State Industries GFK-0827 User Manual
GE Fanuc Automation
Programmable Control Products
Series 90t-70
Hot Standby CPU Redundancy
User’s Guide
GFK-0827 December 1993
Warnings, Cautions, and Notes
as Used in this Publication
Warning notices are used in this publication to emphasize that hazardous voltages,
currents, temperatures, or other conditions that could cause personal injury exist in this
equipment or may be associated with its use.
In situations where inattention could cause either personal injury or damage to
equipment, a Warning notice is used.
Caution notices are used where equipment might be damaged if care is not taken.
GFL–002
Warning
Caution
Note
Notes merely call attention to information that is especially significant to understanding
and operating the equipment.
This document is based on information available at the time of its publication. While
efforts have been made to be accurate, the information contained herein does not
purport to cover all details or variations in hardware or software, nor to provide for
every possible contingency in connection with installation, operation, or maintenance.
Features may be described herein which are not present in all hardware and software
systems. GE Fanuc Automation assumes no obligation of notice to holders of this
document with respect to changes subsequently made.
GE Fanuc Automation makes no representation or warranty, expressed, implied, or
statutory with respect to, and assumes no responsibility for the accuracy, completeness,
sufficiency, or usefulness of the information contained herein. No warranties of
merchantability or fitness for purpose shall apply.
The following are trademarks of GE Fanuc Automation North America, Inc.
Alar m Master CIMST AR Helpmate PROMA CRO Series Six
CIMPLICITY GEnet Logicmaster Series One Series 90
CIMPLICITY 90–ADS Genius Modelmaster Series Three VuMaster
CIMPLICITY PowerTRA C Genius PowerTRA C ProLoop Series Five Workmaster
Copyright 1993 GE F anuc A utomation North America, Inc.
All Rights Reserved
This manual is a reference to the hardware components, configuration and operation of
the Hot Standby CPU Redundancy system for the Series 90t-70 Programmable Logic
Controller. This redundancy system is one of several redundancy alternatives that may
be incorporated into a Series 90-70 Programmable Logic Controller system (see
Appendix A).
The information in this manual is intended to supplement the information contained in
the system installation, programming, and configuration information found in the
manuals listed below under ”Related Publications”.
Content of this Manual
Chapter 1. Introduction: describes the basic system features of the Hot Standby CPU
Redundancy system Control Strategy, and provides an overview of system components,
configuration, and operation.
Chapter 2. Components: describes the hardware components for the Hot Standby CPU
Redundancy system.
Chapter 3. Configuration: describes the special configuration requirements of a Hot
Standby CPU Redundancy system and provides an example of system configuration.
Preface
Chapter 4. Operation: describes the operation of a Hot Standby CPU Redundancy
system, fault detection and actions taken, and the on-line repair of a failed component.
Appendix A. Redundancy Alternatives: describes the redundancy alternatives for the
Series 90-70 Programmable Logic Controller for those readers not familiar with those
alternatives.
Related Publications
For more information, refer to these publications:
Genius I/O System User’s Manual (GEK-90486-1). Reference manual for system
designers, programmers, and others involved in integrating Genius I/O products in a
PLC or host computer environment. This book provides a system overview, and
describes the types of systems that can be created using Genius products. Datagrams,
Global Data, and data formats are defined.
Genius Discrete and Analog Blocks User’s Manual (GEK-90486-2). Reference manual for
system designers, operators, maintenance personnel, and others using Genius discrete
and analog I/O blocks. This book contains a detailed description, specifications,
installation instructions, and configuration instructions for discrete and analog blocks.
Series 90-70 PLC Installation Manual (GFK-0262). This book describes the hardware
components in a Series 90-70 PLC system, and provides the details of system installation.
Logicmaster 90-70 Programming Software User’s Manual (GFK-0263). A programming
software user’s manual for system operators and others using the Logicmaster 90-70
software to program, configure, monitor, or control a Series 90-70 PLC system.
GFK-0827
iii
Preface
Series 90-70 PLC Reference Manual (GFK-0265). Reference manual which describes
operation, fault handling, and Logicmaster 90-70 programming instructions for the
Series 90-70 PLC.
Series 90-70 Remote I/O Scanner User’s Manual (GFK-0579). Reference manual for the
Remote I/O Scanner, which interfaces a drop containing Series 90-70 modules to a
Genius bus. Any CPU capable of controlling the bus can be used as the host. This book
describes the Remote I/O Scanner features, configuration, and operation.
Series 90-70 Bus Controller User’s Manual (GFK-0398). Reference manual for the bus
controller, which interfaces a Genius bus to a Series 90-70 PLC. This manual describes
the installation and operation of the Bus Controller. It also contains the programming
information needed to interface Genius I/O devices to a Series 90-70 PLC.
We Welcome Your Comments and Suggestions
At GE Fanuc automation, we strive to produce quality technical documentation. After
you have used this manual, please take a few moments to complete and return the
Reader’s Comment Card located on the next page.
Henry A. Konat
Senior Technical Writer
iv
Hot Standby CPU Redundancy User’s Manual - December 1993
GFK-0827
Contents
Chapter 1 Introduction 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Hot Standby CPU Redundancy Product 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Features of the Hot Standby CPU Redundancy Product 3 . . . . . . . . . . . . .
Benefits of the Hot Standby CPU Redundancy Product 3 . . . . . . . . . . . . .
I/O Systems for Hot Standby CPU Redundancy Systems 4 . . . . . . . . . . . .
Genius I/O System 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Local I/O System 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cable Connections 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Control Strategy 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Basic Hot Standby Operation 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Redundancy CPU Module 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Redundancy Communications Module 7 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Bumpless Switching 8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Synchronized CPUs 8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Effect on Scan Time 8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fail Wait Time 8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Switch to Backup Unit Time 8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Configurable Backup Data Size 9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
On-Line Programming 9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
On-Line Repair 9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Programming Considerations 10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Configuration Requirements 10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Definition of Terms 11 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Commonly Used Acronyms 12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
GFK–0827 Series 90–70 Hot Standby CPU Redundancy User ’s Guide – December 1993
v
Contents
Chapter 2 System Components 13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Redundancy CPU 13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CPU Architecture 14 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CPU Features 15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CPU Mode Switch 16 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Memory Protect Keyswitch 17 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CPU Status LEDs 17 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Batter y Connectors 17 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Serial P ort Connector 18 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Expansion Memory Board 18 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Redundancy Communications Module 19 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
RCM Features 19 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
RCM System Status LEDS 20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Unit Selection Pushbutton 21 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
RCM Connectors 21 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Bus Transmitter Module 22 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
LED Status Indicators 22 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
BTM Connectors 23 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Bus Receiver Module 23 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
I/O Bus Signal T ermination 24 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
LED Status Indicators 24 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
BRM Connectors 24 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Genius Bus Controller 24 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Genius Bus Controller User Features 25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
LED Status Indicators 25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
GBC Connectors 26 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Racks 26 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
GFK–0827 Series 90–70 Hot Standby CPU Redundancy User ’s Guide – December 1993
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Contents
Chapter 3 Configuration 27 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Configuring a Hot Standby CPU Redundancy System 27 . . . . . . . . . . . . . . . . .
Redundancy System Requirements 28 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Basic Redundancy System Setup 28 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Logicmaster 90 Configuration 28 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
I/O System Configuration 28 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Screens for Fault Category Configuration 29 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Handling Folders 30 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Configuration with Logicmaster 90-70 30 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Configuration of a Redundancy CPU Module 31 . . . . . . . . . . . . . . . . . . . . . . . . .
Redundant CPU Requirements 33 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Redund Type 34 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Background Window 34 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Normal Sweep Mode 34 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Constant Window Sweep Mode 35 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Constant Sweep Mode 35 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Ctrl Strgy 36 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fail Wait 36 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Shared I/O 36 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Configuring a CPU Expansion Memory Board 39 . . . . . . . . . . . . . . . . . . . . .
Configuration of a Redundancy Communications Module 40 . . . . . . . . . . . . . .
Configuration of a Genius Bus Controller 42 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Paired GBC Parameter 42 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Configuring a Primary Redundant PLC 44 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Select the Redundancy CPU Module 45 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Select an Expansion Memory Board 46 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Configure the Redundant Communications Module 47 . . . . . . . . . . . . . . . .
Configure a Genius Bus Controller 48 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Configure Genius I/O Blocks 50 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Configure the Bus Transmitter Module 51 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Configuring a Secondary Redundant PLC 52 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Change Redund Type 53 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
GFK–0827 Series 90–70 Hot Standby CPU Redundancy User ’s Guide – December 1993
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Contents
Chapter 4 Operation 55 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Section 1: System Operation 55 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power-Up Sequence of a Redundant CPU 55 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Incompatible Configurations 56 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Resynchronization of the Redundant CPU 57 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Hot-Standby Redundancy Control Strategy 58 . . . . . . . . . . . . . . . . . . . . . . . . . .
Synchronous Scan 59 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
First Data Transfer %I, %AI and Synchronization 59 . . . . . . . . . . . . . . . . . . .
Data T ransfer from Backup Unit to Active Unit 60 . . . . . . . . . . . . . . . . . . . . .
Second Data Transfer %Q, %AQ, %R, and %M 61 . . . . . . . . . . . . . . . . . . . . .
Switching Control to Backup Unit 61 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Role Switch SVCREQ 62 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
%S References for CPU Redundancy 63 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Redundancy CPU Considerations 64 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Features not A vailable with CPU 780 64 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
I/O Interrupts 64 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Timed Interrupts 64 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
VME Integrator Racks 64 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
STOP/IOSCAN Mode 64 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Flash Operation 64 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Differences in Operation for CPU 780 65 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
RUN Disabled Mode 65 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Configuration of Fault Actions 67 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
STOP to RUN Mode Transition 68 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Background Window Time 68 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Background User Checksum and Background Window
Timing Instructions 69 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Miscellaneous Operation Information 70 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Timer and PID Function Blocks 70 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Timed Contacts 70 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
OVR_PRE %S Reference 70 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Genius Bus Controller Switching 71 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
GFK–0827 Series 90–70 Hot Standby CPU Redundancy User ’s Guide – December 1993
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Contents
Section 2: Fault Detection and Control Actions 72 . . . . . . . . . . . . . . .
Fault Detection 72 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fault Categories 72 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Changing Fault Category Actions 73 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
PLC Fault Table 74 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Faulting RCMs, Losing Links, and Terminating Communications 75 . . . . .
Fault Actions in a CPU Redundancy System 77 . . . . . . . . . . . . . . . . . . . . . . .
On-Line Repair 80 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maintaining Parallel Bus Termination 80 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
On-Line Repair Recommendations 80 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
P ower Supply 81 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Racks 81 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Central Processor Unit 81 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Redundancy Communications Module and Cables 81 . . . . . . . . . . . . . . . . .
Redundancy Communications Link Failures 82 . . . . . . . . . . . . . . . . . . . . . . .
Bus Transmitter Module 82 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Genius Bus Controller 82 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Genius Bus 83 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Genius Blocks 83 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Appendix A Redundancy Alternatives 85 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Redundancy Alternatives 85 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Series 90-70 Redundancy Through Application Logic 88 . . . . . . . . . . . . . . . . . .
GFK–0827 Series 90–70 Hot Standby CPU Redundancy User ’s Guide – December 1993
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Contents
Figure 1. Example of a Local I/O Configuration with Expansion Racks in a
Figure 2. Synchronized Hot Standby CPU Redundancy System Configuration 6 . . . . . . . . . . . . .
Figure 3. CPU 780 Locations in a Hot Standby CPU Redundancy System 14 . . . . . . . . . . . . . . . . . .
Figure 4. Redundancy CPU - IC697CPU 780 15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 5. Redundancy Communications Module - IC697RCM711 19 . . . . . . . . . . . . . . . . . . . . . . . .
Figure 6. Example of RCM Location in a Hot Standby CPU Redundancy System 20 . . . . . . . . . . .
Figure 7. Example of Multiple Genius Busses in a Hot Standby CPU Redundancy System 26 . . .
Figure 8. Active and Backup Sweeps 59 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 9. Guide to Selection of Redundancy Option Key for Table 1 (Redundancy Options) 86 . .
Hot Standby CPU Redundancy System 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
GFK–0827 Series 90–70 Hot Standby CPU Redundancy User ’s Guide – December 1993
x
Contents
Table 1. Capacities for Redundancy CPU, IC697CPU780 14 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Table 2. Valid Operating Mode Selection 16 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Table 3. Expansion Memory Boards for CPU 780 18 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Table 4. Shared I/O Data Parameters 37 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Table 5. Shared I/O Reference V alues 37 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Table 6. Transfer Data Size 38 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Table 7. Definition for% S Reference for Redundancy Status 63 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Table 8. Fault Zoom Help Text for Redundancy Error Codes 74 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Table 9. Maskable Fault Group Descriptions 77 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Table 10. Maskable Fault Group Actions 78 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Table 11. Non-Maskable Fault Group Descriptions 79 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Table 12. Non-Maskable Fault Action Descriptions 79 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Table 13. Redundancy Options 87 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
GFK–0827 Series 90–70 Hot Standby CPU Redundancy User ’s Guide – December 1993
xi
restart lowapp ARestart oddapp: ARestarts for autonumbers that do not restart in
each chapter . figure bi level 1, reset table_big level 1, reset chap_big level 1, reset1
Lowapp Alwbox restart evenap:A1app_big level 1, resetA figure_ap level 1, reset
table_ap level 1, reset figure level 1, reset Figure 1. table level 1, reset Table 1.
these restarts oddbox reset: 1evenbox reset: 1must be in the header frame of
chapter 1. a:ebx, l 1 resetA a:obx:l 1, resetA a:bigbx level 1 resetA a:ftr level 1 resetA
c:ebx, l 1 reset1 c:obx:l 1, reset1 c:bigbx level 1 reset1 c:ftr level 1 reset1
Reminders for autonumbers that need to be restarted manually (first instance will
always be 4) let_in level 1: A. B. C. letter level 1:A.B.C. num level 1: 1. 2. 3.
num_in level 1: 1. 2. 3. rom_in level 1: I. II. III. roman level 1: I. II. III. steps level 1:
1. 2. 3.
Chapter 1 Introduction
section level 1 1
1
This chapter is an introduction to a method of CPU Redundancy for the Series 90-70
Programmable Logic Controller which is referred to as the Hot Standby CPU
Redundancy product.
figure bi level 1
table_big level 1
The contents of this chapter provide:
h
a basic description of what Hot Standby CPU Redundancy is;
h
tells what it does for you - the user;
h
provides a basic description of the components of the Hot Standby CPU
Redundancy system;
h
provides a basic description of how a system is configured using the Logicmaster
90-70 programming software configurator function;
h
lists certain restrictions that you must be aware of;
h
and defines terminology unique to this product.
For those who are not familiar with the various redundancy alternatives
which may be applied to a Series 90-70 PLC system, please refer to
A ppendix A before proceeding with this chapter. Fo r tho s e w ho a re fa m il i a r
with those redundancy alternatives please proceed with the dicussion of the ’Hot
Standby CPU Redundancy Product” below.
Note
Hot Standby CPU Redundancy Product
CPU Redundancy for the Series 90-70 Programmable Logic Controller provides a
method of allowing a critical application or process to continue operating if a failure
occurs in any single component. The CPU Redundancy system described in this guide
is the Hot Standby CPU Redundancy product. A Hot Standby CPU Redundancy system
consists of two CPUs connected to one or more Genius I/O buses. Each PLC is
configured as either Primary or Secondary. The Primary PLC is the preferred PLC and
GFK-0827
1
1
contains all redundant Genius Bus Controllers at Serial Bus Address 31; the Secondary
PLC contains all redundant Genius Bus Controllers at Serial Bus Address 30. The CPU
that currently controls the system is called the active unit, the other CPU is the standby
unit.
If certain system failures are detected in the active unit, control is switched to the
standby unit. Control can also be switched by depressing a pushbutton on the
Redundancy Communications Module, or through the user’s logic program. When a
switch of control occurs, the units switch roles; the active unit becomes the standby unit
and the standby unit becomes the active unit.
Each PLC must have a Redundancy CPU module (catalog number IC697CPU780) and a
Redundancy Communications module (IC697RCM711) which provides the synchronization
link between the two units, (and a Bus Transmitter Module (IC697BEM713)). The
scanning process of both CPUs is synchronized to keep active and standby units in
lockstep to minimize ”bumps” or upsets to the process when switching from the active
to the standby unit. The effect of this action is a bumpless switch.
The Series 90-70 CPU Redundancy system runs synchronously with a transfer of all
control data that defines machine status and any internal data needed to keep the two
CPUs operating in sync, and is capable of executing the same program and obtaining the
same results. The transfer of data from the active unit to the standby unit occurs once
per sweep. These CPU to CPU transfers are checked for data integrity.
2 Series 90-70 Hot Standby CPU Redundancy User’s Guide – December 1993
GFK-0827
Features of the Hot Standby CPU Redundancy Product
H
Bumpless switching
h
Synchronized CPUs
h
20 millisecond scan extension (nominal). This figure is variable, depending on
amount of data transferred.
h
One scan switching (in most cases)
h
Configurable backup data size
H
No single point of failure (excluding Genius I/O)
H
Redundant backup communications
H
On–line repair of failed component
H
On–line programming
H
Same or different programs in Primary and Secondary units
H
Redundancy CPU has a 16 MHz microprocessor, configurable memory and
configurable addressing capacity
H
Redundancy Communications Module
1
h
Manual pushbutton switch for switching control between active and backup
CPUs
h
Five Status LEDs
– Board OK
– Local System Ready
– Local System Active
– Remote System Ready
– Remote System Active
H
Status Bits (%S) reflect redundancy status of Primary/Secondary units
H
Program control switching
H
Memory parity and checksums
H
Common I/O on Genius bus
H
Background Diagnostics
– Processor test
– PLC CPU EPROM CRC Validation
– User program checksumming
– Time-of-Day/Elapsed Time Clock test
H
Memory Protect Keyswitch
Benefits of the Hot Standby CPU Redundancy Product
Implementation of the Hot Standby CPU Redundancy product provides you with a
method of ensuring that a critical control system or process is uninterrupted in the event
of a failure of any single component (excluding I/O) of the PLC system.
3GFK-0827 Chapter 1 Introduction
1
I/O Systems for Hot Standby CPU Redundancy Systems
Both Series 90-70 Local I/O and Genius I/O systems can be present in a Hot Standby
CPU Redundancy control system. The two units are not required to have matching I/O
systems. They may have different numbers of I/O racks, and different local I/O or
option modules.
Genius I/O System
A Genius I/O system is the I/O system that is included in the redundancy system as
shown below. The system can have multiple Genius I/O buses. Any Genius device can
be placed on the bus (Genius blocks, Remote I/O Scanner, etc.). The Genius devices are
under control of the active unit in the Redundancy system. The Genius Bus Controller
in the Primary Unit has a Serial bus Address of 31; the Genius Bus Controller in the
Secondary Unit has a Serial Bus Address of 30. Data from Serial Bus Address 31 is the
preferred data when data is being sent from both units to devices on the Genius bus.
Local I/O System
Local I/O can be configured in the overall PLC system; however, it is not part of the Hot
Standby CPU Redundancy system. Control of Local I/O is done normally through the
user’s logic program. The user may choose to transfer or not transfer this data. A failure
in the Local I/O system will affect the system as described in GFK-0265, the Series 90-70
Programmable Controller Reference Manual.
Cable Connections
The I/O system is configured ”normally” except as described below (see the following
figure). That is, a Bus Transmitter Module configured in rack 0 is connected through a
parallel I/O cable to a Bus Receiver Module in the next rack. The link is continued from
this Bus Receiver Module to the Bus Receiver Module in the next rack. This link is
continued with a maximum of six expansion racks. Then, the last Bus Receiver is
connected via an I/O cable with built-in termination (catalog IC697CBL811 (10 feet (3m))
or IC697CBL826 (25 feet (7.5m)). The last module in the parallel I/O bus link must be a
Redundancy Communications Module (RCM). This terminated I/O cable allows
replacement of the RCM without interrupting the running system. If no expansion
racks are used, the terminated I/O cable is connected directly from the Bus T ransmitter
Module to the Redundancy Communications Module.
Note
The exception to a normally configured system is that Rack 7, which
normally can contain I/O modules is not available for physical I/O
modules in a Hot Standby CPU Redundancy system.
4 Series 90-70 Hot Standby CPU Redundancy User’s Guide – December 1993
GFK-0827
PRIMARY UNIT SECONDARY UNIT
1
a47000
LOCAL I/0
CAN BE IN
RACKS
0 - 6
P
B
C
S
T
P
U
M
P
B
S
R
M
Y
Y
P
B
S
R
M
RACK 0
G
IOIOIOIOI
R
B
C
C
M
31
TERMINATED I/O CABLE
*
B
L
O
C
K
RACK 1
IOIOIOIOIOIOIOI
RACK 6
IOIOIOIOIOIOIOI
RACK 0
C
B
R
G
P
O
B
L
O
C
K
O
O
S
B
L
O
C
K
IOIOIOIOI
T
C
B
P
M
M
C
U
30
REMOTE DROP
S
IOIOIOIOIOI
P
C
S
A
N
N
E
R
O
IOI
O
O
*
Figure 1. Example of a Local I/O Configuration with Expansion Racks in a
Hot Standby CPU Redundancy System
Control Strategy
Control strategy refers to the type of redundancy alternative that may be used. For the
Hot Standby CPU Redundancy product, the control strategy is referred to as Genius Hot
Standby (GHS). The control strategy must be selected when configuring the system with
the Logicmaster 90-70 programming Software Configurator function.
Basic Hot Standby Operation
In a basic Genius Hot Standby CPU Redundancy system, Genius blocks receive outputs
from two PLCs (Primary PLC and Secondary PLC), but they are normally controlled
directly by the Genius Bus Controller at serial bus address 31 (Genius Bus Controller in
the Primary PLC). If no output data is available from bus address 31 (the preferred data)
TERMINATED I/O CABLE
I/O CABLE WITH BUILT-IN TERMINATION
*
IC697CBL811 (10 FEET (3m))
IC697CBL826 (25 FEET (7.5m)
5GFK-0827 Chapter 1 Introduction
1
for three consecutive Genius I/O bus scans, the outputs are then controlled by the
Genius Bus Controller at serial bus address 30 (Genius Bus Controller in the Secondary
PLC).
If output data is not available from either bus address 31 or 30, the outputs go to their
configured default (OFF or hold last state). The PLC at serial bus address 31 always has
priority, therefore when the PLC with serial bus address 31 is On-line, it always has
control of the outputs.
The redundancy system configuration is shown in the following figure. This example
configuration shows only the redundancy system components. As described previously,
a system can also contain Local I/O which is not a part of the redundancy scheme.
PRIMARY UNIT SECONDARY UNIT
P
P
C
G
R
B
S
P
B
C
T
U
C
M
M
31
TERMINATED I/O CABLE
*
TERMINATED I/O CABLE
*
B
L
O
C
K
B
L
O
C
K
B
C
S
T
P
M
U
B
L
O
C
K
Legend
PS.................... Power Supply.............................................. IC697PWRXXX
CPU................. Central Processor Unit.............................. IC697CPU780
BTM................. Bus Transmitter Module............................. IC697BEM713
RCM................ Redundancy Communications Module..... IC697RCM711
GBC................ Genius Bus Controller................................ IC697BEM731
BLOCK........... Genius I/O Block........................................ IC660XXXYYY
SCANNER....... Remote I/O Scanner.................................... IC697BEM733
*...................... T erminated I/O Cable................................. IC697CBL811/826
a47001
G
R
B
C
C
M
30
other Genius devices
REMOTE DROP
IOIOIOIOIOI
S
P
C
S
A
N
N
E
R
IOI
O
O
Figure 2. Synchronized Hot Standby CPU Redundancy System Configuration
6 Series 90-70 Hot Standby CPU Redundancy User’s Guide – December 1993
GFK-0827
Redundancy CPU Module
The same model of CPU must be installed in both the Primary and Secondary PLCs.
This CPU, which is the only CPU that currently supports synchronized Hot Standby
CPU redundancy, is the CPU 780 (catalog number IC697CPU780). This CPU is similar to
the existing IC697CPU782 CPU in that it has an 80386DX microprocessor which operates
at a speed of 16 MHz, supports floating point calculations, and requires an expansion
memory board which can be 128 KBytes, 256 Kbytes with 256 KBytes of non-volatile
flash memory, 256 KBytes or 512 KBytes.
It is important to note that the following features available with other
Series 90-70 CPUs are not supported by the CPU 780: I/O interrupts,
timed interrupts, the VME Integrator Racks (IC697CHS782 and
IC697CHS783), Flash memory operation, and STOP/IOSCAN mode. In
addition, the operation of several other features is changed. For more
detailed information on these features, please see Chapter 4.
As with the other Series 90-70 CPUs, the CPU 780 must be installed in slot 1 of rack 0
(CPU rack). The Primary unit and the Secondary unit must each have a Redundancy
CPU installed in slot 1 of rack 0 with one CPU configured as the Primary CPU and the
other CPU configured as the Secondary CPU. Configuration of the CPU 780 in the
Primary unit and the CPU 780 in the Secondary unit must be done separately (see
Chapter 3 for details of configuration with the Logicmaster 90-70 configurator function).
1
NOTE
Redundancy Communications Module
The Redundancy Communications Module (RCM), catalog number IC697RCM711,
provides a path (see Figure 1) for sharing data between the two CPUs in the redundant
system. The RCM has five LEDS:
H
BOARD OK
H
LOCAL SYSTEM READY
H
LOCAL SYSTEM ACTIVE
H
REMOTE SYSTEM READY
H
REMOTE SYSTEM ACTIVE.
These LEDs report the status of the health of the RCM and the control status of the Hot
Standby CPU Redundancy system. The status provided by these LEDs is also provided
in an area of %S memory (%S33 through %S39) which is accessible from the user logic
program but cannot be altered or overridden.
The module has a momentar y pushbutton switch which when depressed for 1 second
and released allows you to manually switch control from the active unit to the standby
unit. The switch between units can also be controlled through user logic
implementation of a SVC_REQ function that is activated by a discrete input point. Both
of these switch requests may only be made every 10 seconds.
In a synchronized system, I/O data is controlled by only one unit (the active unit) but is
shared between both units (active and backup units). The RCM provides the path for a
synchronizing message from the active to the backup unit which is used to synchronize
7GFK-0827 Chapter 1 Introduction
1
the two CPUs and provides the communications path for the transfer of I/O data
between the two units. An RCM must be configured in both the Primary PLC and the
Secondary PLC. The RCM must reside in the CPU rack (rack 0) in a system and there
can be no empty slot between the RCM and the CPU (there can be other modules).
Bumpless Switching
Bumpless switching occurs when the active unit fails and system control is transferred to
the backup unit without affecting the operation of the process under control.
Synchronized CPUs
For bumpless swi tc hing to occur, the CPU in the active and backup units must operate in a
synchronous fashion, that is, the operation of both units must occur at the same time (or as
close to the same time as possible). There are two synchronization points in the swee p: on e
immediately after the input scan and the other immediately before the output scan.
Synchronization data is passed from the active to the backup unit at the first
synchronization point, which occurs after the input scan. Specifically, after the inputs are
scanned, the inputs that were just read (%I and %A I) are sent from the active to the backup
unit and the synchronization message is passed after the input data.
The second synchronization point occurs immediately after the end of the logic solution
before the output scan begins. During this time, all remaining control data, including the
%Q, %AQ, %M and %R memories is transferred from the active unit to the backup unit.
Effect on Scan Time
When a system is operating normally (no faults exist in the system) redundancy adds about
21 ms (includes 5 ms default background window setting) per PLC scan. The effect on scan
time depends on the system configuration. The followi ng number of data points and
registers is considered the base configuration on which the 21 ms was calculated.
512 %I, 512 %Q, 512 %M
256 %AI, 256 %AQ
2048 %R
Each additional 1K %I, %Q, or %M data points adds about 1.8 ms to the scan impact
(add 25% for each %I or %Q reference if point faults enabled) and each additional 1K of
%R, %AI, or %AQ registers adds about 5 ms to the scan impact (add 50% for each %AI
or %AQ reference if point faults enabled).
Fail Wait Time
When the active CPU has a failure, the backup CPU will wait for a specified time (in
milliseconds) before assuming that the link has failed. This time is referred to as the Fail
Wait time. The duration of this time must be specified during configuration of both the
Primary and Secondary units and can range from 60 ms to 400 ms (in increments of 10
ms), with the default value being 60 ms.
Switch to Backup Unit Time
The amount of time it takes to switch control from the active unit to the backup unit
depends on what caused the switch to take place.
8 Series 90-70 Hot Standby CPU Redundancy User’s Guide – December 1993
GFK-0827
If the switch occurs due to a controlled condition such as toggling the unit selection
switch on the Redundancy Communications Module or forcing a switch in the user logic
program with a SVC_REQ, or because of a fault detected by the PLC CPU, then the
switch-over will occur at the beginning of the next sweep. The delay will be up to 1
sweep with the possibility of an input and an output scan after failure detection.
If the switch occurs due to a failure of the PLC CPU (including loss of power), then the
switch will occur after the backup unit determines that the active unit has failed to
rendezvous at the synchronization point. Failure to rendezvous may take up to 2 failwait
timeouts (1 for each link) to determine that a failure has occurred. Control will not
transfer , in this case, until both links have been tried unsuccessfully.
Configurable Backup Data Size
The maximum size of the backup data (Shared I/O) is 20 KBytes of Input data and 28
KBytes of Output data. The shared I/O data configuration must be the same in both the
Primary and Secondary units. This shared I/O data is transferred from the active CPU to
the backup CPU during the CPU sweep process. A total of up to 56 KBytes of user
memory is consumed by this data transfer. A maximum of 48 KBytes of the 56 KBytes is
the total Shared I/O (20 KBytes %I, %AI; 28 KBytes %Q, %M, %AQ, and %R), while the
remainder (8 KBytes) is used by the system for internal data transfers, including
synchronizing data.
1
On-Line Programming
On-line changes to the user logic program are permitted in both the active unit and the
backup unit. The programming device must be connected to the system in which
changes are to be made in order to make any on-line changes. Note that all precautions
regarding power source and grounding for connecting the programming device must be
followed in accordance with instructions in the Series 90-70 Programmable Controller
Installation Manual, GFK-0262.
A connection and disconnection of the parallel programmer cable should only be made
with the programmer properly grounded, and Logicmaster 90 software properly booted
up and in OFF-LINE mode. For more information, refer to the Series 90-70 Installation
manual, GFK–0262.
On-Line Repair
A Hot Standby CPU Redundancy system allows you to do on-line repair of failed
components without disrupting the process under control. Control status of both the
Primary and the Secondary units can be monitored by the LEDS on the Redundancy
Communications Modules in each system. When a component of the active unit fails,
control is switched to the backup unit. The failed component can then be replaced by
removing power from the rack in which it is installed.
After replacing the failed component and returning power to the rack, the backup unit
will resynchronize with the currently active unit. The unit which had failed and was
previously the active unit will determine its role in the system as part of the
resynchronization process. If it is the Primary unit (with Serial Bus Address 31) it will
once again become the active unit, the unit with Serial Bus Address 30 (Secondary unit)
will again become the backup unit. F or mor e detailed information on replacing failed
components and resynchronization, see Chapter 4, ”System Operation”.
9GFK-0827 Chapter 1 Introduction
1
Programming Considerations
There are several features in the operation of the Redundancy CPU which are not
supported or are different then operation of other CPUs. These features are listed below
and are described in detail in Chapter 4, ”System Operation”.
The following features are not available with the Redundancy CPU (CPU 780):
H
I/O Interrupts
H
Timed Interrupts
H
VME Integrator Rack
H
STOP/IOSCAN mode
H
Flash memory operation
The operation of the following features is different with the CPU 780 than with other
Series 90-70 CPUs:
H
RUN/DISABLED mode
H
Configuration of fault actions
H
STOP to RUN mode
H
Default Background Window Time
Configuration R equirements
The Redundancy CPU and the Redundancy Communications Module must be
configured into the redundancy system. There are several additional parameters (other
than the normal CPU parameters) that must be configured with the Logicmaster 90-70
Configurator function which are unique to the Hot Standby CPU Redundancy system.
The following items require configuration when specifying the CPU 780 (the
Redundancy CPU) as the CPU for configuration:
Configuration
Parameter Description
Fail-wait (60 ms to 400 ms) The time to wait on a failed active PLC before switching to
Control Strategy The control strategy for the cur rent configuration. Config-
Shared I/O Refer ences The references within the control of the Redundancy sys-
the backup CPU. The default value is 60 ms.
ured as a three-character identifier (GHS for Hot Standby
CPU Redundancy). The default value is GHS (currently
the only value that is valid).
tem; up to 20 KBytes of Input data and 28 KBytes of Output data is transferred. The references which may be used
as shared I/O are %I, %Q, %AI, %AQ, %R, and %M.
Redund Type Whether the CPU being configured is the Primary or Sec-
ondary CPU in the Redundancy system. Redund Type
has three possible values: PRIMARY, SECONDARY , or
SIMPLEX. SIMPLEX (not supported in this release of the
product) indicates a non–redundant system. The default
value is PRIMARY.
10 Series 90-70 Hot Standby CPU Redundancy User’s Guide – December 1993
GFK-0827
The Primary Unit and the Secondary Unit must be configured separately. That is, the
programming device should be connected directly to either the Primary or the
Secondary Unit to configure that unit. When you have completed configuring that unit,
disconnect the programmer from the configured unit and move it to the other unit and
proceed with configuration of the second unit. Refer to Chapter 3, ”System
Configuration” for details of configuring a Redundancy system
Definition of Terms
Several new or unfamiliar terms are used throughout this manual which are relevant to
the discussions of CPU Redundancy. These terms are defined in the following table.
Term Definition
A ctive Unit The unit that is actively controlling the process.
Back up Unit That unit that is synchronized with the active unit and able to take over the process.
CPU Redundancy A system with two PLC CPU units cooperating to control the same process.
Critical Component A component whose failure causes the PLC (either active or backup) in which it resides to
stop.
Hot Standby A feature of Genius blocks whereby the block prefers output data from the
Bus Controller at Serial Bus A ddress 31. When inputs from that Bus Controller are not
available, the block tak es output data from the Bus Controller at Serial Bus Address 30.
If inputs from neither Controller are available, the block places its outputs in the
designated default state.
1
Local Unit The RCM LEDs and %S status bits refer to the PLC in which they reside as
the ”Local Unit”.
Primar y Unit The unit in which the Genius Bus Controller’s Serial Bus A ddress is 31.
Redundancy A system feature that has multiple elements controlling the same process to provide alter-
nate functional channels in case of failure.
Remote Unit The RCM LEDs and status bits refer to the other PLC as the ”Remote Unit”.
For example, the P rimary Unit is the Remote Unit to the Secondary Unit and likewise
the Secondary Unit is the Remote Unit to the Primary Unit.
Secondary Unit The unit in which the Genius Bus Controller’s Serial Bus A ddress is 30.
Synchronized A unit is considered to be synchronized when it has received the latest status information
from the Active unit and is running the PLC program in parallel.
11GFK-0827 Chapter 1 Introduction
1
Commonly Used Acronyms
A list of acronyms used in this manual are defined for your convenience in the following
table.
Acronym Definition
BRM Bus Receiver Module
BSM Bus Switching Module
BTM Bus T ransmitter Module
CPU Central Processor Unit
EPROM Erasable Programmable Read Only Memory
GBC Genius Bus Controller
GHS Genius Hot Standby Redundancy
GMR Genius Modular Redundancy
HHM Hand Held Monitor
LED Light Emitting Diode
OI Operator Interface
PLC Programmable Logic Controller
PROM Programmable Read–Only Memory
RAM Random Access Memory
RCM Redundancy Communications Module
PLD Relay Ladder Diagram
SBA Serial Bus A ddress
SNP Series 90 Protocol
VME VersaModule Europe: the backplane standard
used by the Series 90-70 PLC system
12 Series 90-70 Hot Standby CPU Redundancy User’s Guide – December 1993
GFK-0827
Chapter 2 System Components
section level 1 1
2
This chapter describes the hardware components for a Hot Standby CPU Redundancy
system. It describes the modules required for the system and provides catalog numbers
of the components. For detailed installation instructions for the Series 90-70 PLC, refer
to GFK-0262, the Series 90-70 Programmable Controller Installation Manual.
Redundancy CPU
The IC697CPU780 Central Processing Unit (CPU) has been designed specifically for
Series 90-70 Hot Standby CPU Redundancy applications. This is the only Series 90-70 CPU
that currently supports CPU redundancy .
figure bi level 1
table_big level 1
Note
It is important to note that the following features available with other
Series 90-70 CPUs are not supported by the CPU 780: I/O interrupts,
timed interrupts, the VME Integrator Racks (IC697CHS782 and
IC697CHS783), Flash Memory operation, and STOP/IOSCAN mode. In
addition, the operation of several other features is changed. For more
detailed information on these features, please see Chapter 4.
The CPU 780 supports floating point calculations, offers remote programmer keyswitch
memory protection, and has four status LEDs. Operation of this module may be
controlled by the three-position RUN/STOP switch on the module, or remotely by an
attached programmer and Logicmaster 90-70 Programming Software. Program and
configuration data can be locked through software passwords or manually by the
memory protect keyswitch. When the key is in the ”protected” position, program and
configuration data can only be changed by a programmer connected for parallel
communications (that is, to the Bus Transmitter Module).
As with the other Series 90-70 CPUs, the CPU 780 must be installed in slot 1 of rack 0
(CPU rack). In a Hot Standby CPU Redundancy system, the Primary unit and the
Secondary unit must each have a Redundancy CPU installed in slot 1 of rack 0. One
CPU is configured as the Primary CPU and the other CPU is configured as the
Secondary CPU. Configuration of the CPU 780 in the Primary unit and the CPU 780 in
the Secondary unit must be done separately (see Chapter 3 for details of configuration
with the Logicmaster 90-70 configurator function). The following figure shows the CPU
location in a Hot Standby CPU Redundancy system.
GFK-0827
13
2
CPU 780
The capacities for the CPU 780 are as listed in the following table.
Speed
(MHz) Processor
16 80386DX 12288
[
The total number of Input points and Output points on the model 780 CPU cannot ex ceed 12288.
CPU Architecture
PRIMARY UNIT SECONDARY UNIT
C
P
S
G
R
B
P
B
C
T
U
C
M
M
31
Redundancy Communications Link
Redundancy Communications Link
B
C
P
T
P
S
M
U
G
R
B
C
C
M
30
Genius Bus
a47002
Figure 3. CPU 780 Locations in a Hot Standby CPU Redundancy System
Table 1. Capacities for Redundancy CPU, IC697CPU780
Input
Points
[
Output
Points
12288
On-Board
User Memory
[
not available 128/256/512 Yes
Expansion Memor y
(KBytes)
Floating Point
Math
The CPU 780 has an 80386DX microprocessor as the main processing element, on-board
memory, a dedicated VLSI processor for performing boolean operations and interfaces
to a serial port and the system bus. The microprocessor provides all fundamental sweep
and operation control, plus execution of non-boolean functions. Boolean functions are
handled by a dedicated, VLSI, Boolean Coprocessor (BCP) designed by GE Fanuc.
Program and data memory on the CPU 780 is available by the attachment of an
expansion memory board with either 128 Kbytes, 256 Kbytes or 512 Kbytes of
battery-backed CMOS RAM, or 256 Kbytes with 256 Kbytes of non-volatile flash
memory.
When the CPU board is in storage, disconnect the lithium battery if there is no
application program stored in memory. If a program is stored in memory, do not
disconnect the battery; otherwise the data will be lost.
Caution
If a Low Battery Warning occurs, replace the battery before removing
power from the rack. Otherwise there is the possibility that data will
be corrupted or the program will be cleared from memory.
Watchdog Timer
The CPU provides a watchdog timer to catch certain failure conditions. The value of this
timer is controlled by the user from the programmer. The valid range of the watchdog
14 Series 90-70 Hot Standby CPU Redundancy User’s Guide – December 1993
GFK-0827
CPU Features
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timer is 10 milliseconds to 1000 milliseconds. The default value for the watchdog timer is
200 milliseconds. The watchdog timer resets at the beginning of each sweep. The fail
wait time is included in the watchdog check. The watchdog timer should be set to allow
for the expected scan plus two fail wait times.
The CPU must reside in Slot 1 in rack 0, the main (CPU) rack. An illustration of the CPU
780 is shown in the following figure, followed by a description of the CPU features.
a47003
MEMORY
PROTECT
KEY
SWITCH
OK
ÎÎÎ
RUN
ENABLED
ÎÎÎ
ÎÎÎ
MEM PROTECT
ÎÎÎ
CENTRAL
ÎÎÎ
PROCESSOR
ÎÎÎ
UNIT
ÎÎÎ
ÎÎÎ
ÎÎÎ
ÎÎÎ
ÎÎÎ
ÎÎÎ
ÎÎÎ
ÎÎÎ
ÎÎÎ
ÎÎÎ
ÎÎÎ
ÎÎÎ
ÎÎÎ
ÎÎÎ
ÎÎÎ
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CPU
STATUS
LEDS
CPU MODE
SWITCH
OPEN
REPLACEMENT
BATTERY
CONNECTOR
CURRENTLY
INSTALLED
BATTERY
CONNECTOR
EXPANSION
MEMORY
BOARD
IC697MEM731
IC697MEM732
IC697MEM733
IC697MEM735
RS-485
COMPATIBLE
SERIAL PORT
B
A
T
T
E
R
TOP
Y
REMOTE P R O GR AMMER
MEMORY PR OTECT
FRONT
ON = OK, ENABLED
INSTALL NEW
BATTERY BEFORE
UNPLUGGING OLD
BATTERY. USE
IC697ACC701
MODULE FUNCTION
16MHz 32 BIT CENTRAL
PROCESSING UNIT
WITH FLOATING POINT
MATH COPROCESSOR
FOR HOT STANDBY
CPU APPLICATIONS
USE THIS MODULE
MODULE
IC697CPU 780
LABEL
44A726758-130R03
CPU 780
OFF
ON
KEY POSITION
MODULE OK
RUN
OUTPUTS
ENABLED
MEMORY PR OTECT
REMOTE
PROGRAMMER
ONLY
PROTECTED
RUN WITH
OUTPUTS
ENABLED
RUN WITH
OUTPUTS
DISABLED
STOP
BATTERY
CONNECTORS
SERIAL PORT
RS-485
COMPAT IBLE
IN SLOT 1 ONLY
Figure 4. Redundancy CPU - IC697CPU 780
2
15GFK-0827 Chapter 2 System Components
2
CPU Mode Switch
Allowable Programmer
CPU Mode Switch
Position
Allowable Programmer
CPU Mode Switch
A three-position toggle switch is mounted near the top of the CPU board. This switch
selects one of three operating modes for the CPU: RUN/ENABLED, RUN/DISABLED, or
STOP. Although the mode of operation for the CPU can be controlled from both the
switch and the programmer, the switch position restricts the ability of the programmer
to put the CPU into certain modes.
The following table shows the modes that can be selected by the programmer based
upon the position of the CPU mode switch.
Table 2. Valid Operating Mode Selection
Mode Command
STOP
RUN/OUTPUTS ENABLED RUN/DISABLED
RUN/ENABLED
STOP
RUN/OUTPUTS DISABLED RUN/DISABLED
STOP STOP
Run/Outputs Enabled
The top position of the switch is Run with Outputs Enabled. With the switch in this
position, the CPU executes all portions of the sweep normally.
Run/Outputs Disabled
The middle position of the switch is Run with Outputs Disabled. When the switch is in
this position, the CPU executes all portions of the sweep normally, but physical outputs
are held in their default state, and therefore remain unchanged. Refer to Chapter 4,
page 65 for important information on the Run/Disabled mode in a Hot Standby CPU
Redundancy system.
STOP
NOTE
The STOP/IOSCAN mode is not a valid mode in a redundancy system.
Refer to Chapter 4 for detailed information.
The bottom position of the switch is labeled STOP. With the switch in this position, the
CPU communicates only with the programmer and devices connected to the serial port,
and recovers faulted modules. Any of the values in the I/O tables can be changed using
the programming computer.
16 Series 90-70 Hot Standby CPU Redundancy User’s Guide – December 1993
GFK-0827
Memory Protect Keyswitch
The Memory Protect keyswitch is located at the top of the module and has two
positions: ON and OFF. This keyswitch is used to manually lock program and
configuration data. When the key is in the ”protected” (ON) position, program and
configuration data can only be changed by a programmer connected for parallel
communications with the CPU 780 (that is, to the Bus Transmitter Module).
CPU Status LEDs
There are four LEDs mounted at the top of the CPU board which indicate the current
state of the CPU. The normal state of these LEDs when the CPU is running is ON. They
are OFF or flashing to indicate special or failure conditions.
OK
The top LED, labeled OK is an indicator of the health of the CPU. It is ON when the CPU
is functioning properly. The LED blinks when the CPU executes the power-up
diagnostics, when the system has failed, and when the remote unit is powered-up.
However, when in this state, the CPU can still communicate with the programmer (the
CPU cannot communicate with the programmer during power-up diagnostics) . The
LED is OFF when the system has failed and the CPU cannot communicate with the
programmer.
2
RUN
The middle LED, labeled RUN is an indicator of the RUN/STOP status of the CPU. It is
ON when the CPU is in the RUN/ENABLE or RUN/DISABLE mode. When the CPU is in
the STOP mode, the LED is OFF.
ENABLED
The bottom LED, labeled ENABLED indicates the state of the outputs. This LED is ON
when the outputs are enabled, and OFF when the outputs are disabled.
MEM PROTECT
This LED indicates the status of the memory protect keyswitch. When the keyswitch is
in the OFF position the LED is OFF, and the CPU can be programmed (if connected for
parallel communications, the CPU can be programmed regardless of the keyswitch
position). After the program has been verified, the toggle switch for mode selection can
be moved to the appropriate mode position. When the memory protect keyswitch is in
the ON position, the LED will be ON.
Battery Connectors
Directly below the mode switch are two identical battery connectors. The connector
wired to the lithium backup battery cable plugs into one of these connectors to connect
the battery to the CMOS memory devices. Two connectors are provided for use when
the battery requires replacement. The battery currently installed can remain connected
until the new battery is connected, thus minimizing the possibility of losing data.
17GFK-0827 Chapter 2 System Components
2
Serial Port Connector
The 15-pin D-connector at the bottom of the module provides the connection to an
RS-422/RS-485 serial port. Its port provides a serial connection to the W ork Station
Interface (WSI) board installed in the programming computer. For applications
requiring RS-232 communications, an RS-232 to RS-422 converter (IC690ACC900) or
RS-232 to RS422 miniconverter (IC690ACC901) is available.
Note
An RS-422 Isolated Repeater/RS-232 Converter (IC655CCM590) is
available for applications requiring ground isolation where a common
ground cannot be established between components.
A standard serial COM port version of Logicmaster 90-70 programming software
provides logic programming and configuration for the Series 90-70 PLC using the COM1
or COM2 serial port of the programming device (a Work Station Interface board is not
needed). Connections for this configuration are made from the programmer’s COM1 or
COM2 serial port to the converter to the serial port on the Series 90-70 CPU.
Expansion Memory Board
The CPU 780 requires an expansion memory board (see GFK-0837 and GFK-0531C, or
later versions), for more information. The expansion memory board uses battery-backed
CMOS RAM memory devices for program and data storage. These expansion memory
boards are arranged in a 32-bit memory configuration and can only be used on the
models 780, 781 and 782 CPUs. Error checking is provided by a CPU checksum routine.
Logic program memory is continually error-checked by the CPU as a background task.
Memory parity errors are reported to the CPU when they occur.
These expansion memory boards are not compatible with the expansion memor y boards
used with the models 771 and 772 CPUs or the Programmable Coprocessor Module.
Four versions of the 32-bit memory expansion board are available as listed in the table
below. These expansion memory boards are installed on the CPU 780 module by
mounting them on a connector provided for that purpose. The CMOS RAM memory on
the expansion memory boards is backed-up by the Lithium battery mounted on the CPU
module on which the boards are installed.
Table 3. Expansion Memory Boards for CPU 780
Catalog Number Memory Size
IC697MEM731 128K Bytes
IC697MEM732 256K Bytes w/256 K Bytes Non-Volatile Flash Memory
IC697MEM733 256K Bytes
IC697MEM735 512K Bytes
Note that the current version of the expansion memory boards must be used with the
CPU 780. consult your local PLC Distributor or PLC sales office for more
information.
18 Series 90-70 Hot Standby CPU Redundancy User’s Guide – December 1993
GFK-0827
Redundancy Communications Module
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The Redundancy Communications Module (RCM), catalog number IC697RCM711, provides
a communications path for sharing data between the two CPUs in the redundant system.
In a synchronized system, I/O data is controlled by one unit (the active unit) but is shared
between both units (active and backup units). The RCM provides the communications path
between the two units. An RCM must be configured in both the Primary PLC and the
Secondary PLC. The RCM must reside in rack 0 and there can be no empty slot between
the RCM and the CPU (there can be other modules).
RCM Features
The followi ng figure shows the features of the RCM module.
ÎÎÎ
OK
LOCAL READY
LOCAL ACTIVE
ÎÎÎ
REMOTE READY
REMOTE ACTIVE
ÎÎÎ
ÎÎÎ
REDUNDANCY
ÎÎÎ
COMMUNICATIONS
MODULE
ÎÎÎ
ÎÎÎ
ÎÎÎ
Figure 5. R edundancy Communications Module - IC697RCM711
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a47004
RCM 711
BOARD OK
LOCAL SYSTEM
READY
LOCAL SYSTEM
ACTIVE
REMOTE SYSTEM
READY
REMOTE SYSTEM
ACTIVE
ON = TRUE
DEPRESS 1 SEC.
TO SWITCH ACTIVE
CPU (MIN 10 SECS
BETWEEN SWITCHES)
MODULE FUNCTION
REDUNDANCY
COMMUNICATIONS
MODULE.
HIGH SPEED INTERFACE
BETWEEN HOT.
STANDBY REDUNDANCY
SUPPORTED CPUs.
CONNECT TO END
OF EXPANSION BUS
EXPANSION
PORT IN
(TOWARDS CPU)
TO BEM711
OR BEM713
(USE TERMINATED
CABLE CBL811
OR CBL826)
50 FT. MAXIMUM
CABLE LENGTH FROM
BEM 713 TO TO RCM711
UNUSED PORT
DO NOT INSTALL
CABLE OR
TERMINATOR
MODULE
IC697RCM711
LABEL:
44A726758–136R02
2
19GFK-0827 Chapter 2 System Components
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