Rockwell Automation 1775-MX, 1775-S4A, D17756.3.1 User Manual

Chapter

PLC3 Programmable Controller Backup Systems

User Manual

Important User Information

Because of the variety of uses for this product and because of the differences between solid-state products and electromechanical products, those responsible for applying and using this product must satisfy themselves as to the acceptability of each application and use of this product. For more information, refer to publication SGI-1.1 (Safety Guidelines for the Application, Installation and Maintenance of Solid-State Control).

The illustrations, charts, and layout examples shown in this manual are intended solely to illustrate the text of this manual. Because of the many variables and requirements associated with any particular installation, Allen-Bradley Company cannot assume responsibility or liability for actual use based upon illustrative uses and applications.

No patent liability is assumed by Allen-Bradley Company with respect to use of information, circuits, equipment, or software described in this text.

Reproduction of the contents of this manual, in whole or in part, without written permission of Allen-Bradley Company is prohibited.

Throughout this manual we make notes to alert you to possible injury to people or damage to equipment under specific circumstances.

WARNING: Tells readers where people may be hurt if procedures are not followed properly.

CAUTION: Tells readers where machinery may be damaged or economic loss can occur if procedures are not followed properly.

Warnings and cautions:

identify a possible trouble spot tell what causes the trouble give the result of improper action tell the reader how to avoid trouble

Important: We recommend that you frequently backup your application programs on appropriate storage media to avoid possible data loss.

PLC is a registered trademark of Allen-Bradley Company

Preface P1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Manual

Objectives Audience P1 What This Manual Contains P1 WARNINGS, Terms and Conventions P2 Related

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CAUTIONS and Important Information

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Publications

Choosing a Backup Configuration 11. . . . . . . . . . . . . . . . . . .

P1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

P2. . . . . . . . . . .

P3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chapter Backup Concepts 11 Choosing a Backup Configuration 14 Choosing a Switchover Method 17

Objectives

11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Installing a Backup System 21. . . . . . . . . . . . . . . . . . . . . . . .

Chapter Installing the Hardware 21 Power Supply Considerations 26 Grounding Considerations 26 Shielding Considerations 26 Configuring Configuring Scanner Modules 28 Connecting the I/O Channel Wiring 215 Configuring 1775MX Memory Communication Modules 224

Objectives

the I/O Chassis

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

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Operating a Backup System 31. . . . . . . . . . . . . . . . . . . . . . .

Chapter Starting Up a Backup System 31 Shutting Down a Backup System 34 Restarting a Backup System 34 Disconnecting a Faulted Processor 35 Restarting a Repaired Processor 35

Objectives

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

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Using the 1775MX Memory Communication Module 41. . . . .

Chapter Controlling the Operation of Memory Communication Modules 42 Using LIST Functions for Control 43 Using Message Instructions for Control 417 Error Codes 433

Objectives

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Table of Contentsii

Programming Techniques 51. . . . . . . . . . . . . . . . . . . . . . . . .

Chapter Signal Timers and Counters at Switchover 52 Timing Considerations at Switchover 53 Forcing Executing Block Transfers 55 Restarting a Repaired Processor 55 Reducing Backup Communication Overhead 56 Using Data T Programming Considerations for Data Highway and

Programming Considerations for Memory Communication Modules 522

Objectives

Conditioning

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I/O

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able Status Bits

Data Highway Plus 516

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

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Diagnosing Faults 61. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chapter How the Backup System Behaves When a Major Fault Occurs 61 Locating A Logic Diagnostic Routine 68

Objectives

a Fault

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Preface

Manual Objectives

Audience

What This Manual Contains

This manual shows you how to install, configure, and operate a backup system configured with PLC-3 or PLC-3/10 processors.

In this manual we describe:

backup system concepts procedures for installing backup systems procedures for operating backup systems programming techniques fault diagnosis

Before you read this manual or attempt to use a backup system, you should be familiar with the PLC-3 or PLC-3/10 programmable controller. Also, you may need to be familiar with one or more optional modules used in backup systems.

Table A describes the contents of each chapter in this manual.

Table A Manual

Contents

If you want to read about: Refer to Chapter:

an overview of backup concepts; description of scanner and memory backup configurations

procedures for installing a backup system; wiring diagrams

procedures for starting up, shutting down, restarting, disconnecting and restarting a repaired processor

controlling memory communication modules using LIST commands and message instructions

signal conditioning, timing requirements, forcing I/O, block transfers, status words, considerations when using communication adapter and memory communication modules

what happens when a fault occurs; locating faults by using indicators and status words

1  Choosing a Backup Configuration

2  Installing a Backup System

3  Operating a Backup System

4  Using the 1775MX Memory Communication Module

5  Programming Techniques

6  Diagnosing Faults

P-1

Preface

WARNINGS, CAUTIONS and Important Information

Terms and Conventions

Information that is especially important to note is identified by three labels:

WARNING CAUTION Important

WARNING: tells you of circumstances or practices that can lead to personal injury as well as damage to equipment.

CAUTION: tells you of circumstances or practices that can lead to damage of equipment.

Important: provides you with information that is important for the successful application of the PLC-3 backup system.

Some terms used in this manual may be unfamiliar to you. We list these terms with a brief definition of each.

Bit terminology - the states of logic bits are defined as follows:

ON = Set = 1 = high state OFF = Reset = 0 = low state

Channel configuration - using LIST functions or message instructions to assign specific parameters to the I/O channels on scanner modules.

Communication adapter module - refers to the 1775-KA module used in PLC-3 and PLC-3/10 processors.

Memory communication module - refers to the 1775-MX module used in PLC-3 processors.

Processor - refers to a PLC-3 or PLC-3/10 programmable controller system consisting of a power supply, chassis, modules, cables, and all other components needed to achieve an operational system.

Programming terminal - refers to an industrial terminal system, e.g., Allen-Bradley -T4, -T47, -T50, or -T60 terminals, or an AT-type computer with 6200 software.

Scanner module - refers to 1775-S4A or -S5 modules used in PLC-3 processors and/or 1775-SR or -SR5 modules used in PLC-3/10 processors.

P-2

Preface

Related Publications

For more information about components used with the PLC-3 backup system, see the publications listed in Table B.

Table B Related

Publications

Publication Title Publication Number

PLC3 Programmable Controller Installation and Operation Manual

PLC3 Family Programmable Controller Programming Reference Manual

I/O ScannerProgrammer Interface Module User's Manual

PLC3 Communication Adapter Module User's Manual

1770T4 Industrial Terminal System 17706.5.15

PLC3 Family I/O Scanner Communication Adapter Module User's Manual

17756.7.1

17756.4.1

17756.5.2

17756.5.1

17756.5.5

Additionally, you can use our publication index (publication SD499) as a guide to further information about products related to the PLC-3 and PLC-3/10 processors. Consult your local Allen-Bradley Company sales engineer or distributor for information regarding this publication or others.

P-3

Chapter

Choosing a Backup Configuration

Chapter Objectives

Backup Concepts

The information in this chapter can help you:

understand backup concepts evaluate different backup configurations choose a switchover method

A backup system consists of two processors configured in such a way that the backup processor will take control of outputs if the primary processor faults. Figure 1.1 shows the basic concept of a backup system.

Figure 1.1 Basic

Backup System

BACKUP

PRIMARY

PROCESSOR

I/O I/O

COMMUNICATION

BACKUP

PROCESSOR

TO/FROM I/O

A second processor, which is identical to the first, is connected to the main processor. During normal operation, the backup processor operates in a listen-only mode. If the primary processor encounters a major fault, the backup processor takes control of the outputs. This transfer of control also can occur due to a loss of power to the primary processor or a broken cable.

10971I

1-1

Chapter 1

Choosing a Backup Configuration

Why

Use a Backup System?

Backup is useful for applications in which an unexpected shutdown is costly or otherwise undesirable. By configuring a PLC-3 or PLC-3/10 system for backup communication, you can guard against shutdowns caused by processor faults.

Shutdowns can also be caused by power losses or faults in equipment other than the programmable controller. For these cases, you must take other measures to guard against shutdown.

Important: Backup does not protect you from faults caused by programming errors or system timeouts, because the error or timeout will also occur in the backup processor.

Backup

Some terms you should be familiar with are: Backup communication - communication between the primary and the

backup processors. Backup communication channel - transfers data from the primary to the

backup processor; transfers data table values from the backup to the primary processor; and, identifies the default processor if a cable breaks. A backup communication channel is required for backup systems using the scanner backup configuration.

Backup mode - a mode in which a processor performs a listen-only function (monitors inputs without controlling outputs) while remaining ready to take control of the outputs.

Backup processor - a programmable controller which performs a listen-only function (monitors inputs without controlling outputs). It remains ready to take control of outputs should a fault occur in the primary processor.

Backup system - includes the primary and backup processor. When we use the term processor we are referring to a processor chassis, modules, cables, and the other components needed for operation.

erminology

1-2

Channel configuration - a procedure using the LIST feature of the processor to assign a specific operation to one of the channels on an I/O scanner module.

Hardware configuration - the manner in which the backup processor is installed with the primary processor.

Chapter 1

Choosing a Backup Configuration

Primary processor - the processor that is controlling outputs. When switchover to the backup processor occurs, the backup processor becomes the primary processor, since now it is controlling outputs.

Stand-alone processor - a programmable controller that is not configured for backup.

Switchover - transfer of control from the primary processor to the backup processor.

Backup

Backup communication is communication between the primary and backup processors. Without backup communication, the backup processor receives only input and peer-to-peer data.

Since the primary and backup processors may have started at different times and are not synchronized, the data table values may be different in each processor. You can reduce these differences by transferring internal storage points via backup communication.

You can establish backup communication using:

Communication

one or more of the serial I/O channels as a backup communication

channel.

the parallel data communication of the 1775-MX memory

communication module

Data Highway or Data Highway Plus communication

1-3

Chapter 1

Choosing a Backup Configuration

TO/FROM

OTHER

PEERTOPEER

CHANNELS

I/O

There are two backup configurations:

scanner backup (Figure 1.2) which uses only I/O scanner modules MX backup (Figure 1.3) which uses 1775-MX memory communication

modules

How

Scanner Backup W

orks

Figure 1.2 shows the implementation of scanner backup. The number one scanner module controls switchover as well as backup, peer-to-peer, and I/O communication channels.

Figure 1.2 Scanner

CH2

CH3TO/FROM

Backup Configuration

PRIMAR

Y PROCESSOR

SCANNER

MODULE #1

B/U

CH1

CH2

CH3

CH4

BACKUP CABLE

BACKUP COMMUNICA

PEERTOPEER

COMMUNICATION

I/O COMMUNICA

TION

BACKUP PROCESSOR

SCANNER

MODULE

B/U

CH1

CH2

CH3

CH4

1-4

10972I

The data table of the backup processor can be updated in three ways.

The backup processor listens only to discrete real world inputs.

The input/output buffer transfers data files over the backup

communication cable. (You must program move and move file instructions to transfer critical data table information.)

Data Highway or Data Highway Plus communication

Chapter 1

Choosing a Backup Configuration

How MX Backup Works

Figure 1.3 shows the implementation of MX backup. The scanner modules still control I/O communication channels but the memory communication modules handle data transfers between the primary and backup processors.

Figure 1.3

Backup Configuration

PRIMAR

Y PROCESSOR

BACKUP PROCESSOR

TO/FROM

OTHER

PEERTOPEER

CHANNELS

TO/FROM

I/O

CH1

CH2

CH3

SCANNER

MODULE #1

B/U

CH1

CH2

CH3

CH4

MEMORY

COMMUNICATION

MODULE

B/U

XMTG

RCVG

PEERTOPEER

COMMUNICATION

I/O COMMUNICA

INTERCONNECT CABLE

BACKUP COMMUNICA

TION

SCANNER

MODULE

B/U

CH1

CH2

CH3

CH4

MEMORY

COMMUNICATION

MODULE

B/U

XMTG

RCVG

10973I

1-5

Chapter 1

Choosing a Backup Configuration

Selecting Scanner or MX Backup

Table 1.A and Table 1.B summarize the attributes of scanner backup and MX backup, respectively. Choose the backup configuration most suitable for your application.

Table 1.A Scanner

Advantages: Disadvantages:

Backup Attributes

 No additional cost (every 1775S4A, SR, S5, and SR5 has this feature built in).

 Backup communication channel is necessary for transferring data table and the transfer is relatively slow (8 words per 14 milliseconds.)

 External switch box may be required.

 Processor restart procedure is not flexible.

Table 1.B MX

Backup Attributes

Advantages: Disadvantages:

 Data table in the backup processor is virtually identical to the one in the primary processor.

 No external hardware is needed.

 Highspeed data transfer from the primary to the backup processor. (100k words per second for continuous or 10k words per second for onetime transfers).

 Ability to transfer program data from the primary processor to the backup processor.

 Extra features are available, such as memory download, memory compare, backup status, etc.

 More costly than scanner backup.

 Requires an extra slot in each processor chassis.

 Increased time required for other operations such as program scan. This increase is approximately 10% for file intensive programs and approximately 15% for I/O intensive programs. You must consider this increase when developing your program and configuring your system.

 The only permissible switchover method is automatic switchover with controllable switchback.

1-6

 Easily configurable through LIST.

 Simple restart procedure.

Chapter 1

Choosing a Backup Configuration

Choosing a Switchover Method

The three methods of switching control of outputs from the primary to the backup processor are:

automatic switchover with no switchback automatic switchover with controllable switchback manual switchover

You can use any one of these methods for scanner backup, but you must use automatic switchover with controllable switchback for MX backup. Table 1.C lists the attributes associated with each method.

Table 1.C Switchover

Switchover Method:

Automatic Switchover with No Switchback

Method Attributes

Attributes:

 Backup processor automatically takes control of outputs when the primary processor faults.

 No operator intervention required at switchover.

 Shutting off the primary processor initiates switchover.

 Both the primary and the backup processor must be shut down and restarted when reinstalling a repaired processor.

Automatic Switchover with Controllable Switchback

 Not recommended for applications using multidrop modems with 1775KA modules because the modem port is not disabled after a processor fault.

 Backup processor automatically takes control of outputs when the primary processor faults.

 No operator intervention required at switchover.

 Shutting off the primary processor initiates switchover.

 Either processor can be the primary" processor.

 The backup processor does not have to be shut down when reinstalling a repaired primary processor.

 Not recommended for applications using multidrop modems with 1775KA modules because the modem port is not disabled after a processor fault.

Continued

on Next Page

1-7

Chapter 1

Choosing a Backup Configuration

Switchover Method:

Manual Switchover

Attributes:

 When the primary processor faults, the system shuts down as though no backup system were available.

 Operator intervention is required at switchover.

 Control of the process is lost until switchover occurs.

 Quickly resume control of a process following a fault in the primary processor.

 Easy to transfer between primary and backup processor.

 Manual switchovers do not guard against unexpected shutdowns as well as automatic switchovers do.

 We suggest this method for applications using multidrop modems with 1775KA modules.

1-8

Chapter

Installing a Backup System

Chapter Objectives

Installing the Hardware

This chapter describes how to install PLC-3 and PLC-3/10 backup systems. Specifically, it provides recommendations for:

power supplies grounding shielding configuring I/O chassis configuring scanner modules connecting I/O channel wiring configuring memory communication modules

In general, the recommendations and procedures for installing a PLC-3 or PLC-3/10 backup system closely resemble those of a stand-alone

processor. To install a backup system, do the following:

read the power supply, grounding, and shielding recommendations.

configure all I/O chassis.

configure all scanner modules.

connect and configure I/O channels.

configure 1775-MX memory communication modules (necessary only if

MX backup will be used).

This chapter describes each of these tasks. For additional detailed information about installing PLC-3 and PLC-3/10 processors, see the PLC-3 Programmable Controller Installation and Operation Manual (publication 1775-6.7.1).

CAUTION: To guard against damage to equipment, make sure that all modules in the backup processor are the same series and revision as their counterparts in the primary processor. If not, the backup system may not work properly.

2-1

Chapter 2

Installing a Backup System

Important: The number one scanner module (thumbwheel set to 1) in both primary and backup processors must be a 1775-S4A or -S5 for PLC-3 based processors, or a 1775-SR or -SR5 for PLC-3/10 based processors.

Figure 2.1 on page 2-3 shows typical connections for a PLC-3 backup system using scanner backup. Figure 2.2 on page 2-4 shows typical connections for a PLC-3 backup system using MX backup. Figure 2.3 on page 2-5 shows typical connections for a PLC-3/10 backup system using scanner backup.

2-2

Figure 2.1 Connections

Chapter 2

Installing a Backup System

for a PLC3 Backup System Using Scanner Backup

To Earth Ground

6 6

Blue

Shield

1. PLC-3 Processor (Primary)

2. Power Supply (cat. no. 1775-P1)

Clear

3. 1771 I/O Chassis (cat. no. 1771-A1B, -A2B, A3B, -A4B)

4. Power Supply (cat. no. 1771-P2)

5. Processor Chassis Power Cable, 6ft. (cat. no. 1775-CAP)

6. I/O Power Cable, 1ft. (cat. no. 1771-CE)

7. Twinaxial Cable (cat. no. 1770-CD) 10,000 ft. Max. Each I/O Channel at 57.6K Baud

8. Terminator (cat. no. 1770-XT) Connect one at each end of the I/O Channel

9. PLC-3 Processor (backup)

10. Backup Cable (cat. no. 1775-CBA, -CBB)

11. Backup Communication Cable (cat.no. 1770-CD)

12. Ground Bus Plate

13. Connection between Power Supply System Common studs

To other I/O Chassis in the Channel

10391

2-3

Chapter 2

Installing a Backup System

Figure 2.2 Connections for a PLC3 Backup System Using MX Backup

To Earth Ground

6 6

Blue

Shield

1. PLC-3 Processor (Primary)

2. Power Supply (cat. no. 1775-P1)

Clear

3. 1771 I/O Chassis (cat. no. 1771-A1B, -A2B, A3B, -A4B)

4. Power Supply (cat. no. 1771-P2)

5. Processor Chassis Power Cable, 6ft. (cat. no. 1775-CAP)

6. I/O Power Cable, 1ft. (cat. no. 1771-CE)

7. Twinaxial Cable (cat. no. 1770-CD) 10,000 ft. Max. Each I/O Channel at 57.6K Baud

8. Terminator (cat. no. 1770-XT) Connect one at each end of the I/O Channel

9. PLC-3 Processor (backup)

10. Memory Communication Cable (cat. no. 1775-CM)

11. Memory Communication Cable (cat. no. 1775-CM)

12. Ground Bus Plate

13. Connection between Power Supply System Common studs

To other I/O Chassis in the Channel

18720

2-4

Chapter 2

Installing a Backup System

Figure 2.3 Connections for a PLC3/10 Backup System Using Scanner Backup

4 4

Blue

Shield

Clear

1. PLC-3/10 Processor (Primary)

2. 1771 I/O Chassis (cat. no. 1771-A1B, -A2B, A3B, -A4B)

3. Power Supply (cat. no. 1771-P2)

4. I/O Power Cable, 1ft. (cat. no. 1771-CE)

5. Twinaxial Cable (cat. no. 1770-CD) 10,000 ft. Max. Each I/O Channel at 57.6K Baud

6. Terminator (cat. no. 1770-XT) Connect one at each end of the I/O Channel

7. PLC-3/10 Processor (backup)

8. Backup Cable (cat. no. 1775-CBA, -CBB)

9. Backup Communication Cable (cat.no. 1770-CD)

10. Ground Bus Plate

To Earth Ground

To other I/O Chassis in the Channel

18756

2-5

Chapter 2

Installing a Backup System

Power Supply Considerations

Grounding Considerations

For a PLC-3 backup system, it is important to choose suitable power supplies and make sure they are connected properly.

To reduce the chance of inadvertent shutdowns due to loss of power, we recommend using two separate 1775-P1 or -P3 power supplies. Use one power supply for the primary processor and the other power supply for the backup processor. Further, connect each power supply to a separate source of AC power.

Important: In backup systems, never use the processor supply for powering an I/O chassis. A processor failure could cause the I/O to fail also.

For detailed information about installing power supplies, refer to the PLC-3 Programmable Controller Installation and Operation Manual (publication 1775-6.7.1).

All grounding requirements applicable to a stand-alone PLC-3 or PLC-3/10 processor also apply to backup systems. In addition, you need to do the following:

When using a 1775-P1 power supply, connect the system common studs

together on the power supplies of the primary and backup processors . Use 1-inch braid or 8 AWG wire.

Shielding Considerations

If the primary and backup processors are in separate enclosures, connect

the ground bus plates of the primary and backup processors together. Use 1-inch braid or 8 AWG wire.

Connect the ground bus plate of either the primary or backup processor,

but not both, to earth ground.

Use star washers to assure a positive ground connection between metal

surfaces and ground lugs.

For detailed information about grounding, see Wiring and Grounding Guidelines (publication 1770-4.1).

Use shielded cable for I/O channel wiring as specified in the PLC-3 Programmable Controller Installation and Operation Manual (publication 1775-6.7.1) to minimize noise pickup. Also, use shielded cable for peer-to-peer communication channels, backup communication channels, and Data Highway/Data Highway Plus channels. We recommend using 1770-CD twinaxial cable (Belden 9463), or equivalent.

2-6

Chapter 2

Installing a Backup System

Configuring the I/O Chassis

OFF

You must configure all I/O chassis for backup mode operation. Each I/O chassis has eight switches. Two of the switches, switches 2 and 8, are especially important because they affect the operation of a backup system. See Figure 2.4 for the function and location of the I/O chassis switches.

Figure 2.4 Location

and Function of I/O Chassis Backplane Switches

Switch

OFF

Switch

Always On

OFF

Always On

OFF

Outputs of this I/O chassis remain in their last state when a fault is detected by this I/O adapter.

Outputs of this I/O chassis are turned off when a fault is detected by this I/O adapter.

Switches

Processor Restart Lockout

The I/O chassis can be restarted from the processor.

The processor is locked out from restarting the I/O chassis after a fault.

Addressing

2-slot

OFF

1-slot

OFF

1/2 - slot

Not allowed

Last S tate

2, 3

Pressed in attopClosed(ON)

Pressed in at bottom Open (OFF)

NOTES:

1. CAUTION: If you set this switch to the ON position, when a fault is detected, outputs connected to this

chassis remain in their last state to allow machine motion to continue. We recommend that you set switch 1 to the OFF position to de - energize outputs wired to this chassis when a fault is detected.

2. The 1771 - AS adapter does not support 1 -slot or 1/2 - slot addressing. When you use this adapter, set switches 5 and 6 to the OFF position.

3. The 1771 - ASB series A adapter does not support 1/2 - slot addressing.

16191

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Chapter 2

Installing a Backup System

Setting

The processor restart lockout switch (switch 2) must be ON so the backup processor is capable of restarting the I/O chassis at switchover, if necessary. If the system has more than one I/O chassis, switch 2 must be ON in each chassis. For more detailed information about the processor restart lockout feature, refer to the PLC-3 Programmable Controller Installation and Operations Manual (publication 1775-6.7.1).

Setting

The chassis I/O to backup processor switch (switch 8) must be ON so the backup processor can receive inputs from the I/O chassis. The backup processor will not be able to receive inputs from the I/O chassis if switch 8 is set incorrectly.

Switch 2

Switch 8

CAUTION: To guard against damage to equipment, make sure that switch 8 on a 1771-A1B I/O chassis with starting module group 0 is set to ON. If this switch is not ON, the backup processor will not receive inputs from the I/O chassis.

Configuring Scanner Modules

You set up and install scanner modules whether you are configuring a system for scanner backup or MX backup. The only difference is the cable used between the backup connectors on the various modules.

To configure a scanner module you must:

set backup switches select a backup cable connect the backup cable connect I/O channel wiring.

Setting

Each scanner module has four switches for selecting a switchover method or stand-alone mode. Figure 2.5 and Figure 2.7 show the location of these switches for the various scanner modules.

To select the backup mode, do the following:

1. Set backup switches 1 through 4 on the number one scanner module

Backup Switches

(thumbwheel set to 1) in both primary and backup processors for the type of switchover desired. See Table 2.A for 1775-S4A and 1775-SR scanners or Table 2.B for 1775-S5 and 1775-SR5 scanners.

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Chapter 2

Installing a Backup System

2. Set all backup switches on all other scanner modules, if any are

present, in both the primary and backup processors to the up position.

Figure 2.5 Location Modules

of Backup Switches for 1775S4A and 1775SR Scanner

TopEdge ofModule

18753

Figure 2.6 Setting Backup Switches on the 1775S4A and 1775SR Scanner Modules

OFF

Not Used

(always UP)

1234

Set per

Table 2.A

Not Used

(always UP)

Switch Positions:

UP = DOWN=

Set per

Table 2.A

Table 2.A Backup

Switches on 1775S4A and 1775SR Scanner Modules

Switch

Switchover Method 2 4 Processor

Automatic switchover with controllable switchback

DOWN UP both primary and backup

Switch is away from board Switch is toward board

10794I

Automatic switchover with no switchback DOWNUPUPUPprimary

backup

Manual switchover UP DOWN both primary and backup

Standalone mode UP UP both primary and backup

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Chapter 2

Installing a Backup System

Figure 2.7 Location

of Backup Switches for 1775S5 and 1775SR5 Scanner

Modules

Backup Switch at Bottom Edge of Module

erminator Switch at

Bottom Edge of Module

Figure 2.8 Setting

Backup Switches on 1775S5 and 1775SR5 Scanner Modules

18754

OFF

Not Used

(always UP)

1234

Set per

Table 2.B

Not Used

(always UP)

Switch Positions:

UP = DOWN=

Table 2.B Backup

Switches for 1775S5 and 1775SR5 Scanner Modules

Switch

Switchover Method 2 3 Processor

Automatic switchover with controllable switchback

Automatic switchover with no switchback

DOWN UP both primary and backup

DOWNUPUP

primary backup

Switch is away from board Switch is toward board

10975I

2-10

Manual switchover UP DOWN both primary and backup

Standalone mode UP UP both primary and backup

Chapter 2

Installing a Backup System

Selecting

a Backup Cable

Choose a backup cable for the switchover method desired. Table 2.C lists the choices. See Figure 2.9 through Figure 2.11 for wiring information.

Table 2.C Backup

Cables

Switchover Method: Backup Cable:

Automatic switchover with no switchback 1775CBA

Automatic switchover with controllable switchback 1775CBB

1775CM

Manual switchover 1775CBB

1. Use for scanner backup configuration.

2. Use for MX backup configuration.

Figure 2.9 Backup

Cable W

iring for Scanner Backup with Automatic Switchover

with No Switchback (Cat. No. 1775CBA)

PRIMARY

PROCESSOR

SCANNER #1

BACKUP

CONNECTOR

SHIELD

1775CBA

BACKUP

CABLE

BACKUP

PROCESSOR

SCANNER #1

BACKUP

CONNECTOR

10976I

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Chapter 2

Installing a Backup System

Figure 2.10 Backup

Cable W

iring for Scanner Backup with Automatic Switchover

with Controllable Switchback (Cat. No. 1775CBB)

PRIMARY

PROCESSOR

SCANNER #1

BACKUP

CONNECTOR

SHIELD

SWITCH

1775CBB

BACKUP

CABLE

BACKUP

PROCESSOR

SCANNER #1

BACKUP

CONNECTOR

10977I

CAUTION: To guard against damage to equipment, make sure that:

switch 2 closes within 8 milliseconds of switch 4 switch 3 closes within 8 milliseconds of switch 1

CAUTION: If these conditions are not satisfied when you throw the switch to change the processor that is designated as the primary processor to the processor currently controlling outputs, the new primary processor may fault.

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Figure 2.11 Backup

Cable W

Chapter 2

Installing a Backup System

iring for Manual Switchover (Cat. No. 1775CBB)

PRIMARY

PROCESSOR

SCANNER #1

BACKUP

CONNECTOR

SWITCH

1775CBB

BACKUP

CABLE

SYSTEM

COMMON

BACKUP

PROCESSOR

SCANNER #1

BACKUP

CONNECTOR

10978I

Connecting

the Backup Cable

Figure 2.12 shows how to connect a backup cable for the scanner backup configuration.

Important: If you are configuring the system for MX backup instead of scanner backup, do not connect the backup cable as shown. See the instructions in Configuring 1775-MX Memory Communication Modules for information about installing the interconnect cables.

To configure scanner backup, do the following:

1. Locate the backup cable.

2. Connect one end of the backup cable to the backup connector on the

number one scanner module (thumbwheel set to 1) in the primary processor.

3. Connect the other end to the backup connector on the number one

scanner module (thumbwheel set to 1) in the backup processor.

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Chapter 2

Installing a Backup System

Figure 2.12 Connections

for Scanner Backup

Primary Processor Backup Processor

Backupcable(seetext)

Application: Cable:

Automatic switchover with no switchback 1775CBA

Automatic switchover with controllable switchback 1775CBB

Manual switchover 1775CBB

10395

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Chapter 2

Installing a Backup System

Connecting the I/O Channel Wiring

There are four I/O serial communication channels per scanner. Depending on your system architecture, you can use one or more of them for:

I/O communication Peer-to-peer communication Backup communication

To do this, you connect I/O cables to the terminal swing arm and configure each channel for the type of communication desired. You configure I/O channels by using LIST.

Figure 2.13 shows how to identify the terminals on a terminal swing arm.

Figure 2.13 I/O

Cables Terminate at Terminal Swing Arms

Line 1

Shield

Line 2

Line 1

Shield

Line 2

Channel No. 4

Channel No. 2

Channel No. 3

Channel No. 1

Line 1

Shield

Line 2

Line 1

Shield

Line 2

10044

Important: For 1775-S4A or -SR scanner modules used as the number one scanner, when using I/O channel 5 to communicate with a peripheral device, I/O channel 4 of the number one scanner module cannot be used. Do not make any connections to I/O channel 4.

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