At thi s point, th e modem lost bit is also se t. If DSR remains active, then DTR is ra ised again in 5 to 6 seconds.

Reception r equir es DSR and DCD to be active. Transmission require s all three inputs (CTS, DCD, and DSR) to be active. Whenever DSR

and DCD are both active, the modem lost bit is reset.

Half-Duplex Modem without Continuous Carrier Selected

DTR is always active and RTS is only active during transmissions (and any programmed delays before and after transmissions). The processor does not monitor DCD.

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4-6 Configuring SLC 5/03, 5/04, and 5/05 Processors

If DSR goes inactive, RTS is dropped. The modem lost bit (S:5/14) is turned on immediately. While DSR is inactive, neither recepti ons no r transmissions are performed.

Reception requires DSR to be active. Transmission requires two inputs, CTS and DSR, to be active. Whenever DSR is active, the

modem lost bit is reset.

Configuring DF1 Half-Duplex Channel 0 Parameters

RTS Send Delay and RTS Off Delay

Through your programming software, the parameters RTS Send Delay and RTS Off Delay give you the ability to set how long RTS is on prior to transmission, as well as how long to keep it on after transmission is complete. These parameters only apply when you select half-duplex modem with or without continuous carrier. For maximum communication throughput, leave these parameters at zero.

For use with half-duplex modems that require extra time to turnaround or key-up their transmitter even after they have activated CTS, the RTS Send Delay specifies (in 20 millisecond increments) the amount of delay time after activating RTS to wait before checking to see if CTS has been activated by the modem. If CTS is not yet active, RTS remains active, and as long as CTS is activated within one second, the transmission occurs. After one second, if CTS is still not activated, then RTS is set inactive and the transmiss ion is abor te d.

For modems that do not supply a CTS signal but still require RTS to be raised prior to transmission, jumper RTS to CTS and use the shortest delay possible without losing reliable operation.

If an RTS Send Delay of 0 is selected, then transmis sion starts as soon as CTS is activated. If CTS does not go ac tive within one s econd af ter RTS is raised, RTS is set inactive and the transmission is aborted.

Publication AG-6.5.8 - October 1998

Certain modems will drop their carrier link when RTS is set inactive even though the transmission has not quite been finished. The RTS Off Delay paramet er spe ci fi es in 20 millisecond increments the de la y between when the last seria l charact er is sen t to the mode m and when RTS is deactivated. This gives the modem e xtra time to trans mit the last character of a packet.

ATTENTION: For almost all modem applications,

the RTS Off Delay should be left at 0. Never Select an RTS Off De lay th at is gr e ater t han the RTS Send Delay in the other devi ces on the network, or you may incur two devices trying to transmit simultaneously

Configuring SLC 5/03, 5/04, and 5/05 Processors 4-7

Configuring a Standard-Mode DF1 Half-Duplex Master Station

To bring up the Channel Configuration interface, double-click on the Channel Configuration icon.

Choose standard mode if you want to query slave stations for information based upo n use r-configured polling ranges. This mode is used most often in point-to-multipoint configurations.

To configure the processor for a master station using standard communication, place the processor into program mode and do the following using your programming software:

Define the location of the diagnostic file used for Channel Status here. For Channel Status details, see page 4-14.

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4-8 Configuring SLC 5/03, 5/04, and 5/05 Processors

1. On the Channel 0 tab, choose

DF1 Half-Duplex for your Driver.

2. Choose a Standard Polling Mode.

3. Configure the rest of the communication driver characteristics according to Table 4.A on page 4-8.

Use Worksheet 4.1 (page D-9) for an example configuration and to

record your station’s configuration.

Table 4.A Define these parameters when configuring a SLC 5/03, 5/04, or 5/05 processor as a master station using standard -communicatio n mode to t alk to slave stations.

Tab: Parameter: Selections:

General Diagnostic File SLC 5/03 (OS 303 or higher), 5/04 (OS 402 or higher) and 5/05 only. Select an unused file

to store channel status information. You must define a diagnostic file in order to be able to view channel 0 status. See Table 4.C on page 4-12 for a file description.

Channel 0 System Baud Rate Select a communication rate that all devices in your system support. Configure all devices

in the system for the same communication rate.

Parity Parity provides additional message packet error detection. To implement even parity

Stop Bits Match the number of stop bits to the device with which you are communicating. Node Address A node address identifies the processor on the DF1 half-duplex link. Each station on a link

Control Line This parameter defines the mode in which the driver operates. Choose a method

checking, choose Even. To implement no parity checking, choose None.

must have a unique address. Choose an address between 0 address255

address

appropriate for your system’s configuration:

• If you are not using a modem, choose NO HANDSHAKING.

• If the master modem is full duplex, choose FULL-DUPLEX MODEM.

• If all the modems in the system are half-duplex, choose HALF-DUPLEX WITHOUT CONTINUOUS CARRIER.

See page 4-5 for a description of the control line operation settings.

is the broadcast address, and cannot be selected as a station’s individual

and 254

10.

Node

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Tab: Parameter: Selections:

Configuring SLC 5/03, 5/04, and 5/05 Processors 4-9

Channel 0 System Error Detection With this selection, you choose the how the processor checks the accuracy of each DF1

Polling Mode If you want to receive:

Duplicate Packet Detect Duplicate Detect lets the SLC detect if it has received a message that is a duplicate of its

ACK Timeout The amount of time in 20 millisecond increments that you want the processor to wait for

packet transmission. BCC: This algorithm provides a medium level of data security. It cannot detect:

• transposition of bytes during transmission of a packet

• the insertion or deletion of data values of zero within a packet

CRC: This algorithm provides a higher level of data security. Select an error detection method that all devices in your configuration can use. When possible, choose CRC.

• only one message from a slave station per its turn, choose STANDARD (SINGLE MESSAGE TRANSFER PER NODE SCAN). Choose this method only if it is critical to keep the poll list scan time to a minimum.

• as many messages from a slave station as it has, choose STANDARD (MULTIPLE MESSAGE TRANSFER PER NODE SCAN).

most recent message from another station. If you choose duplicate detect, the processor will acknowledge (ACK) the message but will not act on it since it has already performed the message’s task when it received the command from the first message.

If you want to detect duplicate packets and discard them, check this parameter. If you want to accept duplicate packets and execute them, leave this parameter unchecked.

an acknowledgment to the message it has sent before the processor retries the message or the message errors out. This timeout value is also used for the poll response timeout. See page 4-10 for recommendations to minimize this value.

RTS Off Delay Defines the amount of time in 20 millisecond increments that elapses between the end of

RTS Send Delay Defines the amount of time in 20 millisecond increments that elapses between the

Pre-Transmit Delay Defines the amount of time in 1 millisecond increments that elapses between when the

Message Retries Defines the number of times a master station retries either:

Priority Polling Range – High Select the last slave station address to priority poll. Priority Polling Range – Low Select the first slave station address to priority poll. Entering 255 disables priority polling. Normal Polling Range – High Select the last slave station address to normal poll. Normal Polling Range – Low Select the first slave station address to normal poll. Entering 255 disables normal polling. Normal Poll Group Size Enter the quantity of active stations located in the normal poll range that you want polled

the message transmission and the de-assertion of the RTS signal. This time delay is a buffer to make sure that the modem has transmitted the message but should normally be left at zero. See page 4-6 for further guidelines for setting this parameter.

assertion of the RTS signal and the beginning of the message transmission. This time allows the modem to prepare to transmit the message. The Clear-to-Send (CTS) signal must be high for transmission to occur. See page 4-6 for further guidelines for setting this parameter.

processor has a message to send and when it asserts the RTS signal.

• a message before it declares the message undeliverable

• or a poll packet to an active station before the master station declares that station to be inactive.

during a scan through the normal poll range before returning to the priority poll range. If no stations are configured in the Priority Polling Range, leave this parameter at 0.

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4-10 Configuring SLC 5/03, 5/04, and 5/05 Processors

Minimum DF1 Half-Duplex Master Channel 0 ACK Timeout

The governing timeout parameter to conf igure f or a DF1 Ha lf-Duplex Master is the channel 0 ACK Timeout. The ACK Timeout is the amount of time you want the processor to wait for an acknowledgment of its message transmissions. Set in 20 millisecond intervals, th e value is the amount of time the master will wait for:

• an ACK to be returned by a s la ve whe n th e mast er has just sent it a message, or

• a poll response or message to be returned by a slave when the master has just sent it a poll packet.

The timeout must be long enoug h that a fter th e master h as trans mitted the last charact er of the poll packe t, ther e is enough time fo r a slave t o transmit (and the master receive) a maximum sized packet before the time expires.

To calculate the minimum ACK timeout, you must know:

• the modem baud rate

• maximum sized data packet (the maximum number of da ta words that a slave write command or read reply packet might contain)

• the RTS/CTS or “turnaround” delay of the slave modem

• the configured RTS Send Delay in the slave

• the program scan time of the slave

Determining Minimum Master ACK Timeout

To determine the minimum ACK Timeout, you must first calculate the transmission time by multiplying the maximum sized data packet for your processor by the modem rate in ms/byte. For an example we will assume an SLC 5/03 p rocessor (103 data words or 224 bytes total packet size including overhead) and a 9600 bps modem, which transmits at approximately 1 ms/byte. Therefore, the message transmission time is 224ms. For approximate modem transmission rates, see the following table.

Table 4.B Approximate modem transmission rates

modem bps approx. ms/byte

4800 2 ms/byte 9600 1 ms/byte

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19200 .5 ms/byte

Configuring SLC 5/03, 5/04, and 5/05 Processors 4-11

Next, you need to determine the average slave program scan time. In RSLogix 500, double click on the Processor Status icon and then locate Average on the Scan Times tab. For this example, lets assume an average slave program scan time of 20 ms. Remember, program scan time will vary by application.

Finally, you must determine the larger o f two values, e i ther the configured slave RTS Send Delay or the turnaround time of the slave modem. The RTS Send Delay time can be found by double-clicking

on the slave’s Channel Configuration icon and looking at the Chan. 0 System tab of the Channel Configuration screen. Note that the RTS Send Delay time is in intervals of 20 ms, so with a value of 3 in the box, the R TS Send Del ay time would be 20 ms mul tiplied by 3. Using this value (60 ms) for our example, and assuming that the turnaround time of the modem is 50 ms (which will vary by modem) you would choose to use the RTS Send Delay time of 60 ms for your calculat ion.

Having determined the maximum message transmission time (224 ms), the average slave program scan time (20 ms) and the largest of either RTS Send Delay (60 ms) or the modem turnaround time, the minimum ACK timeout is simply the sum of these values.

Use only the largest of these two values

Parameter Example Values (in ms)

Max message transmission time

Average program scan time 20 RTS Send Delay 60 modem turnaround time 50 calculated ACK Timeout 304 round up to nearest 20 ms 320

224

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4-12 Configuring SLC 5/03, 5/04, and 5/05 Processors

DF1 Half-Duplex Master Channel Status

Channel Status data is stored in the diagnostic file defined on the Channel 0 Configuration screen. Table 4.C on page 4-12 explains information regarding the diagnostic counter data displayed.

Double-click on the Channel Status Icon Located beneath the Configuration icon to bring up the Channel Status screen.

See Table 4.C for details concerning the DF1 Half-Duplex Master Channel Status Screen.

Table 4.C Understanding The DF1 Half-Duplex Master Status Screen Fields

Status Field Diagnostic File Location Definition

DCD Recover word 11 The number of times the processor detects the DCD handshaking line has

gone low to high

Messages Sent word 1 The total number of DF1 messages sent by the processor (including message

Messages Received word 2 The number of messages received with no errors EOT Received on First Poll word 8 Not implemented

retries)

Last Normal Poll List Scan word 5 Time in 100 ms increments of last scan through Normal Poll List Last Priority Poll List Scan word 10 Time in 100 ms increments of last scan through Priority Poll List Lost Modem word 12 The number of times the lost modem bit has gone low to high Message Retry word 4 The number of message retries sent by the processor

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Status Field Diagnostic File Location Definition

Configuring SLC 5/03, 5/04, and 5/05 Processors 4-13

Undelivered Messages word 3 The number of messages that were sent by the processor but not

Duplicate Messages Received word 9 The number of times the processor received a message packet identical to the

Bad Packet/No ACK word 7 The number of incorrect data packets received by the processor for which no

Max Normal Poll List Scan word 6 Maximum time in 100 ms increments to scan the Normal Poll List Max Priority Poll List Scan word 13 Maximum time in 100 ms increments to scan the Priority Poll List DTR (Data Terminal Ready) word 0;bit 4 The status of the DTR handshaking line (asserted by the processor) DSR (Data Set Ready) word 0;bit 2 The status of the DSR handshaking line (received by the processor) RTS (Request to Send) word 0;bit 1 The status of the RTS handshaking line (asserted by the processor) CTS (Clear to Send) word 0;bit 0 The status of the CTS handshaking line (received by the processor) DCD (Data Carrier Detect) word 0;bit 3 The status of the DCD handshaking line (received by the processor)

acknowledged by the destination device

previous message packet

ACK was returned

Monitor Active Stations

To see what stations are active, view the channel 0 active node table in the SLC 5/03, 5/04, or 5/05 processor status file (S:67/0-S:82/15). Each bit in the file represents a station on the link. The stations are numbered in order a s a continu ous bit stream fil e start ing with the first bit in word S:67 (see Figure 4.1 below).

Figure 4.1 Example Active Node Table

At powerup or after reconfiguration, the master station assumes that all slave stations are inactive. A station is shown active only after it responds to a poll packet.

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4-14 Configuring SLC 5/03, 5/04, and 5/05 Processors

Configuring a Message-based Mode DF1 Half-Duplex Master Station

To bring up the Channel Configuration interface, double-click on the Channel Configuration icon.

Message-based communica tion should a lso be used i n redundant SLC master station systems implemented with the 1746-BSN backup communication module.

With message-based mode, you do not have an active node file that you can use to monitor station status. Also, you cannot implement slave station-to-slave station messaging or slave programming.

To configure the processor for a master station using message-based communication, place the processor in program mode and do the following using your programming software:

Define the location of the diagnostic file used for Channel Status here. For Channel Status details, see page 4-14.

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1. On the Channel 0 tab, choose DF1 Half-Duplex Master for your Driver.

2. Choose a Message-based Polling Mode.

3. Configure the communication driver characteristics according to Table 4.D.

Configuring SLC 5/03, 5/04, and 5/05 Processors 4-15

Use Worksheet 4.2 (page D-10) for an example configuration and to

record your station’s configuration.

Table 4.D Define these parameters when configuring a SLC 5/03, 5/04, or 5/05 processor as a master stati on using me ssage-based c ommunic ation mode to talk to slave stations.

Tab: Parameter: Selections:

General Diagnostic File SLC 5/03 (OS 303 or higher), 5/04 (OS 402 or higher) and 5/05 only. Select an unused file

Channel 0 System Baud Rate Select a communication rate that all devices in your system support. Configure all devices

Parity Parity provides additional message packet error detection. To implement even parity

Stop Bits Match the number of stop bits to the devices with which you are communicating. Node Address A node address identifies the processor on the DF1 half-duplex link. Each station on a link

Control Line This parameter defines the mode in which the driver operates. Choose a method

(9-255) to store channel status information. You must define a diagnostic file in order to be able to view channel 0 status. See Table 4.C on page 4-12 for a file description.

in the system for the same communication rate.

checking, choose Even. To implement no parity checking, choose None.

must have a unique address. Choose an address between 0 address255

address

appropriate for your system’s configuration:

• If you are not using a modem, choose NO HANDSHAKING.

• If the master modem is full duplex, choose FULL-DUPLEX.

• If all the modems in the system are half-duplex, choose HALF-DUPLEX WITHOUT CONTINUOUS CARRIER.

See page 4-5 for descriptions of control line operation settings.

is the broadcast address, and cannot be selected as a station’s individual

and 254

10.

Node

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4-16 Configuring SLC 5/03, 5/04, and 5/05 Processors

Tab: Parameter: Selections:

Channel 0 System Error Detection With this selection, you choose the how the processor checks the accuracy of each DF1

Polling Mode If you want to:

Duplicate Packet Detect Duplicate Detect lets the SLC detect if it has received a message that is a duplicate of its

packet transmission. BCC: This algorithm provides a medium level of data security. It cannot detect:

• transposition of bytes during transmission of a packet

• the insertion or deletion of data values of zero within a packet

CRC: This algorithm provides a higher level of data security. Select an error detection method that all devices in your configuration can use. When possible, choose CRC.

• accept unsolicited messages from slave stations, choose MESSAGE BASED (ALLOW SLAVES TO INITIATE MESSAGES)

Slave station-initiated messages are acknowledged and processed after all master station-initiated (solicited) messages.

Note: Slave stations can only send messages when they are polled. If the message-based master station never sends a slave station a message, the master station will never send the slave station a poll. Therefore, to regularly obtain a slave station-initiated message from a slave station, you should choose to use standard communication mode instead.

• ignore unsolicited messages from slave stations, choose MESSAGE BASED (DO NOT ALLOW SLAVES TO INITIATE MESSAGES)

Slave station-initiated messages are acknowledged and discarded. The master station acknowledges the s lav e st ation -in iti ated me ssage so t hat th e sl ave s tati on re move s the message from its transmit queue, which allows the next packet slated for transmission into the transmit queue.

If you want to detect duplicate packets and discard them, check this parameter. If you want to accept duplicate packets and execute them, leave this parameter unchecked.

Reply Message Wait Time Define the amount of time in 20 millisecond increments that the master station will wait

ACK Timeout The amount of time in 20 millisecond increments that you want the processor to wait for

RTS Off Delay Defines the amount of time in 20 millisecond increments that elapses between the end of

RTS Send Delay Defines the amount of time in 20 millisecond increments that elapses between the

Pre-Transmit Delay Defines the amount of time in 1 millisecond increments that elapses between when the

Message Retries Defines the number of times a master station retries a message before it declares the

after receiving an ACK (to a master-initiated message) before polling the slave station for a reply.

Choose a time that is, at minimum, equal to the longest time that a slave station needs to format a reply packet. This would typically be the maximum scan time of the slave station.

processor has a message to send and when it asserts the RTS signal.

message undeliverable.

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Configuring SLC 5/03, 5/04, and 5/05 Processors 4-17

Configuring a Slave Station To choose the processor as a slave station, do the following using

your programming software:

To bring up the Channel Configuration interface, double-click on the Channel Configuration icon.

Define the location of the diagnostic file used for Channel Status here. For Channel Status details, see page 4-20.

1. On the Channel 0 tab, choose DF1 Half-Duplex Slave for your Driver.

2. Configure the communication driver characteristics according to Table 4.E.

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4-18 Configuring SLC 5/03, 5/04, and 5/05 Processors

Use Worksheet 4.3 (page D-11) for an example configuration and to

record your station’s configuration.

Table 4.E Define these parameters when configuring a SLC 5/03, 5/04, or 5/05 processor as a slave station.

Tab: Parameter: Selections:

General Diagnostic File SLC 5/03 (OS 303 or higher), 5/04 (OS 402 or higher) and 5/05 only. Select an unused file to

store channel status information. You must define a diagnostic file in order to be able to view channel 0 status. See Table 4.F on page 4-20 for a file description.

Chan. 0 System Baud Rate Select a communication rate that all devices in your system support. Configure all devices in

the system for the same communication rate.

Parity Parity provides additional message packet error detection. To implement even parity

Stop Bits Match the number of stop bits to the device with which you are communicating. Node Address A node address identifies the processor on the DF1 half-duplex link. Each station on a link

Control Line This parameter defines the mode in which the driver operates. Choose a method appropriate

Error Detection With this selection, you choose the how the processor checks the accuracy of each DF1

Duplicate Packet Detect Duplicate Detect lets the SLC detect if it has received a message that is a duplicate of its most

checking, choose Even. To implement no parity checking, choose None.

must have a unique node ad dre ss . Choo s e an ad dre ss bet wee n 0 255

is the broadcast address, which you cannot select as a station’s individual address.

for your system’s configuration:

• If you are not using a modem, choose NO HANDSHAKING.

• If the master modem is full duplex and the slave modem is half-duplex, choose HALF-DUPLEX WITH CONTINUOUS CARRIER.

• If all the modems in the system are half-duplex, choose HALF-DUPLEX WITHOUT CONTINUOUS CARRIER.

See page 4-4 for descriptions of the control line operation settings.

packet transmission. BCC: This algorithm provides a medium level of data security. It cannot detect:

• transposition of bytes during transmission of a packet

• the insertion or deletion of data values of zero within a packet

CRC: This algorithm provides a higher level of data security. Select an error detection method that all devices in your configuration can use. When possible, choose CRC.

recent message from the master station. If you choose duplicate detect, the processor will acknowledge (ACK) the message but will not act on it since it has already performed the message’s task when it received the command from the first message.

If you want to detect duplicate packets and discard them, check this parameter. If you want to accept duplicate packets and execute them, leave this parameter unchecked.

and 254

Node address

10.

Poll Timeout The timer keeps track of how often the station is polled. If the station has a message to send,

Publication AG-6.5.8 - October 1998

it starts a timer. If the poll timeout expires before the message timeout, which you specify in the MSG control

block, the MSG error bit is set and the message is removed from the transmit queue. If the message timeout, which you specify in the MSG control block, expires before the poll

timeout expires, the MSG error bit and MSG timeout bit are set. The poll timeout can be disabled by entering a zero. See page 4-19 for recommendations to

minimize this value

Tab: Parameter: Selections:

Configuring SLC 5/03, 5/04, and 5/05 Processors 4-19

Chan. 0 System RTS Off Delay Defines the amount of time in 20 millisecond increments that elapses between the end of the

RTS Send Delay Defines the amount of time in 20 millisecond increments that elapses between the assertion

Message Retries Defines the number of times a slave station resends its message to the master station before

Pre-Transmit Delay Defines the amount of time in 1 millisecond increments that elapses between when the

EOT Suppression If you want to minimize traffic on the network, you can choose to have the slave station not

message transmission and the de-assertion of the RTS signal. This time delay is a buffer to make sure that the modem has transmitted the message, but should normally be left at zero. See page 4-6 for further guidelines for setting this parameter.

of the RTS signal and the beginning of the message transmission. This time allows the modem to prepare to transmit the message. The Clear-to-Send (CTS) signal must be high for transmission to occur.See page 4-6 for further guidelines for setting this parameter.

the slave station declares the message undeliverable.

processor has a message to send and when it asserts the RTS signal.

send EOT packets to the master station. When EOT packets are suppressed, the master station automatically assumes a slave station has no data to give if the slave station does not send a message packet as a response to a poll.

A disadvantage of su ppr ess i ng EO Ts is that th e m a st er stat i on canno t d is ti ng ui sh b etw ee n a n active station that has no data to transmit and an inactive station.

A possible application for suppressing EOTs is the following: conserving power with a radio modem because the radio transmitter does not have to power-up to transmit a DLE EOT

packet (”no data to give” packet). To suppress EOTs, check this parameter. To have the processor send EOTs, leave this

parameter unchecked.

Configuring Channel 0 Poll Timeout The Channel 0 Poll Timeout is only used when the DF1 half-duplex

slave is initiating MSG instructions in ladder logic. This implies that the Master is most likely conf igured for Standard Polling Mode. The minimum Poll Timeout value is dependent on the maximum Master

poll scan rate. Since the Mas ter’ s poll ing a nd the Slave ’s triggering of a MSG instruction are asynchronous events, it is possible that in the instant just after the slave was polled, the MSG instruction gets triggered. This means the MSG ins truct ion wi ll re main que ued-up for transmission until the Master has polled every other slave first. Therefore , the minimum Slave channel 0 Poll Timeout value is equal to the maximum Master poll scan rate rounded up to the next 20 ms increment.

(maximum Master scan poll rate)

Minimum Channel 0 Poll Timeout

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4-20 Configuring SLC 5/03, 5/04, and 5/05 Processors

DF1 Half-Duplex Slave Channel Status

Channel Status data is stored in the diagnostic file defined on the Channel 0 Configuration screen. Table 4.F on page 4-20 explains information regarding the diagnostic counter data displayed.

Double-click on the Channel Status Icon Located beneath the Configuration icon to bring up the Channel Status screen.

See Table 4.F for details concerning the DF1 Half-Duplex Slave Channel Status Screen.

Table 4.F Understanding The DF1 Half-Duplex Slave Status Screen Fields

Status Field Diagnostic File Location Definition

DCD Recover word 11 The number of times the processor detects the DCD handshaking line has

Messages Sent word 1 The total number of DF1 messages sent by the processor (including message

gone low to high

retries)

Lack of Memory/No ACK Sent word 8 The number of times the processor could not receive a message because it did

Lost Modem word 12 The number of times the lost modem bit has gone low to high Messages Retry word 4 The number of message retries sent by the processor

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not have available memory

Status Field Diagnostic File Location Definition

Configuring SLC 5/03, 5/04, and 5/05 Processors 4-21

Undelivered Messages word 3 The number of messages that were sent by the processor but not

Duplicate Messages Received word 9 The number of times the processor received a message packet identical to the

Bad Packet/No ACK word 7 The number of incorrect data packets received by the processor for which no

Configuring a Station on a Point-to-Point Link

To configure the processor for point-to-point communication, do the following using your programming software:

acknowledged by the destination device

previous message packet

ACK was returned

To bring up the Channel Configuration interface, double-click on the Channel Configuration icon.

Define the location of the diagnostic file used for Channel Status here. For diagnostic file details, see Table 4.H on page 4-24.

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4-22 Configuring SLC 5/03, 5/04, and 5/05 Processors

1. On the Channel 0 tab, choose

DF1 Half-Duplex Slave for your Driver.

2. Configure the communication driver characteristics according to Table 4.G.

Use Worksheet 4.4 (page D-12) for an example configuration and to

record your station’s configuration.

Tab le 4.G Define these communication parameters when configuring a SLC 5/03, 5/04, or 5/05 processor for DF1 full-duplex communication.

Tab: Parameter: S elec tions:

General Diagnostic File SLC 5/03 (OS 303 or higher), 5/04 (OS 402 or higher) and 5/05 only. Select an unused file

Chan. 0 System Baud Rate Select a communication rate that all devices in your system support. Configure all devices

Parity Parity provides additional message packet error detection. To implement even parity

Stop Bits Match the number of stop bits to the devices with which you are communicating. Source ID This is the address, in decimal, that is used as the source address in any message initiated

Control Line This parameter defines the mode in which the driver operates. Choose a method

to store channel status information. You must define a diagnostic file in order to be able to view channel 0 status. See Table 4.H on page 4-24 for a file description.

in the system for the same communication rate.

checking, choose Even. To implement no parity checking, choose None.

by this processor.

appropriate for your system’s configuration:

• If you are not using a modem, choose NO HANDSHAKING.

• If you are using full-duplex modems, choose FULL-DUPLEX MODEM. See page 4-4 for descriptions of the control line operation settings

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Tab: Parameter: Selections:

Configuring SLC 5/03, 5/04, and 5/05 Processors 4-23

Chan. 0 System Error Detection With this selection, you choose the how the processor checks the accuracy of each DF1

Embedded Responses To use embedded responses, choose Enabled. If you want the processor to use embedded

Duplicate Packet Detect Duplicate Detect lets the SLC detect if it has received a message that is a duplicate of its

ACK Timeout The amount of time in 20 millisecond increments that you want the processor to wait for an

NAK Retries The number of times the processor will resend a message packet because the processor

packet transmission. BCC: This algorithm provides a medium level of data security. It cannot detect:

• transposition of bytes during transmission of a packet

• the insertion or deletion of data values of zero within a packet CRC: This algorithm provides a higher level of data security. Select an error detection method that all devices in your configuration can use. When possible, choose CRC.

responses only when it detects embedded responses from another device, choose Auto-detect.

If you are communicating with another Allen-Bradley device, choose Enabled. Embedded responses increase network traffic efficiency.

most recent message from the master station. If you choose duplicate detect, the processor will acknowledge (ACK) the message but will not act on it since it has already performed the message’s task when it received the command from the first message.

If you want to detect duplicate packets and discard them, check this parameter. If you want to accept duplicate packets and execute them, leave this parameter unchecked.

acknowledgment to the message it has sent before sending an enquiry (ENQ) for the reply.

received a NAK response to the previous message packet transmission.

ENQ Retries The number of enquiries (ENQs) that you want the processor to send after an ACK timeout

Double-click on the Channel Status Icon Located beneath the Configuration icon to bring up the Channel Status screen.

occurs.

DF1 Full-Duplex Channel Status

Channel Status data is stored in the diagnostic file defined on the Channel 0 Configuration screen. Table 4.H on page 4-24 explains information regarding the diagnostic counter data displayed.

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4-24 Configuring SLC 5/03, 5/04, and 5/05 Processors

See Table 4.H for details concerning the DF1 Full-Duplex Channel Status Screen.

Table 4.H Understanding The DF1 Full-Duplex Status Screen Fields

Status Field Diagnostic File Location Definition

DCD Recover word 11 The number of times the processor detects the DCD handshaking line has

Messages Sent word 1 The total number of DF1 messages sent by the processor (including message

Messages Received word 2 The number of messages received with no errors Inquiry Received word 6 The number of ENQs received by the processor Received NAK word 5 The number of NAKs received by the processor Lack of Memory/Sent NAK word 8 The number of times the processor could no t receive a message be cause it did

Lost Modem word 12 The number of times the lost modem bit has gone low to high Undelivered Messages word 3 The number of messages that were sent by the processor but not

Duplicate Messages Received word 9 The number of times the processor received a message packet identical to the

Inquiry Sent word 4 The number of ENQs sent by the processor Bad Packet/No ACK word 7 The number of incorrect data packets received by the processor for which a

gone low to high

retries)

not have available memory

acknowledged by the destination device

previous message packet

NAK was returned

RTS (Request to Send) word 0;bit 1 The status of the RTS handshaking line (asserted by the processor) CTS (Clear to Send) word 0;bit 0 The status of the CTS handshaking line (received by the processor) DCD (Data Carrier Detect) word 0;bit 3 The status of the DCD handshaking line (received by the processor)

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Configuring SLC 5/03, 5/04, and 5/05 Processors 4-25

Messaging Messaging can occur between:

• a master station and a slave station

• a slave station and its master station (See “Polled Report-by-Exception”)

• slave stations or between two processors connected via a point-to-point link

Master Station to Slave Station

A SLC 5/03, 5/04, or 5/05 master station communicates with the slave stations that are connected to it via modems in a

For: See page:

list of considerations 4-26 examples 4-30

point-to-multipoint configuration. A master station sends a slave station message to receive status or issue commands. For sample messaging ladder logic to use as a guide when using Standard or Message-based Polling Modes, see Appendix E-2.

Polled Report-by-Exception

Slave stations can gathe r information from the I/O po i nts they are responsible for and can send any anomalous readings to the master station. To do this, write ladder logic in the slave station to monitor certain conditions and send the data in an MSG instruction to the master station. For sample messaging ladder logic to use as a guide when using an SLC 500 as a Slave, see page Appendix E-6.

Processor-to-Processor

A processor-to-processor message can be the following types:

• In a point-to-multipoint configuration, the messaging would be between slave stat ions; the ma ster stat ion automatic ally route s the message.

Master Station routes MSG to Slave Station 2

Modem

Slave Station 2

MSG from Slave Station 1 to Slave Station 2

Master Station

Modem

Slave Station 1

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4-26 Configuring SLC 5/03, 5/04, and 5/05 Processors

• In a point-to-point configuration, the messaging would be between the two connected peer devices.

MSG

Modem

Station 1

Modem

Station 2

The configuration of the network (point-to-multipoint vs. point-to-point) and the configuration of the station (master, slave, or peer) does not affect how you configure an MSG instruction. That is, an MSG inst ruction being sent between two SLC slave stations is configured the same as an MSG instruction between two SLC processors connected point-to-point, which is configured the same as an MSG instruction between a SLC master station and a SLC slave station. See Figure 4.2 through Figure 4.5 for example MSG control blocks.

Considerations When Configuring MSG Control Blocks

Keep these considerations in mind when configuring messages between a SLC 5/03, 5/04, or 5/05 processor and other processors.

For both Point-to-Multipoint and Point-to-Point Link Configurations

• All SLC 5/04 and 5/05 processors, and 5/03 processors with operating system 301or greater have the capability to initiate and reply to PLC-5-type re ad and writ e messages by choosing PLC-5 as the Target Device. Use this for both PLC-5 and Logix5550 processors.

• The maximum read or write message for a SLC 5/03, 5/04, or 5/05 processor through Channel 0 is 103 words.

• The maximum read or write mes sage for a Micro Logix 1000 is 41 words.

Minimum Master MSG Block Message Timeout

Once the master ACK timeout is determined (See page 4-10) then a minimum MSG block Message Timeout value can be determined. This value is calculated differently depending on the master polling mode.

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Configuring SLC 5/03, 5/04, and 5/05 Processors 4-27

Message-based Polling Mode

Message based polling mode messages are executed serially - each message in the queue must complete as done, or in error, before the next message in the queue is executed. For this mode, the minimum MSG Timeout should be:

# of MSG instructions

Maximum number of simultaneously triggered MSG instructions

Realize that if the Message Retries is set for the default (3), then the number of ACK Timeout periods is (3)*2+1=7 (message, poll, retry_1, poll, retry_2, poll, retry_3), because a poll packet is sent between every Message Retry.

However, the slave may still respond to retry 3 with an ACK just before the ACK Timeout period expires, and the master would poll after the Reply Message timeout period for the reply...which could take approximately another ACK Timeout period to receive.

Therefore, for message-based polling mode, set the MSG Timeout value to at least:

2*(Message_Retries+1)

The sum of ACK Timeouts due to the maximum

number of Message Retries for each queued-up message

ACK Timeout + Reply Message Timeout

Reply Message

Wait timeout

The minimum

MSG Timeout

The minimum

MSG Timeout

T o continue th e example, if Mess age Retries is confi gured for 3, ACK Timeout is configured for 16 * 20 ms = 320, and Reply Message Timeout is configured for 1* 20 ms, the MSG Timeout value would be:

2.58 seconds

2 (3+1)

Round up the MSG Timeout value to the nearest second (3)

.320 seconds + .02

If 5 MSG instructions were triggered at the same time, each MSG would need a timeout value of 5*2.58 = 12.9, which would be rounded up to 13 seconds.

Note: leave the channel 0 Message Retries at default (3) unless you have an extremely error free or error prone network.

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4-28 Configuring SLC 5/03, 5/04, and 5/05 Processors

Standard Polling Mode

For standard polling mode, the transmission of messages by the master can occur anywhere in the poll scan. This means that the master might transmit a message to station A just after it has completed polling stat ion A as part of the pol l scan . In thi s worst cas e scenario, it will take almost an entire poll scan befo re station A will be polled again and can reply to the master message so that the message can complete done or in error. In standard polling mode, the MSG Timeout should be at least as long as this maximum poll scan.

The maximum poll scan

The minimum MSG

timeout

Standard Polling Mode With Single Message Transfer

For standard polling mo de with si ngle mess age tr ansfer per pol l scan, the maximum poll scan would be achieved when every slave had a maximum- sized message packet to tran smit when polled. Recall that the ACK Timeout is calculated as being just long enough for the master to receive a maximum siz ed message packet , so the maxi mum poll scan time would be approximately:

The number of slave stations

ACK

Timeout

Therefore, if there are 10 slave stations and the ACK Timeout is 320 ms, then the maximum single message transfer poll scan time would be:

10 (slave stations)

.320 seconds

The maximum single

message transfer poll scan time

3.20 seconds

The minimum

MSG Timeout

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Round up the MSG Timeout value to the nearest second (4)

Standard Polling Mode With Multiple Message Transfer

For standard polling mode with multiple message transfer per poll scan, the maximum poll scan would be achieved when every slave had multiple maximum sized message packets to transmit when polled. If the worst case sc enario is 2 maxi mum sized message packet to transmit, then the maximum poll scan time is approximately 2 times the maximum single message transfer poll scan time plus the minimum poll scan time.

Configuring SLC 5/03, 5/04, and 5/05 Processors 4-29

The minimum poll scan time occurs when the master sends out a 4 byte poll packet to each sl ave and i n retur n recei ves a 2 byt e respon se from each slave. This time is approximately the master modem turnaround time or RTS Send Delay (whichever is greater) plus the slave modem turnaround time or RTS Send Delay (whichever is greater), multiplied by the number of slave stations in the poll range.

# of MSG instructions per slave

Master modem turnaround time

Use only the greater of these two values

Maximum single message transfer poll

scan time

RTS Send

Delay

Slave modem

turnaround time or RTS Send Delay

Use only the greater of these two values

Number of

slave stations

The minimum

poll scan time

For example, if the master modem turnaround time and RTS Send Delay are both 0 ms, and the slave modem turnaround time is 50 ms and RTS Send Delay is 60 ms, the minimum poll scan time would be:

600 ms

0 + 60 ms

10 (slave stations)

To f i nish the example:

Minimum poll scan time

The maximum multiple

message transfer poll scan time

The minimum

MSG Timeout

2 (3.20 seconds) + .600 seconds = 7 seconds

For this example, the MSG Timeout value should be at least 7 seconds.

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4-30 Configuring SLC 5/03, 5/04, and 5/05 Processors

Minimum Slave MSG Block Message Timeout

The minimum slave MSG Block Message Timeout should allow for the Master to go through Message Retries plus one number of maximum poll scans before timing out. Therefore, the minimum MSG Block Message Timeout value should be at least (Slave Channel 0 Poll Timeout) * (Slave channel 0 Message Retries + 1), rounded up to the next whole second. Note: leave the channel 0 Message Retries at defaul t (3) unless you ha ve an extremely error free or extremely error prone network.

Minimum Slave MSG Block Message Timeout

Minimum Point-to-Point MSG Block Message Timeout

(Slave channel 0 Poll Timeout)*(Slave Channel 0 Message Retries + 1)

Minimum Point-to-Point MSG Block Message Timeout

The minimum point-to-point MSG Block Message Timeout should allow for the processor to go through Message Retries plus one ACK time out. Therefore, the minimum MSG Block Message Timeout value should be at least (ACK Timeout) * (Channel 0 Message Retries + 1), rounded up to the next whole second. Note: leave the channel 0 Message Retries at default (3) unless you have an extremely error free or extremely error prone network.

(ACK Timeout)*(Channel 0 Message Retries + 1)

Example MSG Control Blocks

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Application: See page:

SLC 5/03, 5/04, or 5/05 write message to a PLC-5 or Logix5550 processor

SLC 5/03, 5/04, or 5/05 read message to a PLC-5 or Logix5550 processor

SLC 5/03, 5/04, or 5/05 write message to another SLC 500 or MicroLogix 1000 processor

SLC 5/03, 5/04, or 5/05 read message to another SLC 500 or MicroLogix 1000 processor

4-31

4-32

4-33

4-34

adder rung

setup screen

Configuring SLC 5/03, 5/04, and 5/05 Processors 4-31

Figure 4.2 This is an example of a write MSG from a SLC 5/03, 5/04, or 5/05 proc essor to a PLC-5 processor or Logix5550 controller.

MSG being sent to a PLC-5 processor or a Logix5550 controller

This MSG example tells the SLC 5/03, 5/04, or 5/05 master station to write the information from its S:37 through its serial port (channel 0) to the PLC-5 slave station 11

. The data’s destination is N19:0 of the PLC-5 slave station. For a Logix5550 slave

station, a tag name would have to already have been mapped to N19. Alternatively, SLC 5/03 (OS 303 or higher), 5/04 (OS 402 or higher) and 5/05 processors support logical ASCII addressing, which means any Logix5550 controller tag can be written to by entering the tag name in double quotes in the Targets Destination File field.

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4-32 Configuring SLC 5/03, 5/04, and 5/05 Processors

Figure 4.3 This is an example of a read MSG from a SLC 5/03, 5/04, or 5/05 proces sor to a PLC-5 processor or Logix5550 controller.

ladder rung

MSG being sent to a PLC-5 processor or a Logix5550 controller

setup screen

This MSG example tells the SLC 5/03, 5/04, or 5/05 master station to read the information from PLC-5 slave station 1110’s

N19:1 and place the information in master station file N9:0. For a Logix5550 slave station, a tag name would have to already have been mapped to N19. Alternatively, SLC 5/03 (OS 303 or higher), 5/04 (OS 402 or higher) and 5/05 processors support logical ASCII addressing, which means any Logix5550 controller tag can b e read by enterin g the tag name in double quot es in the Targets File Address/ Offset field.

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ladder rung

setup screen

Configuring SLC 5/03, 5/04, and 5/05 Processors 4-33

Figure 4.4 This is an example of a write MSG from a SLC 5/03, 5/04, or 5/05 proc essor to another SLC 500 or a MicroLogix 1000 controller.

MSG being sent to another SLC 500 or a MicroLogix 1000 controller

In this example, the SLC master station is issuing a write request through its serial port (channel 0) to SLC station 1310. The master station wants to

write the information from S:37 into station 1310’s file N7:0.

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Allen AB SCADA Diagram

Specifications and Main Features

Frequently Asked Questions

User Manual

Important User Information Because of the variety of uses for the products described in this

Introduction This document has been revised since the June 1996 printing.

Scope of Changes This SCADA Application Guide represents the latest developments

Audience We designed this document for individuals who are configuring a

Book Overview

Terms We use these terms frequently in this book:

Conventions This section explains the following conventions:

Related Publications Use these manuals as necessary::

Table of Contents

Choosing a Polling Mode for DF1 Half-Duplex Master

Communication Scheme Design Using Standard-Mode

Communication Scheme Design Using Message-based Mode

Designing Communication for Full-Duplex Protocol

What to Do Next? Make sure you:

Overview To configure an Enhanced PLC-5 processor, perform these tasks:

Installing the Processor Before install ing the p rocessor, set the processor s witch ass emblies.

Configuring a DF1 Half-Duplex Standard Mode Master Station

Configuring a DF1 Half-Duplex Message-based Mode Master Station

Configuring the Processor as a Slave Station

Configuring the Processor as a Station on a Point-to-Point Link

Messaging Messaging can occur between:

Overview To configure a Classic PLC-5 remote station, perform these tasks:

Installing the Processor Before installing the processor, set the switch assemblies.

Configuring and Installing the 1785-KE Module

Connecting the Processor and 1785-KE Module

Messaging Messaging can occur between:

Overview To configure a SLC 5/03, 5/04, or 5/05 processor, perform these

Installing the Processor For details about installing the processor into an I/O chassis, see the

Using Modems that Support DF1 Communication Protocols

Modem Control Line Operation The following explains the operation of the SLC 5/03, 5/04 and 5/05

Configuring DF1 Half-Duplex Channel 0 Parameters

Configuring a Standard-Mode DF1 Half-Duplex Master Station

Configuring a Message-based Mode DF1 Half-Duplex Master Station

Configuring a Slave Station To choose the processor as a slave station, do the following using

Configuring Channel 0 Poll Timeout The Channel 0 Poll Timeout is only used when the DF1 half-duplex

Configuring a Station on a Point-to-Point Link

Messaging Messaging can occur between:

Example MSG Control Blocks