Rockwell Automation 1785-LTx, D17856.2.1 User Manual

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AllenBradley

Classic 1785 PLC5 Programmable

User

Controllers

(1785LT,

L

T2, LT3, L

Manual

T4)

Important User Information

Because of the variety of uses for the products described in this publication, those responsible for the application and use of this control equipment must satisfy themselves that all necessary steps have been taken to assure that each application and use meets all performance and safety requirements, including any applicable laws, regulations, codes, and standards.

The illustrations, charts, sample programs, and layout examples shown in this guide are intended solely for purposes of example. Since there are many variables and requirements associated with any particular installation, Allen-Bradley does not assume responsibility or liability (to include intellectual property liability) for actual use based on 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 or circumstances that can lead to personal injury or death, property damage, or economic loss.

Attention statements help you to:

identify a hazard avoid the hazard recognize the consequences

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

Summary of Changes

This manual has been revised to cover only Classic PLC-5 programmable controllers: PLC-5/10, -5/12, -5/15, and -5/25.

It has also been revised to include the accompanying design worksheets that were formerly available as a separate publication: 1785-5.2. This separate publication is no longer available; see Appendix B for these worksheets.

For information about Enhanced and Ethernet PLC-5 processors, see the Enhanced and Ethernet PLC-5 Programmable Controllers User Manual, publication 1785-6.5.12.

Summary of Changes

Classic PLC5 Programmable Controllers

Purpose Manual Organization How to Use this Manual

of this Manual

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Understanding Your System 11. . . . . . . . . . . . . . . . . . . . . . .

Using this Chapter 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Understanding the Terms Used in this Chapter 11 Designing Systems 12 Preparing Your Functional Specification 13 Introducing Classic PLC5 Processor Modules 15 Using the Classic PLC5 Processor as a Remote I/O Scanner 18 Using the Classic PLC5 Processor as a Remote I/O Adapter 19

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Choosing Hardware 21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chapter Selecting Selecting I/O Adapter Modules 24 Selecting Selecting an Operator Interface 26 Choosing a Classic PLC5 Processor for Your Application 29 Selecting Power Supplies 29 Selecting Memory Modules 213 Selecting a Replacement Battery 213 Selecting Selecting a PLC5 Processor Backup System 214 Selecting Link Terminators 215 Connecting a Programming Terminal to a Processor Module 215 Choosing Cables 215

Objectives

I/O Modules

I/O Chassis

Complementary I/O

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21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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26. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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iii

iii iv iv

Placing System Hardware 31. . . . . . . . . . . . . . . . . . . . . . . . .

Chapter Determining the Proper Environment 31 Protecting Your Processor 34 Avoiding Electrostatic Damage 34 Laying Planning Laying Out the Backpanel Spacing 36 Grounding

Objectives

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Out Y

our Cable Raceway 34. . . . . . . . . . . . . . . . . . . . . . . . .

Cabling

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Configuration

31. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

35. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

37. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Table of Contentsii

Assigning Addressing Modes, Racks, and Groups 41. . . . . .

Chapter Placing Understanding the Terms Used in this Chapter 42 Choosing the Addressing Mode 43 Assigning Racks 49 Addressing

Choosing

Chapter Identifying Classic PLC5 Processor Channels/Connectors 51 Configuring Configuring a DH+ Link 53 Connecting a DH+ Link to Data Highway 510 Choosing Programming Terminal Connection 510

Objectives

I/O Modules in Chassis

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Complementary I/O

Communication

Objectives

Communication for Y

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41. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

41. . . . . . . . . . . . . . . . . . . . . . . . . .

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412. . . . . . . . . . . . . . . . . . . . . . . . . .

51. . . . . . . . . . . . . . . . . . . . . . . . .

51. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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our Processor 53. . . . . . . . . . . . . .

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Planning Your System Programs 61. . . . . . . . . . . . . . . . . . . .

Chapter Planning Application Programs 61 Using SFCs with PLC5 Processors 61 Preparing the Programs for Your Application 63 Addressing Data T Using the Processor Status File 69

Objectives

able Files

61. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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67. . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Selecting Interrupt Routines 71. . . . . . . . . . . . . . . . . . . . . . .

Chapter Using Programming Features 71 Writing Understanding ProcessorDetected Major Faults 711

Objectives

a Fault Routine

71. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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73. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Transferring Discrete and BlockTransfer Data 81. . . . . . . . .

Chapter Transferring Data Using Adapter Mode 81 Programming Discrete Transfer in Adapter Mode 84 Programming Block Transfer in Adapter Mode 87 Transferring Data Using Scanner Mode 816 Programming Discrete Transfer in Scanner Mode 816 Programming Block Transfer in Scanner Mode 817 Programming Considerations 821

Objectives

81. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Table of Contents iii

Calculating

Chapter Introduction to Classic PLC5 Processor Scanning 91 I/O ScanningDiscrete and Block Transfer 95 Instruction Timing and Memory Requirements 97 Program Constants 913 Direct and Indirect Elements 913

Program T

Objectives

iming 91. . . . . . . . . . . . . . . . . . . . . . . .

91. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Maximizing System Performance 101. . . . . . . . . . . . . . . . . . . .

Chapter Components of Throughput 101 Input and Output Modules Delay 101 I/O Backplane Transfer 102 Remote Processor Time 106 Calculating Throughput 106

Objectives

I/O Scan T

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101. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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ime 102. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Selecting Switch Settings A1. . . . . . . . . . . . . . . . . . . . . . . . .

Chassis Backplane with Classic PLC5 Processor A1. . . . . . . . . . . . .

Chassis Backplane with Adapter Module A2 Chassis Configuration Plug for Power Supply A3 Remote I/O Adapter Module 1771ASB Series C without

Complementary I/O

Remote I/O Adapter Module 1771ASB Series C with

Complementary I/O

SW1 A7

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AdapterMode ProcessorsSW2 in a PLC5 or Scanner Module A8 AdapterMode ProcessorsSW2 in a PLC2/20, 2/30,

or Sub I/O Scanner Module System A9

AdapterMode ProcessorsSW2 in a PLC3 or PLC5/250

System with 8Word Groups A10

AdapterMode ProcessorsSW2 in a PLC3 or PLC5/250

System with 4Word Groups A11

SW3 A12

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A4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

A6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Design Worksheets B1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Conventions Used in These Worksheets B1. . . . . . . . . . . . . . . . . . .

Prepare Determine Control Strategy B4 Identify Chassis Locations B6 Select Module T Total Assign I/O Modules to Chassis and Assign Addresses B10 Select Adapter Modules B12 Place System Hardware B14

a Functional Specification

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ypes and List I/O Points

I/O Module Requirements

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B2. . . . . . . . . . . . . . . . . . . . . . . .

B7. . . . . . . . . . . . . . . . . . . .

B9. . . . . . . . . . . . . . . . . . . . . . . . . .

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Table of Contentsiv

Configure Determine Communication Requirements B17 Select a Classic PLC5 Processor B21 Select Power Supplies B23 Choose a Programming Terminal B24 Select Programming T Select Operator Interface B26 Develop Programming Specifications B28

Switch Settings

erminal Configuration

B15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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B25. . . . . . . . . . . . . . . . .

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Preface

Classic PLC5 Programmable Controllers

How to Use Your Documentation

Your Classic PLC-5 Programmable Controllers documentation is organized into manuals according to the tasks you perform. This organization lets you easily find the information you want without reading through information that is not related to your current task. The arrow in Figure 1 points to the book you are currently using.

Figure 1 Classic

PLC5 Programmable Controllers Documentation Library

Classic 1785 PLC5

Programmable Controllers

User Manual

Explanation of processor

functionality, system

design, and programming

considerations and worksheets

17856.2.1

6200 or AI Series Software

Classic 1785 PLC5

Programmable Controllers

Hardware Installation

How to install and set

switches for chassis,

PLC5 processor, how

to wire and ground

your system

17856.6.1

Instruction Set

Reference

Instruction execution,

parameters, status

bits and examples

1785 PLC5

Programmable Controllers

Quick Reference

Quick access to switches,

status bits, indicators,

instructions, SW screens

17857.1

Purpose

of this Manual

17856.1

For more information on 1785 PLC-5 programmable controllers or the above publications, contact your local Allen-Bradley sales office, distributor, or system integrator.

This manual is intended to help you design a Classic PLC-5 programmable controller system. Use this manual to assist you in:

selecting the proper hardware components for your system

determining the important features of classic PLC-5 processors and how

to use those features

planning your classic PLC-5 system layout

iii

Preface

Manual Organization

Chapter

Appendix

1 Understanding Your System Provides an overview of Classic PLC5 processors in different system configurations. Provides

2 Choosing Hardware Provides information on your hardware choices when you design a Classic PLC5 processor

3 Placing System Hardware Describes proper environment, Classic PLC5 processor protection, and prevention of

4 Assigning Addressing Mode,

Rack, and Groups

5 Choosing Communication Identifies each Classic 5 processor channel/connector, and explains how to configure your

6 Planning Your System Programs Explains the use of sequential function charts (SFCs). Provides guidelines and examples for

This manual has ten chapters and two appendices. The following table lists each chapter or appendix with its corresponding title and a brief overview of the topics covered in it.

Title Topics Covered

an introduction to Classic PLC5 processors and their primary features and configurations. Also provides information on using a Classic PLC5 processor as a remote I/O scanner or a remote I/O adapter.

system.

electrostatic damage for your Classic PLC5 programmable controller system. Also covers raceway and cable layout, backpanel spacing, and grounding configurations.

Describes the I/O addressing modes that you can choose for your chassis. Explains how you assign group and rack numbers to your I/O chassis. Also covers how you configure complementary I/O by assigning rack and group addresses.

Classic PLC5 processor. Provides additional information about the Data Highway Plust (DH+t) link, programming software, and programmingterminal connections.

preparing system programs. Provides a map of data table files and methods to address the data table files. Explains how to use the processor status file.

7 Selecting Interrupt Routines Summarizes the conditions for which you would choose fault routines for your application.

Provides a definition of fault routines.

8 Transferring Discrete and

BlockTransfer Data

9 Calculating Program Timing Provides an overview of processor scan timing. Lists execution times and memory

10 Maximizing System Performance Explains how to calculate throughput, and provides methods for optimizing I/O scan time.

A Selecting Switch Settings Describes the switch settings for configuring a Classic PLC5 programmable controller system.

B Design Worksheets Provides worksheets to help the designer plan the system and the installer to install the system.

How to Use this Manual

Explains how your CLassic PLC5 processor transfers discrete and blocktransfer data in both scanner and adapter modes.

requirements for bit and word instructions as well as file instructions.

The following flow chart demonstrates a thought process that you can use when you plan your Classic PLC-5 programmable controller system.

System Design Determined

Select I/O modules, terminals

Place hardware

Preface

Assign addressing

Configure processor communication

Assigning Addressing Mode, Racks, and Groups

Select adapter modules

Select I/O chassis

Select power supply

Select PLC5 processor

Select batteries and memory modules

Complementary I/O selected?

Backup system selected?

Choosing Hardware and Placing System Hardware

Configure Data Highway Plus

Select programming software

Design SFCs

Data table layout and processor status

Use fault routines

Transfer data in adapter and scanner modes

I/O update and ladder program scan times

Choosing Communication

Planning Your System Programs

Transferring Discrete and Block Data

Calculating Program Timing and Maximizing System Performance

Since your decisions cannot always be made as a part of a strictly linear process, you can choose to complete tasks in parallel. When you select your I/O modules, for example, you can also begin to lay out and address your modules. Consult chapter 3, “Placing System Hardware,” to determine environmental requirements, enclosures needed, cable layout, and grounding requirements for your chassis and I/O links. Also, you can choose to assess block-transfer timing when you determine where you will place your block-transfer modules (in the processor-resident local I/O chassis, extended-local I/O chassis, or remote I/O chassis).

Chapter

Understanding Your System

Using this Chapter

Understanding the Terms Used in this Chapter

If you want to read about: Go to page:

Terms used in this chapter 11

Designing systems 12

Preparing your functional specification 13

Identifying Classic PLC5 processor features 15

Using the Classic PLC5 processor as a remote I/O scanner 18

Using the Classic PLC5 processor as a remote I/O adapter 19

Become familiar with the following terms and their definitions.

Term Definition

Processorresident local I/O chassis

Processorresident local I/O

Remote I/O link a serial communication link between a PLC5 processor port in scanner

the I/O chassis in which the PLC5 processor is installed

I/O modules located in the same chassis as the PLC5 processor

mode and an adapter as well as I/O modules that are located remotely from the PLC5 processor

Remote I/O chassis the hardware enclosure that contains an adapter and I/O modules that

are located remotely on a serial communication link to a PLC5 processor in scanner mode

Discretetransfer data data (words) transferred to/from a discrete I/O module

Blocktransfer data data transferred, in blocks of data up to 64 words, to/from a block

transfer I/O module (for example, an analog module)

1-1

Chapter 1

Understanding Your System

Designing

Centralized

Systems

control

is a hierarchical system where control over an entire process is concentrated in one processor

Distributed

control

is a system in which control and management functions are spread throughout a plant. Multiple processors handle the control and management functions and use a Data Highway

or a bus system

for communication.

You can use Classic PLC-5 processors in a system that is designed for centralized control or in a system that is designed for distributed control.

HP 9000 or VAX Host

Programming Terminal with

ControlView

Software

Remote I/O Link

Chassis with Chassis with

1771ASB

Remote I/O

Adapter

6200 VMS INTERCHANGE

Software



Pyramid Integrator

To DECnet



DH+ Link

Classic PLC5 Processor

1771ASB

Remote I/O

Adapter

Programming Terminal

ControlView

INTERCHANGE Software

DH+ Link

PanelView Operator Terminal

SLC 5/01 Processor 7slot Modular System with 1747DCM Module



Remote I/O Link

Series 8600 CNC with

Remote I/O

Consider the following items as general guidelines when designing your system.

Will your processor(s) be used in a centralized or distributed system? What type of process(es) will be controlled by the PLC-5 system? What processes will be controlled together? What are the environmental and safety concerns? What is the flow and functionality of your system?

18084

1-2

System Design Determined

Select I/O modules, terminals

Place hardware

Chapter 1

Understanding Your System

Determine the general criteria for your system. Use the chapters that follow to guide you through the criteria and choices for selecting the major Classic PLC-5 programmable controller system elements, as shown in Figure 1.1.

Figure 1.1

Processor System Design Flow

PLC5

Assign addressing

Configure processor communication

Assigning Addressing Mode, Racks, and Groups

Select adapter modules

Select I/O chassis

Select power supply

Select Classic PLC5 processor

Select batteries and memory modules

Complementary I/O

selected?

Backup system selected?

Preparing Your Functional Specification

Choosing Hardware and Placing System Hardware

Configure Data Highway Plus

Select programming software

Design SFCs

Data table layout and processor status

Use fault routines

Transfer data in adapter and scanner modes

I/O update and ladder program scan times

Choosing Communication

Planning Your System Programs

Transferring Discrete and Block Data

Calculating Program Timing and Maximizing System Performance

We recommend that you first develop a specification that defines your hardware selection and your programming application. The specification is a conceptual view of your system. Use it to determine your:

control strategy hardware selection, layout, and addressing sequential function chart (SFC) special programming features ladder-logic requirements

1-3

Chapter 1

Understanding Your System

Figure 1.2 illustrates a program-development model that you can use.

Figure 1.2 ProgramDevelopment

Functional Specification (General Conception)

Model

Acceptance Signoff

Detailed Anaylsis

Program

Development

Testing

This model allows for the interaction of activities at the different levels. Each section represents an activity that you perform. Prepare a functional specification to start; then, prepare the detailed analysis.

Based on the detailed analysis, you can also develop your programs, enter your programs, and test them. When testing is complete, you are ready to implement the programs in your application. The detailed analysis can be used as the basis for developing your testing procedures and requirements. Because the functional specification is well thought out, it can be used as the program sign-off document.

Functional Specification Content

1-4

The functional specification represents a very general view of your process or a description of operation. Identify the events and the overall order in which they must occur. Identify the equipment that you will need for your process/operation. Generally indicate the layout of your system. If your application requires a distributed control system, for example, indicate where you will need remote I/O links. Also, you can have a process that is located close to your processor. The process can require faster update time than that provided by a remote I/O link, so you can select an extendedlocal I/O link for that process.

Important: Choose a communication rate for your remote I/O link at which every device on the link can communicate.

Chapter 1

Understanding Your System

The program-development portion of your functional specification can be in any form: written statement; flowchart; or rough-draft MCPs, SFCs, and subroutines. Use the form that is most familiar to you. We recommend, however, that you generate rough-draft SFCs and subroutines so that you have a better correspondence between your beginning diagrams and your finished program.

Detailed Analysis

In this phase, you identify the logic needed to plan your programs. This includes inputs, outputs, specific actions, and transitions between actions (i.e., the bit-level details needed to write your program).

Program Development

Introducing

Classic PLC5

Processor Modules

You enter the programs either offline into your computer or online into a processor. In the next phase, you test the programs that you have entered. Once testing is complete, your resulting programs should match your functional specification.

Checking for Completeness

When you complete the functional specification and the detailed analysis, review them and check for missing or incomplete information such as:

input conditions safety conditions startup or emergency shutdown routines alarms and alarm handling fault detection and fault handling message display of fault conditions abnormal operating conditions

The following is a list of the PLC-5 processors and their catalog numbers.

Processor Catalog Number

PLC5/10t

PLC5/12t

PLC5/15t

PLC5/25t

1785LT4

1785LT3

1785LT

1785LT2

For information on other PLC-5 processors (Enhanced, Ethernet, or ControlNet), see your Allen-Bradley representative.

1-5

Chapter 1

Understanding Your System

Classic PLC5 Family Processor Features

From the family of PLC-5 processors, you can choose the processor(s) that you need for your application. Features common to all Classic PLC-5 processors are:

same physical dimensions use of the left-most slot in the 1771 I/O chassis can use any 1771 I/O module in the processor-resident local I/O chassis

with up to 32 points per module same programming software and programming terminals same base set of instructions ladder programs and SFCs can be used by any of the PLC-5 processors

Check with your Allen-Bradley sales office or distributor if you have questions regarding any of the features of your PLC-5 processor.

Subprogram Calls

Use a subroutine to store recurring sections of program logic that can be accessed from multiple program files. A subroutine saves memory because you program repetitive logic only once. The JSR instruction directs the processor to go to a separate subroutine file within the logic processor, scan that subroutine file once, and return to the point of departure.

For detailed information about how you generate and use subroutines, see your programming software documentation set.

Sequential Function Charts

Use SFCs as a sequence-control language to control and display the state of a control process. Instead of one long ladder program for your application, divide the logic into steps and transitions. A step corresponds to a control task; a transition corresponds to a condition that must occur before the programmable controller can perform the next control task. The display of these steps and transitions lets you see what state the machine process is in at a given time.

1-6

For detailed information about how you generate and use SFCs, see you programming software.

Ladder Logic Programs

A main program file can be an SFC file numbered 1-999; it can also be a ladder-logic file program numbered 2-999 in any program file.

Chapter 1

Understanding Your System

Consider using this technique:

SFC

Ladder Logic

If you are:

• defining the order of events in a sequential process

• more familiar with ladder logic than with programming

languages such as BASIC

• performing diagnostics

• programming discrete control

For detailed information about how you use ladder logic, see your programming software documentation.

Backup System

The following diagram shows a typical PLC-5 backup system:

Local I/O Chassis

1785BCM Module

PLC5 Processor

1771P4S Power Supply

HSSL

DH+ Link

Remote I/O Link

Local I/O Chassis

1785BCM Module

PLC5 Processor

1771P4S Power Supply

DH+ LInk

Remote I/O Chassis Remote I/O Chassis

Remote I/O Link

18691

In a PLC-5 backup system configuration, one system controls the operation of remote I/O and DH+ communications. This system is referred to as the “primary system.” The other system is ready to take control of the remote I/O and DH+ communications in the event of a fault in the primary system. This is referred to as the “secondary system.”

See chapter 2, “Choosing Hardware,” to select backup system hardware. See the PLC-5 Backup Communication Module User Manual, publication 1785-6.5.4, for more information on configuring a PLC-5 backup system.

1-7

Chapter 1

Understanding Your System

Using the Classic PLC5 Processor as a Remote I/O Scanner

Use scanner mode whenever you want a Classic PLC-5 processor to scan and control remote I/O link(s). The scanner-mode processor also acts as a

supervisory processor for other processors that are in adapter mode.

The scanner-mode processor scans the processor memory file to read inputs and control outputs. The scanner-mode processor transfers discrete-transfer data and block-transfer data to/from the processor-resident local rack as well as to/from modules in remote I/O racks.

A PLC-5 processor scans processor-resident local I/O synchronously to the program scan. A PLC-5 processor scans remote I/O asynchronously to the program scan, but the processor updates the input/output image data table from the remote I/O buffer(s) synchronously to the program scan. This occurs at the end of each program scan.

ProcessorResident Local I/O Scan

Synchronous to Program Scan

ScannerMode PLC5 Processor

Input

Output

Remote I/O Buffer

Input Output

Processor

Resident

I/O

Remote I/O Scan

Asynchronous to Program Scan

OutputInput

Remote I/O

Link

The scanner-mode PLC-5 processor can also:

gather data from node adapter devices in remote I/O racks process I/O data from 8-, 16-, or 32-point I/O modules address I/O in 2-, 1-, or 1/2-slot I/O groups support a complementary I/O configuration support block transfer in any I/O chassis

Configure the PLC-5/15 or -5/25 processor for scanner mode by setting switch assembly SW1.

1-8

Chapter 1

Understanding Your System

Using the Classic PLC5 Processor as a Remote I/O Adapter

Use a Classic PLC-5 processor (except the PLC-5/10 processor) in adapter mode when you need predictable, real-time exchange of data between a distributed control PLC-5 processor and a supervisory processor. You connect the processors via the remote I/O link (see Figure 1.3). You can monitor status between the supervisory processor and the adapter-mode PLC-5 processor at a consistent rate (i.e., the transmission rate of the remote I/O link is unaffected by programming terminals and other

non-control-related communications).

Figure 1.3 AdapterMode

Supervisory Processor

The following programmable controllers can operate as supervisory processors:

PLC2/20t and PLC2/30t processors

PLC3t and PLC3/10t processors

PLC5/11, 5/15, 5/20, 5/25, and 5/30 processors as well as PLC5/VMEt processors PLC5/40, 5/40L, 5/60, 5/60L, and 5/80 processors as well as PLC5/40BVt and PLC5/40LVt processors PLC5/20Et, 5/40Et PLC5/250t

All PLC5 family processors, except the PLC5/10, can operate as remote I/O adapter modules.

Communication

Remote I/O Link

PLC5 Processor in Adapter

Mode

1771

I/O

Remote I/O Link

DL40 Message Display

The PLC-5 processor in adapter mode acts as a remote station to the supervisory processor. The adapter-mode PLC-5 processor can monitor and control its processor-resident local I/O while communicating with the supervisory processor via a remote I/O link.

The supervisory processor communicates with the PLC-5/12, -5/15, or

-5/25 adapter with either eight or four I/O image table words.

A PLC-5 processor transfers I/O data and status data using discrete transfers and block transfers. You can also use block-transfer instructions to communicate information between a supervisory processor and an adapter-mode processor. The maximum capacity per block transfer is 64 words.

1-9

Choosing Hardware

Chapter

Objectives

Selecting I/O Modules

Use this chapter to guide you in the selection of system hardware for your application.

To select: Go to page:

I/O modules 21

I/O adapters 24

Chassis 26

Operator interface 26

PLC5 processor 29

Power supplies 29

Memory modules 213

Batteries 213

Complementary I/O 213

Backup system 214

Termination resistor 215

Cables 215

System Design Determined

Choosing Hardware

Placing System Hardware

Assigning Addressing Mode, Racks, and Groups

Choosing Communication

Planning Your System Programs

Selecting Interrupt Routines

Transferring Discrete and Block Data

Calculating Program Timing

You select I/O modules to interface your PLC-5 processor with machines or processes that you have previously determined.

Use the following list and Table 2.A as guidelines for selecting I/O modules and/or operator control interface(s).

How much I/O is required to control the process(es)? Where will you concentrate I/O points for portions of an entire process

(when an entire process is distributed over a large physical area)? What type of I/O is required to control the process(es)?

What is the required voltage range for each I/O module? What is the backplane current required for each I/O module? What are the noise and distance limitations for each I/O module? What isolation is required for each I/O module?

2-1

Chapter 2

Choosing Hardware

Table 2.A Guidelines

Choose this type of I/O module:

Discrete input module and block I/O module

Discrete output module and block I/O module

Analog input module Temperature transducers, pressure transducers, load cell transducers,

Analog output module Analog valves, actuators, chart recorders, electric motor drives,

Specialty I/O modules Encoders, flow meters, I/O communication, ASCII, RF type devices,

A 1791 block I/O module is a remote I/O device that has a power supply, remote I/O adapter, signal conditioning circuitry, and I/O connections. A block I/O module does not require a chassis mount. It is used to control concentrated discrete remote I/O such as control panels, pilot lights, and status indications.

For these types of field devices or operations (examples): Explanation:

Selector switches, pushbuttons, photoelectric eyes, limit switches,

circuit breakers, proximity switches, level switches, motor starter contacts, relay contacts, thumbwheel switches

Alarms, control relays, fans, lights, horns, valves, motor

starters, solenoids

humidity transducers, flow transducers, potentiometers

analog meters

weigh scales, barcode readers, tag readers, display devices

for Selecting I/O Modules

Important: Determine addressing in conjunction with I/O module selection. The selection of addressing and the selection of I/O module density are mutually dependent.

Input modules sense ON/OFF or OPENED/ CLOSED signals. Discrete signals can be either ac or dc.

Output module signals interface with ON/OFF or OPENED/CLOSED devices. Discrete signals can be either ac or dc.

Convert continuous analog signals into input values for PLC processor.

Interpret PLC processor output to analog signals (generally through transducers) for field devices.

Are generally used for specific applications such as position control, PID, and external device communication.

Selecting I/O Module Density

The density of an I/O module is the number of processor input or output image table bits to which it corresponds. A bidirectional module with 8 input bits and 8 output bits has a density of 8. Table 2.B provides guidelines for selecting I/O module density.

Table 2.B Guidelines

Choose this I/O density: If you:

8point I/O module

16point I/O module

32point I/O module

for Selecting I/O Module Density

• currently use 8point modules

• need integral, separatelyfused outputs

• want to minimize cost per module

• currently use 16point modules

• need separately fused outputs with a special wiring arm

• currently use 32point modules

• want to minimize number of modules

• want to minimize the space required for I/O chassis

• want to minimize cost per I/O point

2-2

Chapter 2

Choosing Hardware

Master/Expander I/O Modules

Some I/O modules (called “masters”) communicate with their expanders over the backplane. These master/expander combinations either:

can time-share the backplane, or cannot time-share the backplane

For masters that can time-share the backplane, you can use two masters in the same chassis. For a master/expander combination that cannot time-share the backplane, you cannot put another master/expander combination in the same I/O chassis.

Example: The stepper-controller module (cat. no. 1771-M1, part of a 1771-QA assembly) and the servo-controller module (cat. no. 1771-M3, part of a 1771-QC assembly) always act as masters and cannot time-share the backplane. Therefore, you cannot put a second master module in the same chassis with either of these modules.

Table 2.C summarizes the compatibility of master modules within a single I/O chassis.

Table 2.C Compatibility

1st Master

Module

1771IX

1771IF

1771OF

1771M1

1771M3

of Master Modules within a Single I/O Chassis

2nd Master Module

1771IX

1771IF1 1771OF1 1771M1 1771M3

Valid

These

modules have been superseded by 1771IXE, IFE, and OFE master modules that do not exhibit the master/expander conflict in a chassis as 1771IX, IF modules shown in this table.

These are the only master combinations that you can use in a single I/O chassis. These combinations are valid with or without the module' M3 have expander modules). Y chassis; you can use any other intelligent I/O modules not shown here with these masters.

Valid

ou can use a maximum of two masters in the same

Valid

s associated expanders (1771M1 and

, and OF master

Important: Density is not relevant to an expander module because it communicates only with its master; an expander module does not communicate directly with an adapter.

2-3

Chapter 2

Remote I/O Adapter

I/O Density

Choosing Hardware

Selecting I/O Adapter Modules

ASB

ALX

Select I/O adapter modules to interface your PLC-5 processor with I/O modules. Use Table 2.D as a guide when you select I/O adapter modules.

Table 2.D Guidelines

Choose: When your requirements are:

1771AS or 1771ASB Remote I/O Adapter Module (or 1771AM1, AM2 chassis with integral power supply and adapter module)

1771ALX ExtendedLocal I/O Adapter Module

1771ASB

series C and later have 230.4 kbps communication rate in addition to 57.6 kbps and 1

for Selecting Adapter Modules

a remote I/O link with:

• 57.6 kbps with a distance of up to 10,000 cable feet or

• timing that isn't critical enough to place I/O modules in a processor local

I/O chassis or an extendedlocal I/O chassis

an extendedlocal I/O link with timing that is critical and all extendedlocal I/O chassis are located within 100 ft of the processor.

17 71AS/ASB Remote I/O Adapter Modules

Table 2.E shows the I/O density per module and addressing modes you can use with I/O chassis and remote I/O adapter modules.

Table 2.E

Chassis/Adapter Module Combinations

I/O

15.2 kbps.

Remote I/O Adapter I/O Density

Module Cat. No.

1771AS 8

1771ASB

Series A

1771ASB

Series B, C, and D

1771AM2 8

Conditional

adjacent slots (even/odd pair) of the I/O chassis beginning with slot 0. If you cannot pair the modules this way

module placement; you must use an input module and an output module in two

, leave the adjacent slot empty

per Module

16 32

8 16 32

16 32

2Slot 1Slot 1/2Slot

Yes

 No

Yes

 No

Yes

 No

  

Addressing

No No No

Yes Yes



Yes Yes



Yes Yes



No No No

Yes Yes Yes

Using the 1771-ASB Series C or D adapter module, you can choose one of three communication rates: 57.6 kbps, 115.2 kbps, or 230.4 kbps.

2-4

Chapter 2

Module C

I/O Density

Choosing Hardware

1771ALX ExtendedLocal I/O Adapter Module

Table 2.F shows the I/O density per module and addressing modes you can use with I/O chassis and extended-local I/O adapter modules.

Table 2.F

Chassis/Extended Local I/O Adapter Module Combinations

I/O

at. No.

1771ALX

Series A

Conditional

module placement; you must use an input module and an output module in two adjacent slots (even/ odd pair) of the I/O chassis beginning with slot 0. If you cannot pair the modules this way empty.

I/O Density per Module

8 16 32

2Slot 1Slot 1/2Slot

Yes

 No

Addressing

Yes Yes



, leave the adjacent slot

Other Devices on an I/O Link

Other devices that you can use on a remote I/O link are:

PLC-5 processor in adapter mode PLC-5/250 remote scanner in adapter mode PLC interface module for digital ac and dc drives remote I/O adapter for Bulletin 1336 drives RediPANELt pushbutton and keypad modules Datalinert PanelView (see operator interface) F30D option module (for T30 plant-floor terminal) 8600 or 9/SERIES CNC with remote I/O adapter option CVIMt in adapter mode Pro-Spect 6000 Fastening System with remote I/O adapter option 1747-DCM module (to SLC-500 rack) 1771-DCM module 1771-GMF robot (remote I/O interface module)

Yes Yes Yes

See the appropriate Allen-Bradley product catalog for more information on these devices.

2-5

Chapter 2

Choosing Hardware

Selecting

I/O Chassis

4-Slot

1771A1B

An I/O chassis is a single, compact enclosure for the processor, power-supply modules, remote and extended-local I/O adapter modules, and I/O modules. The left-most slot of the I/O chassis is reserved for the processor or adapter module. Consider the following when selecting a chassis:

When you determine the maximum number of I/O in your application,

allow space for the I/O slots dedicated to power-supply modules, communication modules, and other intelligent I/O modules.

You must use series B or later chassis with 16- and 32-point

I/O modules.

Allow space for future addition of I/O modules to chassis.

I/O chassis available are:

4-slot (1771-A1B) 8-slot (1771-A2B) 12-slot—rack mount (1771-A3B), panel mount (1771-A3B1) 16-slot (1771-A4B)

You can also choose a chassis with an integral power supply and remote I/O adapter (show at left). The two types are:

1771AM1

1771AM2

Selecting an Operator Interface

1-slot (1771-AM1) 2-slot (1771-AM2)

PanelView and ControlView are operator interface products or packages that communicate with a PLC-5 processor. Use Table 2.G as a guideline when selecting either PanelView or ControlView for your PLC-5 programmable controller system. Use Table 2.H for a comparison of PanelView and ControlView features.

2-6

Table 2.G Guidelines

Chapter 2

Choosing Hardware

for Selecting an Operator Interface

Choose this operator interface:

PanelView

For these types of operations (examples):

Starts/stops, auto/manual operations, setpoints, outputs, alarms

Explanation:

Used as an operator window to enter commands that make process adjustments such as starts/stops and loop changes. Can also be used for alarming operations. Can communicate with a single PLC5 processor on a remote I/O link. Has a fixed number of devices and amount of data that it can handle. Has builtin error checking. Is an industrialhardened CRT with pushbuttons, solid state memory and processor, and no moving parts (i.e., disk drive).

Utilizes pass through, which is the ability to download/upload via DH+/remote I/O links.

ControlView

Refer

Store, display, and manipulate data on process performance (i.e., trends, process graphics, formulas, reports, and journals)

to your local AllenBradley sales of

Used as an operator window that communicates with a PLC5 processor on Data Highway Plus (DH+) link. Designed for use as an information link. Can communicate to multiple PLC processors. ControlView is a software package that runs on an IBMr DOSbased personal computer.

fice or AllenBradley distributor for more information on PanelV

iew and ControlV

iew.

Table 2.H Comparison

of PanelV

Category PanelView ControlView

Communication with PLC processor

Remote I/O

5 block transfers per terminal maximum (32 words per transfer)

1 discrete transfer per terminal (64 words maximum, one way) This is 8 racks of transfer

Graphics Character graphics

Create screens with PanelBuilder software Monochrome or color (8 of 16 colors displayed at a time)

Number of Screens per Terminal/Workstation

8 to 12 screens of medium complexity typical 200 objects maximum per screen Limited by terminal memory size: 128 Kbytes

Data Capacity 200 objects maximum per screen 10,000 points maximum in database

Communication

Limited by blocktransfer and discretetransfer timing

Rate

Depends on PLC processor and remote I/O link size

Hardware Keypad or Touchscreen terminals, color or monochrome

AllenBradley, IBM, or compatible computer required for PanelBuilder software

Programming PanelBuilder software

Menudriven with fillintheblank information entry

Use PanelBuilder to create application file that defines screens, messages, alarms, then download application file to PanelView terminal

Messages 496 maximum per terminal Not Applicable

Alarms 496 maximum per terminal 2000 points with Alarming option

Security 8 levels 16 levels with individual operator login capability

Options Remote serial port

EEPROM or EPROM memory

iew and ControlV

DH+ link Data Highway Data Highway II Native Mode

Pixel Graphics Create screens with Mouse Grafix editor option or C Toolkit EGA, VGA, or equivalent with 256K RAM Monochrome or color monitor

Limited only by hard disk capacity 50 data entry locations per screen 50 tags per command list per screen 300 tags/points maximum per screen

8 scan classes, each with userconfigurable foreground and background update times; limited by performance of Data Highway, DH+, or Data Highway II link

AB, IBM, or compatible computer with 286 or 386 processor, math coprocessor, hard disk required at each operator station

Create data base online via the menu. Menudriven, fillintheblank information entry, or import data via the ASCII import capability

Create screens with the mouse GRAFIX editor option or C toolkit option

Individual objects with security Screen lockout

Lots of software options

iew Features

2-7

Chapter 2

Choosing Hardware

For more information on selecting and configuring PanelView, see:

PanelView Operator Terminal and PanelBuilder Development Software

User Manual, cat. no. 2711-ND002 version C, PN40061-139-01— request latest revision

Replacing Node Adapter Firmware for PanelView Terminals Installation

Data, PN40062-236-01—request latest revision

For more information on selecting and configuring ControlView, see:

ControlView Core User Manual, publication 6190-6.5.1

ControlView Allen-Bradley Drivers User Manual,

publication 6190-6.5.5

ControlView Networking User Manual, publication 6190-6.5.9

Other Operator Interfaces

You can use the following as operator interfaces in your PLC-5 processor system:

RediPANEL pushbutton and keypad modules Dataliner 1784-T47 and 1784-T53 programming terminals

See the appropriate Allen-Bradley product catalog for more information on these operator interfaces.

2-8

Chapter 2

Choosing Hardware

Choosing

a Classic PLC5 Processor for Your Application

Processor/

No.

Cat.

PLC5/10 (1785LT4)

PLC5/12 (1785LT3)

PLC5/15 (1785LT)

PLC5/25 (1785LT2)

Processor/ Cat. No.

PLC5/10 (1785LT4)

PLC5/12 (1785LT3)

PLC5/15 (1785LT)

PLC5/25 (1785LT2)

Maximum User Memory Words

6 K

6 K expandable to 10 K or 14 K

13 K expandable to 17 K or 21 K

Number of Remote I/O, ExtendedLocal I/O, and DH+ Ports

•

1 DH+

•

1 DH+

•

1 Remote I/O (Adapter Only)

•1

DH+

•

1 Remote I/O (Adapter or Scanner)

•1

DH+

•

1 Remote I/O (Adapter or Scanner)

EEPROM Module Memory (W Module Number

8 K (1785MJ)

8 K (1785MJ) or 16 K (1785MK)

ords) &

Choose from the following PLC-5 processors.

Table 2.I

PLC5 Processor Selection ChartPart 1

Classic

Total I/O Maximum (any mix)

•

512 (32I/O modules)

•

256 (16I/O modules)

•

128 (8I/O modules)

•

512 (32I/O modules)

•

256 (16I/O modules)

•

128 (8I/O modules)

•

512 (any mix) or

•

512 in + 512 out (complementary)

•

1024 (any mix) or

•

1024 in + 1024 out (complementary)

Table 2.J

PLC5 Processor Selection ChartPart 2

Classic

Maximum Number of I/O Racks

1 1 0 0 0  2.5A

4 1 0 0 0

4 13 0 12 0

8 17 0 16 0

Analog I/O Max

256

512

1024

Maximum Number of I/O Chassis

Total

Program Scan T K W

2 ms (discrete logic) 8 ms (typical)

Ext Local

ord

Remote

ime /

Number of RS232/ 422/ 423 ports

I/O Scan time/Rack (in a single Chassis, extlocal or remote)

N/A

•

10 ms @ 57.6 kbps (remote)

•

10 ms @ 57.6 kbps (remote)

•

10 ms @ 57.6 kbps (remote)

Remote I/O Transmission

Rates

57.6 kbps

Multiple MCPs / Quantity

No / 1

Backplane Current Load

2.5A

Selecting Power Supplies

1771P7

Use the following steps as guidelines for selecting a power supply for a chassis that contains a PLC-5 processor, a 1771-AS or -ASB remote I/O adapter module, or a 1771-ALX extended-local I/O adapter module.

1. Determine the input voltage for the power supply.

2. Calculate the total backplane current draw for I/O modules by

adding together the backplane current draw for each I/O module in that chassis.

2-9

Chapter 2

Choosing Hardware

3. Add to the total of the I/O module backplane current draw either:

a. 3.3 Amps when the chassis will contain a PLC-5 processor

(maximum current draw for any PLC-5 processor) or

b. 1.2 Amps when the chassis will contain either a remote I/O

1771-AS or -ASB module or a 1771-ALX extended-local I/O adapter module

4. If you leave slots available in your chassis for future expansion:

a. list backplane current draw for future I/O modules

b. add the total current draw for all expansion I/O modules to the

total calculated in step 3.

5. Determine whether the available space for the power supply is in the

chassis or mounted external to the chassis.

Choose your power supply from Table 2.K or Table 2.L using the input voltage requirement and the total backplane current draw as determined in the previous steps, 1 through 5.

See the Automation Products Catalog, publication AP100, for more information on power supplies.

Powering a Chassis Containing a PLC5 Processor

Table 2.K lists the power-supply modules that you can use with a Classic PLC-5 processor.

2-10

Chapter 2

Power

Input

Output Current

Power Supply

Choosing Hardware

Table 2.K Powering

Power

Input Output Current

Supply

1771P3 120V ac 3 6 11 11 chassis, 1slot

1771P4 120V ac 8 11 16 16 chassis, 2slot

1771P4S 120V ac 8 11 16 16

1771P4S1 100V ac 8 16

1771P4R 120V ac 8/16/24

1771P5 24V dc 8 16 chassis, 2slot

1771P6S 220V ac 8 16

1771P6S1 200V ac 8 16

1771P6R 220V ac 8/16/24

1771P7 120/220V ac 16

1771PS7 120/220V ac 16

See

publication 17712.136 for more information.

ou cannot use an external power supply and a slotbased power supply module to power the same chassis;

they are not compatible.

Power

a Chassis Containing a Classic PLC5 processor

Output Current (in Amps) When Parallel with:

(in Amps)

P3 P4 P4S P4S1 P5 P6S P6S1

Power Supply Location

chassis, 1slot

external

2-11

Chapter 2

Power

Input

Output Current

Power Supply

Choosing Hardware

Powering a Remote I/O Chassis Containing a 1771AS or 1771ASB or an ExtendedLocal I/O Chassis Containing a 1771ALX

Table 2.L lists the power supply modules that you can use with a remote I/O chassis or an extended-local I/O chassis.

Table 2.L Powering

a Remote I/O Chassis (Containing a 1771AS or ASB)

or an ExtendedLocal I/O Chassis (Containing a 1771ALX)

Power

Input Output Current

Supply

Power

(in Amps)

1771P3 120V ac 3 6 11 11 chassis, 1slot

1771P4 120V ac 8 11 16 16 chassis, 2slot

1771P4S 120V ac 8 11 16 16

1771P4S1 100V ac 8 16

1771P4R 120V ac 8/16/24

1771P5 24V dc 8 16 chassis, 2slot

1771P6S 220V ac 8 16

1771P6S1 200V ac 8 16

1771P6R 220V ac 8/16/24

1771P1 120/220V ac 6.5

1771P2 120/220V ac 6.5

1771P7 120/220V ac 16

1771PS7 120/220V ac 16

Output Current (in Amps) When Parallel with:

P3 P4 P4S P4S1 P5 P6S P6S1

Power Supply Location

chassis, 1slot

external

2-12

1777P2 120/220V ac 9

1777P4 24V dc 9

See

publication 17712.136 for more information.

ou cannot use an external power supply and a slotbased power supply module to power the same chassis;

they are not compatible.

Chapter 2

Choosing Hardware

Selecting

Memory Modules

Selecting a Replacement Battery

Select a memory module from Table 2.M for your PLC-5 processor.

Table 2.M

Processor Memory Modules

PLC5

Nonvolatile Memory Backup (EEPROM) RAM Memory (CMOS)

Words Catalog Number (and Processor) Words Catalog Number (and Processor)

8 K 1785MJ 4 K 1785MR (PLC5/15 and 5/25)

16 K 1785MK (PLC5/25) 8 K 1785MS (PLC5/15 and 5/25)

A battery ships with your PLC-5 processor. Select a replacement battery using Table 2.N and Table 2.O. See the Allen-Bradley Guidelines for Handling Lithium Batteries, publication ICCG-5.14, for more information.

Table 2.N Processor

Processor Battery

PLC5/10, 5/12, 5/15, and 5/25

The

their part number TL 5104 and type AEL/S.

Batteries

1770XY is a 3.6 V

1770XY, AA lithium

olt AA size lithium thionyl chloride battery manufactured by T

Function

Retains the processor memory and the memory in an optional CMOS RAM module if the processor is not powered.

adiran as

Selecting Complementary I/O

Table 2.O Average

Battery Life

Battery Temperature Power Off 100%

1770XY

60° C 25° C

(Average)

329 days 2 years

Power Off 50% (Average)

1.4 years

3.3 years

You configure complementary I/O by assigning an I/O rack number of one I/O chassis (primary) to another I/O chassis (complementary). You complement I/O functions in the primary chassis with opposite functions in the complementary chassis. Use chapter 4, “Assigning Addressing Mode, Racks, and Groups,” in conjunction with the following selection of complementary I/O hardware.

2-13

Chapter 2

Choosing Hardware

Use the following modules in either primary or complementary I/O chassis opposite any type of module:

Communication Adapter Module (1771-KA2) Communication Controller Module (1771-KE) PLC-2 Family/RS-232-C Interface Module (1771-KG) Fiber Optics Converter Module (1771-AF) DH/DH+ Communication Adapter Module (1785-KA) DH+/RS-232C Communications Interface Module (1785-KE)

Use the following modules in either primary or complementary I/O chassis opposite any type of module. However, these modules do not work as standalone modules; each one has an associated master module. Use care when placing the master modules in the I/O chassis (refer to the paragraph on Master/Expander I/O modules):

Analog Input Expander Module (1771-E1, -E2, -E3) Analog Output Expander Module (1771-E4) Servo (Encoder Feedback) Expander Module (1771-ES) Pulse Output Expander Module (1771-OJ)

Selecting

a PLC5 Processor

Backup System

A PLC-5 processor backup system contains two of each of the following hardware components:

Classic PLC-5 processor module

Processor Catalog Number

PLC5/15 1785LT Series B

PLC5/25 1785LT2

1785-BCM Series C Backup Control Module (for 2 channels) 1785-BEM Backup Expansion Module (for 2 additional channels) Power supply Local chassis

Important: The PLC-5 backup system does not back up I/O in the processor-resident local chassis. Do not install I/O in the processorresident local chassis of a backed up system.

Refer to the PLC-5 Backup Communication Module User Manual, publication 1785-6.5.4, for more information on configuring a PLC-5 processor backup system.

2-14

Chapter 2

Choosing Hardware

Selecting Link Terminators

Connecting a Programming Terminal to a Processor Module

Terminate remote I/O links by setting switch assembly SW3. If you cannot use an 82-Ohm terminator because of devices that you place on your I/O link (see the table below for a list of these devices), you must use 150-Ohm terminators. Using the higher resistance reduces the quantity of devices to 16 that you can place per remote I/O link. Also, this limits your communication rates to 57.6 kbps and 115.2 kbps.

DH+ Network Terminator

Terminate your DH+ network with a 150-Ohm, 1/2-watt terminator.

If you have this processor: Terminate a DH+ link by:

PLC5/10, 5/12, 5/15, or 5/25 Setting switch assembly SW3 of the PLC5

processor (refer to your Classic 1785 PLC5 Family Programmable Controllers Hardware Installation Manual, publication 17856.6.1).

Connect the programming terminal directly to the processor through the D-shell DH+ COMM INTFC connector on the front panel. You can also connect the programming terminal remotely to a DH+ link through the 3-pin connector or at a remote station.

Choosing Cables

Select cables from the options listed below. See chapter 3, “Placing System Hardware,” to determine the lengths that you will need for cables in your system.

Remote I/O Link

Use Belden 9463 twinaxial cable (1770-CD) to connect your PLC-5 processor to remote I/O adapter modules.

Connect your I/O devices using:

single-conductor wire (analog and some discrete applications)

multi-conductor cable (analog and some discrete applications)

multi-conductor shielded cable (some specialty I/O modules and

low-voltage dc discrete modules)

2-15

Chapter 2

PLC 5/10, 5/12, 5/15

1784 KT, KT2

1784 CP

Choosing Hardware

See the Classic 1785 PLC-5 Programmable Controllers Hardware Installation Manual, publication 1785-6.6.1, and the installation data for the I/O modules that you have selected for more information on I/O wiring. Also, see Allen-Bradley Programmable Controller Wiring and Grounding Guidelines, publication 1770-4.1, and Control, Communication and Information Reference Guide, publication ICCG-1.2, for more information.

Programming Terminal

The cable that you use to connect a processor to a programming terminal depends on the communication device used. Table 2.P lists the cables that you need for different configurations.

Table 2.P Cables

for Connecting a Classic PLC5 Processor and Programming

Terminal

If you have this device: With this

PLC5/10, 5/12, 5/15, 1784KT, KT2 1784CP or 5/25

6160T60, 6160T70, 6121 IBM PC/AT (or compatible)

1784T47, 6123, 6124 IBM PC/XT (or compatible)

6120, 6122 1785KE 1784CYK

communication device:

1784KL, KL/B

1784KTK1 1784CP5

1784PCMK 1784PCM5

1785KE 1784CAK

1785KE 1784CXK

Use this cable:

You can also use a 1770-KF2/B communication interface to connect to a PLC-5 processor. You build your own cables to connect your programming terminal via the COM1 or COM2 serial ports to the 1770-KF2/B. For the cable pin assignments, see the Classic 1785 PLC-5 Programmable Controller Hardware Installation Manual, publication 1785-6.6.1.

2-16

Chapter

Placing System Hardware

Chapter

Objectives

Determining the Proper Environment

A well-planned layout is essential to the proper installation of your Classic PLC-5 programmable controller system. Read this chapter for information on placing hardware.

System Design

If you want to read about: Go to

page:

Proper environment 31

Protecting your system 34

Avoiding electrostatic damage 34

Planning your raceway layout 34

Planning your cabling 36

Grounding your system 37

Determined

Choosing Hardware

Placing System Hardware

Assigning Addressing Mode, Racks, and Groups

Choosing Communication

Planning Your System Programs

Selecting Interrupt Routines

Transferring Discrete and Block Data

Calculating Program Timing

Place the processor in an environment with conditions that fall within the guidelines described in Table 3.A.

Table 3.A Proper

Environmental Conditions For Y

Environmental Condition Acceptable Range

Operating temperature

Storage temperature

Relative humidity 5 to 95% (without condensation)

0 to 60° C (32 to 140° F) 40 to 85° C (40 to 185° F)

our Processor

Separate your programmable controller system from other equipment and plant walls to allow for convection cooling. Convection cooling draws a vertical column of air upward over the processor. This cooling air must not exceed 60 If the air temperature exceeds 60

° C (140° F) at any point immediately below the processor.

° C, install fans that bring in filtered air or

recirculate internal air inside the enclosure, or install air-conditioning/heatexchanger units.

3-1

Chapter 3

Placing System Hardware

To allow for proper convection cooling in enclosures containing a processor-resident chassis and remote I/O chassis, follow these guidelines.

Minimum spacing requirements for a processorresident chassis:

102mm

(4")

51mm(2")

Area reserved for disconnect.

transformer, control relays, motor

starters or other user devices.

(6")

51mm

(2")

Wiring Duct

153mm

(6")

• Mount the I/O chassis horizontally.

• Allow 153 mm (6 in) above and below the chassis.

• Allow 102 mm (4 in) on the sides of each chassis.

• Allow 51 mm (2 in) vertically and horizontally between

any chassis and the wiring duct or terminal strips.

• Leave any excess space at the top of the enclosure,

where the temperature is the highest.

102mm

(4")

13081

3-2

153mm (6")

102mm

(4")

51mm (2")

Area reserved for disconnect.

transformer, control relays,mot or

starters or other user devices.

153mm

(6")

Wiring Duct

Chapter 3

Placing System Hardware

Minimum spacing requirements for a remote I/O chassis:

• Mount the I/O chassis horizontally.

• Allow 153 mm (6 in) above and below all

chassis. When you use more than one chassis in the same area, allow 152.4 mm (6 in) between each chassis.

• Allow 102 mm (4 in) on the sides of each

chassis. When you use more than one chassis in the same area, allow 101.6 mm (4 in) between each chassis.

• Allow 51 mm (2 in) vertically and

horizontally between any chassis and the wiring duct or terminal strips.

• Leave any excess space at the top of

the enclosure, where the temperature is the highest.

102mm

(4")

102mm

(4")

153mm (6")

Wiring Duct

18749

3-3

Chapter 3

Placing System Hardware

Protecting Your Processor

Avoiding Electrostatic Damage

You provide the enclosure for your processor system. This enclosure protects your processor system from atmospheric contaminants such as oil, moisture, dust, corrosive vapors, or other harmful airborne substances. To help guard against EMI/RFI, we recommend a steel enclosure.

Mount the enclosure in a position where you can fully open the doors. You need easy access to processor wiring and related components so that troubleshooting is convenient.

When you choose the enclosure size, allow extra space for transformers, fusing, disconnect switch, master control relay, and terminal strips.

ATTENTION: Under some conditions, electrostatic discharge can degrade performance or damage the processor module. Read and observe the following precautions to guard against electrostatic damage.

Wear an approved wrist strap grounding device when handling the processor module.

Laying Out Your Cable Raceway

Touch a grounded object to discharge yourself before

handling the processor module.

Do not touch the backplane connector or connector pins.

When not handling the processor module, keep it in its

protective packaging.

The raceway layout of a system reflects where the different types of I/O modules are placed in I/O chassis. Therefore, you should determine I/O-module placement prior to any layout and routing of wires. When planning your I/O-module placement, however, segregate the modules based on the conductor categories published for each I/O module so that you can follow these guidelines. These guidelines coincide with the guidelines for “the installation of electrical equipment to minimize electrical noise inputs to controllers from external sources” in IEEE

standard 518-1982.

3-4

Chapter 3

Placing System Hardware

To plan a raceway layout, do the following:

categorize conductor cables route conductor cables

Categorize Conductors

Segregate all wires and cables into categories as described in the Industrial Automation Wiring and Grounding Guidelines, publication 1770-4.1. See the installation data for each I/O module that you are using for information about its classification.

Route Conductors

To guard against coupling noise from one conductor to another, follow the general guidelines for routing cables described in the Industrial Automation Wiring and Grounding Guidelines, publication 1770-4.1. You should follow the safe grounding and wiring practices called out in the National Electrical Code (NEC, published by the National Fire Protection Association, in Quincy, Massachusetts), and local electrical codes.

Planning Cabling

DH+ Link Cabling

At a DH+ transmission rate of 57.6 kbps, do not exceed 3,048 cable-m (10,000 cable-ft) for a trunkline cable length or 30.5 cable-m (100 cable-ft) for a dropline cable length.

Remote I/O Link Cabling

Refer to Table 3.B for remote I/O link trunkline cable length restrictions.

Table 3.B Maximum

Transmission Rate Maximum Cable Length

57.6 kbps 3,048 m (10,000 ft)

115.2 kbps 1,524 m (5000 ft)

230.4 kbps 762 m (2500 ft)

Important: All devices on the remote I/O link must be communicating at the same transmission rate.

Cable Lengths per Communication Rate

3-5

Chapter 3

Placing System Hardware

Laying Out the Backpanel Spacing

1771A1B 1771A2B 1771A3B1 1771A4B

Power Connector

193mm (7.60")

Side

Use 6.35 mm (0.25 inch) mounting bolts to attach the I/O chassis to the enclosure backpanel.

Figure 3.1 Chassis

Dimensions (Series B)

315mm (12.41")

591mm (23.25")

337mm (13.25")

464mm (18.25")

210mm (8.25")

16slot 1771

12slot

8slot

4slot

254mm

(10")

1771A3B

217mm (8.54")

Side

171mm (6.75")

339mm (13.53")

610mm

483mm (19.01")

229mm (9.01")

465mm (18.31")

(24.01")

356mm (14.01")

484mm (19")

Front

Total

maximum depth dimension per installation will be dependent upon module wiring and connectors.

16slot 1771A4B

12slot 1771A3B1

8slot 1771A2B

4slot 1771A1B

9mm (.34")

26mm (1.02")

178mm (7")

130mm (5.10")

12450I

3-6

Chapter 3

Placing System Hardware

Figure 3.2

Chassis and 1771P2 Power Supply Dimensions

I/O

591mm

Use .25" dia

mounting bolts

(4 places)

(23.25")

337mm

(13.25")

464mm

(18.25")

210mm

(8.25")

16-slot

12-slot

8-slot

4-slot

Grounding Configuration

315mm (12.41")

Clearance depth is 204 mm (8 in) for 8 I/O connection points per module.

1771P1 1771P2 1771P7

1771PS7

Power Supply

91mm

(3.6")

483mm

(19.01")

229mm

(9.01")

610mm

(24.01")

356mm

(14.01")

See Figure 3.3 for the recommended grounding configuration for remote I/O systems.

Figure 3.3 Recommended

Grounding Configuration for Remote I/O Systems

254mm

(10")

16-slot 1771-A4B

12-slot 1771-A3B1

8-slot 1771-A2B

4-slot 1771-A1B

12451I

Enclosure

Ground Bus

Grounding Electrode Conductor

To Grounding Electrode System

I/O Chassis Wall

Star Washer

Ground Lug

Nut

15561

3-7

Chapter

Assigning Addressing Modes, Racks, and Groups

Chapter

Objectives

This chapter conveys basic hardware addressing concepts and gives you guidelines with which to choose the addressing modes (including complementary I/O), racks, and groups to use in your system.

System Design

If you want to read about: Go to

page:

Placing I/O modules in chassis 41

Understanding terms 42

Choosing I/O addressing mode 43

Rack number assignments 49

Addressing complementary I/O 412

Determined

Choosing Hardware

Placing System Hardware

Assigning Addressing Mode, Racks, and Groups

Choosing Communication

Planning Your System Programs

Selecting Interrupt Routines

Transferring Discrete and Block Data

Calculating Program Timing

Placing I/O Modules in Chassis

Place I/O modules in a chassis depending on the electrical characteristics of the modules. The placement is made left to right, with the left-most position being closest in the chassis to the PLC-5 processor or the I/O adapter module. The placement order is as follows:

1. block-transfer modules (all types)

2. dc input modules, placed left to right from lowest to highest voltages

3. dc output modules, placed left to right from lowest to highest voltages

4. ac input modules, placed left to right from lowest to highest voltages

5. ac output modules, placed left to right from lowest to highest voltages

4-1

Chapter 4

Assigning Addressing Modes, Racks, and Groups

The following guidelines are for placing block-transfer modules.

Place as many modules as possible for which you need fast

block-transfer times in your processor-resident local I/O chassis .

Place modules that need fast block-transfer times (but space is not

available in processor-resident local I/O chassis) in an extended-local I/O chassis.

Place modules in which timing is not as critical as in other

block-transfer modules in remote I/O chassis.

ac output modules should always be the furthest I/O modules from any

block-transfer modules in the same chassis.

Understanding the Terms Used in this Chapter

Become familiar with the following terms and their definitions: An I/O group is an addressing unit that corresponds to an input

image-table word (16 bits) and an output image-table word (16 bits). An I/O group can contain up to 16 inputs and 16 outputs; and it can occupy 2-, 1-, or 1/2-module slots for addressing purposes.

Output or

Input Terminals

00 01 02 03 04 05 06

07 10 11 12 13 14 15 16 17

Output Terminals

00 01 02 03 04 05 06 07 10 11 12 13 14 15 16 17

Input Terminals

00 01 02 03 04 05 06 07 10 11 12 13 14 15

16 17

4-2

2Slot I/O Module Group 1Slot I/O Module Group

(I/O Group #0) (I/O Group #0)

13073

Chapter 4

Assigning Addressing Modes, Racks, and Groups

An I/O rack is an addressing unit that corresponds to 8 input image-table words and 8 output image-table words. A rack contains 8 I/O groups.

Choosing the Addressing Mode

I/O Group Numbers

1234

567

13074

Depending on I/O chassis size and I/O group size, an I/O rack can occupy a fraction of an I/O chassis, a full I/O chassis, or multiple I/O chassis.

Select an addressing mode for each chassis independently, based on the type and density of the I/O modules contained therein. When you select addressing mode, limit the number of remote I/O adapters and I/O modules to the maximum number that the PLC-5 processor can support.

Using 2Slot Addressing

When you select 2-slot addressing, the processor addresses two I/O module slots as one I/O group. Each physical 2-slot I/O group corresponds to one word (16 bits) in the input image table and one word (16 bits) in the output image table. The type (unidirectional or bidirectional) and density of a module that you install determines the number of bits that are used in each word.

Important: You cannot use 32-point I/O modules with 2-slot addressing.

4-3

Chapter 4

Assigning Addressing Modes, Racks, and Groups

8-Point I/O Modules

Eight-point digital discrete I/O modules have a maximum of eight inputs or up to eight outputs. Because they do not interfere with each other’s I/O image, you can place any mix of 8-point I/O modules (including bidirectional modules, such as block-transfer modules) in any order.

2Slot I/O Group with Two 8pt Input Modules

2-Slot

I/O Group

Input Terminals

00 01 02 03 04 05 06 07

Input Terminals

10 11 12 13 14 15 16 17

2Slot I/O Group with One 8pt Input Module and One 8pt Output Module

2-Slot I/O G roup

Input Terminals 00

01 02 03 04 05 06 07

Output Terminals

10 11 12 13 14 15 16 17

Output ImageTable Word Corresponding to the I/O Group.

17 16 15 14 12 10 07 06 05 03 02 01 00041113

Unused

Input ImageTable Word Corresponding to the I/O Group.

17 16 15 14 12 10 07 06 05 03 02 01 00041113

This

I/O group uses 16 bits of the input image table.

4-4

11867

Output ImageTable Word Corresponding to the I/O Group.

17 16 15 14 12 10 07 06 05 03 02 01 00041113

Output Bits Used

Input ImageTable Word Corresponding to the I/O Group.

17 16 15 14 12 10 07 06 05 03 02 01 00041113

This

I/O group uses 8 bits of the input image table and

Unused

Input Bits UsedAlways 0

8 bits of the output image table.

14965

Chapter 4

Assigning Addressing Modes, Racks, and Groups

16-Point I/O Modules

Sixteen-point digital discrete I/O modules have up to 16 inputs or up to 16 outputs. A 16-point I/O module uses a full word in the input or output image table.

2Slot I/O Group with One 16pt Input Module and One 16pt Output Module

2-Slot

I/O Group

Input Terminals 00

01 02 03 04 05 06 07 10 11 12 13 14 15 16 17

Output Terminals

00 01 02 03 04 05 06 07

11 12 13 14 15 16 17

01234567

IOIOIOIOIOIOIOIO

Word #

Output Image Table

0 1 2 3 4 5 6 7

I/O Group Designation

I/O Chassis Containing 16pt Modules

Input/Output Designation

Input Image Table

0 1 2 3 4 5 6 7

Output ImageTable Word Corresponding to the I/O Group.

17 16 15 14 12 10 07 06 05 03 02 01 00041113

Input ImageTable Word Corresponding to the I/O Group.

17 16 15 14 12 10 07 06 05 03 02 01 00041113

This

I/O group uses 16 bits of the input image table and

16 bits of the output image table.

15559

Because

each 16pt module uses a full word in the image table, the only type of module that you can install in a 2slot I/O group with a 16pt input module is an 8 or 16pt output module that performs a complementary function (inputs and outputs complement each other).

Since all blocktransfer modules are bidirectional, they cannot be used to complement either input or output modules.

4-5

Chapter 4

Assigning Addressing Modes, Racks, and Groups

Using 1Slot Addressing

When you select 1-slot addressing, the processor addresses one I/O module slot as one I/O group. Each physical slot in the chassis corresponds to an input and output image-table word. The type (unidirectional or bidirectional) and density of module that you install determines the number of bits used in these words.

1Slot

I/O Group with One 16pt Digital Discrete

I/O Module

1-Slot I/O Group

Input Terminals

0 01 02 03 04 05 06 07 10 11 12 13 14 15 16 17

1-Slot

I/O G roup

Output Terminals

00 01 02 03 04 05 06 07 10 11 12 13 14 15 16 17

8-Point I/O Modules

You can place any mix of 8- or 16-point I/O modules (including bidirectional modules such as block-transfer modules) in any order with 1-slot addressing. The 8- or 16-point modules do not interfere with the I/O image of the other 8- or 16-point modules.

16-Point I/O Modules

A single 16-point module uses an entire word of the processor image table.

Block-Transfer Module Addressing

To address a single-slot block transfer module in a 1-slot I/O group, use the assigned I/O rack and group numbers of the slot (in which the module resides) and 0 for the module number. To address a double-slot block-transfer module, use the assigned I/O rack number, the lower assigned I/O group number, and 0 for the module number.

Output ImageTable Word Corresponding to the I/O Group.

17 16 15 14 12 10 07 06 05 03 02 01 00041113

Input ImageTable Word Corresponding to the I/O Group.

17 16 15 14 12 10 07 06 05 03 02 01 00041113

A single 16pt module uses an entire word of image table.

4-6

11869

Chapter 4

Assigning Addressing Modes, Racks, and Groups

32-Point I/O Modules

To use 32-point I/O modules with 1-slot addressing, you must install, as a pair, an input module and an output module in two adjacent slots (even/odd pair) of the I/O chassis, beginning with I/O slot 0. If you cannot pair the modules in this way, one of the two slots of the pair must be empty. For example, if I/O slot 0 holds a 32-point input module, I/O slot 1 must hold an 8-, 16-, or 32-point output module (or a module using the backplane for power only); otherwise the slot must be empty.

1Slot

I/O Group with 32pt I/O Modules

Slot 0 Input Module I/O Group 0, 1

Slot 1 Output Module I/O Group 0, 1

2301

IOI IOIOO

4567

Wor d #

I/O Group Designation

I/O Chassis with 1Slot Addressing

Input/Output Designation

Word #

Output Image Table

0 1 2 3 4 5 6 7

Input Image Table

0 1 2 3 4

5 6

Output ImageTable Words Corresponding to I/O Groups 0 and 1.

17 16 15 14 12

Input

ImageT

able W

ords

17 16 15 14 12

05 03

Corresponding to I/O Groups 0 and 1.

05 03

02 01

02 01 00

000

001

000

001

14258

4-7

Chapter 4

Assigning Addressing Modes, Racks, and Groups

1/2Slot

I/O Group with One 32pt Input Module

17 010 7

17 10 07

Input Word 0

Output Word 0

Unused

Using 1/2Slot Addressing

When you select 1/2-slot addressing, the processor addresses one-half of an I/O module slot as one I/O group. Each physical slot in the chassis corresponds to two input and two output image-table words. The type (unidirectional or bidirectional) and density of the module that you install determines the number of bits that are used in each word.

You can mix 8-, 16- and 32-pt I/O modules in any order in the I/O chassis because 32 input bits and 32 output bits are available in

ImageTable Words Allocated for I/O Group 0

the image table for each I/O slot. When you use 8- and 16-pt I/O modules with 1/2-slot addressing, however, you use fewer total I/O bits in our image table.

1/2-Slot

I/O Group

1/2-Slot

I/O Group

Input

01 03 05 07

11 13 15 17

01 03 05 07

11 13 15 17

Input

00 02 04 06

10 12 14 16

00 02 04

10 12 14 16

1/2-Slot

I/O Group

1/2Slot

I/O Group

456

IIOO

I/O Group Designation

Word #

0 1 2 3 4 5 6 7

I/O Chassis with 1/2Slot Addressing

Input/Output Designation

Word #

0 1 2 3 4 5 6 7

Output Image Table

nputImageTable

14974

Not

Used

Always

Input Word 1

17 10 07

Output Word 1

17 10 07

Unused

This I/O group uses two words of the image table.

4-8

ImageTable Words Allocated for I/O Group 1

Chapter 4

Assigning Addressing Modes, Racks, and Groups

Summary

Table 4.A summarizes the guidelines for selecting an addressing mode.

Addressing Mode

2slot

1slot

1/2slot

Table 4.A Addressing

Guidelines

• Two I/O module slots = 1 group

• Each physical 2slot I/O group corresponds to one word (16 bits) in the input image table and one word

(16 bits) in the output image table

• When you use 16point I/O modules, you must install as a pair an input module and an output module in

an I/O group; if you use an input module in slot 0, you must use an output module in slot 1 (or it must be empty). This configuration gives you the maximum usage of I/O.

• You cannot use a blocktransfer module and a 16point module in the same I/O group because

blocktransfer modules use 8 bits in both the input and output table. Therefore, 8 bits of the 16point module would conflict with the blocktransfer module.

• You cannot use 32point I/O modules.

• One I/O module slot = 1 group

• Each physical slot in the chassis corresponds to one word (16 bits) in the input image table and one

word (16 bits) in the output image table

• When you use 32point I/O modules, you must install as a pair an input module and an output module in

an even/odd pair of adjacent I/O group; if you use an input module in slot 0, you must use an output module in slot 1 (or it must be empty). This configuration gives you the maximum usage of I/O.

• Use any mix of 8 and 16point I/O modules, blocktransfer or intelligent modules in a single I/O chassis.

Using 8point modules results in fewer total I/O.

• One half of an I/O module slot = 1 group

• Each physical slot in the chassis corresponds to two words (32 bits) in the input image table and two

words (32 bits) in the output image table

• Use any mix of 8, 16, and 32point I/O or blocktransfer and intelligent modules. Using 8point and

16point I/O modules results in fewer total I/O.

• With the processorresident local rack set for 1/2slot addressing, you cannot force the input bits for the

upper word of any slot that is empty or that has an 8point or 16point I/O module. For example, if you have an 8point or a 16point I/O module in the first slot of your local rack (words 0 and 1 of the I/O image table, 1/2slot addressing), you cannot force the input bits for word 1 (I:001) on or off.

Mode Summary

Assigning

Racks

The number of racks in a chassis depends on the chassis size and the addressing mode:

If using this chassis size:

4slot 1/4 rack 1/2 rack 1 rack

8slot 1/2 rack 1 rack 2 racks

12slot 3/4 rack 11/2 racks 3 racks

16slot 1 rack 2 racks 4 racks

With 2slot addressing, rack type is:

With 1slot addressing, rack type is:

With 1/2slot addressing, rack type is:

4-9

Chapter 4

Assigning Addressing Modes, Racks, and Groups

When assigning rack numbers, use the following guidelines:

One I/O rack number is eight I/O groups, regardless of the addressing

mode that you select.

You can assign from one to four racks in your processor-resident

local chassis (128 inputs and 128 outputs) depending on the chassis size and addressing mode. You cannot split a processor-resident local I/O rack over two or more chassis or assign unused processor-resident local I/O groups to remote I/O racks.

The default address of the processor-resident local rack is 0. You can

change the default to 1 by setting bit 2 in the processor control word (S:26) on the processor configuration screen; you must also change the mode of the processor from run to program to run.

An extended-local I/O and a remote I/O chassis cannot be addressed by

the same I/O rack number. For example, if an 8-slot extended-local I/O chassis is configured as I/O groups 0-3 of I/O rack 2, an 8-slot remote I/O chassis cannot be configured as I/O groups 4-7 of I/O rack 2.

Remote I/O Racks

You can assign a remote I/O rack to a fraction of a chassis, a single I/O chassis, or multiple I/O chassis:

I/O Rack No.0 I/O Rack No.1

01 23 45 67 01 23 45 67 0123 456 7

16slot chassis, two racks

One Power source not indicated Power source not indicated

I/O Rack No.3

0123

4slot chassis, 1/2 rack

One 2slot chassis, 1/4 rack each Power source not indicated

Two Power source not indicated

I/O Rack No.2

16slot chassis, one rackOne

16466

4-10

Chapter 4

Assigning Addressing Modes, Racks, and Groups

When assigning remote I/O rack numbers, use the following guidelines:

Limit the number of remote I/O rack numbers to those that your PLC-5

processor can support.

The PLC-5 processor and the 1771-ASB adapter module automatically

allocate the next higher rack number(s) to the remaining I/O groups of the chassis. For example, if you select 1/2-slot addressing for your processor-resident local chassis and you are using a 16-slot (1771-A4B) chassis, the processor will address racks 0, 1, 2, and 3 in this chassis.

BlockTransfer Module Racks Using 1/2Slot Addressing

To address a block-transfer module in a 1/2-slot I/O group, use the assigned rack number, the lower assigned I/O group number of the slot(s) in which the module resides, and 0 for the module number (Figure 4.4).

Figure 4.4 Example

I/O Group Number

BlockT

This example is valid for a singleslot

ransfer Module Address Using 1/2Slot Addressing

Rack 0 Rack 1 Rack 2 Rack 3

0–3 4–7 0–3 4–7 0–3 4–7 0–3 4–7

BT module only.

Rack = 2 Group = 4 Slot = 0

4-11

Chapter 4

Assigning Addressing Modes, Racks, and Groups

Addressing Complementary I/O

You configure complementary I/O by assigning an I/O rack number of one I/O chassis (primary) to another I/O chassis (complementary), complementing modules I/O group for I/O group. The I/O modules in the complementary chassis perform the opposite function of the corresponding modules in the primary chassis.

The PLC-5/15 and -5/25 processors operating as a remote I/O scanner support complementary I/O.

Use these guidelines when you configure your remote system for complementary I/O:

Assign the complementary I/O rack number to a chassis of any size.

Do not place an input module opposite an input module; they will use

the same bits in the input image table.

You can place an output module opposite another output module; they

use the same bits in the output image table. This allows you to use one output module to control a machine and use the other module with the same address to control an annunciator panel to display the machine condition. We do not, however, recommend this placement of modules for redundant I/O.

You cannot configure the PLC-5 processor-resident local chassis with

complementary I/O. The PLC-5 processor communicates with each processor-resident local I/O chassis as if it were a full I/O rack (eight I/O groups). Thus, if the processor-resident local chassis contains four I/O groups, the remaining four I/O groups of that I/O rack are unused; you cannot assign them to another chassis.

You cannot use complementary I/O with a chassis that uses a

combination of 32-point I/O modules and 1-slot addressing or 16-point I/O modules with 2-slot addressing.

Important: For the PLC-5/15 and -5/25 processors, an autoconfigure is performed before the scanner begins communicating with the adapter.

Placing the Modules with 2Slot Addressing

Figure 4.5 shows a possible module placement to configure complementary I/O using 2-slot addressing.

4-12

Chapter 4

Assigning Addressing Modes, Racks, and Groups

Primary 16Slot

Chassis

I/O Group

Number

Complementary 16Slot Chassis

Primary 16Slot

Chassis

I/O Group

Number

Complementary

Chassis Not

Allowed

Except for Output

Figure 4.5 Complementary

021 34567

O8O

02134567

Outputs in the complementary chassis use the same bits in the output image table as the outputs in the primary chassis.

8I8

I16O

I/O Configurations with 2Slot Addressing

E P

T Y

O8O

E M P

Example A

Example B

P T Y

E M P T Y

Double–slotBTDouble–slot

M P T Y

333

I = Input Module O = Output Module BT = Block Transfer Module 8 = 8point I/O Modules 16 = 16 point I/O Modules

1 Output modules use the same output image transfer bits 2 Can be 8point input or output module or singleslot block transfer module 3 Must be empty if corresponding primary slot is block transfer module

13079

4-13

Chapter 4

Assigning Addressing Modes, Racks, and Groups

Placing the Modules with 1Slot Addressing

Figure 4.6 shows a possible module placement to configure complementary I/O using 1-slot addressing.

Primary 16Slot

Chassis

I/O Group

Number

Complementary 16Slot Chassis

Primary 16Slot

Chassis

I/O Group

Number

Complementary 16Slot Chassis

Figure 4.6 Complementary

IIO IOO

021 34567

OO I I O OI

021 34567

I/O Configurations with 1Slot Addressing

P T

Example A

Example B

Double–slot

01234567

P T

01234567

OI I I OO

I, O,

IIIOOO

4-14

I = Input Module (8 or 16point) O = Output Module (8 or 16point) BT = Block Transfer Module

1 Output modules use the same output image table bits 2 Can be input or output module (8 or 16point) singleslot block transfer module 3 Must be empty if corresponding primary slot is block transfer module

13080

Chapter 4

Assigning Addressing Modes, Racks, and Groups

Placing the Modules with 1/2Slot Addressing

Figure 4.7 shows a possible module placement to configure complementary I/O using 1/2-slot addressing.

Figure 4.7 Complementary

Primary 12Slot

Chassis

I/O Group

Number

Complementary

12Slot Chassis

Primary 12Slot

Chassis

I/O Group

Number

Complementary

12Slot Chassis

I/O Configurations with 1/2Slot Addressing

IIO IOO

Double-slot

OO I I O OI

Example A

01 232345456767010123234545676701012323454567

Example B

I, O , BT

I = Input Module (8, 16, 32point) O = Output Module (8, 16, 32point) BT = Block Transfer Module

14261

4-15

Chapter 4

Assigning Addressing Modes, Racks, and Groups

Placing Complementary I/O Modules

See Table 4.B for a summary of 8-, 16-, and 32-point I/O module

placement guidelines. See Table 4.C for a summary of block-transfer

module placement guidelines.

Table 4.B

Placement

Complementary I/O

Addressing

Method

Types of Modules Used: Placement

2Slot 8 point

1Slot 8 point, 16point,

1/2Slot 8 point, 16point, 32point

Table 4.C

Placement

Complementary I/O

Addressing

Method

Using singleslot modules: Using doubleslot modules:

2Slot

• The right slot of the primary I/O group can be

another singleslot block transfer module, or an 8point input or output module.

• The left slot of the complementary I/O group must be

empty.

• In the right slot of the complementary I/O group, you

can place an 8point output module; this slot must be empty if the corresponding slot in the primary I/O group is a singleslot block transfer module.

Summary for 8, 16, and 32point Modules Used in

Guidelines

Install input modules opposite output modules and output modules opposite input modules.

Summary for Blocktransfer Modules Used in

BlockTransfer Placement Guidelines in Primary Chassis

• The left slot of the complementary I/O group must be

empty.

• In the right slot of the complementary I/O group, you

can only place an 8point output module (if any).

4-16

1Slot Leave the corresponding I/O group in the

complementary chassis empty.

1/2Slot Leave the corresponding I/O group in the

complementary chassis empty.

• The left slot of the two corresponding I/O slots in the

complementary chassis must be empty.

• In the right slot of the two corresponding I/O slots in

the complementary chassis, you can place an input, output, or singleslot block transfer module (if any); the modules can be either 8point or 16point I/O modules.

• The left slot of the two corresponding I/O slots in the

complementary chassis must be empty.

• In the right slot of the two corresponding I/O slots in

the complementary chassis, you can place an input, output, or singleslot block transfer module (if any); the modules can be 8point ,16point and/or 32point I/O modules.

Chapter

Choosing Communication

Chapter

Objectives

Identifying Classic PLC5 Processor Channels/Connectors

Use this chapter to choose the appropriate communication for

your application.

If you want to read about: Go to

Identifying channels for the processor 52

Configuring communication for your processor

Configuring Data Highway Plus (DH+)

Connecting DH+ to Data Highway

Choosing programming software 5-10

Choosing programming terminal connections

page:

53

510

This section illustrates and describes the processor front-panels. After you

are familiar with the processor hardware, see page 5-3 for information on

configuring communication.

System Design Determined

Choosing Hardware

Placing System Hardware

Assigning Addressing Mode, Racks, and Groups

Choosing Communication

Planning Your System Programs

Selecting Interrupt Routines

Transferring Discrete and Block Data

Calculating Program Timing

5-1

Chapter 5

Choosing Communication

Figure 5.1

Processor

PLC5/10 Processor PLC5/12, 5/15,

Communication Indicator ACTIVE/FAULT (green/red)

Keyswitch

Connect programming terminal here

Connect DH+ link here

Front Panels

Battery Indicator (red)

Processor RUN/FAULT Indicator (green/red)

FORCE Indicator (amber)

Battery

Holder

Write the DH+ network station number on this label

PLC5 family member designation

and 5/25 Processors

REM I/O Indicator ACTIVE/FAULT (green/red)

Adapter Indicator (green)

Connect remote I/O link here

P R O G

Connector Name Connector

Description

Type

Programming terminal 9pin, Dshell Use this connector to directly connect a programming terminal to the processor. This programming

terminal connector has a parallel connection with the 3pin DH+ communications link connector.

DH+ communications link 3pin Use this connector to connect to DH+ communications link.

Remote I/O 3pin Use this connector for the remote I/O link. (This connector is not available for a PLC5/10 processor.)

5-2

Chapter 5

Choosing Communication

Configuring Communication for Your Processor

You select scanner or adapter mode for your PLC-5 processor by setting

switches.

Configure Processor Communication

You configure the processor by setting switch assemblies SW1 and SW2

on the processor. See Appendix A for information on switch settings.

Follow these steps to plan configuration for your processor.

1. Select scanner or adapter mode on switch assembly SW1 (the

PLC-5/10 and -5/12 can not be configured as scanners).

2. If you select adapter mode, assign a rack address (rack number 0-77

octal) on switch assembly SW2. The supervisory processor uses this address to reference the adapter-mode processor.

3. If you select adapter mode, specify the simulated chassis size, either

an 8-slot or 16-slot I/O chassis, and the corresponding first I/O group on switch assembly SW2. The simulated chassis size and first I/O group determine the number of discrete-transfer data words (4 words for an 8-slot chassis, 8 words for a 16-slot chassis) that the processor transfers to and from the supervisory processor during the supervisory processor’s remote I/O scan.

Configuring a DH+ Link

Note that the actual size of the chassis has no bearing on the simulated size of the chassis.

You can use a DH+ link for data transfer to higher level computers and as a

multiple PLC-5 processor programming link. A PLC-5 processor can

communicate over a DH+ link with other processors and with a

programming terminal. You can connect a maximum of 64 stations to a

DH+ link. The network operates under a token-passing protocol with data

transfer at 57.6 kbps.

See your programming software documentation set to configure a

processor for DH+ communication.

Estimating Data Highway Plus Link Performance

Many factors can affect the performance of your DH+ link, including:

nodes size and number of messages message destination internal processing time

5-3

Chapter 5

Choosing Communication

Nodes

Nodes affect transmission time in the following ways:

During one complete token rotation, each node on the DH+ link

receives the token whether or not it has something to send.

Each node spends from 1.5 ms (if it has no messages to send) to 38 ms

(maximum time allotted) with the token, assuming there are no retries (Figure 5.2).

Figure 5.2

Token

Passing

Station

Min.

1.5 ms

the token

with

DH+ link

Station

Max. 38 ms with the token

Size and Number of Messages

A PLC-5 processor encodes messages into packets for transmission on the

DH+ link. The maximum number of data words in a packet depends on

the sending station and command type. This limit comes from the network

protocol, which limits a station to transmitting a maximum of 271 bytes

per token pass. A station can send more than one message in a token pass,

provided that the total number of combined command and data bytes does

not exceed 271.

If a message exceeds the maximum packet size allotted, however, the

sending station will require more than one token pass to complete the

message. For example, if a PLC-5 processor wants to send a 150-word

message, it will have to transmit two messages, possibly requiring many

token rotations.

5-4

The number of messages a station has to send also affects throughput time.

For example, if a station has three messages queued and a fourth is

enabled, the fourth message may have to wait until the previous three

are processed.

Chapter 5

Choosing Communication

Message Destination

Throughput times vary depending on whether a receiving station can

process the message and generate a reply before that station receives the

token. Figure 5.3 assumes that station 1 wants to send a message to

station 4.

Figure 5.3

Message

DestinationExample 1

Station

Message

Station

Station 1 has the token. Only the station that has the token can send a

message. Station 1 sends the message to station 4. Now station 1 must

pass the token on to the next highest station number, which is station 2.

Station 2 has the token. Assume that station 2 has messages to send and

holds the token for 30 ms. During this time, station 4 has processed the

message from station 1 and has a reply queued up. When finished, station

2 passes the token on to the next highest station number, which is station 4.

Station 4 can now reply to the message from station 1. This completes the

message transaction.

In Figure 5.3, station 4 has had time to process the message and generate a

reply. But, that is not the case with station 2 in Figure 5.4.

Figure 5.4

Message

DestinationExample 2

Station

Message

Station

5-5

Chapter 5

Choosing Communication

In Figure 5.4, we assume that station 1 wants to send the identical message

as shown in Figure 5.3 but to station 2. Station 1 has the token. Station 1

sends the message to station 2 and then passes the token on to station 2.

Now station 2 has the token but has not had time to generate a reply to

station 1. So station 2 sends any other messages it has queued and then

passes the token on to station 4. Stations 4, 5, and 1 all receive the token

in order and send any messages they have queued. The token then returns

to station 2, which then sends its reply to station 1. In this example, it took

an extra token pass around the network to complete the message

transaction even though the message was identical to the one shown in

Figure 5.3.

Internal Processing Time

Internal processing time depends on how busy a given processor on the

network is when sending or receiving a message.

For example, processor A has just received a READ request from

processor B on the network. If processor A already has three messages of

its own to send, the reply to the READ request from processor B will have

to wait until the station completes the processing of the messages queued

ahead of it.

Average DH+ Link Response Time Test Results

This section shows graphically the results of testing performed on a DH+

link where the number of stations and words sent in the message varies.

Figure 5.5 shows the average response time of messages of varying sizes

on a DH+ link with a varying numbers of stations. It also gives you an

idea of the typical response time you can expect on a given DH+ link.

5-6

Chapter 5

Choosing Communication

Response

Time

(Sec)

Figure 5.5

Average

5.0

4.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0.0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22

Response T

Number of PLC5 Processors

ime for all PLC5 Processors

Figure 5.6 shows the effect of a programming terminal on message response time under various configurations.

Figure 5.6 Response

ime Increase (%)

50 W

100 W

•

250 W

500 W

W=Words

Effect

Response

Time

(%)

1 2 3 4 5 6 7 8 9 10111213141516171819202122

Number of PLC5 Processors

Test Setup

One to 22 PLC-5 processors were used with one programming terminal online. Each PLC-5 processor executes 1K of ladder logic.

50 W

100 W

•

250 W

500 W

W=Words

5-7

Chapter 5

Choosing Communication

Initial testing was done with one PLC-5 processor writing data to another PLC-5 processor. The response time was recorded. Additional PLC-5 processors were added to the network, each writing the same amount of data to a PLC-5 processor at the next highest station address. Four separate tests were run using data transmissions of 50, 100, 250, and 500 words.

Application Guidelines

Consider the following application guidelines when configuring a DH+ link for your system.

Configure the number of nodes on your network dependent on the size

and frequency of messages exchanged between devices.

Limit the number of nodes on your network when you are trying to

achieve fastest control response time.

Do not add or remove nodes from the network during machine or

process operation. If the network token resides with a device that is removed, the token may be lost to the rest of the network. The network is automatically re-established, but it could take several seconds. Control would be unreliable or interrupted during this time.

Include watchdog timers in logic programs for DH+ transfer of data (to

provide an orderly shutdown if failure occurs).

Do not program processors online during machine or process operation.

This could result in long bursts of DH+ activity that could increase response time.

When possible, add a separate DH+ link for programming processors to

keep effects of the programming terminal from the process DH+ link.

Connecting Devices to DH+ Link

You can connect devices on a DH+ link with:

daisy-chain connection trunkline/dropline connection

5-8

See Figure 5.7. Also, see the Data Highway and Data Highway Plus Cable Guide, publication 1770-6.2.1, for complete network wiring instructions.

Chapter 5

Choosing Communication

PLC5 PLC5 PLC5 PLC5

Daisychain configuration

PLC5 PLC5 PLC5

Figure 5.7 Examples

of DH+ Link Connections (DaisyChain and

Trunkline/Dropline)

T50

When the processor is an end device, terminate the link.

Station connector (see notes)

Trunkline/dropline configuration

T50

Notes:

Once a programming terminal is connected to one processor, it can communicate with each processor you connect on DH+.

Use only AllenBradley station connectors.

13061

5-9

Chapter 5

Choosing Communication

The PLC-5 processor has two connectors that are electrically identical. Connection to either one provides the same communication link. These connectors are:

9-pin D-shell DH+ COMM INTFC connector 3-pin DH+ COMM INTFC connector

Connecting a DH+ Link to Data Highway

Choosing Programming Terminal Connection

You can connect DH+ links to Data Highway via a communication interface such as the 1785-KA module. The 1785-KA module allows nodes on a DH+ link to communicate with nodes on Data Highway or on another DH+ link.

See your local Allen-Bradley sales office or distributor for more information on connecting DH+ to Data Highway. Also, see the Data Highway/Data Highway Plus Protocol and Command Set, publication 1770-6.5.16, for more information.

You can connect your programming terminal to a PLC-5 processor in several ways:

direct connect to the DH+ link remote connection (DH+ to Data Highway to DH+) serial connections

Direct Connect to DH+ Link

Use a 1784-KT to connect a T53 or IBM-compatible programming terminal directly to a processor or to a DH+ link that connects processors (Figure 5.8).

5-10

Chapter 5

Choosing Communication

Figure 5.8 Connection

to DH+ Link through 1784KT Communication

Interface Module

DH+ link

1784CP

T53 or IBM compatible with 1784KT

PLC5/10, or 5/25 processor

5/12 5/15,

Use a 1784-KL/B to connect a T47 programming terminal directly to a processor or to a DH+ link that connects processors (Figure 5.9).

Figure 5.9 Connection Interface Module

to DH+ Link through 1784KL Communication

DH+ link

1784CP

T47 with 1784KL

PLC5/10, or 5/25 processor

5/12,

5/15,

Remote Connection

The remote programming configurations available with the 1784-KT, 1784-KT2, and 1784-KL boards provide you communication with processors on other DH+ links in the network to expand the range of processors that you can use for program development (Figure 5.10).

5-11

Chapter 5

Choosing Communication

Figure 5.10 Example

DH+ to Data Highway to DH+ Link Configuration

1785KA

Data Highway

Remote DH+ link

PLC5/10, 5/12, 5/15, 5/25

processor

17195

Serial Connections

You can connect a programming terminal to a PLC-5/10, -5/12, -5/15, or

-5/25 processor through a serial port (COM1 or COM2) on the terminal with one of the following communication modules:

1785-KE Series A or B Communication Interface Module

(resides in a 1771 I/O rack)

1770-KF2, Series B Communication Interface Module

(desktop unit as shown in Figure 5.12)

Important: The communication driver is interrupt-driven; the serial port must support hardware interrupts. On most machines, COM1 and COM2 support these interrupts.

5-12

Chapter 5

Choosing Communication

Figure 5.11 1785KE

(Series B) Connection through an RS232C Serial Port

DH+ link

T53 serial port COM1 or COM2

Figure 5.12 1770KF2/B

1785KE Series B

PLC5/10, 5/12, 5/15, or 5/25 processor

Connection through an RS232C Serial Port

DH+ link

T53 serial port COM1 or COM2

1770KF2/B

PLC5/10, 5/12, 5/15, or 5/25 processor

5-13

Chapter

Planning Your System Programs

Chapter

Objectives

This chapter covers basic programming considerations for planning a Classic PLC-5 programmable controller system.

System Design Determined

If you want to read about: Go to

Planning application programs 61

Using SFCs 61

Preparing programs for your application

Addressing the data table 67

Using the processor status file 69

See your programming software documentation for a discussion of the instructions used in ladder-logic programming.

page:

63

Choosing Hardware

Placing System Hardware

Assigning Addressing Mode, Racks, and Groups

Choosing Communication

Planning Your System Programs

Selecting Interrupt Routines

Transferring Discrete and Block Data

Calculating Program Timing

Planning Application Programs

Using SFCs with PLC5 Processors

Use the functional specification that you previously developed to define your programming application. The specification is a conceptual view of your application and is used to determine your main program, sequential function chart (SFC), and logic requirements.

In planning and developing the programs for your application, we recommend that you use the program-development model shown in chapter 1, “Understanding Your System.”

Use SFCs as a sequence-control language by which you can control and display the state of a control process. Instead of one long program for your application, divide the logic into steps and transitions. The display of these steps and transitions lets the user see what state the machine process is in at a given time.

6-1

Chapter 6

Planning Your System Programs

008

012

002

Initial Step

003

Each step corresponds to a control task (displayed as a box); each step is related to a program file that contains the logic for the associated control task. Each transition (displayed as a horizontal line) examines conditions, specified in an associated program file, that determines when the processor

007

011

005

can continue to the next task.

Deciding How to Use an SFC

After you identify the major areas of machine operation, convert the

004

006

009

010

logical paths and steps that you labeled in your design specification to SFC

013

014

015

If you have: Then draw: Using these rules:

An independent machine state A step with its transition A step must always be followed by a transition.

building blocks. Table 6.A helps explain when to use which SFC building blocks.

Important: At this point, do not worry about the actual logic for each step and transition. After you complete the SFC, you can develop the logic.

Table 6.A Deciding

When to Use the SFC Structures

A clearly defined chain of events that occur sequentially

For example, in one heattreating area, the temperature must ramp up at a particular rate; maintain the temperature for a certain duration, then cool at a particular rate.

Two or more alternative paths where only one is selected

For example, depending on a build code, one station must either drill or polish.

Two or more parallel paths that must be scanned simultaneously at least once

For example, communications and block transfers must occur while control logic is executing.

A simple path of steps and transitions

A selection branch The transitions beginning each path are scanned from left

A simultaneous branch All paths are active in the structure.

For design purposes, number steps and transitions consecutively from 2.

Start the path with a step; end the path with a transition.

to right. The first true transition determines the path taken.

You can define up to 7 parallel paths.

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Chapter 6

Planning Your System Programs

Application Example for SFCs

For typical SFC applications, an SFC program controls the order of events in your process by issuing commands. A command, such as

fwdcyr_cmd

to move a conveyor forward, is simply a data table storage bit (for example B3:0/7) that you set up in the SFC. You then program the logic for

fwdcyr_cmd in a separate ladder program to control the actual outputs to

move the conveyor. You can have only one main program file, which is either an SFC or a

ladder-logic program. You enter the programs into your computer using the SFC or ladder editor. For more information on entering SFCs or ladder logic, see your programming software documentation set.

Programming Considerations for SFCs

Use the information in Table 6.B for SFC rules for special programming.

Preparing the Programs for Your Application

Table 6.B

Rules for Special Programming Considerations

SFC

If you have: Use these rules:

To jump within the SFC Use a GOTO statement and label.

A step that needs to be run in multiple places within the SFC

A step that can be ignored based on logic conditions

An SFC branch structure within another branch structure (nesting)

A miniSFC (compressed steps) within the main SFC

To reset the logic in an SFC program Set the SFR instruction to reset the chart.

To disable an MCP Set the disable bit on the Processor Configuration screen.

See your programming software documentation for further information on any of the techniques listed in this table.

Repeat the step where needed or use a global subroutine that gets called from multiple steps.

Create two selection branches, one with and one without the step; or place the step in a subroutine; or combine the step with another step that is segregated by an MCR zone.

Nest the branch structures. The software supports as many levels of nested branches as you can store based on processor memory.

Create an SFC macro. A macro begins a with a step; the transition for the ending step follows the macro.

This section uses a drill-machine application example. Information on the program entry phase is in the programming software documentation set.

You can use only one main program; but you can still apply some of the steps by incorporating them into your main SFC and supporting ladder programs.

6-3

Chapter 6

Planning Your System Programs

FWD

AUTO

Organizing a Machine Example

This section uses an example of a specific machine operation to show how to identify conditions and actions and how to group the actions into steps of machine operation.

Figure 6.1 Hardware

OFF

Block Diagram and Description of Machine Process

L oad

St a t i on

FWD

Conveyor

Motor

Advance

Assembly

LS2

Held Open

A description of this operation might be as follows:

1. The operator starts the conveyor by selecting AUTO.

2. The operator puts a block of wood onto the conveyor.

3. The wood moves into position and actuates LS1.

4. When the wood is in position:

a. the conveyor stops b. CL1 clamps the wood c. the drill station moves forward

5. The drill station moves forward and closes LS3. This

action turns on the drill motor.

Drill

Motor

LS1

.. ..

NO NO

6. The drill station moves to full depth and closes LS4. This action:

a. stops forward motion of the drill station b. initiates a 2second dwell

7. The drill station backs up after the 2second dwell.

8. The drill motor stops when LS3 is released.

9. The drill station reaches home position and opens LS2. This action:

a. stops the reverse motion b. opens the clamp c. starts the conveyor forward

10. The wood is ejected when LS5 toggles to indicate that the cycle is complete.

LS4LS3

LS5

load

St a t i on

Clamp

CL1

6-4

Chapter 6

Planning Your System Programs

We recommend that you then create a rough-draft SFC to represent the operation (see Figure 6.2).

Figure 6.2

Machine Example Functional Specification

Drill

Step

Transition

initialization

010 AUTO operator starts cycle

conveyor forward

011 LS1 wood in position

drill

012 LS4 hole drilled

dwell

013 TMR1 dwell timer done

reverse drill

014 LS2 station home

eject

015 LS5 wood ejected

Creating the Detailed Analysis for Your Functional Specification

Begin determining the details of your process as discussed in chapter 1, “Understanding Your System.” Identify the hardware requirements. Table 6.C identifies hardware requirements for the inputs and outputs of the drill machine.

6-5

Chapter 6

Planning Your System Programs

Table 6.C Hardware

Input Part Description

AUTO selector switch select automatic mode

LS1 N.O. limit switch part in place

LS2 N.C. limit switch drill station home

LS3 N.O. limit switch drill motor on

LS4 N.O. limit switch drill station at full depth

LS5 N.O. limit switch cycle complete

DSF drive motor move drill station forward

DSB drive motor move drill station back

DM drill motor drill motor on

CL1 electric clamp clamp 1 on

CMF drive motor move conveyor forward

TMR1 timer dwell timer

Requirements for the Inputs and Output of the Drill Example

Use the hardware requirements (with the functional specification) to match the inputs and outputs with the actions of the process. Table 6.D shows the hardware requirements with the general description of the drill machine example.

Table 6.D

of Conditions and Actions for the Drill Example

List

When this happens: This happens:

AUTO switch closes Conveyor moves forward (CMF = on)

LS1 closes Conveyor stops

Clamp holds wood Drill station advances

LS3 closes Drill motor starts (DM = on)

LS4 closes Drill station stops

Dwell timer starts

Timer done Drill station backs up (DSB = on)

LS3 opens Drill motor stop (DM = off)

LS2 opens Drill station stops

Clamp releases wood Conveyor starts

LS5 closes Wood is ejected

(CMF = off) (CL1 = on) (DSF = on)

(DSF = off) (TMR1 = on)

(DSB = off) (CL1 = off) (CMF = on)

6-6

Chapter 6

Planning Your System Programs

Once you identify the individual actions, you can add these actions to your plan to complete your program. Once you have an SFC program that defines the individual machine actions for your process, you can create a ladder-logic program that controls the outputs of those machine actions. It does not matter in what order you program these rungs. This program merely contains the ladder logic that defines a command for each machine action in your process.

Program Entry

When you finish your detailed analysis, you have your main program planned. Now, enter your program into your terminal.

Addressing Data T

Input Output

ExamineData ReturnResults

DATA STORAGE

I/O Image Files

BlockTransfer Files

Other Data Files

PROGRAM FILES

able Files

DataData

PLC-5 memory is divided into two areas: data and program-file storage.

Areas of Storage Description

Data All of the data the processor examines or changes is stored in files in data

storage areas of memory. These storage areas store:

•Data received from input modules

•Data to be sent to output modules; this data represents decisions made

by the logic

•Intermediate results made by the logic

•Preloaded data such as presets and recipes

•Control instructions

•System status

Program Files You create files for program logic, depending on the method you are using:

ladder logic, sequential function charts, and/or structured text. These files contain the instructions to examine inputs and outputs and return results.

Data Table Memory

You can address data files in different formats when you write your programs. Refer to Table 6.E for valid data table file-type specifications.

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Chapter 6

Planning Your System Programs

Table 6.E

able Memory Usage

Data

Memory Used in Over

File Type

Output Image O 0 2 1/word

Input Image I 1 2 1/word

Status S 2 2 1/word

Bit (binary) B 3 2 1/word

Timer T 4

Counter C 5

Control R 6

Integer N 7

FloatingPoint F 8

ASCII A 3999 2

BCD D 3999 2 1/word

Undefined  9999 2 0

This

is the default file number

File Type Identifier

. For this file type, you can assign any file number from 3 thru 999.

File

Number

head for Each File

(16bit words)

2 3/structure

2 1/word

2 2/float word

Memory Used

(16bit words) per

Word, Float Word,

Character, or Structure

/2 per character

Data table files are contiguous in memory. Size in words for I/O files 0 and 1 are:

For this processor: Files O0 and I1 memory size:

PLC5/10, 5/12, 5/15 Is fixed at 32 words

PLC5/25 Varies from 3264 words (32 is the default)

6-8

Status file 2 is fixed at 32 words for each processor. Files 3-999 vary in size. These files contain only the number of words corresponding to the highest address that you assign. Each B, N, A, and D file can be 1,000 words maximum. Each F file can be 1,000 float words (32-bit words) maximum. Each T, C, R, and SC file can be 1,000 structures maximum.

Data Table Addressing Formats

Address Type Description Example

Chapter 6

Planning Your System Programs

Logical address Alphanumeric coded format to specify

the data location

I/O image address Logical address format, but relates

physical locations in the I/O chassis to memory locations in the I/O image file

Indirect address Logical address format, but allows you to

change address values in the base address with your ladder logic program

Indexed address Index prefix (#) is followed by a logical

address format, but it adds an index value (offset) from processor status file to the base address

Symbolic address ASCII character string that relates the

address (file, structure, word, or bit) to a descriptive, meaningful name that you assign

Using

the Processor

Status File

Use the Processor Status screen to monitor:

processor status information major and minor faults STIs program scan times I/O status

N23:0 addresses an integer file 23, word 0

I:017/17 addresses input file word 017 (octal), bit 17 (octal), which corresponds to rack 01, module group 7, and terminal 17

N[N7:6]:0 has the file number as the variable The file number is stored in integer file 7, word 6

When #N23:0 is the indexed address and the offset value stored in the processor status file is 10, then

•the base address is integer file 23, word 0

•and the offset address is integer file 23, word 10

For example, a floating point address F10:0 could be given a symbolic address of Calc_1. These symbols are a feature of the programming software and not of the

processor. Guidelines for setting up an address are as follows:

•Start the name with an alphabetic character.

•The symbol must begin with a letter and can have up to 10 of the following

characters: AZ (upper and lower case), 09, underscore (_) and @.

•You can substitute a symbolic address for structure, word, or bit addresses.

•Record the symbols you define and their corresponding logical addresses.

Processor status data is stored in status file S2. See Table 6.F.

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Chapter 6

Planning Your System Programs

Table 6.F Processor

This word of the status file: Stores:

Arithmetic flags

S:0

S:1

S:2

S:3 to S:6

S:8 Last program scan duration (in ms)

S:9 Maximum program scan duration (in ms)

S:10 Minor fault bits

S:11 Major fault bits

S:12 Fault code storage location

S:13 Program file where fault occurred

S:14 Rung number where fault occurred

S:16 I/O status file number storage location

S:18

S:19 Processor clock month

S:20 Processor clock day

S:21 Processor clock hour

S:22 Processor clock minute

S:23 Processor clock second

S:24 Indexed addressing offset

S:25 (PLC5/12, 5/15, 5/25 only) I/O adapter image file

S:26 User control bits for processor startup routine

• bit 0= carry

• bit 1 = overflow

• bit 2= zero

• bit 3 = sign

Processor status and flags

Switch settings:

• bits 0  5 = DH+ station #

• bit 7 = set is scanner; reset is adapter (PLC5/15, 5/25 only)

• bit 11, 12 = HW addressing

• bit 13, 14 = EEPROM

• bit 15 = set is memory unprotected

Active Node table: Word Bits DH+ Station # 3 015 0017 4 015 2037 5 015 4057 6 015 6077

Processor clock year

Status File Addresses

bit 12 0 0 illegal 1 0 1/2slot 0 1 1slot 1 1 2slot

bit 13 0 0 EEPROM transfer if processor memory bad 0 1 EEPROM transfer disabled 1 1 EEPROM transfer at powerup

bit 11

bit 14

6-10

This word of the status file: Stores:

S:28 Program watchdog setpoint (in ms)

S:29 Fault routine file

S:30 STI setpoint (in ms)

S:31 STI file number

Chapter 6

Planning Your System Programs

6-11

Chapter

Selecting Interrupt Routines

Chapter

Objectives

Using Programming Features

This chapter covers interrupt routines that you can choose to include when you program your system.

System Design Determined

If you want to read about: Go to

page:

Using programming features 71

Writing a fault routine 73

Choosing Hardware

Placing System Hardware

Assigning Addressing Mode, Racks, and Groups

Choosing Communication

Planning Your System Programs

Selecting Interrupt Routines

Transferring Discrete and Block Data

Calculating Program Timing

Use your design specification to determine if you need one or more of the following programming features:

If a portion of logic should execute:

Immediately on detecting conditions that require a startup

Immediately on detecting a major fault

Example:

Restart the system after the system has been shut down

Send critical status to a supervisory processor via DH+ after detecting a major fault

program execution control power-up routines

Use: By doing the following:

Powerup/Fault Routine

Fault Routine Create a separate file for a controlled response to a major fault. The first fault

Create a separate file for a controlled startup procedure for the first time that you start a program or when you start a program after system down time. The processor executes the powerup/fault routine to completion.

detected determines which fault routine is executed. The processor executes the fault routine to completion. If the routine clears the fault, the processor resumes the main logic program where it was interrupted. If not, the processor faults and switches to program mode.

7-1

Chapter 7

Selecting Interrupt Routines

Program Execution States

User programs in the Classic PLC-5 processor are always in one of the following five states: completed, ready, executing, waiting, or faulted.

Completed State

Program has completed execution

or has not yet started execution

Ready State

Program would be executing if it were of a higher priority;

all programs pass through this state; there can be

several programs in this state at any given time

Rescheduling Operation

Waiting State

While block transfer is taking place,

a rescheduling operation is performed

and lowerpriority programs are executed

(unless all other executions are prohibited by

a UID/UIE zone around the block transfer)

Yes

Waiting State

Program is ready for execution but is waiting

for some event to occur (such as an input to

transition or a timer to complete)

Executing State

Program is executing; only one program can be in this

state at one time

Has a new program

with a higher priority

become ready?

(e.g., an MCP, STI, PII)

Does the program fault?

Does the program request

a remote block transfer?

(STI and PII routines only)

Completed State

Program has completed execution

or has not yet started execution

Rescheduling Operation

Yes

Does an appropriate fault routine

Faulted State

A runtime error

has occurred within

the program

Program counter is adjusted to point to

next instruction

choose to clear the fault?

All active user programs

are aborted and processor

enters faulted state

Rescheduling Operation

Yes

7-2

Chapter 7

Selecting Interrupt Routines

Writing a Fault Routine

You can write a fault routine that the processor runs when it detects a major fault. For example, if your program file becomes corrupted, you can tell the processor to interrupt the current program, run your fault routine and then continue processing the original program.

This section shows you how to set and write a fault routine and how to protect your processor from powering up in run mode after a power loss.

Responses to a Major Fault

When the processor detects a major fault, the processor immediately interrupts the current program. If a fault routine exists (i.e., specified in S:29 as a fault routine), the processor runs that fault routine program for recoverable faults. Then, depending on the type of fault, the processor:

returns to the current ladder program file if the processor can recover

from the fault

enters fault mode if the processor cannot recover from the fault

For example, the rung in Figure 7.3 includes an instruction that causes a major fault.

Figure 7.3

Ladder Logic for a Fault

Sample

][

Causes a major fault

In the example in Figure 7.3, the processor runs the fault routine after detecting the fault. If the fault routine resets the faulted bits, the processor returns to the next instruction in the program file that follows the one that faulted and outputs on the remainder of the rung.

If you do not program a fault routine for fault B, the processor immediately faults.

The bits in word 11 of the processor status file indicate the type of major fault. See Table 7.G to determine whether a fault is recoverable.

7-3

Chapter 7

Selecting Interrupt Routines

Table 7.G Response

This

00 Corrupted program file

01 Corrupted address in ladder program (see fault codes 1019)

02 Programming error (see fault codes 2029)

05 Startup protection fault (see word 26, bit 1)

07 Usergenerated fault; processor jumped to fault routine

08 Watchdog faulted

13 STI file does not contain ladder logic or does not exist

03 Processor detected an SFC fault (see fault codes 7479)

04 Processor detected an error when assembling a ladder

09 System is configured wrong; you installed a RAM cartridge but

10 Nonrecoverable hardware error

14 Fault routine does not contain ladder logic or does not exist

15 Fault routine program file does not contain ladder logic

to Major Faults (W

bit:

Indicates this fault: And the fault is:

Processor sets bit 5; if your fault routine does not reset this bit, the processor inhibits startup

(see fault codes 09)

program file (see fault code 70)

configured the system for an EEPROM or you violated 32point I/O module placement rules for 1slot addressing

ord 11 of the Status File)

Recoverable

hfl i

the fault routine can instruct the processor to clear the fault and then

the fault and then resume scanning

the program.

Notrecoverable

Not recoverable the processor enters fault mode without scanning

without scanning the fault routine.

A remote block transfer from a fault routine causes the processor to stop scanning all programs until the block transfer completes.

Major Fault Codes

Table 7.H lists major fault codes. The processor stores the fault code in word 12 of the processor status file.

7-4

Chapter 7

Selecting Interrupt Routines

Table 7.H

Fault Codes

Major

Code Fault

0009 Reserved for userdefined fault codes

12 Bad integer operand type, restore new processor memory file

13 Bad mixed mode operation type, restore new processor memory file

14 Not enough operands for instruction, restore new processor memory file

15 Too many operands for instructions, restore new processor memory file

16 Corrupted instruction, probably due to restoring an incompatible processor memory file

17 Can't find expression end; restore new processor memory file

18 Missing end of edit zone; restore new processor memory file

20 You entered too large an element number in an indirect address

21 You entered a negative element number in an indirect address

22 You tried to access an undefined program file

23 You used a negative file number, you used a file number greater than the number of existing files, or

you tried to indirectly address files 0, 1, or 2

24 You tried to indirectly address a file of the wrong type

30 You tried to jump to one too many nested subroutine files

31 You did not enter enough subroutine parameters

32 You jumped to an invalid (nonladder) file

34 You entered a negative preset or accumulated value in a timer instruction

35 You entered a negative time variable in a PID instruction

36 You entered an outofrange setpoint in a PID instruction

37 You addressed an invalid module in a block transfer, immediate input, or immediate output instruction

38 You entered a return instruction from a nonsubroutine file

39 FOR instruction with missing NXT

40 The control file is too small for the PID, BTR, BTW, or MSG instruction

41 NXT instruction with missing FOR

42 You tried to jump to a deleted label

4469 Reserved

70 The processor detected duplicate labels

74 SFC file error detected

75 The SFC has too many active functions

77 SFC missing file or of wrong type for step, action, transition; or

78 The processor cannot continue to run the SFC after power loss

79 You tried to download an SFC to a processor that cannot run SFCs; or

80 You incorrectly installed a 32point I/O module in a 1slot configuration (PLC5/15, 5/25)

81 You illegally set an I/O chassis backplane switch; either switch 4 or 5 must be off

You entered a CAR routine file that is not 68000 code

Subchart is created but empty; or SC or timer file specified in SFC empty or too small

This specific PLC does not support this enhanced SFC

7-5

Chapter 7

Selecting Interrupt Routines

Important: If the PLC-5 processor detects a fault in the fault routine (double fault condition), the PLC-5 processor goes directly to fault mode without completing the fault routine.

Programming a Fault Routine

If you choose to program a fault routine, first have the fault routine examine the major fault information recorded by the PLC-5 processor and decide whether to do the following before the PLC-5 processor automatically goes to fault mode:

set an alarm clear the fault shutdown in an orderly manner

On detecting a major fault, the PLC-5 processor immediately suspends the program file it was running and, if programmed, runs the fault routine file once to completion. If the PLC-5 processor does not run a fault routine, or the fault routine does not clear the fault, the PLC-5 processor automatically switches to fault mode.

Set an Alarm

You may need an alarm to signal when a major fault occurs. Put this rung first in your fault routine program

alarm

output

and combine it with a counter. You can also set an alarm in your fault routine to signal when the fault routine clears a major fault.

Clearing the Fault

If you decide to clear the fault in the fault routine, place the ladder logic for clearing the fault at the beginning of the fault routine. You can compare the fault code with a reference.

Compare fault code with a reference—Identify the possible major faults and then select only those your application will let you safely clear. These are your reference fault codes.

From the fault routine, examine the major fault code that the processor stores in S:12. Use an FSC instruction to compare the fault code to the reference file that contains “acceptable” fault codes (word-to-file comparison). If the processor finds a match, the FSC instruction sets the found (.FD) bit in the specified control structure. Use a MOV instruction to clear the fault in S:11. Then jump to the end of the fault routine to quickly complete running the fault routine.

7-6

Chapter 7

Selecting Interrupt Routines

In Figure 7.4, #N10:0 is the reference file.

Figure 7.4 Example

Last rung in fault routine

of Comparing a Major Fault Code with a Reference

R6:0

][

FSC

FILE SEARCH/COMPARE

Control

Length

Position

Mode Expression

S:12 = #N10:0

MOV

MOVE

Source

Dest

S:11

R6:0

ALL

R6:0

RES

R6:0

JMP

][LBL

TND

The processor completes the scan of the fault routine. If the routine clears S:11, the processor returns to the program file and resumes program execution. If the fault routine does not clear S:11, the processor executes the rest of the fault routine and goes into FAULTED mode.

Important: If the fault routine clears the major fault, the processor completes the fault routine and returns to the next instruction in the program file that follows the one that contained the faulted instruction. The remainder of the rung is executed. It appears that the fault never occurred. The fault routine execution continues until you correct the cause of the fault.

7-7

Chapter 7

Selecting Interrupt Routines

Using Shutdown Logic

Shutdown programming should include the following considerations.

Store initial conditions and reset other data to achieve an orderly

start-up later.

Monitor the shutdown of critical outputs. Use looping if needed to

extend the single fault routine scan time up to the limit of the processor watchdog timer so that your program can confirm that critical events took place.

Testing a Fault Routine

To test a fault routine, use a JSR instruction to jump to the fault routine. Send a fault code as the first input parameter of the JSR instruction. The processor stores the fault code in status word 12 and sets the corresponding bit in word 11.

You may detect and set your own faults using fault codes 0-9 or by using the processor-defined fault codes 10-87.

Setting Up a Fault Routine

You can write multiple fault routine programs and store them in multiple fault routine files, but the logic processor runs only one fault routine program when the PLC-5 processor detects a major fault. The number of the fault routine the PLC-5 processor runs is stored in word 29 of the processor status file. Typically, you enter a fault routine file number with the programming software and change the specified fault routine file from the ladder program.

To set up a fault routine, you need to:

enable the fault routine by entering a fault routine file number in the

status file

create the program file and enter fault routine logic

clear a major fault (other than by the fault routine)

7-8

Enabling a Fault Routine

To enable a fault routine, store the program file number (3-999) of the file that contains the fault routine logic in word 29 of the processor status file. When the processor encounters a major fault, the processor runs the fault routine logic to handle the fault.

Chapter 7

Selecting Interrupt Routines

If you do not specify a program file number, the processor immediately enters fault mode after detecting a fault.

Changing the Fault Routine File Number from Ladder Logic

You can change the specified fault routine from ladder logic by copying a new fault routine file number into word 29 of the processor status file.

Figure 7.5 shows an example program for changing the fault routine file number.

Figure 7.5 Example

of Changing the Fault Routine File Number

MOV

MOVE

Source

Dest S:29

ATTENTION: Do not corrupt the program-file number of the fault routine or use the same file for any other purpose. If the file number that you specify results in a non-existent fault routine, the processor immediately enters fault mode after detecting a fault. Unexpected machine operation may result with damage to equipment and/or injury to personnel.

Clearing a Major Fault

You can clear a major fault with one of the following methods.

Use the programming software to clear the major fault.

For more information about using the programming software to clear major faults, see the chapter on clearing faults in the programming software documentation set.

Turn the keyswitch on the PLC-5 processor from REM to PROG

to RUN.

Important: Clearing a major fault does not correct the cause of the fault. The PLC-5 processor might continue to repeat the fault cycle until you correct the cause(s) for the major fault.

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Chapter 7

Selecting Interrupt Routines

Setting PowerUp Protection

You can set your processor so that after a power loss the processor does not come up in run mode. Bit 1 in word 26 of the processor status file sets power-up protection. Table 7.I shows the states for this bit.

Table 7.I

and Resetting the PowerUp Protection Bit

Setting

If word 26, bit 1 Is: After power loss, the processor:

Set (1) Scans the fault routine before returning to normal program scan

Reset (0) Powers up directly at the first rung on the first program file

Set word 26, bit 1 manually from the processor status screen (see the chapter on using status data in programming software documentation). Or you can latch this bit through ladder logic. When set, the processor scans the fault routine once to completion after the processor recovers from a power loss. You can write the fault routine to determine whether or not the processor’s current status permits the processor to respond correctly to ladder logic—i.e., whether to allow or inhibit the startup of the processor.

Allowing or Inhibiting Powerup

Bit 5 of status word 11 indicates whether or not you want to power up the processor after a loss of power. After a power loss, the processor automatically sets this bit; Table 7.J shows how you can change it from your fault routine.

Table 7.J

and Resetting the Startup Bit

Setting

If the fault routine makes word 11, bit 5:

Set (1) Faults at the end of scanning the fault routine.

Reset (0) Resumes scanning the processor memory file.

Important: You can use JMP and LBL instructions to scan only the portion of the fault routine associated with a particular fault or power-up condition.

For information about startup protection on SFCs, see the programming software documentation set.

Then the processor:

Leave this bit set to inhibit startup.

Reset this bit to allow startup

7-10

Chapter 7

Selecting Interrupt Routines

Understanding ProcessorDetected Major Faults

In general, if the processor detects a hardware fault, it sets a major fault and resets I/O. If the processor detects a run-time error, it sets a major fault bit and the remote I/O racks are set according to their last state switch. Module outputs in remote racks remain in their last state or they are de-energized, based on how you set the last state switch in the 1771 I/O chassis.

To decide how to set this switch, evaluate how the machines in your process will be affected by a fault. For example, how will the machine react to outputs remaining in their last state or to outputs being automatically de-energized? What is each output connected to? Will machine motion continue? Could this cause the control of your process to become unstable?

To set this switch, see the Classic 1785 PLC-5 Family Programmable Controllers Hardware Installation Manual, publication 1785-6.6.1.

Important: In the PLC-5 processor local chassis, outputs are reset—regardless of the last state switch setting—when one of the following occurs:

processor detects a run-time error you set a status file bit to reset a local rack you select program or test mode

Fault in a ProcessorResident Local I/O Rack

The chassis that contains the Classic PLC-5 processor is the processor-resident local I/O chassis. If a problem occurs with the chassis backplane, the input and output data table bits for the resident local I/O rack are left in their last state. The processor sets a minor fault and continues scanning the program and controlling extended-local and remote I/O.

Your ladder program should monitor the I/O rack fault bits and take the appropriate recovery action (covered later in this section).

ATTENTION: If a resident local I/O rack fault occurs and you have no recovery methods, the input image table and outputs for the faulted rack remain in their last state. Potential personnel and machine damage may result.

7-11

Chapter 7

Selecting Interrupt Routines

Fault in a Remote I/O Chassis

In general, when a remote I/O chassis faults, the processor sets an I/O rack fault bit and then continues scanning the program and controlling the remaining I/O. The outputs in the faulted rack remain in their last state or they are de-energized, based on how you set the last state switch in the 1771 I/O chassis.

ATTENTION: If outputs are controlled by inputs in a different rack and a remote I/O rack fault occurs (in the inputs rack), the inputs are left in their last non-faulted state. The outputs may not be properly controlled and potential personnel and machine damage may result. Make sure that you have recovery methods.

Recovering from a ProcessorResident Local I/O or Remote I/O Rack Fault

In the PLC-5 processor, you can monitor I/O rack faults using processor status bits and then recover from the fault using a fault routine or ladder logic.

Using Status Bits to Monitor Rack Faults

There are two types of status bits used to display information about your I/O system: global status bits and I/O rack status bits.

The global status bits are set if a fault occurs in any one of the logical racks.

Processor Possible Logical Rack Bits

PLC5/105/12, or 5/15 4

PLC5/25 8

Each bit represents an entire rack, no matter how many chassis make up a rack. (Remember that you can have up to four chassis configured as quarter racks to make up one logical rack.) These bits are stored in the lower eight bits of words 7, 32, and 34 of the status file.

7-12

For more information on these global status bits, see your programming software documentation set.

Chapter 7

Selecting Interrupt Routines

The I/O rack status bits, also known as the “partial rack status bits,” are used to monitor the racks in your I/O system. The software automatically creates an integer data file to store this information when an I/O status file is defined. This file contains 2 words of status bits for every rack configured in your system. The number of the data file that contains this I/O information is stored in word 16 (low byte) of the status file. You must enter this information on the processor status screen. For more information on monitoring I/O status with I/O rack status bits, see your programming software documentation set.

Using Fault Routine and Ladder Logic to Recover

You may want to configure a I/O rack fault as a minor fault if you have the appropriate fault routine and ladder logic to perform an orderly shutdown of the system. You can program ladder logic in several ways to recover from a I/O rack fault. These methods are:

user-generated major fault reset input image table fault zone programming

Methods:

Usergenerated major fault

Reset input image table

Fault zone programming method

Description:

You jump to a fault routine when a remote I/O rack fault occurs. In other words, if the status bits indicate a fault, you program the processor to act as if a major fault occurred (i.e., jump to the fault routine). You then program your fault routine to stop the process or perform an orderly shutdown of your system. When the processor executes the endoffile instruction for the fault routine, a usergenerated major fault is declared.

You monitor the status bits and, if a fault is detected, you program the processor to act as if a minor fault occurred. After the status bits indicate a fault, use the I/O Status screen to inhibit the remote rack that faulted. You then use ladder logic to set or reset critical input image table bits according to the output requirements in the nonfaulted rack.

If you reset input image table bits, during the next I/O update, the input bits are set again to their last valid state. To prevent this from occurring, your program should set the inhibit bits for the faulted rack. The global inhibit bits control the input images on a rackbyrack basis; the partial rack inhibit bits control the input images on a 1/4 rack basis. For more information on these bits, see the programming software documentation set.

This method requires an extensive and careful review of your system for recovery operations. For more information on inhibiting I/O racks, see your programming software documentation set

Using fault zone programming method, you disable sections of your program with MCR zones. Using the status bits, you monitor your racks; when a fault is detected, you control the program through the rungs in your MCR zone. With this method, outputs within the MCR zone must be nonretentive to be deenergized when a rack fault is detected.

For more information, see your programming software documentation.

7-13

Chapter

Transferring Discrete and BlockTransfer Data

Chapter

Objectives

This chapter covers discrete and block transfer of I/O data when a processor is configured for either adapter or scanner mode. Discretetransfer data are words transferred to/from a digital discrete I/O module. Block-transfer data is transferred, in blocks of data of up to 64 words, to/from a block-transfer I/O module (such as an analog module).

System Design

If you want to read about: Go to

Adapter mode:

Discretetransfer data

Blocktransfer data

Example ladder logic

Scanner mode:

Discretetransfer data

Blocktransfer data

Programming considerations 821

page:

81

84

87

810

816

817

Determined

Choosing Hardware

Placing System Hardware

Assigning Addressing Mode, Racks, and Groups

Choosing Communication

Planning Your System Programs

Selecting Interrupt Routines

Transferring Discrete and Block Data

Calculating Program Timing

Transferring Data Using Adapter Mode

You can transfer data in adapter mode in two ways.

If you want to transfer: Use this method:

Wordsto/fromadigitalI/Omodule DiscretedatatransferWords to/from a digital I/O module Discretedata transfer

Blocks of data (up to 64 words) to/from a blocktransfer module (such as an analog module)

Block transfer

The processor transfers discrete and block I/O data in a similar way. The adapter-mode processor and the supervisory processor automatically

discrete transfer I/O data between themselves via the supervisory processor’s remote I/O scan.

8-1

Chapter 8

Transferring Discrete and BlockTransfer Data

During each remote I/O scan:

the supervisory processor transfers 2, 4, 6 or 8 words—depending on

whether the adapter-mode processor is configured as a 1/4, 1/2, 3/4 or full rack

the adapter-mode processor transfers 2, 4, 6 or 8 words—depending on

whether the adapter-mode processor is configured as a 1/4, 1/2, 3/4 or full rack

Supervisory Processor in Scanner Mode

Remote I/O Buffer

Read Inputs

Write Outputs

Remote I/O Scan

I/O Image

Table

Figure 8.1 shows the transfers between supervisory processor output file and adapter-mode processor input file as well as between adapter-mode processor output file and supervisory processor input file.

Data Exchange

x y

I/O Image

Table

Processor

Resident

Rack

PLC5 Processor in Adapter Mode

Read Inputs

Write Outputs

Data

Exchange

Housekeeping

Immediate I/O

IOT (x) IIN (y)

Logic Scan

Program Scan

8-2

Chapter 8

Transferring Discrete and BlockTransfer Data

Supervisory Processor PLC2 0X0-0X7 PLC3 OXX0-OXX7 PLC5 O:X0-O:X7

Supervisory Processor PLC2 1X0-1X7 PLC3 IXX0-IXX7 PLC5 I:X0-I:X7

Figure 8.1 Automatic

I/O Transfer between Supervisory and

AdapterMode Processors

Supervisory Processor

Word

0 1

2 3 4 5 6 7

Word

0 1

2 3 4

5 6

Word 0 is reserved for block transfer and status.

Output File

Supervisory Processor

Input File

AdapterMode Processor

I:30 - I:37 (or adapter image file)

0003040710131417 0003040710131417

Input File

AdapterMode Processor

O:30 - O:37 (or adapter image file)

0003040710131417 0003040710131417

Output File

15298

If data from the supervisory processor is intended to control outputs of the adapter-mode processor, the ladder logic in the adapter-mode processor must move the data from its input file (I/O rack 3 or the adapter image file) to its output file (local I/O). Use XIC and OTE instructions for bit data; use move and copy instructions for word data.

If you want the supervisory processor to read data from a data file in the adapter-mode processor, ladder logic in the adapter-mode processor must move that data to its output file (I/O rack 3 or the adapter image file) for transfer to the supervisory processor.

8-3

Chapter 8

Transferring Discrete and BlockTransfer Data

Programming

Discrete

Transfer in Adapter Mode

For the supervisory processor, use the adapter’s configured I/O rack number to receive data or store data for transfer.

Using Rack 3 (Addresses 0:300:37 and I:30I:37)

Rack 3 is the default discrete-transfer file for PLC-5/12, -5/15, and -5/25 processors. Typically, each output instruction in one processor should have a corresponding input instruction in the other processor. The rack number determines the addresses you use.

The ladder logic in the supervisory processor uses the rack number

(0-76 octal) of the adapter-mode processor.

Condition the ladder logic in the adapter processor with I30/10. When

set, this bit indicates a communication failure between the adapter and supervisory processors.

Creating an Adapter Image FilePLC5/12, 5/15, and 5/25 Processors

If you use 1/2-slot addressing in a 16-slot chassis, you need rack 3 addresses for scanning processor-resident local I/O on the adapter-mode processor. In this case, you can create an adapter image file for transferring data. Before you create an adapter image file, make sure that these conditions are true:

the PLC-5 processor is in adapter mode the adapter-mode processor is in a 1771-A4B I/O chassis you are using 1/2-slot addressing you have not inhibited rack 3 by setting the rack inhibit bit 3 in

processor status word 27

To create the adapter image file, create a 16-word integer file. This file must be 16 words regardless of whether you use 4-word or 8-word transfers. This file must be a unique integer file, for use only as an adapter image file. Words 0-7 are used for output; words 8-15 are used for input. Bits are numbered in decimal 0-15 for each word.

To tell the processor which file is the adapter image file, enter the file number in word 25 of the processor status file. You enter this file number on the processor status screen. For more information about the processor status screen, see the chapter on using status data in the programming software documentation.

Important: If you are using an adapter image file (instead of the rack 3 image), then you cannot use block transfers between the supervisor and the adapter-mode processor.

8-4

Chapter 8

Transferring Discrete and BlockTransfer Data

Condition the ladder logic in the adapter-mode processor with word 8, bit 8 decimal of the adapter image file. When set, this bit indicates a communication failure between the adapter and supervisory processors.

ATTENTION: Do not program block transfers to a supervisory processor if you create an adapter image file.

Transferring Bits between Supervisory and AdapterMode Processors

Figure 8.2 shows ladder logic for transferring bit 17 of the supervisory processor’s output image word 7 and bit 16 of the adapter-mode processor’s output image word 5. The x represents the adapter-mode processor’s rack number; rack 3 is the simulated rack for the adapter-mode processor. This example assumes 1-slot or 2-slot hardware addressing.

Figure 8.2 Transferring

Supervisory Processor (PLC2) Adapter Processor (PLC5)

0x7

Ix5

Bits Using Rack 3 in the AdapterMode Processor

I:37

When the supervisory processor sets its output file bit 0x:7/17, input file bit I:37/17 in the adapter-mode processor is automatically set. In the same way, when the adapter-mode processor sets output file bit O:35/16, input file bit Ix:5/16 in the supervisory processor is automatically set.

Figure 8.3 shows the ladder logic if you created an adapter image file because you need rack 3 addresses for local I/O. This example uses N51 as the adapter image file.

Figure 8.3 Transferring

Supervisory Processor (PLC2) Adapter Processor (PLC5)

0x7

Bits Using Your Own Adapter Image File

N51:15

O:35

Ix5

N51:05

8-5

Rockwell Automation 1785-LTx, D17856.2.1 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

Summary of Changes

Table of Contents

Preface