Schneider Electric Stroller 840 USE 106 0 User Guide

Quantum Hot Standby  
Planning and Installation Guide  
840 USE 106 00  
Version 4.0  
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Table of Contents  
Safety Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9  
About the Book. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11  
Chapter 1 Overview of Quantum Hot Standby . . . . . . . . . . . . . . . . . . . . .13  
At a Glance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13  
1.1 Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15  
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15  
Primary and Standby Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16  
Hardware Components in a Quantum Hot Standby System. . . . . . . . . . . . . . . . 17  
The CHS 110 Hot Standby Module. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18  
1.2 Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21  
Modes of Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21  
1.3 Cabling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23  
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23  
Fiber Optic Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24  
The CHS 210 Hot Standby Kit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25  
1.4 984 HSBY and IEC HSBY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26  
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26  
984 HSBY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27  
IEC HSBY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28  
Chapter 2 Theory of 984 Ladder Logic HSBY Operation . . . . . . . . . . . . .31  
At a Glance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31  
How a 984 HSBY System Works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32  
System Scan Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33  
The State RAM Transfer and Scan Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36  
Default Transfer Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38  
Customizing Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40  
Custom Scans. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41  
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Chapter 3 Theory of IEC HSBY Operation. . . . . . . . . . . . . . . . . . . . . . . . . 43  
At a Glance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43  
IEC Hot Standby Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44  
How an IEC HSBY System Works. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46  
System Scan Time. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47  
State Ram Transfer and Scan Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51  
Layout of completely transferred state RAM in an IEC Hot Standby system. . . . 53  
Chapter 4 Planning a Quantum Hot Standby System . . . . . . . . . . . . . . . 55  
At a Glance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55  
Guidelines for Planning a Hot Standby System. . . . . . . . . . . . . . . . . . . . . . . . . . 56  
Electrical Safety Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57  
Remote I/O Cable Topologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58  
A Single Cable Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59  
A Dual Cable Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60  
Chapter 5 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61  
How to Install a Hot Standby System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61  
Chapter 6 Using a Quantum 984 HSBY System . . . . . . . . . . . . . . . . . . . . 67  
At a Glance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67  
6.1 Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69  
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69  
Configuring 984 HSBY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70  
Configuration Extension. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72  
CHS Instruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73  
6.2 Using the CHS Instruction Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74  
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74  
Using CHS Instruction Block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75  
Command Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76  
Elements of the Nontransfer Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78  
Zoom screen of CHS Instruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80  
The Hot Standby Status Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81  
The Reverse Transfer Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82  
Reverse Transfer Logic Example. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83  
6.3 Using Configuration Extension. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85  
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85  
Configuration Extension. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86  
Hot Standby Dialog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87  
Bits in the Hot Standby Command Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88  
Keyswitch Override and Run Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90  
A Software Control Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91  
Standby on Logic Mismatches. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92  
Transfer All State RAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94  
Hot Standby Status Register for Configuration Extension. . . . . . . . . . . . . . . . . . 95  
Advanced Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96  
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Defining the Transfer Area of State RAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97  
Transferring Additional State RAM Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100  
Scan Transfers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102  
6.4 Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103  
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103  
Starting Your Hot Standby System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104  
Synchronizing Time-of-Day Clocks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106  
While Your System Is Running . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108  
Chapter 7 Using a Quantum IEC Hot Standby System . . . . . . . . . . . . .109  
At a Glance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109  
7.1 Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111  
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111  
Loading the Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112  
Controlling the Hot Standby System by Configuration Extension . . . . . . . . . . . 114  
7.2 Hot Standby Dialog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116  
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116  
Hot Standby dialog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117  
Specifying the Command Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118  
Hot Standby Command Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119  
Enable Keyswitch Override. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120  
Advanced Options Concept 2.5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122  
Standby on Logic Mismatch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124  
Swapping Addresses at Switchover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127  
7.3 State RAM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129  
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129  
Nontransfer Area of State RAM. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130  
Hot Standby Status Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132  
Memory Partition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133  
State RAM Size. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134  
7.4 Section Transfer Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135  
Section Transfer Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135  
7.5 Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138  
Starting Your Hot Standby System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138  
7.6 Normal Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140  
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140  
Memory/Scantime optimization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141  
Synchronizing Time of Day Clocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145  
While Your System Is Running . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146  
Chapter 8 Additional Guidelines for IEC Hot Standby . . . . . . . . . . . . . .147  
At a Glance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147  
8.1 General Application Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149  
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149  
Memory Savings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150  
Memory Statistics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151  
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Memory Partition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153  
8.2 State RAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155  
Efficient Use of State RAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155  
8.3 Efficiency Tips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157  
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157  
Use Constants Instead of Equal Literals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158  
Use Constants Instead of Open Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159  
Programmed Logic. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161  
Reduce the Use Of Complex Data Structures . . . . . . . . . . . . . . . . . . . . . . . . . . 162  
Chapter 9 Ethernet Hot Standby Solution. . . . . . . . . . . . . . . . . . . . . . . . 163  
At a Glance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163  
Overview of Hot Standby Solution for NOEs . . . . . . . . . . . . . . . . . . . . . . . . . . . 164  
Hot Standby Topology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166  
NOE Configuration and Hot Standby. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167  
IP Address Assignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168  
NOE Operating Modes and Hot Standby. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169  
Address Swap Times. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173  
Network Effects of Hot Standby Solution. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174  
Chapter 10 Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177  
At a Glance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177  
10.1 Health of a Hot Standby System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179  
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179  
Verifying Health of a Hot Standby System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180  
Additional Checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181  
10.2 Errors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183  
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183  
Startup Errors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184  
Communications Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185  
Board Level Errors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186  
10.3 Failures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187  
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187  
Detecting Failures in a Hot Standby System . . . . . . . . . . . . . . . . . . . . . . . . . . . 188  
Detecting Failures in the Primary Backplane. . . . . . . . . . . . . . . . . . . . . . . . . . . 189  
Detecting Failures in the Standby Backplane . . . . . . . . . . . . . . . . . . . . . . . . . . 190  
Failure of Fiber Link from Primary Transmit to Standby Receiver . . . . . . . . . . . 191  
10.4 Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192  
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192  
Replacing a Hot Standby Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193  
Changing the Program and Performing a Program Update. . . . . . . . . . . . . . . . 194  
Updating PLC System Executives in a 984 HSBY System . . . . . . . . . . . . . . . . 198  
Updating PLC System Executives in an IEC HSBY System . . . . . . . . . . . . . . . 200  
10.5 Testing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201  
Forcing a Switchover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201  
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Chapter 11 Specifications for CHS 110 Hot Standby . . . . . . . . . . . . . . . .205  
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205  
Appendices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207  
Appendices for Quantum Hot Standby Planning and Installation Guide. . . . . . 207  
Appendix A Com Act Error Patterns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .209  
At a Glance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209  
CHS 110 Hot Standby Module Error Patterns. . . . . . . . . . . . . . . . . . . . . . . . . . 210  
CRP Remote I/O Head Processor Error Patterns . . . . . . . . . . . . . . . . . . . . . . . 211  
Appendix B Fiber Optic Cable Guide. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .213  
At a Glance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213  
Fiber Optic Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214  
Other Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216  
Appendix C ProWORX Nxt Configuration . . . . . . . . . . . . . . . . . . . . . . . . . .217  
ProWORX Nxt Hot Standby Configuration Extension . . . . . . . . . . . . . . . . . . . . 217  
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223  
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Safety Information  
§
Important Information  
NOTICE  
Read these instructions carefully, and look at the equipment to become familiar with  
the device before trying to install, operate, or maintain it. The following special  
messages may appear throughout this documentation or on the equipment to warn  
of potential hazards or to call attention to information that clarifies or simplifies a  
procedure.  
The addition of this symbol to a Danger or Warning safety label indicates  
that an electrical hazard exists, which will result in personal injury if the  
instructions are not followed.  
This is the safety alert symbol. It is used to alert you to potential personal  
injury hazards. Obey all safety messages that follow this symbol to avoid  
possible injury or death.  
DANGER  
DANGER indicates an imminently hazardous situation, which, if not avoided, will  
result in death, serious injury, or equipment damage.  
WARNING  
WARNING indicates a potentially hazardous situation, which, if not avoided, can result  
in death, serious injury, or equipment damage.  
CAUTION  
CAUTION indicates a potentially hazardous situation, which, if not avoided, can result  
in injury or equipment damage.  
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Safety Information  
PLEASE NOTE  
Electrical equipment should be serviced only by qualified personnel. No responsi-  
bility is assumed by Schneider Electric for any consequences arising out of the use  
of this material. This document is not intended as an instruction manual for untrained  
persons.  
© 2003 Schneider Electric  
All Rights Reserved  
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About the Book  
At a Glance  
Document Scope This manual contains complete information about programmable controller Hot  
Standby systems.  
Validity Note  
This documentation applies to Concept.  
Related  
Documents  
Title of Documentation  
Reference Number  
840 USE 100 00  
890 USE 101 00  
840 USE 101 00  
890 USE 100 00  
840 USE 493 00  
840 USE 492 00  
840 USE 494 00  
840 USE 496 00  
840 USE 495 00  
Quantum Automation Series Hardware Reference Guide  
Remote I/O Cable System Planning and Installation Guide  
Ladder Logic Block Library User Guide  
Modbus Plus Network Planning and Installation Guide  
Concept V 2.5 User’s Manual  
Concept V 2.5 Installation Instructions  
Concept V 2.5 Block Library: IEC  
Concept V 2.5 Block Library: LL984  
Concept EFB User’s Manual  
Product Related  
Warnings  
Schneider Electric assumes no responsibility for any errors that may appear in this  
document. If you have any suggestions for improvements or amendments or have  
found errors in this publication, please notify us.  
No part of this document may be reproduced in any form or means, electronic or  
mechanical, including photocopying, without express written permission of the  
Publisher, Schneider Electric.  
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About the Book  
User Comments  
We welcome your comments about this document. You can reach us by e-mail at  
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Overview of Quantum Hot  
Standby  
1
At a Glance  
Purpose  
This chapter presents a brief overview of the Hot Standby system, including a  
description of Primary and Standby control, components, the Hot Standby module,  
LEDs and switches, modes of operation, 984 and IEC HSBY, and the application  
size.  
Throughout the rest of this book the Quantum Hot Standby system is referred to as  
HSBY.  
An HSBY system is based on two identically configured programmable logic  
controllers linked to each other and to the same remote I/O network. If one controller  
fails, the other assumes control of the I/O system.  
What’s in this  
Chapter?  
This chapter contains the following sections:  
Section  
1.1  
Topic  
Page  
15  
Control  
1.2  
Operation  
21  
23  
26  
1.3  
Cabling  
1.4  
984 HSBY and IEC HSBY  
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Overview of Quantum Hot Standby  
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Overview of Quantum Hot Standby  
1.1  
Control  
Introduction  
Purpose  
This section describes Primary and Standby Control for a Quantum Hot Standby  
system.  
What’s in this  
Section?  
This section contains the following topics:  
Topic  
Page  
16  
Primary and Standby Control  
Hardware Components in a Quantum Hot Standby System  
The CHS 110 Hot Standby Module  
17  
18  
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Overview of Quantum Hot Standby  
Primary and Standby Control  
Description  
The Quantum Hot Standby system is designed for use where downtime cannot be  
tolerated. The system delivers high availability through redundancy. Two  
backplanes are configured with identical hardware and software.  
One of the PLCs acts as the Primary controller. It runs the application by scanning  
user logic and operating remote I/O.  
The other PLC acts as the Standby controller. The Primary controller updates the  
Standby controller after each scan. The Standby is ready to assume control within  
one scan if the Primary fails.  
Primary and Standby states are switchable. Either controller can be put into the  
Primary state, but to do this, the other must be in the Standby state. The remote I/O  
network is always operated by the Primary controller.  
Note: A Quantum Hot Standby system supports only remote I/O. It does not  
support local I/O or distributed I/O (DIO).  
Role of the CHS  
110 Hot Standby  
Module  
Each controller is paired with a 140 CHS 110 00 Hot Standby module. The module  
monitors its own controller and communicates with the other Hot Standby module.  
The system monitors itself continuously. If the Primary controller fails, the Hot  
Standby module switches control to the Standby, which then becomes the Primary  
controller.  
If the Standby controller fails, the Primary continues to operate without a backup.  
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Overview of Quantum Hot Standby  
Hardware Components in a Quantum Hot Standby System  
Components  
A Quantum Hot Standby system requires two backplanes, each with at least four  
slots. The backplanes must be equipped with identical, compatible Quantum:  
Programmable logic controller  
Remote I/O head processor  
CHS 110 Hot Standby module  
Cables (See Fiber Optic Cable Guide, p. 213)  
Power supply  
Other components, (Backplanes, I/O Modules, Splitters, as required)  
The following illustration shows the hardware components in a Quantum Hot  
Standby System.  
Standby  
Primary  
PS PLC RIO CHS  
PS PLC RIO CHS  
Fiber Optic Link  
Cable to the RIO Network  
Note: The order of the modules in the backplanes must be the same.  
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Overview of Quantum Hot Standby  
The CHS 110 Hot Standby Module  
Topology  
The following diagram shows the module’s front panel, which consists of:  
LED Display  
Function Keyswitch  
Designation slide switch  
Update Button  
Fiber optic cable ports  
CHS 110 Front  
Panel Controls  
The following figure shows the module’s front panel.  
Version Label  
Model Number Module  
Description Color Code  
LED Display  
Removable Door  
Function Keyswitch  
Designation Slide Switch  
Update Button  
Transmit Cable Connector  
Receive Cable Connector  
M0035300  
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Overview of Quantum Hot Standby  
LED Display  
The following illustration shows five status indicators on the face of each CHS 110  
module.  
140  
CHS 110 00  
HOT STANDBY  
Active  
Ready Fault  
Run  
Bal Low  
Pwr ok  
Modbus Com Err  
Modbus! Error A  
Com Act Error B  
Primary  
Mem Prt Standby  
The following table shows the five status indicators.  
Indicator Color  
Ready Green  
Message  
If steady, power is being supplied to the module and it has  
passed initial internal diagnostic tests. If blinking, module is  
trying to recover from an interface error.  
Com Act Green  
If steady, CHS 110 modules are communicating. If blinking, an  
error has been detected.  
Primary  
Green  
Module is Primary controller.  
Com Err Red  
Module is retrying CHS communications or CHS  
communications failure has been detected.  
Standby Amber  
If steady, module is Standby controller, and is ready to assume  
Primary role if needed. If blinking, program update is in  
progress.  
Error messages are discussed in detail in Com Act Error Patterns, p. 209.  
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Overview of Quantum Hot Standby  
Function  
Beneath the LED display on the face of each CHS 110 control panel is a function  
Keyswitch  
keyswitch. It has three positions: Off Line, Xfer (transfer) and Run. You may use this  
switch to force transfer of control functions or to copy the full program from the  
Primary controller to the Standby.  
The following illustration shows a function keyswitch with three positions: Off LIne,  
Xfer and Run.  
Off  
Line  
Xfer  
Run  
Note: For security or convenience, you can disable the function keyswitch with a  
software override. Once the keyswitch is disabled, you can set the module to run  
or offline mode with software. This can be especially helpful when the module is  
not easily accessible.  
Designation  
Slide Switch and  
Update Button  
A slide switch located below and to the right of the keyswitch is used to designate  
the controller as A or B. One unit must be designated as A and the other as B.  
Use the Standby Update Button to initiate the Primary to Standby program transfer.  
You must have the keyswitch in transfer mode.  
Note: If the controllers are given identical designations, the system refuses to  
acknowledge them both. The first unit to power up will be recognized as the  
Primary controller. It is designated A or B according to its switch position. The  
second unit remains offline and the ComAct indicator flashes, indicating a startup  
error.  
Note: Once the system is running, Primary control may be exchanged between the  
units regardless of which is designated as A or B.  
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Overview of Quantum Hot Standby  
1.2  
Operation  
Modes of Operation  
HSBY Modes of  
Operation  
HSBY has three Modes of Operation:  
1. Off Line Mode  
2. Transfer Mode  
3. Run Mode  
These modes are described below.  
Off Line Mode  
Transfer Mode  
This mode is used to take a controller out of service without stopping it or  
disconnecting power. If you turn the key on the Primary unit to Off Line, control  
switches to the Standby. If the Standby controller is taken offline, the Primary  
continues to operate without a backup.  
This mode is used to request a program update of the Standby controller from the  
Primary controller. For a step-by-step description of the procedure refer to  
Replacement, p. 192.  
The Primary controller is able to update the Standby without any interruption in its  
other functions. If the Primary unit is in Run mode and you hold down the update  
button on the Standby unit, the Hot Standby modules prepare to copy the full  
program of the Primary controller to the Standby unit. The program includes the  
configuration table, I/O map, configuration extensions, segment scheduler, user  
logic, all .EXE loadables, ASCII messages and the entire state RAM.  
To complete the transfer, while continuing to press the update button, turn the key  
on the Standby to transfer. The Com Act LED extinguishes. Turn the key to the  
mode you want the Standby to assume after the update, Run or Off Line. The  
Standby indicator flashes. Release the update button.  
The Standby indicator continues to flash during the update and while the Standby  
unit processes the update. If the unit is set to run mode, the Standby indicator  
returns to a steady amber. If the unit is set to offline mode, the Standby indicator  
extinguishes. Remove the key.  
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Overview of Quantum Hot Standby  
Note: If you turn the key on the Primary unit to transfer, the Hot Standby system  
ignores your action.  
Run Mode  
When the keyswitch is in this position, the controller is active and is either serving  
as the Primary controller or is capable of taking over the Primary role, if needed.  
The keyswitch on both Hot Standby modules should be in the Run position at all  
times. When the Standby controller is in Run mode and the standby indicator is on,  
it is actively monitoring the status of the system and is ready to take control if the  
Primary unit fails.  
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Overview of Quantum Hot Standby  
1.3  
Cabling  
Introduction  
Purpose  
This section describes cabling for CHS 110 Hot Standby modules.  
This section contains the following topics:  
What’s in this  
Section?  
Topic  
Page  
24  
25  
Fiber Optic Cable  
The CHS 210 Hot Standby Kit  
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Overview of Quantum Hot Standby  
Fiber Optic Cable  
Cable  
The CHS 110 Hot Standby modules are connected by a fiber optic cable. The cable  
Connections  
has two identical strands. Each strand transmits a signal in only one direction. For  
this reason, each strand must be connected between the upper (transmit) port on  
one module and the lower (receive) port on the other.  
If the cable is not connected properly, the Hot Standby modules are not able to  
communicate and the Hot Standby system does not function. The Primary controller  
operates without a backup. The Standby unit remains offline.  
A 3 meter fiber optic cable is provided in the 140 CHS 210 00 Hot Standby kit. One  
strand of that cable is marked with the manufacturer’s name. This is the only way to  
distinguish the two strands.  
This illustration shows CHS 110 Hot Standby modules connected by a fiber optic  
cable.  
Transmit  
Receive  
Transmit  
Receive  
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Overview of Quantum Hot Standby  
The CHS 210 Hot Standby Kit  
Contents of Kit  
Each 140 CHS 210 00 Hot Standby kit contains the following parts. Part numbers  
are listed in parentheses.  
Two CHS 110 Hot Standby modules with four fiber cable clasps (140 CHS 110  
00)  
A 3 meter duplex fiber optic cable (990 XCA 656 09)  
Two coaxial splitters together with two tap terminators and four self-terminating F  
adapters (140 CHS 320 00)  
A 3 1/2 in. diskette with the CHS loadable (140 SHS 945 00)  
Quantum Hot Standby Planning and Installation Guide,  
840 USE 106 00 Version 2  
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Overview of Quantum Hot Standby  
1.4  
984 HSBY and IEC HSBY  
Introduction  
Purpose  
This section describes 984 HSBY and IEC HSBY.  
This section contains the following topics:  
What’s in this  
Section?  
Topic  
Page  
27  
984 HSBY  
IEC HSBY  
28  
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Overview of Quantum Hot Standby  
984 HSBY  
984HSBY  
In a 984 HSBY system, the user application is written in 984 ladder logic.  
HSBY mode can be activated by implementation of a CHS loadable function block  
into logic, like the earlier PLC systems used the "HSBY" loadable function block. 984  
HSBY may also be activated as a configuration extension that allows additional  
features to be configured. For details refer to Using a Quantum 984 HSBY System,  
p. 67.  
Architecture  
Quantum 984 Hot Standby involves:  
Concept Version 2.1 or greater, Modsoft Version 2.3 or greater, Proworx Version  
1.5 or greater  
All Quantum Controllers  
The existing CHS Modules and Execs (CHS 110 00)  
Changes to the running application are possible only by download changes to the  
Primary controller, whereby the Standby goes offline until it gets updated again by  
using the UPDATE push button (refer to Replacement, p. 192).  
System  
Minimum Module Versions to Support 984 HSBY  
Compatibility  
Module  
Version  
2.1  
PV / SV  
All  
140 CPU x13 0x  
140 CPU 424 02  
140 CPU x34 1x  
140 CRP 93x 00  
140 NOM 2xx 00  
2.1  
All  
All  
All  
2.1  
All  
2.1  
All  
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Overview of Quantum Hot Standby  
IEC HSBY  
IEC HSBY  
IEC Hot Standby means: Programming an application with the choice of 5 different  
Architecture  
IEC compliant languages; FBD, LD, SFC, IL and ST.  
1. The IEC HSBY system uses the same hardware architectures as 984 HSBY  
system for its basic operations. For example, state RAM data transfer and  
switchover control are the same, but there are some differences compared to the  
984 HSBY system.  
2. PLC firmware upgrade is allowed without shutting down the system with Concept  
2.5 or higher. Earlier versions of Concept require shutting down the system to  
upgrade PLC firmware.  
3. RIO is serviced differently.  
4. With Concept 2.5 or higher, it is now possible to download the same application  
to Primary and to the Standby controller. The result is that the Hot Standby  
system will be fully setup (equalized) with identical applications in both  
controllers. Earlier versions of Concept require you to use the UPDATE bush  
button (refer to Using a Quantum IEC Hot Standby System , p. 109) on the CHS  
module in the Standby rack to equalize both controllers. Therefore, the same  
application including the configuration will be running in both controllers.  
5. There’s no CHS function block used in IEC.  
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Overview of Quantum Hot Standby  
Architecture  
As shown below, Quantum IEC Hot Standby involves:  
Concept Version 2.1 or greater  
Two High End Quantum Controllers (CPU 434 12 or CPU 534 14)  
The existing CHS Modules and Execs (CHS 110 00). The existing RIO Heads  
with version 2.0 Execs or greater (CRP 93x).  
All five IEC 1131 languages can be used, however 984 Ladder Logic cannot be  
used.  
The following diagram shows the Quantum IEC Hot Standby Architecture  
Quantum IEC Hot Standby Architecture  
PRIMARY  
SECONDARY  
FIBER OPTIC CHS LINK  
REMOTE I/O  
With Concept 2.1/2.2, changes to the running application are possible only by  
download changes to the Primary controller, whereby the Standby controller goes  
offline until it gets updated again by using the UPDATE push button (refer to  
Updating PLC System Executives in an IEC HSBY System, p. 200). Concept 2.5  
supports the Logic Mismatch option on the Hot Standby Configuration Extension  
which allows the Standby controller to remain online with a different program than  
the Primary controller.  
Note: Unlike Concept 2.1, with Concept 2.2/2.5 it is possible to make changes to  
the IEC logic offline and download them as online changes later. It is not necessary  
to be connected to the controller at the time of editing the IEC logic.  
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Overview of Quantum Hot Standby  
Application size  
For basic mechanisms (data and program transfer), the IEC HSBY and the 984  
HSBY system operate in the same manner. The data transfer during normal  
operation, accomplished by copying the state RAM from the Primary to the Standby,  
causes differences in terms of application size. In IEC HSBY, a part of the state RAM  
is used to transport the IEC application data from the Primary to the Standby.  
Therefore the size of IEC application data cannot exceed the configured size of the  
state RAM itself. The absolute maximum for IEC application data is 128K (64K  
words of state RAM). For the size of an IEC application’s executable code there is  
also a limit of 568K under Concept 2.1/2.2. The IEC application’s executable code  
limit was increased to 1 Megabyte for Concept 2.5.  
QuantumIECHot  
Standby  
IEC Language programs only, no 984 Ladder Logic permitted  
To bring a Standby on-line  
Overview  
Primary and Standby controller executives must be equal.  
Primary and Standby IEC Projects must have the same name and the  
applications must be equal.  
On-line changes to the Primary are permitted  
With Concept 2.1/2.2, the Standby controller is taken off-line as soon as the  
first Primary on-line change is made. The Primary program must be  
transferred to the Standby before it can be brought back on-line.  
Concept 2.5 supports Logic Mismatch in the Hot Standby configuration  
extension. This option allows the Standby controller to remain online with a  
different program than the primary controller.  
Primary controller on-line changes may include  
Addition of sections  
Addition of DFBs allows pre-qualification of user changes in an office  
environment  
Logic Mismatch  
With Concept 2.1/2.2, it is not possible to load a new version of the application  
on Standby, bring it on-line, and transfer control to make it the new Primary.  
Under Concept 2.5, with Logic Mismatch enabled, a new version of the  
application can be downloaded to the Standby controller and brought online.  
Control can then be transferred to the Standby controller to make it the new  
Primary controller.  
To upgrade the controller Execs  
With Concept 2.1/2.2, the process must be stopped. Then Primary and  
Standby controllers must be stopped and downloaded individually.  
Under Concept 2.5, the controller executives can be upgraded while the  
process continues to run.  
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Theory of 984 Ladder Logic HSBY  
Operation  
2
At a Glance  
Purpose  
This chapter covers the 984 Hot Standby and its theory of operation.  
This chapter contains the following topics:  
What’s in this  
Chapter?  
Topic  
Page  
32  
How a 984 HSBY System Works  
System Scan Time  
33  
36  
38  
40  
41  
The State RAM Transfer and Scan Time  
Default Transfer Area  
Customizing Options  
Custom Scans  
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Theory of 984 HSBY Operation  
How a 984 HSBY System Works  
984 Theory  
Both the Primary and the Standby backplanes contain a CHS 110 Hot Standby  
module. The modules monitor their own controller CPU and communicate with each  
other via fiber link. The Primary controller keeps the Standby informed of the current  
state of the application by transferring state RAM values to the Standby controller  
during every logic scan. RIO head communications are also verified.  
Stages of State  
RAM Transfer  
A Hot Standby system transfers state RAM data from the Primary to the Standby  
controller while the Primary controller scans and solves the ladder logic application  
program. There are three steps in this transfer process:  
1
2
3
Primary controller-to-Primary CHS 110 state RAM transfer.  
Primary CHS 110-to-Standby CHS 110 state RAM transfer.  
Standby CHS 110-to-Standby controller state RAM transfer.  
State RAM  
Transfer  
The Primary CHS 110 Hot Standby module initiates the state RAM transfer  
operation. The module requests specified state RAM information from the Primary  
controller.  
At the beginning of each scan, the Primary controller transfers the current state RAM  
data to the CHS 110 Hot Standby module.  
As soon as the transfer (controller-to-CHS 110) finishes, the Primary controller  
resumes scanning user logic and servicing I/O. The state RAM data is  
simultaneously transferred from the Primary CHS 110 module to the Standby CHS  
110 module over the fiber optic link at a rate of 10 megabaud. In turn, the Standby  
CHS 110 module transfers the state RAM data to the Standby controller.  
Note: Schneider Electric defines State RAM as RAM memory that is used to hold  
register and discrete inputs and outputs and internal data storage. State RAM is  
allocated to the four different reference types: 0xxxx, 1xxxx, 3xxxx, and 4xxxx.  
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Theory of 984 HSBY Operation  
System Scan Time  
Effect on System When the ladder logic program being executed by the primary controller is longer  
Scan Time  
than the CHS 110-to-CHS 110 transfer, the transfer does not increase total system  
scan time. However, if the ladder logic program is relatively short, the scan finishes  
before the CHS 110-to-CHS 110 data transfer and the data transfer increases total  
system scan time.  
The following timing diagram shows how the transfer takes place.  
Primary Rack  
1 Scan  
Solve All Segments  
PLC-to-CHS 110 State RAM  
Transfer (over the Quantum Backplane)  
PLC  
CHS 110  
CHS 110-to-CHS 110 State RAM  
Transfer (Over Fiber Optic HSBY Link)  
Standby Rack  
CHS 110  
CHS 110-to-PLC State RAM Transfer  
PLC  
Solve Segment 1  
1 Scan  
Solve Segment 1  
The effect on system scan time of any Hot Standby system depends very much on  
how much state RAM is going to be transferred from Primary to Standby. A Hot  
Standby system always has a higher scan time than a comparable standalone  
system because of the required PLC to CHS data transfer time.  
Since the data transfer depends on the PLC type in the system, the following  
provides information that allows you to forecast a Hot Standby system‘s scan time:  
Calculation of overall scan time for a normal Hot Standby baseline configuration  
containing minimum logic as a reference  
Calculation of a PLC specific constant that expresses the increase of overall scan  
time related to an increase of state RAM memory to be transferred  
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Theory of 984 HSBY Operation  
The normal Hot Standby configuration contains:  
In the local rack: power supply (CPS), PLC (CPU), RIO Head (CRP 93x), Hot  
Standby module (CHS)  
In one remote IO drop equipped with 8 I/O modules, power supply (CPS) and  
remote adapter (CRA)  
Only the logic for the scan time evaluation  
PLC Scan Times  
The scan time increase with different PLCs, after adding HSBY, is outlined in the  
Scan Time Increase table below.  
CPU - HSBY Baseline  
Configuration  
Scantime Increase  
because of HSBY  
Languages Supported  
984 Ladder Logic only  
984 Ladder Logic only  
984 Ladder Logic only  
CPU x13 0x0x: 1536, 1x: 512, 3x: ~ 25 ms  
3000, 4x: 1872  
CPU 424 020x: 1536, 1x: 512, 3x: ~ 40 ms  
1212, 4x: 1872  
CPU 434 12 / CPU 534 140x:  
1536, 1x: 512, 3x: 512, 4x: 1872  
~ 40 ms  
PLC to CHS Data  
Transfer Rate  
The investigation of the PLC specific data transfer rate in a Hot Standby system  
leads to the following results.  
CPU x13 0x  
CPU 424 02  
1.6 ms / byte  
2.0 ms / byte  
1.9 ms / byte  
CPU 434 12 /  
CPU 534 14  
State RAM  
The following table lists the number of bytes required for reference storage in state  
RAM.  
Coil (0x)  
3 bit  
Discrete (1x)  
3 bit  
Input Register (3x)  
Holding Register (4x)  
2 bytes  
2 bytes plus 2 bit  
Based on the data shown in the tables above you may forecast the overall scan time  
of a Hot Standby system once you know how much state RAM is going to be  
transferred and the time required for a particular logic application to be executed in  
a standalone system.  
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Theory of 984 HSBY Operation  
Example  
This example shows the effect of a configuration change from baseline as shown in  
the Scan Time Increase Table in PLC Scan Times, p. 34.  
A particular HSBY application has a standalone scan time of 36 ms in a PLC of type  
CPU 424 02. The state RAM to be transferred consists of 3000 coils (0x), 2500  
discrete inputs (1x), 2500 input registers (3x) and 8000 holding registers (4x).  
The state RAM difference to the reference configuration is shown in the Effects of  
a Configuration Change from Baseline table below:  
0x3000 - 1563 =  
1464  
1464*3/8  
=549 Bytes  
1x2500 - 512 =  
1988  
1988*3/8  
= 746 Bytes  
= 2576 Bytes  
= 13788 Bytes  
3x2500 - 1212 =  
1288  
1288*2  
4x8000 - 1872 =  
6128  
6128*2 + (6128*2/8)  
Total: 17659 bytes = scan time offset = 17659 * 1.6ms ~ 28ms  
This application therefore would have an overall scan time in Hot Standby:  
40 ms (reference with CPU 424 02 0x) added by HSBY  
+ 36 ms (standalone scan time)  
+ 28 ms (offset through configuration increase)  
=104 ms  
Note: No matter how long your transfer takes, it does not cause a watchdog  
timeout.  
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Theory of 984 HSBY Operation  
The State RAM Transfer and Scan Time  
Reduce Scan  
Time  
This section describes manipulating the state RAM transfer to reduce scan time  
Note: The state RAM transfer area contains all the state RAM values that are  
passed between the Primary and Standby controllers. The size of the transfer area  
may be as large as the total size of your controller’s state RAM or a portion  
containing critical I/O reference data types.  
As the simplified block diagram below shows, all 0x references in the state RAM  
transfer area are transferred first, then all 1x references, followed by all the 3x  
references, and finally all the 4x references:  
Total number of discrete  
outputs transferred  
0nnnnn  
Total number of discrete  
inputs transferred  
Where nnnnn is a  
multiple of 16  
1nnnnn  
3nnnnn  
Total number of register  
inputs transferred  
Total number of register  
outputs transferred  
4nnnnn  
36  
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Theory of 984 HSBY Operation  
1. Reduce the reference configuration to minimum requirements (0x, 1x, 3x, 4x).  
Minimizing the state RAM area is one way to reduce scan time.  
2. Another way is to define registers in a non-transfer area, an area contained within  
the state RAM transfer area but ignored during the actual state RAM transfer.  
3. Use the HSBY configuration extension to define transfer amounts.  
Note: If you are customizing the size of your state RAM transfer area, you must  
specify the number of each reference data type (0x, 1x, 3x, and 4x) as either 0 or  
a multiple of 16. In the case of the 4x registers, there must always be at least 16  
registers allotted.  
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Theory of 984 HSBY Operation  
Default Transfer Area  
Automatic  
Transfer  
By default, the Hot Standby system automatically transfers the following from the  
Primary to the Standby controller on every scan:  
The first 8192 points of 0x output reference data  
The first 8192 points of 1x input reference data  
A total of 10K registers, of which 1K is allotted for 3x registers and 9K is allotted  
for 4x registers.  
In any case, the number of 4x registers transferred is a multiple of 16 unless all 4x  
registers have been included. The number of 4x registers may slightly exceed the  
allotment in order to reach the next highest multiple of 16.  
Any state RAM values above the limits shown in the following diagram are not  
included in the state RAM transfer area and therefore are not shared with the  
Standby controller. The state RAM values in the range above these limits must not  
contain the command register or control critical I/O.  
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Theory of 984 HSBY Operation  
The diagram below shows examples of the data transfer area for different  
configurations of 3x and 4x registers.  
Example 1  
If you have 3200 3x and 9600 4x registers, then the  
full allotment of 1000 3x registers will be transferred.  
The acutual number of 4x registers transferred will be  
9008; that is, the full allotment of 9000 registers plus  
8 more to reach the next highest multiple of 16.  
Transfer Area  
Example 2  
If you have 3200 3x and 7000 4x registers, then all  
the 4x registers will be transferred. The full allotment  
of 1000 3x registers will be transferred, plus an  
additional 2000 3x registers to bring the total number  
of registers transferred to 10,000. So a total of 3000  
3x registers will be transferred.  
Example 3  
If you have 700 3x and 9600 4x registers, then all the  
3x registers will be transferred. The full allotment of  
9000 4x registers will be transferred, plus an  
additional 300 registers to bring the total to 10,000,  
plus an additional 12 registers to reach the next  
highest multiple of 16. In all, 9312 4x registers will be  
transferred.  
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Theory of 984 HSBY Operation  
Customizing Options  
Custom State  
RAM Transfer  
Area  
If you want to set up a custom state RAM transfer area, you can control your  
transferred amounts using a Hot Standby configuration extension (refer to Additional  
Guidelines for IEC Hot Standby , p. 147). The configuration extension provides three  
alternatives to the default transfer area:  
You can define the number of 0x, 1x, 3x, and 4x reference data types that you  
want transferred in each scan.  
You can define a certain amount of reference data types to be transferred on  
each scan with additional data to be transferred in groups over multiple scans,  
beginning with 0x registers and proceeding in turn with 1x, 3x, and 4x registers.  
You can transfer all the configured reference data types in your system’s state  
RAM on every scan.  
These options allow you to design a transfer area that is as small as 16 4x output  
registers or large enough to encompass all of your controllers’ state RAM (10K, 32K,  
or 64K, depending on the type of Quantum controllers you are using in your Hot  
Standby system).  
The reference data of each type (0x, 1x, 3x, and 4x) is placed in the state RAM  
transfer area, starting at the lowest reference number (000001 for coils, 100001 for  
discrete inputs, 300001 for register inputs, and 400001 for register outputs). It is  
accumulated contiguously up to the amount of each data type you specify. The total  
number of each reference type in the state RAM transfer area must be a multiple of  
16.  
For example, if you indicate that the number of coils in the transfer area is 96, coils  
000001... 000096 are transferred from the Primary to the Standby controller. Any 0x  
references beyond 000096 used in state RAM are not transferred.  
The additional state RAM data to be sent over multiple scans can also be of any or  
all of the four reference data types, and must also be specified in multiples of 16.  
The additional reference data region for each data type starts at the lowest available  
reference number. For example, if 2048 coils are transferred on every scan  
(000001... 002048), and you schedule 1024 additional coils for transfer over multiple  
scans, references 002049... 003072 are used for the additional transfer data.  
The additional transfer is handled by specifying the number of scans over which you  
want to send the additional data. For example, if you specify two scans in which to  
transfer coils 002049... 003072, then coils 002049... 002560 are sent with coils  
000001... 002048 on one scan and coils 002561... 003072 are transferred with coils  
000001... 002048 on the next scan.  
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Theory of 984 HSBY Operation  
Custom Scans  
Setting up  
Custom Scans  
The following block diagram shows how the state RAM transfer area might be set  
up using multiple scans to transfer all the data.  
Total number of discrete  
outputs transferred  
Critical outputs transferred on  
every scan  
Additional outputs transferred  
in chunks on multiple scans  
0nnnnn  
1nnnnn  
Total number of discrete  
inputs transferred  
Critical inputs transferred on  
every scan  
Additional inputs transferred  
in chunks on multiple scans  
Total number of register  
inputs transferred  
Critical inputs transferred on  
every scan  
Additional inputs transferred  
in chunks on multiple scans  
3nnnnn  
Total number of register  
outputs transferred  
Critical outputs transferred on  
every scan  
Additional outputs transferred  
in chunks on multiple scans  
4nnnnn  
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Theory of 984 HSBY Operation  
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Theory of IEC HSBY Operation  
3
At a Glance  
Purpose  
This chapter presents the Theory of Operation for the IEC Hot Standby system.  
This chapter contains the following topics:  
What’s in this  
Chapter?  
Topic  
Page  
44  
IEC Hot Standby Definitions  
How an IEC HSBY System Works  
System Scan Time  
46  
47  
51  
53  
State Ram Transfer and Scan Time  
Layout of completely transferred state RAM in an IEC Hot Standby system  
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Theory of IEC HSBY Operation  
IEC Hot Standby Definitions  
Definitions  
The following are IEC Hot Standby definitions.  
Exec: Quantum controller operating system with integrated IEC language support  
(IEC runtime system)  
Program Data: A continuous memory block containing all program variables,  
including:  
Non-located IEC variables and constants declared in variable editor  
Links in FBD and LD sections  
Stack (loop) variables in IL and ST  
SFC states  
Literals  
Pointer lists  
Internal states of EFBs  
DFB Instance Data: Multiple memory blocks containing:  
Internal data of each DFB instance  
Process diagnostics buffer  
Mirror buffer: 1 Byte per configured 0x/1x reference (only Concept 2.1 and older)  
Used references list: 1 Bit per configured 0x/1x reference  
IEC Heap: One continuous memory block containing:  
Program data  
DFB instance data  
Maximum IEC Heap Size: 128 KByte together with state RAM. If 10K Words (20  
KByte) of state RAM are used already for I/O references the max. IEC heap size  
would be 128 KByte – 20 KByte = 108 KByte  
Currently used IEC Heap Size: DFB instance data plus (configured) program data  
area size  
State Table: Also called state RAM, controller references for both real world I/O and  
internal referenced (located) variables  
Project: Concept program file containing controller configuration and IEC language  
control code  
Application: Downloaded IEC language control code and data  
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Theory of IEC HSBY Operation  
IEC Heap  
The most important new terms to understand in IEC Hot Standby are the IEC Heap,  
the Currently used IEC Heap Size and the Maximum IEC Heap Size.  
Program Data  
Area  
The program data area has a default size of 16 KByte whenever a new Concept  
project is created. Its size may be adjusted to the amount of memory that’s really  
needed for a particular application. This can be done in the Memory Statistics Dialog  
while Concept is not connected to the PLC. This dialog can be activated through  
Online --> Memory Statistics.  
Configure size of program data area at the Memory Statistics dialog in offline mode.  
Note: Changing the configured size of the program data area results in a complete  
download of the application, no download changes are possible.  
The maximum size of the IEC heap is the maximum amount of memory available for  
data in any particular IEC application. What this means in terms of IEC HSBY is  
shown in the diagram in All State RAM transferred, p. 52.  
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Theory of IEC HSBY Operation  
How an IEC HSBY System Works  
IEC Theory  
Both the Primary and the Standby backplanes contain a CHS 110 Hot Standby  
module. The modules monitor their own controller CPU and communicate with each  
other via fiber link. The Primary controller keeps the Standby informed of the current  
state of the application by transferring state RAM values to the Standby controller  
during every logic scan. RIO head communications are also verified.  
State RAM  
Transfer  
A Hot Standby system transfers state RAM data from the Primary to the Standby  
controller while the Primary controller scans and solves the IEC logic application  
program. There are three steps in the transfer process:  
Stage  
Description  
1
2
3
Primary controller-to-Primary CHS 110 state RAM transfer.  
Primary CHS 110-to-Standby CHS 110 state RAM transfer.  
Standby CHS 110-to-Standby controller state RAM transfer.  
State RAM  
Defined  
Note: Schneider Electric defines State RAM as RAM memory that is used to hold  
register and discrete inputs and outputs and internal data storage. State RAM is  
allocated to the four different reference types: 0xxxx, 1xxxx, 3xxxx, and 4xxxx.  
State RAM  
The state RAM transfer operation is initiated by the Primary CHS 110 Hot Standby  
Transfer Initiated module. The module requests specified state RAM information from the Primary  
controller.  
At the beginning of each scan, the Primary controller transfers the current state RAM  
data to the CHS 110 Hot Standby module.  
As soon as the controller-to-CHS 110 transfer finishes, the Primary controller  
resumes scanning user logic and servicing I/O. The state RAM data is  
simultaneously transferred from the Primary CHS 110 module to the Standby CHS  
110 module over the fiber optic link at a rate of 10 megabaud. In turn, the Standby  
CHS 110 module transfers the state RAM data to the Standby controller.  
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Theory of IEC HSBY Operation  
System Scan Time  
Effect on System The effect on system scan time of any Hot Standby system depends on how much  
Scan Time  
state RAM is going to be transferred from Primary to Standby. A Hot Standby system  
always has a higher scan time than a comparable standalone system.  
The following has been done to provide information that allows you to forecast a Hot  
Standby system’s scan time:  
Calculation of overall scan time for a normal Hot Standby baseline configuration  
containing minimum logic as a reference  
Calculation of a PLC specific constant that expresses the increase of overall scan  
time related to an increase of memory to be transferred  
The normal Hot Standby configuration state RAM contains:  
In the local rack: power supply (CPS), PLC (CPU), RIO Head (CRP 93x), Hot  
Standby module (CHS)  
In one remote IO drop equipped with 8 I/O modules, power supply (CPS) and  
remote adapter (CRA)  
Only the logic for the scan time evaluation  
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Theory of IEC HSBY Operation  
Transfer diagram The following shows a transfer diagram:  
1 Scan  
Primary Rack  
IEC Logic Solve Comm Diag  
IEC Logic Solve Comm Diag  
IEC Logic Solve Diag  
CPU  
CHS  
State RAM & IEC  
Heap download  
128K  
bytes  
128K  
bytes  
128K  
bytes  
State RAM & IEC  
Heap download (Over the  
Fiber Optic HSBY link)  
Standby Rack  
128K  
bytes  
128K  
bytes  
128K  
bytes  
CHS  
CPU  
State RAM & IEC  
Heap download  
Diag  
Comm  
Diag  
Comm  
Diag  
1 Scan  
Note: The size of 128K bytes state RAM memory in the timing diagram being  
transferred with each scan is not a fixed value. It expresses the maximum amount  
of data handled by the CHS module during a data transfer. This is a hardware  
limitation. Therefore, the maximum State RAM limitation for the IEC user is 128 K  
bytes. Unlike a 984 HSBY system, the Standby controller doesn’t solve any logic.  
With the new execs delivered with Concept 2.5, the Standby Controller solves logic  
in Section 1.  
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Theory of IEC HSBY Operation  
OverallPLCScan The overall scan time for the IEC HSBY supporting PLC type is outlined in the IEC  
Time  
Scan Time Increase Table below.  
IEC Scan Time Increase  
CPU - HSBY Baseline Configuration  
Scantime Increase because of HSBY  
~ 40 ms  
CPU 434 12 / CPU 534 14  
0x: 1536, 1x: 512, 3x: 512, 4x: 1872  
IEC-HSBY registers (3x): 700  
PLC to CHS Data  
Transfer Rate  
Calculating the PLC specific data transfer rate in a Hot Standby system leads to the  
following result.  
CPU 434 12 / 534 14  
1.9 ms / byte  
State RAM  
The following table lists the number of bytes required for reference storage  
Coil (0x)  
3 bits  
Discrete (1x)  
3 bits  
Input Register (3x)  
Holding Register (4x)  
IEC HSBY Register (3x)  
2 bytes  
2 bytes plus 2 bits  
2 bytes  
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Theory of IEC HSBY Operation  
Example  
This example shows the effect of a configuration change from baseline as shown in  
the IEC Scan Time Increase Table (See Overall PLC Scan Time, p. 49).  
A particular application has a standalone scan time of 25 ms in a PLC of type CPU  
434 12. The state RAM to be transferred consists of 200 coils (0x), 300 discrete  
inputs (1x), 150 input registers (3x), 400 holding registers (4x) and 14000 IEC HSBY  
registers (3x).  
The state RAM difference to the reference configuration is:  
Effects of a Configuration Change from Baseline  
0x  
200 - 1536 = - 1336  
-1336*3/8  
- 213*3/8  
- 362*2  
= - 501 Bytes  
= - 80 Bytes  
= - 724 Bytes  
1x  
300 - 512 = - 212  
3x  
150 - 512 = - 362  
4x  
400 - 1872 = - 1472  
-1472*2 + ( - 1472*2/8)| = - 3312 Bytes  
IEC Hot Standby regs 14000(3x) = 14000*2 = 28000 bytes Total = 28000 - 501 - 80 - 724  
- 3312 = 23383 bytes Scan time offset = 23383*1.9ms ~ 44ms  
This application therefore would have an overall scan time in Hot Standby:  
40 ms (reference with CPU 434 12/ 534 14)  
+ 25 ms (logic solve)  
+ 44 ms (offset through memory increase)  
= 109 ms  
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Theory of IEC HSBY Operation  
State Ram Transfer and Scan Time  
Reduce Scan  
Time  
The state RAM transfer area contains all the state RAM values that are passed  
between the Primary and Standby controllers. The size of the transfer area is as  
large as the total size of your controller’s state RAM.  
As the simplified block diagram below shows, all 0x references in the state RAM  
transfer area are transferred first, then all 1x references, followed by all the 3x  
references, and finally all the 4x references.  
In the Quantum HSBY system, IEC HSBY does not allow customizing the transfer  
area. This means the whole state RAM is transferred in IEC HSBY, except for the  
nontransfer area, an area contained within the transfer area but ignored during the  
actual state RAM transfer. Placing registers in the nontransfer area is one way to  
reduce scan time because the Primary controller to CHS transfer time is shorter.  
With Concept 2.5, a new function called Section Transfer Control has been added  
which can be used to reduce scan time. See Section Transfer Control, p. 135 for  
further information on this feature.  
Note: No matter how long your transfer takes, it does not cause a watchdog  
timeout.  
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Theory of IEC HSBY Operation  
All State RAM  
transferred  
The following diagram shows the state RAM transfer area.  
Total number of discrete  
outputs transferred  
0nnnnn  
1nnnnn  
Total number of discrete  
inputs transferred  
Where nnnnn is a  
multiple of 16  
Total number of register  
inputs transferred  
Note: No 3x registers  
configured for IEC HSBY  
3nnnnn  
Total number of register  
outputs transferred  
4nnnnn  
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Theory of IEC HSBY Operation  
Layout of completely transferred state RAM in an IEC Hot Standby system  
Layout of  
transferred RAM  
The diagram below illustrates that a significant piece of the controller’s state RAM is  
taken as a transfer buffer for copying the IEC heap from the Primary to the Standby  
controller. The transfer header is located at the very top of the transfer buffer. The  
transfer header contains information about the Primary’s exec version, time  
synchronization information and the IEC application’s version. This information  
allows the Standby controller, once it received the transfer buffer, to decide whether  
to remain online or go offline. When online, the Standby controller copies the  
Primary’s IEC heap out of the transfer buffer into its internal memory, which ensures  
the Standby’s IEC data consistency.  
State RAM  
(Compl. xferred)  
Header  
Safety Buffer  
for Future  
changes/additions  
Program Data  
Used  
(Exec Vers.,  
Timing Info, ..,)  
Prog. Data  
Configured  
Program Data  
Unused  
DFB Instance  
Data  
No. 3x regs  
Configured  
for IEC HSBY  
Free Memory  
for addtl DFB  
Instance Data  
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Planning a Quantum Hot Standby  
System  
4
At a Glance  
Purpose  
This chapter describes how to plan a Quantum Hot Standby System.  
This chapter contains the following topics:  
What’s in this  
Chapter?  
Topic  
Page  
56  
Guidelines for Planning a Hot Standby System  
Electrical Safety Precautions  
Remote I/O Cable Topologies  
A Single Cable Configuration  
A Dual Cable Configuration  
57  
58  
59  
60  
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Planning a Quantum Hot Standby System  
Guidelines for Planning a Hot Standby System  
Primary and  
Standby  
Controllers  
Both the primary and the standby controller in your Hot Standby system must be  
ready to perform as a stand-alone controller in the event that its counterpart fails.  
Therefore, you should install them with equal care, according to Modicon’s standard  
planning and installation guidelines. Refer to the Quantum Automation Series  
Hardware Reference Guide, 840 USE 100 00, and the Remote I/O Cable System  
Planning and Installation Guide, 890 USE 101 00, for details.  
Design your system for safety first, then for economy. Be sure that you understand  
all the cautions and warnings in this manual before you begin to install your system.  
For the Hot Standby system to function, your component modules must meet the  
version requirements in Overview of Quantum Hot Standby, p. 13.  
You must use identical modules in the primary and standby racks. If you have  
different models or different versions of the same model or different flash executive  
software, the Hot Standby system will not function properly.  
Note: The order of the modules in the backplanes must be the same.  
While the controllers and RIO heads must be Quantum models, the remote drops  
may use Quantum, 800 series, 500 series or 200 series I/O with corresponding drop  
processors.  
Positioning  
The CHS 110 Hot Standby modules are connected by fiber optic cable. A 3 meter  
cable is supplied with the kit. However, the primary and standby backplanes may be  
placed as much as 1 km apart. If you will be placing the modules more than 3 m  
apart, use 62.5/125 micrometer cable with ST-style connectors. Refer to Fiber Optic  
Cable Guide, p. 213 for details.  
If you intend to place the units more than 3 meters apart, you must consider the  
effect on the RIO network and any Modbus Plus network.  
The controllers are linked to the RIO network by coaxial cable. The longer the  
distance between the controllers, the higher the grade of trunk cable required to  
maintain signal integrity. Refer to Chapter 3 of the Remote I/O Cable System  
Planning and Installation Guide, 890 USE 101 00, for details regarding cable grades,  
distances and signal integrity. If no coaxial cable will be sufficient to maintain signal  
integrity throughout the RIO network, fiber optic repeaters may be used to boost the  
signal. Refer to the Modbus Plus Network Planning and Installation Guide, 890 USE  
100 00, for details on extending a Modbus Plus network.  
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Planning a Quantum Hot Standby System  
Electrical Safety Precautions  
Safety  
Precautions  
WARNING  
To protect yourself and others against electric shock, obey your  
national electrical code and all applicable local codes and laws.  
When you plan the installation of the electrical cabinets which enclose  
the system’s electronic components, be sure each cabinet is connected  
separately to earth ground and that each backplane is connected to  
solid ground within its cabinet.  
Failure to follow this precaution can result in death, serious injury,  
or equipment damage.  
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Planning a Quantum Hot Standby System  
Remote I/O Cable Topologies  
Cable  
In each configuration:  
Connections  
The cables connecting the RIO head processors to the RIO network must be  
fitted with self-terminating F adapters.  
An MA-0186-100 coaxial splitter must be installed between the RIO head  
processors and the RIO network.  
The remote drops must be connected to the trunk cable via an MA-0185-100 tap  
and a 97-5750-000 (RG-6) drop cable.  
The last tap on a trunk cable must be terminated with a 52-0422-000 trunk  
terminator. Remote drops must not be connected directly to the trunk cable.  
Refer to the Remote I/O Cable System Planning and Installation Guide,  
890 USE 1001 00, for details.  
Note: If you are using a HSBY for data logging, the RIO heads must be configured  
and connected with coaxial cable.  
If you are using 984, you must configure 2 or more segments.  
If you are using IEC, you must configure 2 or more RIO drops.  
Note: For illustrations of both single cable and double cable configurations, please  
see A Single Cable Configuration, p. 59 and A Dual Cable Configuration, p. 60.  
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Planning a Quantum Hot Standby System  
A Single Cable Configuration  
Diagram of a  
Single Cable  
Configuration  
The following diagram shows a single cable configuration for the Quantum Hot  
Standby system.  
Primary PLC  
Standby PLC  
Fiber Optic Cable  
Self-terminating  
Self-terminating  
Coaxial Cable  
F adapter**  
F adapter**  
Splitter  
#52-0411-000  
#52-0411-000  
#MA-0186-100  
RIO Drop #2  
Trunk Cable  
(RG-11) #97-5951-000  
Trunk  
RIO Drop #3  
Tap #MA-0185-100  
Drop Cable*  
(RG-6) #97-5750-000  
Tap #MA-0185-100  
Drop Cable*  
(RG-6) #97-5750-000  
RIO Drop #4  
Last RIO Drop  
Tap #MA-0185-100  
Tap #MA-0185-100  
Drop Cable*  
(RG-6) #97-5750-000  
Trunk Terminator  
#52-0422-000  
Drop Cable*  
(RG-6) #97-5750-000  
**140 CHS 320 00 kit includes:  
2 Splitters  
4 F Adapters  
*Premade RG-6 Drop Cable  
50’ (14m) AS-MBII-003  
140’ (43m) AS-MBII-004  
2 Terminators  
See CHS 210 Hot Standby Kit for entire  
HSBY kit contents (140 CHS 210 00).  
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Planning a Quantum Hot Standby System  
A Dual Cable Configuration  
Diagram of a  
Dual Cable  
Configuration  
The following diagram shows a dual cable configuration for the Quantum Hot  
Standby system.  
Standby PLC  
Primary PLC  
Fiber Optic Cable  
Self-terminating  
F Adapters**  
#52-0411-000  
Self-terminating  
F Adapters**  
#52-0411-000  
Coaxial Cable  
Coaxial Cable  
Splitter #MA-0186-100  
Splitter  
#MA-0186-100  
RIO Drop #2  
(Trunk Cable (RG-11) #97-5951-000)  
Trunk  
Line  
B
Trunk  
Line  
A
RIO Drop #3  
Tap  
#MA-0185-100  
Drop Cable*  
(RG-6) #97-5750-000  
Tap  
Drop Cable*  
RIO Drop #4  
(RG-6) #97-5750-000  
Last RIO Drop  
Tap  
#MA-0185-000  
Drop Cable*  
(RG-6) #97-5750-000  
Trunk Terminator  
#52-0422-000  
Drop Cable*  
(RG-6) #97-5750-000  
Trunk Terminator  
**140 CHS 320 00 kit includes:  
2 Splitters  
4 F Adapters  
*Premade RG-6 Drop Cable  
50’ (14m) AS-MBII-003  
140’ (43m) AS-MBII-004  
2 Terminators  
See CHS 210 Hot Standby Kit for entire  
HSBY kit contents (140 CHS 210 00).  
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Installation  
5
How to Install a Hot Standby System  
Procedure  
This section discusses the procedure for installing a new Hot Standby system. For  
more detailed instructions, refer to the Quantum Automation Series Hardware  
Reference Guide, 840 USE 100 00 or the Remote I/O Cable System Planning and  
Installation Guide, 890 USE 101 00.  
Installing a Hot  
Standby System  
Install the power supplies, controllers, RIO head processors, hot standby  
modules and any option modules in the primary and standby backplanes. Be  
sure:  
The modules meet the version requirements listed in Overview of Quantum Hot  
Standby, p. 13.  
The modules in the primary backplane are identical to those in the standby  
backplane.  
Note: The order of the modules in the backplanes must be the same.  
The rotary address switches on the back of each controller are set. The  
controllers may have different addresses. It is strongly recommended that the  
rotary address switches be set to the same address to eliminate any network  
address conflicts. The same advice applies to the NOM. For details on setting  
the switches, see the Quantum Automation Series Hardware Reference Guide  
or the Remote I/O Cable System Planning and Installation Guide.  
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Installation  
The following diagram illustrates installation of a Hot Standby System.  
Setting  
Designation  
Slide Switches  
The designation slide switch on one Hot Standby module is set to A and the other is  
set to B.  
CAUTION  
HAZARD  
Before installing any controller in your Hot Standby system, be sure its  
battery has been disconnected for at least five minutes.  
Failure to follow this precaution can result in injury or equipment  
damage.  
Note: Be sure your system meets the power and grounding guidelines outlined in  
Appendix D of the Quantum Automation Series Hardware Reference Guide, 840  
USE 100 00.  
Connect Network The following diagram shows how to connect the network.  
Step  
Action  
1
Install a splitter and a self-terminating F adapter between the primary RIO head  
processor and the RIO network.  
2
3
Connect the coaxial cable link.  
Connect the cable between the splitter, another self-terminating F adapter and  
the standby RIO head processor  
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Installation  
Network  
The following diagram illustrates the network connections.  
Connections  
InstallingCoaxial Connect the fiber link between the Hot Standby modules, making sure the cable is  
Cable Link  
properly crossed, so that the transmit cable connector of each module is linked to  
the receive cable connector of the other. Follow these instructions:  
Remove the protective plastic coverings from the cable ports and the tips of the  
cable. Snap one of the fiber cable clasps onto the cable, carefully pressing the cable  
through the slot so that the wider end of the clasp is closest to the boot.  
The following diagram shows the installation of a coaxial cable link.  
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Installation  
Attaching the  
Fiber Cable  
Clasp to the  
Cable  
The key to installing the cable is to align the barrel, the locking ring and the  
connector, as shown in the diagram below.  
Aligning the Key  
and Locking  
Ring  
The table below shows how to align the key and locking ring.  
Step  
Action  
1
Turn the locking ring to align an arrow with the key.  
2
Then align the key with the keyway. As a result, the locking tab, groove and lock  
should also be aligned.  
3
4
Slide the clasp up to the locking ring.  
Gripping the cable with the clasp, plug the cable into the lower (receive) cable  
connector. If it does not connect easily, realign the key with the arrow and try  
again.  
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Installation  
Diagram of  
The diagram below illustrates the alignment of the key and locking ring.  
Aligning Key and  
Locking Ring  
Attaching the  
Cable  
Turn the cable to the right, so that the tab locks securely. You may leave the fiber  
cable clasp on the cable for future use, but slide it off the boot of the cable to allow  
the module door to close.  
Repeat this process with the remaining strand of cable and the upper (transmit)  
cable connector.  
Note: Remember that each strand of cable must be connected to the upper  
(transmit) cable connector on one Hot Standby module and the lower (receive)  
cable connector on the other. If the cable is not properly connected, the modules  
will not be able to communicate and the Standby will remain offline.  
Note: One strand of the cable provided in the CHS 210 Hot Standby kit is marked—  
for instance, with the manufacturer's name. This is the only way to distinguish the  
two strands.  
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Installation  
Adding Hot  
Standby  
Capability to an  
Existing System  
To add Hot Standby capability to an existing Quantum system, you must install a  
second backplane with modules identical to those in the original backplane. Keep  
the following requirements in mind:  
You must remove any local I/O and distributed I/O networks from the original  
backplane, because they will not be supported at switchover.  
The diagram below shows that local I/O must be removed.  
Converting to  
Hot Standby  
System  
You need backplanes with at least four slots.  
The components in both backplanes must meet the version requirements listed.  
You must install a splitter and a self-terminating F adapter between the original RIO  
head processor and the RIO network. A second cable runs from the splitter to the  
Standby RIO head processor, through a second self-terminating F adapter.  
In general, you may follow the installation directions in this Chapter. However, as a  
precaution, you should first stop the controller and disconnect power to the system.  
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Using a Quantum 984 HSBY  
System  
6
At a Glance  
Purpose  
This chapter reviews the procedures for operating a Quantum 984 HSBY System.  
This chapter contains the following sections:  
What’s in this  
Chapter?  
Section  
6.1  
Topic  
Page  
69  
Configuration  
6.2  
Using the CHS Instruction Block  
Using Configuration Extension  
Operation  
74  
85  
6.3  
6.4  
103  
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Using a Quantum 984 HSBY System  
6.1  
Configuration  
Introduction  
Purpose  
This section describes Hot Standby configuration.  
Note: To ensure correct operation of the HSBY system, the user must I/O map at  
least 1 RIO drop and 1 I/O module. This will ensure the proper diagnostic  
information is transfered between Primary and Standby CRPs.  
What’s in this  
Section?  
This section contains the following topics:  
Topic  
Page  
70  
Configuring 984 HSBY  
Configuration Extension  
CHS Instruction  
72  
73  
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Using a Quantum 984 HSBY System  
Configuring 984 HSBY  
CHS software  
To configure a 984 HSBY system, you must load the CHS software into the  
controllers. The software is included on a diskette in the Hot Standby kit. Once you  
have loaded the software, you can choose how to proceed. You may control your  
Hot Standby system through ladder logic or you can use a configuration extension.  
The CHS  
Loadable  
The logic in the CHS loadable is the engine that drives the Hot Standby capability in  
a Quantum control system. The CHS loadable gives you the ability to:  
specify the Hot Standby command register, which is used to configure and control  
Hot Standby system parameters  
define a Hot Standby status register, which can be used to monitor the real  
machine status of the system  
implement a CHS instruction in ladder logic  
Unlike HSBY (a comparable loadable used for Hot Standby configurations in 984  
controllers), the CHS instruction does not have to be placed in a ladder logic  
program. However, the CHS software must be loaded into the Quantum controller  
in order for a Hot Standby system to be supported.  
Installing the  
CHS loadable  
into the 984  
Environment  
The following steps are only necessary if the CHS loadable is not already part of  
your 984 installation. The CHS loadable is provided on a 3 1/2 diskette  
(140 SHS 945 00) as part of your 140 CHS 210 00 Hot Standby kit. The file is named  
QCHSVxxx.DAT, where xxx is the three-digit version number of the software.  
Step  
Action  
1
Insert the diskette in the disk drive.  
2
Either create a new Concept project or open an existing one and have a PLC  
selected  
3
4
5
With the menu command Project Configurator, open the configurator.  
With Configure Loadables, open the dialog box Loadables.  
Press the command button Unpack to open the standard Windows dialog box,  
Unpack Loadable File. Select the loadable file, click the button OK and it is  
inserted into the list box Available.  
Modsoft  
If you are using Modsoft, refer to the Modicon Quantum Hot Standby System  
Planning and Installation Guide, 840 USE 106 00 Version 1, Paragraph 5.1.1.  
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Using a Quantum 984 HSBY System  
Controlling the  
Hot Standby  
System by CHS  
instruction  
If you are upgrading from a 984 Hot Standby system to a Quantum system, you may  
port your ladder logic program by first deleting the HSBY block, then relocating the  
program, and then inserting a CHS instruction. This requires the CHS loadable to be  
installed into your application.  
nnnn  
nnnn  
nnnn  
HSBY  
nnnn  
CHS  
nnnn  
nnnn  
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Using a Quantum 984 HSBY System  
Configuration Extension  
Controlling the  
Hot Standby  
System by  
Configuration  
Extension  
With the Hot Standby configuration extension screens:  
You can specify the parameters in the Hot Standby command register and  
customize the state RAM data transfer between the Primary and Standby units to  
help reduce scan time.  
If you decide to control your system using the configuration extension, you still may  
want to program a CHS instruction in ladder logic. The CHS instruction allows you  
to use Zoom screens, which allows you to access and modify the command register  
while the system is running.  
Note: If both a configuration extension and the CHS instruction are used, the  
configuration extension controls the Hot Standby system. The only function of the  
CHS instruction is to provide Zoom screens. The parameters in the configuration  
screens are applied by the controllers at startup. Once the controllers are running,  
the Zoom screens may be used to access and modify the command register. The  
changes are implemented during runtime, and can be seen in the status register.  
However, if the Hot Standby system is later stopped and then restarted, the  
parameters specified in the configuration extension screens go back into effect.  
Ladder Logic in a All ladder logic for Hot Standby functions should be in segment 1. Network 1 of  
Hot Standby  
System  
segment 1 is reserved exclusively for the CHS instruction block and ladder logic  
directly associated with it.  
program all ladder logic specific to Hot Standby functions in segment 1When the  
Hot Standby system is running, the Primary controller scans all segments, while  
the Standby controller scans only segment 1 of the configured ladder logic  
program. This has very important implications with respect to the way you  
configure system logic:  
do not program I/O control logic in segment 1  
do not schedule any I/O drops in segment 1  
the Standby controller in a Hot Standby system must never execute I/O logic.  
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Using a Quantum 984 HSBY System  
CHS Instruction  
Using CHS  
Instruction  
CAUTION  
Reschedule Segment Hazard  
To help protect against damage to application I/O devices through  
unexpected system actions, do not reschedule segment 1 via the  
segment scheduler.  
Failure to follow this precaution can result in injury or equipment  
damage.  
Segment 1 may contain the ladder logic for diagnostics and optional Hot Standby  
functions, such as time-of-day clock updates.  
Using the CHS  
Instruction to  
Control Your Hot  
Standby System  
If you choose to use the CHS instruction in ladder logic to control the Hot Standby  
configuration, the instruction must be placed in network 1, segment 1 of the ladder  
logic program. The top node must be connected directly to the power rail by a  
horizontal short. No control logic, such as contacts, should be placed between the  
rail and the input to the top node. However, other logic may be placed in network 1.  
Remember, the ladder logic in the Primary and Standby controllers must be  
identical.  
The three nodes in the CHS instruction define the command register, the first  
register in the nontransfer area, and the length of the nontransfer area.  
HSBY System ACTIVE  
Execute HSBY  
Unconditionally  
command  
register  
PLC cannot communicate  
with its CHS module  
nontransfer  
area  
Enable Command  
Register  
CHS  
Configuration extension  
screens are defining the  
HSBY configuration  
Enable Nontransfer Area  
length  
The bottom output node of the CHS instruction indicates whether the configuration  
extension screens have been activated and allows the parameters in the screens to  
override those in the CHS instruction at startup.  
A detailed description of the CHS instruction is provided in the Ladder Logic Block  
Library User Guide.  
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Using a Quantum 984 HSBY System  
6.2  
Using the CHS Instruction Block  
Introduction  
Purpose  
This section describes using the CHS Instruction Block.  
This section contains the following topics:  
What’s in this  
Section?  
Topic  
Page  
75  
Using CHS Instruction Block  
Command Register  
76  
78  
80  
81  
82  
83  
Elements of the Nontransfer Area  
Zoom screen of CHS Instruction  
The Hot Standby Status Register  
The Reverse Transfer Registers  
Reverse Transfer Logic Example  
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Using a Quantum 984 HSBY System  
Using CHS Instruction Block  
CHS Instruction  
Block  
The command register is defined in the top node of the CHS instruction block. The  
bits in this register are used to configure and control various parameters of the Hot  
Standby system.  
The command register must be a 4x register in the portion of the state RAM transfer  
area that is transferred from the Primary to the Standby controller on every scan. It  
also must be outside of the nontransfer area.  
Disables keyswitch override = 0  
Enables keyswitch override = 1  
Sets Controller A to OFFLINE mode = 0  
Sets Controller A to RUN mode = 1  
Sets Controller B to OFFLINE mode = 0  
Sets Controller B to RUN mode=1  
Forces standby offline if there is a logic mismatch = 0  
Does not force standby offline if there is a logic mismatch = 1  
Allows exec upgrade only after application stops = 0  
Allows exec upgrade without stopping application = 1  
1
3
5
7
9
11  
13  
15  
16  
2
4
6
8
10  
12  
14  
0 = Swaps Modbus port 1 address during switchover  
1= Does not swap Modbus port 1 address during switchover  
0 = Swaps Modbus port 2 address during switchover  
1 = Does not swap Modbus port 2 address during switchover  
0 = Swaps Modbus port 3 address during switchover  
1 = Does not swap Modbus port 3 address during switchover  
CAUTION  
Hot Standby Command Register Hazard  
Take precautions to be sure the register you select as the Hot Standby  
command register is reserved for this purpose and not used for other  
purposes in ladder logic.  
Failure to follow this precaution can result in injury or equipment  
damage.  
The values set for the bits in this register determine the system parameters at  
startup. The register can be accessed while the system is running using a reference  
data editor (RDE) or a Zoom screen on the CHS instruction in ladder logic.  
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Using a Quantum 984 HSBY System  
Command Register  
Command  
Register  
CAUTION  
Command Register Hazard  
If you use the command register to enable the keyswitch override while  
the Hot Standby system is running, the Primary controller immediately  
reads bits 14 and 15 to determine its own state and the state of the  
Standby.  
If both bits are set to 0, a switchover occurs and the former Primary  
CPU goes offline. The new Primary CPU continues to operate.  
Failure to follow this precaution can result in injury or equipment  
damage.  
The State RAM  
Transfer Area  
The command register must be contained within the range of 4x registers in the state  
RAM transfer area.  
A fixed block of up to 12K words in state RAM is specified as the transfer area. It  
consists of the following:  
All the 0x discrete outputs in state RAM up to a maximum of 8192, including their  
associated histories  
All the 1x discrete inputs in state RAM up to a maximum of 8192, including their  
associated histories  
If the total number of registers (3x and 4x combined) implemented in state RAM  
is 10,000 or less, then all the registers plus the up/down counter history table  
If the total number of registers (3x and 4x combined) implemented in state RAM  
is greater than 10,000, then a total of 10,000 is transferred, in accordance with  
the previously described formula. See Default Transfer Area, p. 38.  
NontransferArea You also must define a nontransfer area in the middle node of the the CHS  
Within the State  
RAM Transfer  
Area  
instruction block. A nontransfer area:  
is a tool to reduce scan time  
is located entirely within the range of 4x registers in the state RAM transfer area  
which are transferred on every scan  
consists of a block of four or more 4x registers  
allows the user to monitor the status of the Hot Standby system (third register of  
non-transfer area)  
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Using a Quantum 984 HSBY System  
Only 4x reference data can be placed in the nontransfer area. These designated  
registers are not transferred to the Standby controller, thus reducing scan time. The  
following block diagram shows how the nontransfer area exists with respect to the  
rest of the state RAM transfer area.  
NontransferArea  
Within the State  
RAM Transfer  
Area  
State RAM Transfer Area  
Critical outputs transferred  
on every scan  
Note: The command register  
must be outside the  
nontransfer block  
Total number of  
register outputs  
transferred  
Additional outputs transferred  
in chunks on multiple scans  
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Using a Quantum 984 HSBY System  
Elements of the Nontransfer Area  
Nontransfer Area The most important part of the nontransfer area is the Hot Standby status register.  
Once the system has been configured and is running, the status register becomes  
a valuable tool for monitoring the machine states of the two controllers. If you use  
software to change values in the command register, being able to see the result of  
those changes in the status register is very helpful.  
The nontransfer area is defined in the middle and bottom nodes of the instruction  
block. The middle node specifies the first register in the nontransfer area. The  
bottom node specifies the length of the nontransfer area.  
Status Register  
This PLC in OFFLINE mode = 0 1  
This PLC running in primary mode =1 0  
This PLC running in standby mode = 1 1  
The other PLC in OFFLINE mode = 0 1  
The other PLC running in primary mode =1 0  
The other PLC running in standby mode = 1 1  
PLCs have matching logic = 0  
PLCs do not have matching logic = 1  
This PLC’s switch set to A = 0  
This PLC’s switch set to B = 1  
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16  
The nontransfer area must be at least four registers long. The first two registers in  
the nontransfer area are reserved for reverse transfer functions. The third register in  
the nontransfer area is the Hot Standby status register.  
The fourth register and all other contiguous 4x registers specified for nontransfer are  
ignored when the state RAM values of the Primary controller are transferred to the  
Standby controller.  
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Using a Quantum 984 HSBY System  
Example of a  
In the example, the nontransfer area begins at register 40010, as defined in the  
Nontransfer Area middle node. The length is 30 registers, as defined in the bottom node. Thus, the  
last register in the nontransfer area is 40039.  
Execute HSBY Unconditionally  
Enable Command Register  
HSBY System ACTIVE  
PLC cannot communicate with its  
CHS module  
CHS  
Configuration extension screens  
are defining the HSBY  
configuration  
Enable Nontransfer Area  
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Using a Quantum 984 HSBY System  
Zoom screen of CHS Instruction  
Zoom Screen  
When both a CHS instruction and the Hot Standby configuration extension are used,  
the parameters you set for the nontransfer area in the configuration extension  
screens must be identical to those in the CHS block.  
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Using a Quantum 984 HSBY System  
The Hot Standby Status Register  
Hot Standby  
Status Register  
The status register is register 40012, the third register in the nontransfer area. The  
command register, which is defined in the top node, has been placed outside the  
nontransfer area, as required.  
The third register in the nontransfer area is the status register. Use this register to  
monitor the current machine status of the Primary and Standby controllers.  
Bits in the Hot  
Standby Status  
Register  
In the example, the status register is 40012.  
This PLC in OFFLINE mode = 0 1  
This PLC running in primary mode =1 0  
This PLC running in standby mode = 1 1  
The other PLC in OFFLINE mode = 0 1  
The other PLC running in primary mode =1 0  
The other PLC running in standby mode = 1 1  
PLCs have matching logic = 0  
PLCs do not have have matching logic = 1  
This PLC’s switch set to A = 0  
This PLC’s switch set to B = 1  
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16  
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The Reverse Transfer Registers  
Reverse Transfer You can use the reverse transfer registers to transmit diagnostic data from the  
Standby controller to the Primary controller. When you choose to define a  
nontransfer area, registers 4x and 4x + 1 in the nontransfer block are copied from  
the Standby to the Primary controller. This is opposite from the normal forward state  
table transfer from the Primary to the Standby.  
If you choose not to use the reverse transfer registers, do not connect the CHS  
bottom input to the rail in your ladder logic program, so the inputs to these registers  
are not enabled.  
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Reverse Transfer Logic Example  
A Reverse  
Transfer Logic  
Example  
The following example shows I/O ladder logic for a Primary controller that monitors  
two fault lamps and the reverse transfer logic that sends status data from the  
Standby controller to the Primary. One fault lamp turns ON if the Standby memory  
protect is OFF; the other lamp turns ON if the memory backup battery fails in the  
Standby.  
Network 1 of Segment 1  
400005  
400100  
CHS  
30  
Network 2 of Segment 1  
BLKM transfers the status of the  
400103  
Hot Standby status register  
(40103) to internal coils (00801)  
000801  
BLKM  
#001  
STAT sends one register Word from  
400101  
the standby to a reverse transfer  
register (400101 in the primary.  
STAT  
#001  
000815  
(Bit 15)  
000816  
(Bit 16)  
(Enables STAT if this  
PLC is the Standby  
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ReverseTransfer The logic in network 2 of segment 1 contains a BLKM instruction and a STAT  
Logic  
instruction. The Standby enables the STAT. Bits 000815 and 000816 are controlled  
by bits 15 and 16 in the Hot Standby status register. The STAT instruction sends one  
status register word to 400101; this word initiates a reverse transfer to the Primary  
controller.  
Remote I/O Logic Internal coil bit 000715 (status bit 11) controls the STANDBY MEMORY PROTECT  
OFF lamp. Internal coil bit 000716 (status bit 12) controls the STANDBY BATTERY  
FAULT lamp.  
Segment 2  
400101  
000813  
(Bit 13)  
000814  
(Bit 14)  
BLKM Transfers the Status of  
Reverse Transfer Register to  
Internal Coils  
000705  
BLKM  
#001  
Standby MEMORY PROTECT OFF Lamp  
Output Coil  
000715  
(Bit 11)  
000813  
(Bit 13)  
000208  
Standby BATTERY FAULT  
Output Coil  
000716  
(Bit 12)  
000813  
(Bit 13)  
000209  
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6.3  
Using Configuration Extension  
Introduction  
Purpose  
This section describes using the HSBY Configuration Extension.  
This section contains the following topics:  
What’s in this  
Section?  
Topic  
Page  
86  
Configuration Extension  
Hot Standby Dialog  
87  
88  
Bits in the Hot Standby Command Register  
Keyswitch Override and Run Mode  
A Software Control Example  
Standby on Logic Mismatches  
Transfer All State RAM  
90  
91  
92  
94  
Hot Standby Status Register for Configuration Extension  
Advanced Options  
95  
96  
Defining the Transfer Area of State RAM  
Transferring Additional State RAM Data  
Scan Transfers  
97  
100  
102  
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Configuration Extension  
Hot Standby  
Dialog  
The configuration of the 984 Hot Standby can be done with the Hot Standby dialog  
and/or with the CHS instruction of the LL984 instruction library.  
Concept shown  
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Hot Standby Dialog  
Hot Standby  
Dialog in  
The Hot Standby dialog is shown below, it can be activated through Configure Hot  
Standby.  
Concept  
Concept shown  
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Bits in the Hot Standby Command Register  
Specifying the  
Command  
Register  
The command register is used to control various parameters of the Hot Standby  
system.  
Command  
Register  
The command register is specified in the first entry field of the Hot Standby dialog.  
By default, the command register is set to 400001. If register 400001 is used  
elsewhere, enter another number greater than 0. The number you enter becomes  
the 4x command register. For example, if you enter 14, the hot Standby command  
register is 400014.  
Disables keyswitch override = 0  
Enables keyswitch override = 1  
Sets Controller A to OFFLINE mode = 0  
Sets Controller A to RUN mode = 1  
Sets Controller B to OFFLINE mode = 0  
Sets Controller B to RUN mode = 1  
Forces standby offline if there is a logic mismatch = 0  
Does not force standby offline if there is a logic mismatch = 1  
Allows exec upgrade only after application stops =0  
Allows exec upgrade without stopping application =1  
0 = Swaps Modbus port 1 address during switchover  
1 = Does not swap Modbus port 1 address during switchover  
0 = Swaps Modbus port 2 address during switchover  
1 = Does not swap Modbus port 2 address during switchover  
0 = Swaps Modbus port 3 address during switchover  
1 = Does not swap Modbus port 3 address during switchover  
You may enter any number in the range 1... n, where n is the last configured 4x  
register. However:  
The command register must be part of the area of state RAM that gets transferred  
from the Primary to the Standby controller on every scan.  
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Therefore, the number you specify for the command register must be in the range  
of 4x registers you specify in the State RAM area in State RAM dialog. If you are  
using the 12K option, the command register must be one of the first 9000 4x  
registers.  
The command register must not be within the range of the nontransfer area,  
which you specify in the nontransfer area of the Hot Standby dialog.  
CAUTION  
Hot Standby Command Register Hazard  
Be sure the register you select as the Hot Standby command register is  
reserved for this purpose and not used for other purposes elsewhere in  
user logic.  
Failure to follow this precaution can result in injury or equipment  
damage.  
CAUTION  
Hot Standby Dialog Hazard  
If you intend to use the Hot Standby dialog to configure the command  
register and the CHS instruction to modify the command register during  
runtime, make sure that you specify the same register as the command  
register in Hot Standby dialog and the top node of the CHS block. If you  
use different numbers for the command register, the changes that you  
make via the Zoom screen are not applied to the real Hot Standby  
command register.  
Failure to follow this precaution can result in injury or equipment  
damage.  
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Keyswitch Override and Run Mode  
Keyswitch and  
Run  
You may choose to override the keyswitch on the front panel of the CHS 110  
modules for security or convenience. If you override the keyswitch, the command  
register becomes the means for taking the CHS 110 modules on or offline.  
By default, the keyswitch override is disabled. The Hot Standby dialog allows you to  
enable it.  
Keyswitch  
Override  
If you enable the keyswitch override, the Offline/Running operating mode of the  
controllers at startup is determined by the values you set to bits 14 and 15 of the  
command register. These bits are represented as the Run Mode for controller A and  
B (depends on designation slide switch). Remember, that when the keyswitch  
override is enabled you can not initiate a program update (program xfer) at the CHS  
110 module in the Standby rack.  
As long as the keyswitch override is disabled, the settings for the Run Mode can be  
ignored.  
CAUTION  
Keyswitch Override Hazard  
If you use the Zoom screen or RDE to enable the keyswitch override  
while the Hot Standby system is running, the Primary controller  
immediately reads bits 14 and 15 to determine its own state and the  
state of the Standby.  
Failure to follow this precaution can result in injury or equipment  
damage.  
If both bits are set to 0, a switchover occurs and the former Primary CPU goes  
offline. The new Primary CPU continues to operate.  
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A Software Control Example  
Using Software  
Control  
For example: you enabled the keyswitch override and set the operating mode of  
controller B to Offline. Now the system is powered up and you want to put controller  
B in RUN mode.  
The keyswitch does not work, so you must rely on user logic.  
There are three ways you can proceed:  
Option 1  
Change the setting on the Hot Standby dialog. To do this, you must shut  
down the system and make the necessary change in the dialog, then  
power up the system again. Download the new configuration.  
Option 2  
Connect Concept to your Primary controller. Call up the reference data editor  
(RDE). Place the Hot Standby command register and the Hot Standby status  
register in the RDE. The operating mode of controller B is determined by the  
state of bit 14 of the command register. If controller B is offline, bit 14 is set to  
0. To put the controller in RUN mode, change the state of bit 14 to 1. Controller  
B immediately goes into RUN mode if all other HSBY requirements are healthy.  
Option 3  
If you have programmed a CHS instruction into the ladder logic: Connect  
Concept to your Primary controller. In the editor, place the cursor on the top  
node of the CHS instruction and invoke the Zoom screen (CTRL+D). Check the  
Run Mode checkbox for parameter Contoller B in Run Mode and controller B  
immediately goes into RUN mode.The advantage of options 2 and 3 is that the  
Hot Standby system does not have to be shut down in order to change its  
status. If you find the use of the Zoom screen more comfortable than the RDE,  
consider programming a CHS instruction into ladder logic for purposes such as  
this.  
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Standby on Logic Mismatches  
Logic Program  
To function properly, the Primary and the Standby controller in a Hot Standby  
system must be solving an identical logic program, which is updated on every scan  
by a state RAM data transfer between the two controllers.  
By default, the Standby controller is set to go offline if a mismatch is detected  
between its user logic and that of the Primary controller. Switchover cannot occur  
while the Standby controller is Offline.  
The radio buttons provide you with the option to override this default. If you change  
the parameter in this field from Offline to Running, the Standby controller remains  
online if a logic mismatch is detected between its logic program and that of the  
Primary controller.  
CAUTION  
Mismatch Hazard  
A mismatch in the I/O map or configuration is not allowed under any  
circumstances.  
Failure to follow this precaution can result in injury or equipment  
damage.  
CAUTION  
Switchover Hazard  
If switchover occurs when the radio button is set to Running and there  
is a logic mismatch between the two controllers, the Standby controller  
will assume Primary responsibilities and will start solving a different  
logic program from the previous Primary controller.  
Failure to follow this precaution can result in injury or equipment  
damage.  
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Swap Address at In a Hot Standby system, the Modbus ports on the Primary controller may have  
Switchover  
MEM addresses in the range of 1 to 119. This allows an offset of 128 for comparable  
ports on the Standby controller, with 247 the maximum number of addresses.  
For example, if controller A is the Primary controller and its two Modbus ports have  
addresses 1 and 2, then the default addresses for the comparable ports on Standby  
controller B are 129 and 130. By default, this offset is maintained between port  
addresses in the event of switchover. For example, if controller B becomes the  
Primary controller as the result of switchover, its Modbus ports assume the  
addresses of 1 and 2, and the comparable ports on controller A assume addresses  
129 and 130.  
The check boxes allow you to change this default condition on any or all of the  
Modbus ports on the two controllers in your Hot Standby system.  
Modbus ports on the two controllers in your Hot Standby system. For example: if you  
deselect the parameter Modbus Port 1, then no offset is maintained at switchover  
and after switchover the two ports have the same address. Thus if controller A is the  
Primary controller and its Modbus port 1 address is 1, then that port address remains  
1 after a switchover occurs. Likewise, if controller B becomes the Primary controller  
as a result of switchover, its Modbus port 1 address is also 1.  
Note: If you change the selections, the port addresses are not affected until a  
switchover occurs.  
Modbus Plus  
Port Address  
Swapping at  
Switchover  
In a Quantum Hot Standby system, the Modbus Plus port addresses on the Standby  
controller are offset by 32 from the comparable ports on the Primary controller. For  
example, if controller A is the Primary controller and its Modbus Plus port has  
address 1, then the address for the corresponding port on Standby controller B is 33.  
The numerical range for addresses for both ports is 1 through 64. Thus, if the port  
on the Primary controller has address 50, then the address for the corresponding  
port on the Standby cannot be 82, so it is 18 (that is, 50 minus 32).  
These addresses are automatically swapped at switchover; you do not have the  
option to change the offset or prevent the addresses from being swapped.  
Note: The Quantum Hot Standby system swaps Modbus Plus addresses almost  
instantaneously at switchover. This means that host devices polling the Quantum  
controller can be assured that they are always talking to the Primary controller and  
that the network experiences no downtime during switchover.  
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Transfer All State RAM  
"Transfer All  
State RAM"  
check box  
It is not possible to define a special State RAM or additional State RAM range to be  
transferred if this check box is activated.  
Nontransfer Area The nontransfer area contains the Hot Standby status register, which is used to  
monitor the states of both controllers. It also contains a pair of registers which may  
be used for reverse transfer operations. You may include other 4x registers in the  
nontransfer area to reduce scan time.  
The Start: field is used to specify the first 4x register in the nontransfer area. The  
Length: field is used to define the number of contiguous registers in the nontransfer  
block. If you choose to define a nontransfer area, the range of legal values for this  
entry field is 4 ... n, where n is the number of configured 4x registers. However, when  
defining the nontransfer area, you must meet these requirements:  
The nontransfer area must be located entirely within the area of 4x registers  
scheduled for transfer on every scan. The transfer area is defined in the State  
RAM dialog.  
The command register (first entry of the Hot Standby dialog) must be outside the  
nontransfer area.  
Note: If you are also programming a CHS instruction in LL984, the parameters you  
set for the nontransfer area in the Hot Standby dialog must be identical to those in  
the CHS block.  
Hot Standby  
Status Register  
The third register in the nontransfer area is the Hot Standby status register. Use  
this register to monitor the current machine status of the Primary and Standby  
controllers.  
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Hot Standby Status Register for Configuration Extension  
Status Register  
forConfiguration  
extension  
Note: Bits 1 and 2 are used only in conjunction with a configuration extension.  
This PLC in OFFLINE mode = 0  
This PLC running in primary mode = 1  
This PLC running in standby mode = 1  
1
0
1
The other PLC in OFFLINE mode = 0  
The other PLC running in primary mode = 1  
The other PLC running in standby mode = 1  
1
0
1
PLCs have matching logic = 0  
PLCs do not have matching logic = 1  
This PLC’s switch sat to A = 0  
This PLC’s switch sat to B = 1  
The CHS interface is healthy = 0  
An interface error has been detected = 1  
Hot standby capability has not been activated = 0  
Hot standby is active = 1  
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Advanced Options  
Advanced  
When pressing the Advanced Options button in the Hot Standby dialog, you get the  
Options button  
opportunity to allow different firmware versions on the Primary and Standby  
controller while running in full Hot Standby mode.  
Concept shown  
This lets you upgrade the controllers step by step to a new firmware version without  
having to shutdown the system. Since this is only necessary in rare situations, it is  
recommended that you disable this mode by configuration and to enable it by the  
reference data editor or Zoom screen when needed. By default, the controllers must  
have the same versions of firmware. This means the Standby controller would not  
go online while having a newer or older firmware version than the one on the Primary  
controller.  
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Defining the Transfer Area of State RAM  
Additional RAM  
With 984 Hot Standby, you may define additional state RAM (0x, 1x, 3x, and 4x  
registers) that are transferred in groups over multiple logic scans.  
State RAM dialog To open the State RAM dialog, deactivate Transfer All State RAM and then use the  
Options button.State RAM associated with all critical I/O also should be transferred  
in every scan. Additional state RAM can be grouped and transferred over multiple  
scans.  
Concept shown  
State RAM  
State RAM  
Transfer: User Defined  
Number of References to Transfer  
Coils (0xxxx):  
0
0
Input Regs (3xxxx):  
Output Regs (4xxxx):  
0
0
Discrete Inputs (1xxxx):  
Additional State RAM  
Transfer Additional State RAM  
Number of References to Transfer  
Extra Transfer Time (1-255):  
1
Coils (0xxxx):  
0
0
Input Regs (3xxxx):  
Output Regs (4xxxx):  
0
0
Discrete Inputs (1xxxx):  
OK  
Cancel  
Help  
If you use the CHS instruction to configure the Hot Standby system, you are unable  
to transfer any more than 12K words, even though the total amount of state RAM  
could be as much as 64K words. You can limit the number of 4x registers being  
transferred by selecting a block of registers as part of the nontransfer area, but you  
cannot limit the number of 0x, 1x, or 3x registers in the transfer area.  
Note: The command register must be located in the area of state RAM which is  
transferred in every scan.  
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Hot Standby  
Dialog  
Using the Hot Standby dialog, you have a great deal more flexibility in determining  
how much or how little State RAM gets transferred. You also can manage how much  
gets transferred in all scans and how much gets transferred in pieces over multiple  
scans.  
The parameter you select in the Transfer field of the State RAM determines the  
flexibility you have in defining your state RAM transfer area. You may choose from  
two options:  
12K  
User Defined  
Note: The remaining entry fields of the dialog may or may not be used depending  
on which one of these two parameters you choose.  
Note: No matter which option you choose, remember that the command register  
must be included in the block of registers transferred on every scan.  
12K Option  
The 12K option mimics the CHS instruction. It gives you a predefined state RAM  
transfer area with a predetermined maximum of each reference data type to be  
transferred. The predefined transfer area consists of the following:  
All the 0x discrete outputs in state RAM up to a maximum of 8192, including their  
associated histories.  
All the 1x discrete inputs in state RAM up to a maximum of 8192, including their  
associated histories.  
If the total number of registers (3x and 4x combined) implemented in state RAM  
is 10 000 or less, then all the registers plus the up/down counter history table.  
If the total number of registers (3x and 4x combined) implemented in state RAM  
is greater than 10 000, then 10 000 registers transfer in accordance with the  
formula described in System Scan Time, p. 33.  
If you choose the 12K option, the State RAM and Additional State RAM area  
become irrelevant. You can not customize the transfer area or transfer additional  
data in groups over multiple scans. Any entries in these fields are ignored.  
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User Defined  
Option  
The User Defined option lets you specify the amount of each reference data type  
that you want to be transferred on each scan. If the Transfer Additional State RAM  
check box is activated, it allows you to transfer additional data.  
000001  
Outputs transferred  
000002  
on every scan  
000003  
Remaining outputs  
not transferred  
0nnnnn  
100001  
100002  
100003  
Inputs transferred  
on every scan  
Remaining inputs  
not transferred  
1nnnnn  
300001  
300002  
300003  
Inputs transferred  
on every scan  
Remaining inputs  
not transferred  
3nnnnn  
400001  
400002  
400003  
400004  
400005  
400006  
Outputs transferred  
on every scan  
Remaining outputs  
not transferred  
4nnnnn  
User Defined  
State RAM  
Transfer  
Use the State RAM area to define the size of the data range. All of the reference data  
that you specify in this area is transferred from the Primary to the Standby controller  
on every scan (except the defined nontransfer area). All reference data items must  
be 0 or specified in multiples of 16. A minimum of 16 4x registers is required. The  
maximum amount of state RAM to be transferred on every scan can be as much as  
the total amount of available state RAM (10K, 32K, or 64K, depending on the type  
of Quantum controller).  
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Transferring Additional State RAM Data  
Additional Data  
If the Transfer Additional State RAM check box is activated, additional State RAM  
could be transferred.  
In the Additional State RAM area, enter the number of 0x, 1x, 3x, and 4x data  
references that you want to be transferred as additional state RAM. All reference  
data items must be specified in multiples of 16. You must enter a value of 16 or  
greater for at least one of the four reference data types.  
CAUTION  
Transfer Additional State RAM Hazard  
If you choose Transfer Additional State RAM, you must specify  
additional data to be transferred or the controller will not start.  
Failure to follow this precaution can result in injury or equipment  
damage.  
Use the Extra Transfer Time entry field to specify the number of scans over which  
you want the additional data to be transferred. In general, the system divides the  
number of reference data elements specified in the fifth entry field by the number of  
scans specified in the sixth entry field. Accordingly, it divides the data into groups  
that are transferred contiguously over the specified number of scans. These groups  
of data are transferred with the regular state RAM data that has been scheduled on  
every scan.  
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Additional Data  
The diagram below illustrates transfer of additional State RAM data.  
Critical inputs transferred  
on every scan  
000001  
000002  
000003  
Additional inputs transferred  
in chunks on multiple scans  
Remaining outputs not  
transferred.  
0nnnnn  
Critical inputs transferred  
on every scan  
100001  
100002  
100003  
Additional inputs transferred  
in chunks on multiple scans  
Remaining inputs not  
transferred.  
1nnnnn  
Critical inputs transferred  
on every scan  
300001  
300002  
300003  
Additional inputs transferred  
in chunks on multiple scans  
Remaining inputs not  
transferred.  
3nnnnn  
400001  
400002  
400003  
400004  
400005  
400006  
Critical outputs transferred  
on every scan  
Additional outputs transferred  
in chunks on multiple scans  
Remaining outputs not  
transferred.  
4nnnnn  
The system transfers additional data in the following order:  
All 0x references first  
All 1x references second  
All 3x references third  
All 4x references last  
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Scan Transfers  
Data Type  
A minimum of 512 equivalent words of each data type specified in the Additional  
State RAM area are sent in a scan, unless there are less than 512 words of that data  
type left to be transferred. For example, if you specify 528 additional registers to be  
transferred over three scans, the system will send the data faster than expected.  
The first 512 additional registers are transferred in the first scan, and the remaining  
16 registers are transferred in the second scan. On the third scan, the process  
begins again, sending the first 512 additional registers.  
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6.4  
Operation  
Introduction  
Purpose  
This section describes Hot Standby operation.  
This section contains the following topics:  
What’s in this  
Section?  
Topic  
Page  
104  
Starting Your Hot Standby System  
Synchronizing Time-of-Day Clocks  
While Your System Is Running  
106  
108  
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Starting Your Hot Standby System  
Preconditions  
Note: Start one controller at a time.  
Be sure...  
The controller you are starting first has been fully programmed.  
The function keyswitch on the CHS 110 module is in the Run position.  
The designation slide switches on CHS 110 modules are in opposite positions.  
The first controller to power up will automatically become the primary controller,  
regardless of its designation as A or B.  
Starting the  
System  
The following chart provides the appropriate steps for starting your Hot Standby  
system.  
Step  
Action  
1
Turn on power to the first backplane.  
Download the program to the controller.  
Start the controller in that backplane.  
Turn on power to the second backplane.  
2
3
4
5
Download the program to the standby controller.  
If the switches on the controllers are set to the same address, you will not be able  
to download the program. Use the keyswitch program update procedure.  
6
7
Start the standby controller.  
Check the LED display. If the system is functioning normally, the display should  
match "Indicators of a Properly Functioning Hot Standby System", shown in the  
illustration below. On the CHS 110 module, all three indicators should be steady,  
not blinking. A blinking Com Act light signals that your system has detected an  
error. On the corresponding CRP module, the Ready indicator is a steady green.  
The Com Act indicator on the primary unit should also be a steady green, while  
the Com Act indicator on the standby RIO head should be blinking slowly.  
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LED Display  
Indicators of a  
Properly  
The following graphic shows LED display indicators of a properly functioning Hot  
standby system.  
Primary  
Backplane  
Functioning Hot  
Standby System  
140  
CHS 110 00  
HOT STANDBY  
Active  
RIO Head  
HOT STANDBY  
Active  
Ready Fault  
Ready Fault  
Run  
Bal Low  
Run  
Bal Low  
Pwr ok  
Pwr ok  
Modbus Com Err  
Modbus! Error A  
Com Act Error B  
Primary  
Modbus Com Err  
Modbus! Error A  
Com Act Error B  
Primary  
Mem Prt Standby  
Mem Prt Standby  
Standby  
Backplane  
140  
CHS 110 00  
RIO Head  
HOT STANDBY  
HOT STANDBY  
Active  
Ready Fault  
Active  
Ready Fault  
Run  
Bal Low  
Run  
Bal Low  
Pwr ok  
Pwr ok  
Modbus Com Err  
Modbus! Error A  
Com Act Error B  
Primary  
Modbus Com Err  
Modbus! Error A  
Com Act Error B  
Primary  
Mem Prt Standby  
Mem Prt Standby  
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Synchronizing Time-of-Day Clocks  
Clock  
In a Hot Standby system, the Primary and Standby controllers have their own time-  
Synchronization  
of-day clocks. They are not synchronized. At switchover, the time of day changes by  
the difference between the two clocks. This could cause problems if you are  
controlling a time-critical application.  
To solve this problem, program the Standby controller to reset its clock from the  
state table provided by the Primary controller. If you are controlling your system via  
configuration extension screens, put the logic for time synchronization first.  
Otherwise, put the logic for time synchronization in segment 1, but do not put it in  
network 1.  
Since both controllers run the same program, you must read CHS status register bits  
12...16 to be sure that only the standby clock is resetting. If bits 12...16 are 01011,  
you know three things:  
which controller is the Standby  
that the remaining controller is the Primary  
that both controllers are running the same logic  
If these conditions are true, then the logic should clear bit 2 and set bit 1 of the time-  
of-day control register. The clock in the Standby controller will be reset from the state  
table of the Primary controller at the end of a scan and bit 1 will be cleared.  
Note: Be sure that the registers for synchronizing the time-of-day clocks are  
included in the state RAM transfer area.  
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The following diagram shows synchronizing time-of-day clocks.  
Network 1 of Segment 1  
40001  
40101  
CHS  
4
40001 = Address of CHS Command Register  
40101 = First Register Reserved for Nontransfer Area in State RAM  
4 = Number of Registers Reserved in Nontransfer Area  
Network 2 of Segment 1  
0015  
0
40103  
42221  
42221  
0011  
0002  
0001  
ADD  
42221  
AND  
0001  
SUB  
42222  
TODC  
TODC  
MBIT  
MBIT  
0001  
0001  
40103 = CHS Status Register  
42221 = Mask Out Status Bits Not Required  
42222 = Junk Register  
TODC = Time-of-day Clock Register  
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While Your System Is Running  
ConstantInternal After your Hot Standby system has been started and is running normally, it will  
Monitoring  
continue to function automatically. It constantly tests itself for faults and is always  
ready to transfer control from the Primary to the Standby, if it detects a fault.  
While the system is running, the primary CHS module will automatically transfer a  
predetermined amount of state RAM to the Standby unit each scan. This ensures  
that the Standby is ready to take control if needed.  
If one or both of the links between the Hot Standby modules are broken, the Primary  
controller will function as though no backup is available.  
If the Primary controller fails, the Standby automatically assumes control of the  
remote I/O network. If the Primary controller recovers from failure, it assumes  
Standby responsibilities. If it cannot recover, it remains offline.  
If the Standby controller fails, it goes offline. The Primary controller functions as a  
stand-alone and continues to manage the I/O networks.  
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Using a Quantum IEC Hot Standby  
System  
7
At a Glance  
Purpose  
This chapter presents operating procedures for the IEC HSBY.  
This chapter contains the following sections:  
What’s in this  
Chapter?  
Section  
7.1  
Topic  
Page  
111  
Configuration  
Hot Standby Dialog  
State RAM  
7.2  
116  
129  
135  
138  
140  
7.3  
7.4  
Section Transfer Control  
Operation  
7.5  
7.6  
Normal Operation  
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Using a Quantum IEC Hot Standby System  
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7.1  
Configuration  
Introduction  
Purpose  
This section describes Quantum IEC Hot Standby configuration.  
Note: To ensure correct operation of the HSBY system, the user must I/O map at  
least 1 RIO drop and 1 I/O module. This will ensure the proper diagnostic  
information is transferred between Primary and Standby CRPs. (Remote I/O  
Processor.)  
What’s in this  
Section?  
This section contains the following topics:  
Topic  
Page  
112  
114  
Loading the Software  
Controlling the Hot Standby System by Configuration Extension  
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Loading the Software  
Loading and  
Concept 2.5  
Starting with Concept 2.5, the CHS loadable is a part of the Concept install.  
If you are using Concept 2.5 and for some reason the loadable is deleted, it can be  
reinstalled using the following procedure.  
Load Software  
into Controllers  
To configure a Quantum Hot Standby system, load the CHS software into the  
controllers. The software is included on a diskette in the Hot Standby Kit.  
Once you have installed the software, you can activate the IEC Hot Standby  
configuration extension.  
Installing the  
CHS loadable  
into the Concept  
Environment  
The following steps are only necessary if the CHS loadable is not already part of  
your Concept installation. The CHS loadable is provided on a 3 1/2" diskette  
(140 SHS 945 00) as part of your 140 CHS 210 00 Hot Standby kit. The file is named  
QCHSVxxx.DAT, where xxx is the three-digit version number of the software.  
Step  
Action  
1
Insert the diskette in the disk drive.  
2
Either create a new Concept project or open an existing one and have a PLC  
selected  
3
4
5
With the menu command Project Configurator, open the configurator.  
With Configure Loadables, open the dialog box Loadables.  
Press the command button Unpack to open the standard Windows dialog box,  
Unpack Loadable File. Select the loadable file, click the button OK and it is  
inserted into the list box Available.  
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Concept  
Loadables  
Installation  
Screen  
The following diagram shows a Concept loadables installation screen.  
Loadables  
Bytes Available: 643210  
Bytes Used: 525888  
Installed:  
Available:  
@1S7  
@1SE  
@2I7  
@2IE  
CHS  
V196  
V196  
V196  
V196  
V208  
V196  
Install  
Remove  
Unpack  
IHSB  
Warning: Confirm user loadables  
are valid for your PLC  
Edit  
OK  
Cancel  
Help  
The CHS loadable is now part of the Concept environment and may be installed into  
a project configuration whenever needed.  
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Using a Quantum IEC Hot Standby System  
Controlling the Hot Standby System by Configuration Extension  
Configuration  
Extension  
Use the Hot Standby Concept configuration extension screen as follows:  
Specify the parameters in the Hot Standby command register  
Define a nontransfer area to help reduce scan time  
The parameters in the configuration screens are applied by the controllers at startup.  
You can change the settings/behavior of the IEC Hot Standby system after already  
having downloaded the configuration to the controller. Do this either by setting or  
resetting the particular bits of the Hot Standby command register or by using the Hot  
Standby specific EFBs of the "System" library.  
Note: If the Hot Standby system is later stopped and then restarted, the  
parameters specified in the configuration extension screens go back into effect.  
IEC Logic in a  
Hot Standby  
System  
In the Concept 2.1/2.2 Hot Standby system, there is no logic executed in the  
Standby controller. This is different from the 984 Hot Standby system, where the  
Standby controller executes the logic of segment 1.  
In the Concept 2.5 Hot Standby system, the Standby controller executes section 1  
logic; this is similar to the way segment 1 is handled in a 984 Hot Standby System.  
Section 1 may contain logic for diagnostic and optional Hot Standby functions, such  
as battery coil status. Do not program I/O control logic in section 1.  
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Using the  
Configuration  
Extensions  
screen  
The Configuration Extension offers two check boxes regarding Hot Standby. Since  
you are using the IEC environment, check the IEC Hot Standby check box.  
When exiting the Configuration Extension dialog with OK, the CHS Hot Standby  
loadable is automatically added to the project, but this requires the loadable being  
part of the Concept environment (refer to Loading the Software, p. 112). There is a  
second loadable with the name IHSB added as well. It is needed for the program  
transfer from Primary to Standby.  
In turn, when the IEC Hot Standby check box is unchecked, the CHS and IHSB  
loadables are removed from the project automatically.  
The following diagram shows the Configuration Extensions dialog box.  
Concept  
Configuration extensions dialog (IEC Hot Standby activated)  
IEC Hot Standby ensures that the Primary and Standby controllers contain identical  
IEC applications so that backup is always available in case of a Primary controller  
failure. The configuration of the IEC Hot Standby must be done with the Hot Standby  
dialog.  
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7.2  
Hot Standby Dialog  
Introduction  
Purpose  
This section describes the Quantum Hot Standby Dialog.  
This section contains the following topics:  
What’s in this  
Section?  
Topic  
Page  
117  
Hot Standby dialog  
Specifying the Command Register  
Hot Standby Command Register  
Enable Keyswitch Override  
Advanced Options Concept 2.5  
Standby on Logic Mismatch  
Swapping Addresses at Switchover  
118  
119  
120  
122  
124  
127  
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Hot Standby dialog  
Activation of Hot  
Standby Dialog  
The Hot Standby dialog is shown below, it can be activated through Configure Hot  
Standby.  
Concept 2.5 shown  
Command Register  
Command Register: 4x  
Run Mode  
Swap Address at Switchover  
Modbus Port 1  
Controller A: Offline  
Modbus Port 2  
Modbus Port 3  
Controller B: Offline  
Standby On Logic Mismatch  
Offline  
Enable Keyswitch Override  
Advanced Options...  
Running  
State RAM  
Non-Transfer Area  
Start: 4x  
Length:  
OK  
Cancel  
Help  
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Specifying the Command Register  
Bits in the Hot  
Standby  
The command register controls various parameters of the Hot Standby system.  
Command  
Register  
Disables keyswitch override = 0  
Enables keyswitch override = 1  
Sets Controller A to OFFLINE mode = 0  
Sets Controller A to RUN mode = 1  
Sets Controller B to OFFLINE mode = 0  
Sets Controller B to RUN mode = 1  
Forces standby offline if there is a logic mismatch = 0  
Does not force standby offline if there is a logic mismatch = 1  
(Supported only with Concept 2.5 or higher)  
Allows exec upgrade only after application stops = 0  
Allows exec upgrade without stopping application = 1  
(Supported only with Concept 2.5 or higher)  
0 = Swaps Modbus port 1 address during switchover  
1 = Does not swap Modbus port 1 address on switchover  
0 = Swaps Modbus port 2 address during switchover  
1 = Does not swap Modbus port 2 address on switchover  
0 = Swaps Modbus port 3 address during switchover  
1 = Does not swap Modbus port 3 address on switchover  
Note: Bit 16 in Modicon convention (shown in the diagram above) is bit 0 in IEC  
convention. Setting bit 16 means writing a 0x0001 into the command register.  
Specify  
Command  
Register  
The command register is specified in the first entry field of the Hot Standby dialog.  
By default, the command register is set to 400001. If register 400001 is used  
elsewhere, enter another number greater than 0. The number you enter becomes  
the 4x command register. For example, if you enter 14, the hot Standby command  
register is 400014.  
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Hot Standby Command Register  
Range  
You may enter any number in the range 1 ... n, where n is the last configured 4x  
register. However:  
the command register must be part of the area of state RAM that gets transferred  
from the Primary to the Standby controller on every scan.  
therefore the command register must not be within the range of the nontransfer  
area, which you specify in the nontransfer area of the Hot Standby dialog.  
CAUTION  
Hot Standby Command Register Hazard  
Be sure the register you select as the Hot Standby command register is  
reserved for this purpose and not used for other purposes elsewhere in  
user logic  
Failure to follow this precaution can result in injury or equipment  
damage.  
Keyswitch  
Override and  
Run Mode  
You may choose to override the keyswitch on the front panel of the CHS 110  
modules for security or convenience. If you override the keyswitch, the command  
register becomes the means for taking the CHS 110 modules on or offline.  
By default, the keyswitch override is disabled. The Hot Standby dialog allows you to  
enable it.  
If you enable the keyswitch override, the Offline/Running operating mode of the  
controllers at startup are determined by the values you set to bits 14 and 15 of the  
command register. These bits are represented as the Run Mode for controller A and  
B (depending on the designation slideswitch). Remember, that when the keyswitch  
override is enabled you cannot initiate a program update (program xfer) at the CHS  
110 module in the Standby rack.  
As long as the keyswitch override is disabled the settings for the Run Mode may be  
ignored.  
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Enable Keyswitch Override  
Keyswitch  
Override  
CAUTION  
Animation Mode or Reference Data Editor Hazard  
If you use the animation mode or reference data editor (RDE) of  
Concept to enable the keyswitch override while the Hot Standby system  
is running, the Primary controller immediately reads bits 14 and 15 to  
determine its own state and the state of the Standby.  
Failure to follow this precaution can result in injury or equipment  
damage.  
If both bits are set to 0, a switchover occurs and the former Primary backplane goes  
offline. The new Primary backplane continues to operate.  
A Software  
For example:  
Control Example  
You have enabled the keyswitch override and set the operating mode of controller  
B to Offline. Now the system is powered up and you want to put controller B in RUN  
mode.  
The keyswitch does not work, so you must rely on user logic. There are two ways  
you can proceed.  
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Options for  
Software Control  
Example  
Option 1  
Stage  
Description  
Comment  
1
Change the setting on the Hot  
Standby dialog.  
To do this, you must shut down the  
system and make the necessary change  
in the dialog, then power up the system  
again.  
2
Download the new configuration.  
Option 2  
Stage  
Description  
Comment  
1
Connect Concept to your Primary  
controller.  
2
3
Call up the Reference Data Editor  
(RDE).  
Place the Hot Standby command  
register and the Hot Standby status  
register in the RDE.  
The operating mode of controller B is  
determined by the state of bit 14 of the  
command register. If controller B is  
offline, bit 14 is set to 0.  
4
To put the controller in RUN mode,  
change the state of bit 14 to 1.  
Controller B immediately goes into RUN  
mode.  
Note: The advantage of option 2 is that the Hot Standby system does not have to be  
shut down in order to change its status.  
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Advanced Options Concept 2.5  
Advanced  
When selecting the Advanced Options button in the Hot Standby dialog you get the  
Options button  
opportunity to allow different firmware versions on the Primary and Standby  
controller while running in full Hot Standby mode.  
Advanced Options  
WARNING!!  
Selecting “Without Stopping” overrides  
all safety checking between  
Primary and Hot Standby controllers.  
Use with extreme caution!!!  
Exec Upgrade  
Without Stopping  
Application Stopped  
Cancel  
Help  
OK  
This lets you upgrade the controllers step by step to a new firmware version without  
having to shutdown the system. Since this is only necessary in rare situations, it is  
recommended that you disable this mode by configuration and to enable it by the  
reference data editor when needed. By default, the controllers must have the same  
versions of firmware. This means the Standby controller would not go online while  
having a newer or older firmware version than the one on the Primary controller.  
Note: This option is available only in Hot Standby systems already running with  
Concept 2.5.  
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IEC HSBY  
System  
The following table shows the steps to upgrade the controller’s executive in an IEC  
HSBY system. Note: You must first have both controllers running in Concept 2.5.  
Executive  
Upgrade  
Procedure  
Step  
Action  
1
Connect to the Primary controller with Concept and use the reference data editor  
to set bit 12 of the Hot Standby command register to 1.  
2
3
Disconnect from the Primary controller.  
Use the Executive Loader to download the new executive to the Standby  
controller.  
4
Connect to the Standby controller with Concept and download the project.  
NOTE: Projects developed with versions of Concept earlier than 2.5 must be  
imported into Concept 2.5 using the Converter.  
5
6
Start the Standby controller.  
Verify that the Standby controller is in Run Mode and the CHS module indicates  
that the Standby Controller is now in Standby mode.  
7
8
9
Disconnect from the controller.  
Initiate a Hot Standby switchover using the Key Switch.  
Download the Executive to the new Standby Controller using the Executive  
loader.  
10  
11  
Use the transfer button on the CHS module to transfer the program to the  
Standby controller. Verify that the Standby controller is in Run Mode and the  
CHS mode indicates that the Standby Controller is now in Standby Mode.  
The Hot Standby Controller Executives have now been uprgaded without  
stopping the process.  
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Standby on Logic Mismatch  
Overview  
To function properly, the Primary and the Standby controller in a Hot Standby  
system must be solving an identical program, which is updated on every scan by a  
state RAM data transfer between the two controllers.  
By default, the Standby controller is set to go Offline if a mismatch is detected  
between its program and that of the Primary controller. Switchover cannot occur  
while the Standby controller is Offline.  
CAUTION  
I/O Map / Configuration Hazard  
A mismatch in the I/O map or configuration is not allowed under any  
circumstances.  
Failure to follow this precaution can result in injury or equipment  
damage.  
CAUTION  
Switchover Hazard  
If switchover occurs when the radio button is set to Running and there  
is a logic mismatch between the two controllers, the Standby controller  
will assume Primary responsibilities and will start solving a different  
logic program from the previous Primary controller.  
Failure to follow this precaution can result in injury or equipment  
damage.  
Logic Mismatch  
for Concept 2.5  
Concept 2.5, and the new PLC Executives delivered with it, support the Standby on  
Logic Mismatch option in the Hot Standby Configuration Extension. Logic mismatch  
allows you to make online changes to the program of the Standby or Primary  
controller while the HSBY system continues to run the process. The Standby on  
Logic Mismatch option also allows up to date process data to be transferred from the  
Primary controller after download of the modifications.  
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Updating Project  
Section Data  
All DATA of a section will be fully updated every scan if it is equal to its counterpart  
on the Primary controller. Section DATA will not be updated at all if it is not equal to  
its counterpart on the Primary controller.  
The section data that is updated if the sections are equal on Primary and Standby  
controllers is:  
Internal states of Elementary Function Blocks (EFBs) used in the section (Timers,  
Counters, PID, etc.)  
All Derived Function Block (DFB)-Instance data blocks of each DFB instantiated  
in the section including nested DFBs  
Hot Standby behavior for the section update process is:  
With matching logic, all section data gets updated on the Standby controller  
After you do an online change to a section, none of its local data gets updated.  
To get it updated again, the controllers’ logic has to be equalized via the CHS  
transfer button or a complete download to the Primary controller with differing  
logic.  
It is not possible to make online changes to one controller and the same online  
changes to the other controller to get matching logic again. To equalize both  
controllers, you should either push the Transfer button of the CHS module or do  
a completer download to the controller which did not receive the download  
changes.  
The change of a literal during animation (called quickwrite) will cause the whole  
section not to be updated or transferred to the Standby Controller.  
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Updating Project  
Global Data  
With a logic mismatch, project global data will be updated with every scan. Global  
data that do not exist on both controllers is not updated.  
The project global data that is updated includes:  
All variables declared in the Variable-Editor  
All Constants declared in the Variable Editor  
All section and transition variables  
Hot Standby behavior for project global data updating is:  
All declared variable/constant will be updated every scan as long as they are  
declared on both controllers  
If a complete download is done to the controller that did not receive the download  
change, then both controllers will have equal logic and therefore the Standby  
controller gets updated fully.  
If, due to a download change, a project global variable/constant has been deleted  
first, and then redeclared, this variable/constant would be treated as a NEW  
variable/constant, even if the same name is used. The update procedure must be  
followed to bring the controllers to an equalized state.  
Note: This is true whether these variables/constants are used in the controller  
program or not. Unused variables consume space and require time to be  
transferred from the Primary to the Standby controller. It is not recommended to  
have many variables that are defined but not used in the Primary controller  
program.  
NontransferArea Although customizing transfers is not an option, you should designate a block of 4x  
of State RAM  
registers as the nontransfer area. These registers are ignored when state RAM  
values are transferred from the Primary controller to the Standby. Placing registers  
in the nontransfer area is one way to reduce scan time because the Primary PLC to  
CHS transfer time is shorter. See State RAM, p. 129 for more detail.  
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Swapping Addresses at Switchover  
Modbus Port  
In a Hot Standby system, the Modbus ports on the Primary controller may have  
Swap Address at MEM addresses in the range of 1 to 119. This allows an offset of 128 for comparable  
Switchover  
ports on the Standby controller, with 247 the maximum number of addresses.  
For example, if controller A is the Primary controller and its two Modbus ports have  
addresses 1 and 2, then the default addresses for the comparable ports on Standby  
controller B are 129 and 130. By default, this offset is maintained between port  
addresses in the event of switchover. For example, if controller B becomes the  
Primary controller as the result of switchover, its Modbus ports assume the  
addresses of 1 and 2, and the comparable ports on controller A assume addresses  
129 and 130.  
The three check boxes allow you to change this default condition on any or all of the  
Modbus ports on the two controllers in your Hot Standby system.  
For example, if you deselect the parameter Modbus Port 1, then no offset is  
maintained at switchover and after switchover the two ports have the same address.  
Thus if controller A is the Primary controller and its Modbus port 1 address is 1, then  
that port address remains 1 after a switchover occurs. Likewise, if controller B  
becomes the Primary controller as a result of switchover, its Modbus port 1 address  
is also 1.  
Note: If you change the selections, the port addresses are not affected until a  
switchover occurs.  
Modbus Plus  
Port Address  
Swapping at  
Switchover  
In a Quantum Hot Standby system, the Modbus Plus port addresses on the Standby  
controller are offset by 32 from the comparable ports on the Primary controller. For  
example, if controller A is the Primary controller and its Modbus Plus port has  
address 1, then the address for the corresponding port on Standby controller B is 33.  
The numerical range for addresses for both ports is 1 through 64. Thus, if the port  
on the Primary controller has address 50, then the address for the corresponding  
port on the Standby can not be 82, so it will be 18 (that is, 50 minus 32).  
These addresses are automatically swapped at switchover; you do not have the  
option to change the offset or prevent the addresses from being swapped  
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Note: The Quantum Hot Standby system swaps Modbus Plus addresses almost  
instantaneously at switchover. This means that host devices which are polling the  
Quantum controller can be assured that they are always talking to the Primary  
controller and that the network has no downtime during switchover.  
IP Address  
Swapping at  
Switchover  
The Quantum network option module NOE 771 (Ethernet TCP/IP) supports address  
swapping at switchover when used in a Hot Standby system. This behaves pretty  
much like the address swap of the Modbus Plus ports, except that the offset is 1  
instead of 32. So when having the NOE 771 installed with an IP address of  
AAA.BBB.CCC.DDD configured, the module in the Primary rack is going to take that  
one. The module in the same slot of the Standby rack takes address  
AAA.BBB.CCC.(DDD+1). In case DDD = 254, (DDD+1) is going to be 1, and at  
switchover the modules exchange their IP addresses. The address swap feature of  
the NOE 771 cannot be controlled, it is always activated.  
Note: NOE 771 XX is the only Ethernet option module that supports the IP address  
swap, all other NOEs will take the IP address that’s being configured for them, no  
matter if they reside in the Standby or Primary rack.  
NOE 771 XX modules must be configured in the same slot of the Primary and  
Standby Backplanes.  
NOE 771 XX requires minimum firmware revision 1.10 or higher.  
Note: Even if the built in I/O-Scanner of the NOE 771 00 module is used for data  
exchange or I/O modules, this mechanism does not provide full uninterrupted  
communication in case of a switchover. Some connection losses may occur and/  
or some non-actual data may be provided by the I/O-Scanner. Therefore,  
Schneider Electric does not recommend applying this feature for I/O serving.  
NontransferArea Although customizing transfers is not an option, you should designate a block of 4x  
of State RAM  
registers as the nontransfer area. These registers are ignored when state RAM  
values are transferred from the Primary controller to the Standby. Placing registers  
in the nontransfer area is one way to reduce scan time because the Primary PLC to  
CHS transfer time is shorter. See State RAM, p. 129 for more detail.  
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7.3  
State RAM  
Introduction  
Purpose  
This section describes Quantum IEC Hot Standby State RAM.  
This section contains the following topics:  
What’s in this  
Section?  
Topic  
Page  
130  
Nontransfer Area of State RAM  
Hot Standby Status Register  
Memory Partition  
132  
133  
134  
State RAM Size  
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Nontransfer Area of State RAM  
Nontransfer Area The nontransfer area contains the Hot Standby status register, which is used to  
monitor the states of both controllers. You may include other 4x registers in the  
nontransfer area to reduce scan time.  
The Start: field is used to specify the first 4x register in the nontransfer area. The  
Length: field is used to define the number of contiguous registers in the nontransfer  
block. If you choose to define a nontransfer area, the range of legal values for this  
entry field is 4... n, where n is the number of configured 4x registers. However, when  
defining the nontransfer area, the command register (first entry of the Hot Standby  
dialog) must be outside the nontransfer area.  
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The following block diagram shows how the nontransfer area exists with respect to  
the rest of the state RAM transfer area.  
State RAM Transfer Area  
0nnnnn  
1nnnnn  
3nnnnn  
Actual transferred registers  
Nontransfer area is excluded from  
state RAM transfer  
Total number of configured  
4x registers  
Actual transferred registers  
4nnnnn  
Note: The command register must not be placed in the nontransfer area. No more  
than one block can be defined as the nontransfer area.  
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Hot Standby Status Register  
Hot Standby  
The third register in the nontransfer area is the Hot Standby status register. Use this  
Status Register  
register to monitor the current machine status of the Primary and Standby  
controllers.  
This PLC in OFFLINE mode  
This PLC running in primary mode =  
This PLC running in standby mode =  
=
0
1
1
1
0
1
The other PLC in OFFLINE mode =  
The other PLC running in primary mode =  
0
1
1
0
The other PLC running in standby mode =  
1
1
PLCs have matching logic =  
0
1
PLCs do not have matching logic =  
(Supported only with Concept 2.5 or higher)  
This PLC’s switch set to A =  
0
This PLC’s switch set to B =  
1
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16  
The CHS interface is healthy =  
An interface error has been detected =  
0
1
Hot standby capability has not been activated =  
Hot standby is active =  
0
1
Note: Bit 16 in Modicon convention (shown in the diagram above) is bit 0 in IEC  
convention. Setting bit 16 means writing a 0x0001.  
IEC Heap Size  
As described in Theory of IEC HSBY Operation, p. 43, the IEC Heap is transferred  
from the Primary to the Standby controller through a reserved partition of state RAM.  
This partition consists of a contiguous block of 3x registers, they are the so called  
IEC HSBY Registers. Since they are part of state RAM, they are never more than  
64K words (128 KByte). To ensure full data consistency in case of a switchover, all  
data of the Primary’s IEC application must be transferred to the Standby in every  
scan. The IEC heap, which contains all the to-be-transferred data, may not be bigger  
than the transfer buffer that carries the IEC heap from the Primary to the Standby  
controller (64K words).  
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Memory Partition  
IEC HSBY  
Registers  
The number of IEC HSBY Registers (size of transfer buffer) is set to the maximum  
whenever the IEC Hot Standby configuration extension is activated the first time for  
a particular project. So after having the IEC Hot Standby configuration extension  
activated, the state RAM is fully occupied with the default values for 0x, 1x, 3x, 4x  
and the remaining maximum for IEC HSBY Registers (3x). The dialog that follows  
shows how the number of IEC HSBY Registers can be modified.  
The diagram below shows a PLC Memory Partition.  
Concept shown  
Note: The higher the number of IEC HSBY Registers (IEC Hot Standby Data in the  
above dialog) the bigger the transfer buffer for the IEC heap and therefore the  
bigger the IEC application may be. See State RAM, p. 155.  
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State RAM Size  
State RAM Size  
Note: The size of the configured state RAM in an IEC Hot Standby project has a  
significant impact on the system’s scan time. Once a logic scan is finished, the next  
does not start before all state RAM data has been transferred to the CHS module.  
Once the number of IEC HSBY Registers has been set, you may deactivate the IEC  
Hot Standby configuration extension and activate it again later, the number of IEC  
HSBY registers remains the same.  
The following diagram shows the IEC State RAM Map.  
State RAM  
(compl. xferred)  
Safety buffer  
Header  
for future  
changes/  
additions  
(Exec vers.,  
Program data  
used  
timing info,...)  
prog. data  
configured  
Program data  
unused  
DFB instance  
data  
No. 3x regs  
configured for  
IEC HSBY  
free memory  
for addtl. DFB  
instance data  
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7.4  
Section Transfer Control  
Section Transfer Control  
Section Transfer  
Control  
Description  
A new function has been added with Concept 2.5 that allows the selection of  
section(s) that will not be transferred from the Primary controller to the Standby  
controller with the exception of SFC sections. SFC sections are always transferred  
every scan.  
A benefit of selecting section(s) to not be transferred is that it allows you to reduce  
the number of IEC Hot Standby registers in the configuration and thus reduce Hot  
Standby scan time. The type of sections that should be slected for non-transfers are  
those that do not have to be updated for every scan, i.e., Section that loads recipe.  
This new function should be used along with guidelines for optimizing an IEC  
application for IEC Hot Standby Operation to reduce HSBY scan time found in  
Additional Guidelines for IEC Hot Standby , p. 147.  
Using Section  
Transfer Control  
The use of this feature requires initial planning of your Hot Standby project to insure  
that logic not requiring an update fore every scan is segregated into its own  
section(s) so that they can be selected for non-transfer. Logic elements that can be  
used in non-transfer sections are those that have no internal states (e.g., contacts,  
coils, etc.). Logic elements that should not be used in non-transfer sections are  
those that have internal states (e.g., timers, counters, etc.) since the internal state  
needs to be updated on every scan.  
After sections are selected for nontransfer, the number of IEC Hot Standby registers  
can be reduced. To insure that you have enough IEC Hot Standby registers  
configured, go to the Memory Prediction dialog to view Hot Standby Memory usage.  
See Normal Operation, p. 140. Additionally, you can perform an analyze program  
under the project menu item. If you do not have enough IEC Hot Standby registers,  
then you will receive an error message. This message will indicate the minimum  
number of registers needed. A safety buffer should be added to this value to  
configure space for future program modifications. The reduction of the IEC Hot  
Standby registers is a change in the configuration and requires a complete  
download of the project (i.e. the Hot Standby process has to be stopped). Selecting  
sections to be not transferred without reducing IEC Hot Standby registers has no  
effect on the Hot Standby scan time.  
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The section data that will not be transferred when its Update (Hot Standby) control  
is set to no Update are:  
internal states of EFBs used in the section  
links  
All DFB-Instance data blocks of each DFB instantiated in the section including  
nested DFBs local Variables inside any DFB instantiated in the section.  
Section Hot Standby transfer status is changed using the Project Browser. Offline  
with Hot Standby project open, open the Project Browser. With your mouse, select  
the section whose Hot Standby tranfer status you want to modify and right click.  
Click on Update (Hsby) to change Transfer State. The Project Browser can also be  
used to view a project’s section(s) Hot Standby Transfer State. Sections that will not  
be transferred will have a "!" to the left of the section name. See the screen shot of  
the Project Browser below.  
Project Browser  
Project: HSBYEXEC  
stby  
monitor  
LD  
SCB4  
sysseg4  
LD  
Open  
FBD pump  
Minimize  
Close  
FBD fan0  
damp  
sump  
FBD  
FBD  
Move  
Properties  
scr5  
Memory prediction  
syss  
pump  
fan0  
LD  
FBD  
FBD  
FBD  
FBD  
Delete  
Update (Hsby)  
damper05  
sump05  
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Transfer Status  
Byte  
The Section Hot Standby Transfer Status Byte can be read by an operator panel or  
by Data Acquisition System. The purpose of the byte is to provide feedback to the  
Application to indicate whether the Section Data is being transferred to the Standby  
controller. If a fault occurs, then the Primary Controller Application or the SCADA  
System will take appropriate measures to indicate a fault.  
A fault could occur if:  
the programmer disables the section from transferring  
modifications are made to the sections but changes are not downloaded to both  
controllers. This would cause the primary and the standby sections to be  
different.  
the Standby controller is not present  
In the example below, the section name is LD1. To access this in the Primary  
Controller application you would use the variable LD1.hsbyState.  
Select Component of Type BOOL  
Components  
LD1: SECT CTRL  
disable: BOOL  
OK  
hsby State: BYTE  
Cancel  
Help  
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7.5  
Operation  
Starting Your Hot Standby System  
Preconditions  
Note: Start one controller at a time.  
Be sure  
the controller you are starting first has been fully programmed;  
the function keyswitch on the CHS 110 module is in the Run position;  
the designation slide switches on CHS 110 modules are in opposite positions.  
Starting the  
System  
The first controller to power up, automatically becomes the Primary controller,  
regardless of its designation as A or B.  
Step  
Action  
1
Turn on power to the first backplane.  
Start the controller in that backplane.  
Turn on power to the second backplane.  
2
3
4
Transfer the program from the Primary to the Standby controller by putting the  
keyswitch in transfer position and pressing the update push button on the  
Standby’s CHS module (refer to Using a Quantum 984 HSBY System, p. 67).  
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Start Standby  
The following table shows the steps to starting Standby.  
Step  
Action  
1
Start the Standby controller.  
2
Check the LED display. If the system is functioning normally, the display should  
be as follows:  
On the CHS 110 module, all three indicators should be steady, not blinking.  
A blinking Com Act light signals that your system has detected an error.  
On the corresponding CRP module, the Ready indicator is a steady green.  
The Com Act indicator on the Primary unit should also be a steady green,  
while the Com Act indicator on the Standby RIO head should be blinking  
slowly  
Illustrations of the Primary and Standby Backplanes are shown below.  
Primary  
Backplane  
140  
CHS 110 00  
HOT STANDBY  
Active  
RIO Head  
HOT STANDBY  
Active  
Ready Fault  
Ready Fault  
Run  
Bal Low  
Run  
Bal Low  
Pwr ok  
Pwr ok  
Modbus Com Err  
Modbus! Error A  
Com Act Error B  
Primary  
Modbus Com Err  
Modbus! Error A  
Com Act Error B  
Primary  
Mem Prt Standby  
Mem Prt Standby  
Standby  
Backplane  
140  
CHS 110 00  
HOT STANDBY  
Active  
RIO Head  
HOT STANDBY  
Active  
Ready Fault  
Ready Fault  
Run  
Bal Low  
Run  
Bal Low  
Pwr ok  
Pwr ok  
Modbus Com Err  
Modbus! Error A  
Com Act Error B  
Primary  
Modbus Com Err  
Modbus! Error A  
Com Act Error B  
Primary  
Mem Prt Standby  
Mem Prt Standby  
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7.6  
Normal Operation  
Introduction  
Purpose  
This section describes Quantum IEC Hot Standby normal operation.  
This section contains the following topics:  
What’s in this  
Section?  
Topic  
Page  
141  
Memory/Scantime optimization  
Synchronizing Time of Day Clocks  
While Your System Is Running  
145  
146  
140  
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Memory/Scantime optimization  
IEC State RAM  
Map  
An illustration of the IEC State RAM Map.  
State RAM  
(compl. xferred)  
Safety buffer  
for future  
changes/  
additions  
Header  
(Exec vers.,  
timing info,...)  
Program data  
used  
prog. data  
configured  
Program data  
unused  
DFB instance  
data  
No. 3x regs  
configured for  
IEC HSBY  
free memory  
for addtl. DFB  
instance data  
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IEC application  
data  
To maintain consistency of the IEC application’s data between the Primary and  
Standby controllers the IEC heap is transferred through a reserved area in the 3x-  
register range, the so called IEC HSBY Registers. The size of this reserved area is  
assigned in the PLC Memory Partition dialog (refer to Additional Guidelines for IEC  
Hot Standby , p. 147). The size of the IEC HSBY Registers can never be smaller  
than the size of the IEC heap (application data), otherwise the copy-and-transfer  
mechanism does not work.  
The size of the configured state RAM has a significant impact on a Hot Standby  
system’s scan time: The more memory (state RAM) that is transferred on every  
scan, the slower the scan (for details refer to Theory of IEC HSBY Operation, p. 43).  
If future modifications to the IEC application are expected to be small, the safety  
buffer can be correspondingly less, reducing the general memory transfer size. The  
term "future modification" focuses on changes to the system that do not need the  
Primary controller to be stopped, which is a "download change".  
You should try to reduce the size of configured 3x-Registers for IEC usage by  
adjusting it to what’s really used in terms of your particular needs regarding future  
modifications. That’s why the term "safety buffer" is used with IEC Hot Standby. The  
diagram above illustrates that the unused parts of the program data and DFB  
instance data areas make up the safety buffer. The important thing is that the size  
of the safety buffer is a configuration item, therefore it cannot change without  
shutting down the system, just as with any other configuration change.  
Memory  
To help optimize the size of the safety buffer and therefore the total amount of IEC  
Prediction Dialog HSBY Registers to be transferred, use the Memory Prediction dialog to determine  
an appropriate final configuration. This optimization with Concept 2.5 can be done  
offline.  
The Memory Prediction dialog shows in the Hot Standby Memory section the  
numbers of bytes configured and used. To determine the number of 3X registers,  
divide the number of bytes by two. As shown below, there are 10000 IEC HSBY  
registers configured and 78.3% of them are used. There is, therefore, a safety buffer  
of approximately 22% of the registers to allow for future application changes. After  
making changes to the IEC HSBY registers in the configuration, reinvoke the  
Memory Prediction dialog to view the effect on the Hot Standby Memory.  
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A screenshot of the Memory Prediction dialog is shown below.  
Memory Prediction  
IEC Memory  
Available:  
Free:  
545116 Byte  
---- Byte  
100.0 %  
---- %  
Used:  
System:  
1024 Byte  
---- Byte  
0.2 %  
---- %  
0.2 %  
Section Code:  
Section Data:  
DFB Code:  
DFB Instance data:  
EFB Library:  
1088 Byte  
---- Byte  
6380 Byte  
7768 Byte  
0 Byte  
---- %  
1.2 %  
1.4 %  
0.0 %  
Upload information:  
Diagnostic information:  
Recommended reserve:  
0 Byte  
0.0 %  
0.8 %  
4096 Byte  
Reusable after optimization:  
0 Byte  
0.0 %  
LL 984 Memory  
Available:  
Used for code:  
63198 Byte  
0 Byte  
100.0 %  
0.0 %  
Global Data  
Configured:  
Used:  
20000 Byte  
44 Byte  
100.0 %  
0.2 %  
Reusable after optimization:  
0 Byte  
0.0 %  
Hot Standby Memory  
Configured:  
Used:  
10000 Byte  
7831 Byte  
100.0 %  
78.3 %  
OK  
Details  
Help  
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Memory  
Memory Statistics HSBY (online) used for downsizing the number of 3x-Registers  
Statistics  
for IEC Hot Standby data.  
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Synchronizing Time of Day Clocks  
Primary and  
Secondary  
controller time-  
of-day clocks  
In a Hot Standby system, although the Primary and Secondary controllers have their  
own time-of-day clocks, they are not implicitly synchronized. At switchover, the time  
of day changes by the difference between the two clocks. This could cause  
problems if you are controlling a time-critical application.  
Assign the time-of-day clock eight 4x registers in the Specials dialog of the  
configurator. Be sure that none of these 4x registers resides in the nontransfer area,  
all of them need to be transferred to the Standby controller after each scan. Then  
use somewhere in the IEC logic the ‘SET_TOD’ EFB, which resides in the system  
library under the HSBY group.  
Elementary  
While the full IEC Hot Standby system is running, meaning the Standby controller is  
also online, your application logic should trigger (rising edge of the S_PULSE input)  
the EFB. This would then not only set the time-of-day clock in the Primary, but the  
one in the Standby as well, at the same time. The trigger on the clocks might again  
run at slightly different speeds, this time-set process should be repeated  
periodically, for example within a period of 1 minute.  
Function Block  
(EFB) to set the  
PLC’s time-of-  
day clock  
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While Your System Is Running  
ConstantInternal After your Hot Standby system has been started and is running normally, it  
Monitoring  
continues to function automatically. It constantly tests itself for faults and is always  
ready to transfer control from the Primary to the Standby if it detects a fault.  
Regular Data  
Transfers  
While the system is running, the module automatically transfers all state RAM to the  
Standby unit at the end of each scan. This ensures that the Standby is aware of the  
latest conditions and is ready to take control if needed.  
If one or both of the links between the Hot Standby modules is not functioning, the  
Primary controller functions as though no backup is available.  
If the Primary controller fails, the Standby automatically assumes control of the  
remote I/O network. If the Primary controller recovers from failure, and a power cycle  
is completed, then it assumes Standby responsibilities. If it cannot recover, it  
remains offline.  
If the Standby controller fails, it goes offline. The Primary controller functions as a  
standalone and continues to manage the I/O networks.  
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Additional Guidelines for IEC Hot  
Standby  
8
At a Glance  
Purpose  
This Chapter discusses optimizing an IEC application to run better in an IEC Hot  
Standby environment, and specifically, how to save data memory. This includes  
existing and newly developed IEC applications.  
What’s in this  
Chapter?  
This chapter contains the following sections:  
Section  
8.1  
Topic  
Page  
149  
General Application Requirements  
State RAM  
8.2  
155  
157  
8.3  
Efficiency Tips  
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Additional Guidelines for IEC Hot Standby  
8.1  
General Application Requirements  
Introduction  
Purpose  
This section describes general application requirements for an IEC Hot Standby  
system.  
What’s in this  
Section?  
This section contains the following topics:  
Topic  
Page  
150  
Memory Savings  
Memory Statistics  
Memory Partition  
151  
153  
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Additional Guidelines for IEC Hot Standby  
Memory Savings  
Memory Savings  
The reasons that memory savings are important to IEC Hot Standby are:  
The full amount of data memory is restricted to what the IEC HSBY Register can  
be set to, which can never exceed 64K words (128K).  
The bigger the configured state RAM is, the higher the overall scan time. Since  
the IEC HSBY Registers are part of the state RAM, the overall scan time gets  
lower with every saved byte of data memory.  
The restriction of the size of executable code to a maximum of 568K is not important,  
since any IEC application is closer to the limit of 128K of data than to the limit of  
568K executable code. Therefore all optimization in terms of either making a bigger  
IEC application fit into the IEC Hot Standby environment or just to make an existing  
application run faster in IEC Hot Standby mode will decrease the size of data  
memory.  
Assessing  
Existing IEC  
Applications  
The assessment of an existing IEC application that will be put into IEC Hot Standby  
mode is fairly simple. Just download the application to the CPU 534 14 or 434 12 or  
into the 32 bit simulator with one of the Quantum CPUs selected. This requires  
having IEC Hot Standby not activated in the configuration. Once the application is  
downloaded, you can view the memory consumption in the Memory Statistics dialog  
while being "Equal" connected to the PLC (or the simulator).  
The diagram below shows the Memory Statistics dialog after having an example  
application downloaded to the PLC. The consumption for executable code of this  
particular application is:  
357,724 bytes (user program)  
+14,980 bytes (EFB library)  
= 372,704 bytes (used for executable code)  
The executable code’s size is less than the limit of 568K, therefore the application  
fits the IEC Hot Standby requirements.  
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Memory Statistics  
Memory  
The following screen shows memory statistics.  
Concept shown  
Statistics  
Data Memory  
The consumption of data memory is:  
54,305 bytes (DFB instance data)  
+ 22,496 bytes (program data used)  
= 76,801bytes (used for data)  
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Data Memory,  
Continued  
This value alone is not enough to verify whether or not the application fits, since we  
need to know how many IEC HSBY Registers (3x) can be reserved to carry the data  
from the Primary to the Standby controller. The diagram below shows that 11,022  
words out of 65,024 are already taken for I/O references and located variables.  
Therefore the maximum for IEC HSBY Registers would be 65,024 – 11,022 =  
54,002 words ~ 108,000 bytes. This is more than what is actually used for  
application data (76,801 bytes), so that the application would fit IEC Hot Standby  
requirements.  
The maximum size of the safety buffer for future modifications would be:  
108,000 – 76,801 = 31,199 bytes which is (31,199 / 76,801) ~ 41%  
Depending on how much safety buffer is required for this particular application, the  
final size of the IEC HSBY Registers could be determined. That, together with the  
table presented in Theory of IEC HSBY Operation, p. 43, would give an idea about  
the application’s overall scan time when operated in IEC Hot Standby mode.  
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Memory Partition  
Memory Partition The following screen shows a PLC Memory Partition.  
Concept shown  
IEC Applications  
Optimization  
Optimization of IEC Hot Standby applications concentrates on two issues:  
Very efficient use of state RAM for purposes other than IEC HSBY Registers (See  
#1, following)  
Very efficient use of IEC application data (See #2, following)  
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IEC Applications  
Optimization,  
Continued  
1. There are 64K words of state RAM as a maximum for IEC HSBY Registers in an  
IEC Hot Standby application. Using as little state RAM as possible for other  
purposes besides IEC HSBY Registers, allows running medium sized IEC  
applications in IEC Hot Standby mode. When using the IEC application data very  
efficiently, the size of the application can grow from medium to large.  
2. To optimize an IEC application to consume as little memory as possible takes  
some effort and may reduce the maintainability of the application. Therefore you  
should always try to reduce data memory to what is needed. The efficient use of  
the State RAM, as described in the following section, should be considered  
whenever possible. It provides large data memory benefits compared to the work  
needed to achieve it.  
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8.2  
State RAM  
Efficient Use of State RAM  
Configured State Since in IEC Hot Standby, all the configured state RAM registers and bits are  
RAM Registers  
transferred on every scan from the Primary to the Standby, it is worth having every  
part of that area provide a purpose for the application. Sometimes application  
designers decide to have gaps between the I/O references of each RIO drop, for  
future changes, but usually those gaps never get filled up, so there is always a  
certain amount of unused state RAM references. However, unused references  
require memory space, and are transferred every scan, which increases the overall  
scan time.  
The better method is to assign contiguous I/O references without gaps. This means  
the designer should not be concerned about the actual reference number an I/O  
point occupies. Just give it a number and a name, and reference it in the IEC logic  
by name. This way, whenever the actual state RAM reference number changes, it  
would not have any impact on the logic itself, because the name does not change.  
The positive effect is that all the configured state RAM is actually used and Ram size  
therefore minimized.  
In Concept 2.1, this downsizing of the configured state RAM is especially important  
with coils (0x) and discretes (1x). In that and earlier versions of Concept, these state  
RAM references are not accessed directly, but rather indirectly through the so called  
"Mirror Buffer". This is a continuous block of memory (part of DFB instance data) in  
which, at the beginning of every scan the 0x and 1x states are copied (mirrored). At  
the end of every scan, the states of the mirror buffer are copied back into the 0x and  
1x area. During the scan the IEC logic accesses the mirrors of the 0x and 1x  
references, instead of accessing them directly. The data memory behind the mirror  
buffer is that every coil and discrete is represented by a byte in the mirror buffer, not  
by a bit. The reason for this was to facilitate generation of the IEC application  
executable code.  
Note: In Concept 2.1 each configured 0x/1x reference consumes per default 1 byte  
of the DFB instance data area, which is IEC data and is going to be transferred from  
Primary to Standby on every scan and that in turn extends the overall scan time. It  
does not matter whether a particular discrete reference is used in IEC logic or not,  
when it’s configured it takes one byte in the mirror buffer.  
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Configured State With Concept 2.2 the mirror buffer does not exist anymore, but it’s still worth not  
RAM Registers,  
Continued  
having significantly more state RAM references configured than actually used.  
The actual use of state RAM references should concentrate on I/O purposes only  
and not on storing some application data, just to make it accessible for a SCADA  
system. The better way would be to use any kind of application related data, which  
includes everything except I/O points, pure IEC variables (non located variables).  
The connection to the SCADA system can then be accomplished more easily with  
an OPC (OLE for Process Control) server, that accesses certain application data by  
name and not by location. This method of SCADA connection is very flexible and  
reliable and saves state RAM, which is good for IEC Hot Standby applications.  
Efficient Use of  
IEC Application  
Data  
There is one thing that can reduce the IEC application data consumption better than  
anything else:  
Program only what’s really necessary to control a particular process.  
When learning about IEC compliant programming and the different EFBs in the  
different libraries, concentrate on which EFBs not to use. This will help you reduce  
the size of an application to the necessary minimum.  
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8.3  
Efficiency Tips  
Introduction  
Purpose  
This section describes efficiency tips for the IEC Hot Standby.  
This section contains the following topics:  
What’s in this  
Section?  
Topic  
Page  
158  
Use Constants Instead of Equal Literals  
Use Constants Instead of Open Inputs  
Programmed Logic  
159  
161  
162  
Reduce the Use Of Complex Data Structures  
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Use Constants Instead of Equal Literals  
Equal Literals  
In the diagram below, when multiple EFB instances use the same fixed value as  
input, they are using equal literals. This is not much logic, but there is already a lot  
of data to save, actually it’s 12 bytes. The trick is to declare a constant of type REAL  
with the value 1.0 and use that in the logic instead of always assigning equal literals  
to the inputs.  
The point is: Every literal, no matter what value it has, is stored separately in data  
memory (program data area), this brings up the advantage that it could be modified  
due to a download change. Literals are rarely modified, therefore the modified logic  
in the diagram below would be more appropriate.  
The four times allocated literal with the value 1.0 has been replaced with a one time  
allocated constant that has the value 1.0 as well. This little change saved 12 bytes  
of data memory, since the type REAL takes 4 bytes and now needs to be allocated  
3 times less.  
.1.7  
.1.9  
MUL_REAL  
ADD_REAL  
real_A  
1.0  
real_B  
real_C  
1.0  
real_D  
.1.8  
.1.10  
SUB_REAL  
ADD_REAL  
real_E  
1.0  
real_F  
real_G  
1.0  
real_H  
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Use Constants Instead of Open Inputs  
Programmed  
Logic  
The number of unused pins should be reduced to the absolute minimum, so as to  
not waste any memory for hidden allocated memory that is used nowhere.  
But there are some cases where this is just not possible, as in the example below.  
Therefore the logic should look like the diagram below.  
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Programmed  
The only problem with logic programmed like that is, for every open pin there is as  
Logic, Continued much memory allocated as its data type requires. In this case there are 13 bytes of  
unused memory allocated. To reduce those 13 bytes to just 1 byte means  
connecting a constant to every open pin that makes the logic work as if the pin was  
open. This is always equivalent to zero, or FALSE in this case.  
Therefore, the logic should look like the diagram below.  
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Programmed Logic  
Reduce DFB  
Instances  
Every DFB instance consumes a certain amount of overhead data memory, which  
grows with the number of input and output pins. To make the ratio between the fixed  
overhead and the DFB internal logic’s data as small as possible, DFBs should be  
used only when they cover a really big part of specialized logic. That means when a  
DFB contains just one section with a few blocks of FBD/LD or a few lines of IL/ST  
logic, you should probably consider replacing it with a macro that links the DFB-logic  
directly to the program logic. Although if a DFB is used just a few times, like 1 to 10  
times, consider not changing it, since the data memory savings might be too small  
to be worth the work.  
When some complicated logic has to be implemented, especially when it comes to  
numeric algorithms, none of the IEC languages allow a really data efficient  
implementation. Therefore, when a DFB should cover some of those kinds of logic,  
it is worth implementing it as an EFB instead. EFBs are implemented in C, C++  
language, which allows highly effective implementations of any kind of logic. To  
implement EFBs, Schneider Electric offers the Concept-EFB-Toolkit. But it should  
be noted, that EFBs do not allow animation of their internal data at runtime like DFBs  
do.  
Even with EFBs you should avoid having any unused input and output pins, because  
every pin takes the data memory that its data type requires.  
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Reduce the Use Of Complex Data Structures  
Reduce Use of  
Complex Data  
Structures  
Usually, when complex data structures are used, the probability that each of its  
members are actually used is fairly low. Additionally, when complex data structures  
are passed as variables or links, each superfluous input/output pin, link or variable  
has a lot more impact on data consumption than when using primitive data types.  
This is especially true whenever the "MOVE" EFB is involved, of which the usage  
should be reduced to the absolute minimum, or to none at all. Whenever the result  
of some preceding logic gets assigned to a variable, make sure that this variable is  
the final target for that value, not just an intermediate storage. Intermediate variables  
are often used for loosening the logic between different sections. However, it makes  
sense to reduce the full amount of global variables, not only in terms of data memory  
savings, but also in terms of application overview.  
Handle the selection of arrays as data types for variables carefully, since the  
selected array is often bigger than needed.  
The choice of all different IEC compliant languages is made for a good reason. For  
many different application problems, the best way to solve them depends heavily on  
what language has been selected for its implementation. Of course, the language  
selection is also a matter of the preferences of the programmers and those who  
maintain the application. The user should be free in his decision about which of the  
IEC languages to select for his particular application.  
Because of the different focus of the IEC compliant languages, it is difficult to  
compare them. It should be mentioned, however, that the SFC language consumes  
more data in accomplishing a stepwise program execution compared than what one  
would expect from the implementation of that feature in another language. The  
overall data consumption of SFC steps ranges between 20 to 25 bytes per step,  
which does not include any data from transition sections.  
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Ethernet Hot Standby Solution  
9
At a Glance  
Purpose  
This chapter describes configuring and then using the Hot Standby solution with the  
NOE 771xx product line which supports Ethernet communication. The chapter  
covers solution-relevant topics such as IP Address assignment, NOE modes and  
Hot Standby states, address swap times, and network effects on the Hot Standby  
solution.  
What’s in this  
Chapter?  
This chapter contains the following topics:  
Topic  
Page  
164  
Overview of Hot Standby Solution for NOEs  
Hot Standby Topology  
166  
167  
168  
169  
173  
174  
NOE Configuration and Hot Standby  
IP Address Assignment  
NOE Operating Modes and Hot Standby  
Address Swap Times  
Network Effects of Hot Standby Solution  
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Ethernet Hot Standby Solution  
Overview of Hot Standby Solution for NOEs  
Please Note  
The Quantum Hot Standby system supports up to four NOE 771 Ethernet  
connections. For a more detailed description of the physical set up of a Hot Standby  
system, refer to the Quantum NOE 771 xx Ethernet Modules User Guide,  
840USE11600, Chapter 9, "Hot Standby".  
Description of  
the Hot Standby  
Solution  
The Hot Standby solution provides bumpless transfer of I/O using remote I/O. The  
NOE Hot Standby support now allows automation IP Address change. Both  
controllers are configured identically. One controller is the Primary NOE; the other  
controller, the Secondary NOE. In case of a failure, the controllers switchover and  
the system recovers quickly.  
The NOEs coordinate the swapping of IP addresses. After closing both the client  
and the server connections, each NOE sends a swap UDP message to its peer  
NOE. The sending NOE then waits a specified timeout (500 ms) for the peer swap  
of UDP messages. Either after receiving the messages or after a timeout, the NOE  
changes its IP address.  
Note: NOEs must communicate with each other in order to swap IP Addresses.  
Schneider Electric recommends that you connect the primary and Secondary  
NOEs to the same switch because  
Communication failures between the NOEs increases the time to swap  
Connecting two NOEs to the same switch, minimizes the probability of a  
communication failure  
Note: Schneider Electric recommends that a switch is used to connect the NOEs  
to each other or to the network. Schneider Electric offers switches; please contact  
a local sales office for more information.  
The NOE waits for either a change in the controller’s Hot Standby state or the swap  
of UDP messages. Then the NOE performs one of two Hot Standby actions.  
If the NOE:  
1. Detects that the new Hot Standby state is either primary or standby:  
The NOE changes the IP address  
2. Receives a swap UDP message:  
The NOE transmits a Swap UDP message and swaps the IP address  
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Ethernet Hot Standby Solution  
All client/server services (I/O Scanner, Global Data, Messaging, FTP, SNMP, and  
HTTP) continue to run after the switchover from the old to the new Primary NOE.  
Note: Failure of an NOE module is not a condition for the primary system to leave  
the primary state.  
Hot Standby and  
NOE Module  
Functionality  
The NOE 771 family provides different Ethernet services. Some services are  
enabled or disabled in a Hot Standby system. The following table shows which  
services are enabled and disabled.  
Service  
NOE 771 x0  
Disabled  
N/A  
NOE 771 x1  
Enabled  
Enabled  
Enabled  
Enabled  
Enabled  
Enabled  
Disabled  
I/O Scanning  
Global Data  
Modbus Messaging  
FTP/TFTP  
SNMP  
Enabled  
FTP Enabled  
Enabled  
Enabled  
N/A  
HTTP Server  
DHCP  
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Hot Standby Topology  
Hot Standby  
The following diagram shows a Hot Standby system the relationship between the  
Interconnection  
two redundant systems.Two CHS 110 modules are connected via a fiber optic link.  
The RIOs are connected both to each other and to the RIO Drops.  
C
P
U
N
O
E
C
H
S
R
I
O
C
P
U
N
O
E
C
H
S
R
I
O
Note: The following three items are important.  
1. The two systems must be identical.  
2. The order of the modules in each rack must be the same.  
3. The software revisions must be the same.  
In the preceding diagram the NOEs are connected to the same switch. Connecting  
to the same switch is recommended but not required. Connecting to the same switch  
is recommended because the NOEs communicate with each other in order to swap  
the IP address.  
There are two reasons for connecting to the same switch:  
If a failure to communicate between the NOEs occurs, the time to swap  
increases.  
Therefore to minimize the probability of a failure, connect the two NOEs to the  
same switch.  
The other requirement for the switches is that they are on the same sub network.  
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NOE Configuration and Hot Standby  
TCP/IP  
Configuration  
When an NOE goes into service the first time, the NOE attempts to get its IP Address  
from a BOOTP server. If no BOOTP server is available, the NOE derives its IP  
Address from its MAC address. Connecting to a BOOTP server or deriving the IP  
Address from a MAC address allows you a connection to the NOE, that enables you  
to download a project to the PLC.  
All standard rules apply to IP addressing with the additional restriction that the IP  
address cannot be greater than 253 or broadcast address minus 2. Also, no other  
device can be assigned the configured IP + 1 address.  
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IP Address Assignment  
Configuring the  
NOE  
The NOE can be configured to work in conjunction with the Hot Standby controller.  
Since the Primary and Secondary controllers must have an identical configuration,  
the configured IP Addresses will be the same. The NOE’s IP Address is either the  
configured IP Address or the configured IP Address +1. The IP Address is  
determined by the current local Hot Standby state.  
In the Offline state, the IP Address is determined by whether or not the other  
controller is in transition to the Primary state.  
Note: For a Hot Standby system, the two IP Addresses will be consecutive.  
The following table shows the IP Address assignments.  
Hot Standby State  
Primary  
IP Address  
Configured IP Address  
Configured IP Address + 1  
Standby  
Transition from Primary to Offline  
Configured IP Address, if peer controller does not  
go to Primary  
Transition from Standby to Offline  
Configured IP Address + 1  
Note: Offline - Results depend on whether or not the other controller is detected as  
in transition into the primary state. If Current IP is the configured IP Address, then  
change the IP Address to the configured IP Address + 1.  
IP Address  
Transparency  
For continued Ethernet communication, the new Primary NOE must have the same  
IP Address as the former Primary NOE. The IP Address in the Secondary NOE (an  
NOE in the secondary state) is IP Address + 1.  
The NOEs integrated in the Hot Standby configuration coordinate this swapping IP  
Address with the management of Ethernet services used.  
Note: Do not use the address IP + 1. For a Hot Standby system, do not use  
consecutive addresses of the configured IP Address. If you configure the last IP  
Address (255), NOE returns diagnostic code "Bad IP configuration".  
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NOE Operating Modes and Hot Standby  
The NOE Modes  
The NOE modes are  
Primary Mode  
The Hot Standby state is primary, and all services are active.  
Secondary Mode  
The Hot Standby state is standby, and all server services are except DHCP.  
Standalone Mode  
Occurs when NOE is in a non redundant system, or if the CHS module is not  
present or is not healthy.  
Offline Mode  
CPU is stopped.  
CHS module is in Offline mode.  
The Hot Standby and the NOE operating mode are synchronized by the conditions  
described in the following table.  
CHS Module Status  
Present and Healthy  
Present and Healthy  
Present and Healthy  
Present and Healthy  
Not present or unhealthy  
HSBY State  
Primary  
Standby  
Offline  
NOE Operating Mode  
Primary  
Secondary  
Offline  
Unassigned  
N/A  
Standalone  
Standalone  
Any one of four events will affect the NOE operating mode. These four events occur  
when the NOE is powered-up, when an NOE executes a Hot Standby switchover,  
when an NOE goes to offline mode, or when a new application is downloaded to the  
NOE.  
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Power-Up and IP  
Address  
Assignment  
The process of powering up affects the NOE’s IP Address assignment. To clarify  
what happens during a power-up, the following two sections describe the power-up  
effects on IP Address assignment and Ethernet services.  
An NOE obtains its IP Address assignment at power-up as follows:  
If the HSBY state is ...  
Unassigned  
Then the IP Address assigned is ...  
Configured IP Address  
Primary  
Configured IP Address  
Secondary  
Configured IP Address + 1  
Unassigned to Offline  
See the Offline Mode at Power-up Sequence table following  
If two NOEs power-up simultaneously, a "resolution algorithm" determines the  
Primary NOE, and after determining the Primary NOE, the "resolution algorithm"  
assigns the configured IP Address to the Primary NOE and then assigns the  
configured IP Address + 1 to the Secondary NOE.  
Offline Mode at Power-up Sequence table:  
Offline Mode at Power-up Sequence  
Result  
IP Address of controller A is configured IP  
Controller A powers-up before controller B  
Address  
IP Address of controller B is the configured  
IP Address + 1  
Both controller A and controller B power-up The resolution algorithm will assign controller A  
a the same time  
the configured IP address and will assign  
controller B the configured IP address + 1.  
The NOE performs a "duplicate IP" test by issuing an ARP request to the configured  
IP Address. If a response is received within 3 seconds, the IP Address remains at  
the Default IP and blinks a diagnostic code.  
If no IP configuration exists, the NOE remains in standalone mode, and the IP  
Address must be obtained from either a BOOTP server or from a MAC address.  
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Ethernet Hot Standby Solution  
Power-Up and  
Ethernet  
Services  
The process of powering up affects the status of client/server services. To clarify  
what happens during a power-up, the following section describes the power-up  
effects on the Ethernet services.  
The following table shows how the status of an NOE service is affected by the Hot  
Standby state.  
HSBY State Status of NOE Services  
Client Services  
Client/  
Server Services  
Server  
Services  
I/O Scanner Global Data Modbus  
Messaging  
Run  
FTP  
SNMP  
HTTP  
Unassigned Run  
Run  
Run  
Stop  
Stop  
Run  
Run  
Run  
Run  
Run  
Run  
Run  
Run  
Run  
Run  
Run  
Run  
Primary  
Secondary  
Offline  
Run  
Stop  
Stop  
Run  
Run  
Run  
Hot Standby  
Switchover  
The following steps describe how NOEs coordinate the Hot Standby switchover.  
Step  
Action  
1
NOE A (installed in a HSBY rack) detects that is local controller changed from  
Primary to Offline.  
2
NOE A changes its HSBY state from Primary to Offline with the same Ethernet  
services running, starts its watch-dog timer (with 500 ms timeout setting), and  
expects from its peer NOE an UDP request to swap the IP Address.  
3
4
NOE B (installed in peer HSBY rack) detects that its local controller changed  
state from Secondary to Primary.  
NOE B stops all Ethernet services, sends an UDP request to its peer NOE (NOE  
A) for the synchronization of the IP Address swap, starts its watch-dog timer  
(with 500 ms timeout setting), and then waits for an UDP response from its peer  
NOE.  
5
Once NOE A receives the UDP request from NOE B (or after its watch-dog timer  
times out), it stops all Ethernet services, sends an UDP response to NOE B (no  
UDP response is sent to NOE B for watch-dog timeout case), swaps IP Address  
as Secondary, and starts Secondary services.  
6
7
As soon as NOE B receives the UDP response from NOE A (or after its watch-  
dog timer times out), it swaps IP Addresses and starts Ethernet services as  
Primary.  
After NOE A senses that its local controller changes state from Offline to  
Standby, it changes to Secondary accordingly.  
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Step  
Action  
8
9
The Secondary NOE now becomes the Primary NOE.  
Primary NOE opens all client connections and listens for all server connections  
and re-establishes those connections.  
10  
Simultaneously, Secondary NOE listens for all server connections and re-  
establishes those connections.  
Additional  
Switchover  
Information  
The following list provides additional information about the NOE’s IP addressing  
process resulting from a Hot Standby switchover.  
Some MSTR/IEC Function blocks will not complete their transaction as a result  
of the IP Address swap.  
In this case, the MSTR/IEC Function block will return the error code 0x8000.  
While the NOE is in the process of performing the above actions, a new MSTR/  
IEC Function block may become active.  
No resources are available to service the new MSTR/IEC Function block.  
Therefore, the NOE will not service this new MSTR/IEC Function block, and all  
three output lines will be low.  
Going to Offline  
When either the CPU stops or the Hot Standby state goes to offline mode, two  
events occur:  
1. NOE mode goes to Offline  
2. NOE uses the IP Address of the present configuration  
IP Address Assignment and Going Offline  
HSBY State  
IP Address Assigned Is ...  
Primary to Offline  
Configured IP Address, if other controller does not go to  
Primary  
Standby to Offline  
Configured IP Address + 1  
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Ethernet Hot Standby Solution  
Address Swap Times  
Description  
The following table details what the "time for an Address swap" comprises, such as  
the time to close connections, time to swap IP addresses, or time to establish  
connections.  
The following table shows the swap time for each of the Ethernet services.  
Service  
Typical Swap Time  
Maximum Swap Time  
Swap IP Addresses  
I/O Scanning  
6 ms  
500 ms  
1 initial cycle of I/O Scanning 500 ms + 1 initial cycle of I/O  
scanning  
Global Data  
For times, please see the  
840USE11600, Quantum  
NOE 771 xx Ethernet  
Modules User Guide  
500 ms + 1 CPU scan  
Client Messaging  
Server Messaging  
1 CPU scan  
500 ms + 1 CPU scan  
1 CPU scan + the time of the 500 ms + the time of the client  
client reestablishment  
connection  
reestablishment connection  
FTP/TFTP Server  
The time of the client  
500 ms + the time of the client  
reestablishment connection  
reestablishment connection  
SNMP  
1 CPU scan  
500 ms + 1 CPU scan  
HTTP Server  
The time of the client  
500 ms + the time of the client  
reestablishment connection  
reestablishment connection  
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Ethernet Hot Standby Solution  
Network Effects of Hot Standby Solution  
Overview  
The Hot Standby solution is a powerful feature of NOEs, a feature that increases the  
reliability of your installation. Hot Standby uses a network, and using the Hot  
Standby feature over a network can affect the behavior of  
Browsers  
Remote and Local clients  
I/O Scanning service  
Global Data service  
FTP/TFTP server  
The following are factors you may encounter while using the Hot Standby solution.  
Browsers  
Note: In Hot Standby configuration the NOE’s I/O scanner is enabled.  
If a browser requests a page and during the process of downloading that page an IP  
Address swap occurs, the browser will either hang or time out. Click the Refresh or  
Reload button.  
Remote Clients  
Hot Standby swaps affect remote clients.  
An NOE will reset under the following conditions:  
Remote Connection Request during Hot Standby Swap  
If a remote client establishes a TCP/IP connection during a Hot Standby swap,  
the server closes the connection using a TCP/IP reset.  
Hot Standby Swap during Remote Connection Request  
If a remote client makes a connection request and a Hot Standby swap occurs  
during the connection request, the sever rejects the TCP/IP connection by  
sending a reset.  
Outstanding Requests  
If there is an outstanding request, the NOE will not respond to the request, but  
the NOE will reset the connection.  
The NOE will do a Modbus logout if any connection has logged in.  
Local Clients  
During a swap, the NOE will reset all client connections using a TCP/IP reset.  
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Ethernet Hot Standby Solution  
I/O Scanning  
Service  
The I/O Scanning provides the repetitive exchange of data with remote TCP/IP  
nodes I/O devices. While the PLC is running the Primary NOE sends Modbus Read/  
Write, read or write request to remote I/O devices, and transfer data to and from the  
PLC memory. In the secondary controller, the I/O scanning service is stopped.  
When the Hot Standby swap occurs, the Primary NOE closes all connections with  
I/O devices by sending a TCP/IP reset. The I/O scanning service in this NOE is  
standby.  
After the swap, the new Primary NOE re-establishes the connection with each I/O  
devices. It restarts the repetitive exchange of data with these re-connections.  
Global Data  
(Publish/  
Subscribe)  
Service  
The Hot Standby NOE is one station within a distribution group. Distribution groups  
exchange application variables. Exchanging application variables allows the system  
to coordinate all the stations in the distribution group. Every station publishes local  
application variable in a distribution group for all other stations and can subscribe to  
remote application variables independent of the location of the producer.  
The communication port has only one multicast address.  
In this network service, the Hot Standby controllers are viewed like only one station.  
The Primary NOE publishes the Hot Standby application variables and receives the  
subscription variables. The Secondary NOE global data service is in a stopped  
state.  
When the Hot Standby swap occurs, the Primary NOE stops the Global Data  
service. The NOE does not publish the local variable during a swap. And after the  
swap, the new Primary NOE starts to publish application variables and to receive the  
subscription variables.  
FTP/TFTP Server The File Transfer Protocol/Trivial File Transfer Protocol (FTP/TFTP) server is  
available as soon as the module receives an IP address. Any FTP/TFTP client can  
logon to the module. Access requires the correct user name and password. Hot  
Standby allows only one active FTP/TFTP client session per NOE module.  
When the Hot Standby swap occurs, the Primary and Secondary NOEs close the  
FTP/TFTP connection. If a user sends an FTP/TFTP request during the swap, the  
communication is closed.  
Whenever you re-open communication, you must re-enter a user name and a  
password.  
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Maintenance  
10  
At a Glance  
Purpose  
This chapter discusses maintenance procedures for the HSBY system.  
This chapter contains the following sections:  
What’s in this  
Chapter?  
Section  
10.1  
Topic  
Page  
179  
Health of a Hot Standby System  
10.2  
Errors  
183  
187  
192  
201  
10.3  
Failures  
Replacement  
Testing  
10.4  
10.5  
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Maintenance  
10.1  
Health of a Hot Standby System  
Introduction  
Purpose  
This section describes checking the health of a Hot Standby System.  
This section contains the following topics:  
What’s in this  
Section?  
Topic  
Page  
180  
Verifying Health of a Hot Standby System  
Additional Checks  
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Maintenance  
Verifying Health of a Hot Standby System  
Health Messages The Hot Standby modules exchange a health message approximately every 10 ms.  
If the Primary has an error, the Standby is notified and assumes the Primary role. If  
the Standby has an error, the Primary continues to operate as a standalone.  
The RIO head processors also verify communication with one another periodically.  
Automatic  
Confidence  
Tests  
The system automatically performs two kinds of confidence tests on the Hot Standby  
modules:  
Startup tests  
Run time tests  
Startup Tests  
The system performs four startup tests:  
Prom checksum  
RAM data test  
RAM address test  
Dual port RAM test  
If the module fails any of these tests, it remains offline and does not communicate  
with the other Hot Standby module. To retest the system, the power must be turned  
off and on again.  
Run Time Tests  
These tests are performed whenever the Ready indicator is on. They are executed  
in small groups to prevent delays in scan time.  
The system performs three kinds of run time confidence tests:  
Prom checksum  
RAM data test  
RAM address test  
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Maintenance  
Additional Checks  
Checking on a  
Redundant  
Power Supply  
If you have a redundant power supply, you may use the STAT block to check its  
operation. The redundant power supply must be I/O mapped for its status to be  
displayed. The I/O module status section of the STAT block begins at word 12.  
Responding to  
and Recognizing  
Errors  
When a CHS 110 Hot Standby module experiences an error, it takes its controller  
offline. It does not communicate with the other CHS 110 module or take part in state  
RAM data transfers.  
The LEDs on the front panel of the module can help you locate the source of the  
error. The display pattern tells you which controller is experiencing problems and  
what kind of error is occurring. There are four kinds of errors associated with the Hot  
Standby system:  
Startup errors  
Communication errors  
Communication errors  
Interface errors  
Board-level errors  
For each type of error, try the suggested remedies in the order given. If no remedy  
suggested here resolves the error, call Schneider Electric customer support at  
1-800-468-5342 for further directions.  
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Maintenance  
Safety  
Before you begin, take the following safety precautions:  
Precautions  
WARNING  
ELECTRIC SHOCK HAZARD  
To protect yourself and others against electric shock, allow no one to  
touch energized high voltage circuits (such as 115V AC). Before  
connecting or disconnecting any high voltage component, open and  
padlock open the disconnect switch which provides power to that  
component.  
Failure to follow this precaution can result in death, serious injury,  
or equipment damage.  
WARNING  
Avoid Damage to Application I/O Devices  
To avoid damage to application I/O devices through unexpected system  
action while disconnecting any remote I/O cable, disconnect only the  
feed through terminator from the module, leaving the terminator  
connected to its cable.  
Failure to follow this precaution can result in death, serious injury,  
or equipment damage.  
Note: Before you replace any module in either backplane, be sure that the spare  
module is compatible with the Hot Standby system. Be sure that you use the  
correct terminator.  
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Maintenance  
10.2  
Errors  
Introduction  
Purpose  
This section will help you determine component failure and causes.  
This section contains the following topics:  
What’s in this  
Section?  
Topic  
Page  
184  
Startup Errors  
Communications Errors  
Board Level Errors  
185  
186  
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Maintenance  
Startup Errors  
LED Display for a When the Hot Standby system detects a mismatch between the Primary and  
Startup Error  
Standby controllers, it reports a startup error. The mismatch may be in the  
configuration, including segment scheduler, I/O map or designation slide switch  
positions. The LEDs display the error pattern. The Ready indicator is a steady green,  
while the Com Act indicator blinks.  
If the LEDs indicate a startup error and if you have difficulty determining why, you  
can access some startup error codes through software. Refer to Chapter 3 of the  
Quantum Automation Series Hardware Reference Guide for details.  
Troubleshooting  
Take the following troubleshooting steps:  
Step  
Action  
1
Be sure the designation slide switches on the CHS 110 modules are in opposite  
positions.  
2
3
4
Be sure the configuration tables in the Primary and Standby controllers are  
identical.  
Be sure the segment schedulers in the Primary and Standby controllers are  
identical.  
Be sure the I/O maps in the Primary and Standby controllers are identical.  
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Maintenance  
Communications Errors  
LEDs  
If the CHS 110 module detects a communications error, the LEDs display the  
following pattern:  
LED display for a communications error.  
140  
CHS 110 00  
HOT STANDBY  
Active  
Ready Fault  
Run  
Bal Low  
Pwr ok  
Modbus Com Err  
Modbus! Error A  
Com Act Error B  
Primary  
Mem Prt Standby  
Troubleshooting  
Interface Errors  
1. Be sure the fiber optic cables are connected properly and functioning correctly  
2. If the fiber optic cables are in good condition, replace the faulty CHS 110 module.  
If the Hot Standby module detects certain errors in its interface with the controller,  
the LED display goes out momentarily as the module tries to recover. It either  
returns to a ready state or reports the error with a blinking Com Act indicator. The  
Com Act error patterns are described in Com Act Error Patterns, p. 209.  
Troubleshooting  
1. If you used the CHS function block, disable it and restart the system. If the Ready  
indicator comes on, the problem is in the CHS 110 module. If you used a  
configuration extension screen, go offline and change the configuration to a  
standalone system. Reload the program. Restart the system. If the Ready  
indicator comes on, the problem is in the CHS 110 module.  
2. If you have replaced the Hot Standby module and the problem still occurs,  
replace the other components, one at a time.  
3. If the problem still occurs, replace the backplane.  
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Maintenance  
Board Level Errors  
PROM, RAM,  
UART  
Board level errors include PROM checksum, RAM data, RAM address and UART  
errors. If the Hot Standby module detects one of these errors, it displays the  
following pattern:  
LED Display for a The diagram below shows a LED Dislplay for a Board Level Error.  
Board Level  
Error  
140  
CHS 110 00  
HOT STANDBY  
Active  
Ready Fault  
Run  
Bal Low  
Pwr ok  
Modbus Com Err  
Modbus! Error A  
Com Act Error B  
Primary  
Mem Prt Standby  
Troubleshooting  
The Ready indicator is a steady green, while the Com Act indicator blinks. This is  
the same pattern the module displays for a startup error. Follow the troubleshooting  
procedures for a startup error. If the module does not recover, replace it.  
Replace the faulty CHS 110 module.  
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Maintenance  
10.3  
Failures  
Introduction  
Purpose  
This section helps you determine component failure and causes.  
This section contains the following topics:  
What’s in this  
Section?  
Topic  
Page  
188  
189  
190  
191  
Detecting Failures in a Hot Standby System  
Detecting Failures in the Primary Backplane  
Detecting Failures in the Standby Backplane  
Failure of Fiber Link from Primary Transmit to Standby Receiver  
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Maintenance  
Detecting Failures in a Hot Standby System  
Main  
If one of the main components of the Primary backplane fails, control shifts to the  
Components of  
the Primary  
Backplane  
Standby. If a component fails in the Standby backplane, the Standby goes offline.  
Likewise, if the fiber cable link between the Hot Standby modules fails, the Standby  
goes offline.  
This section helps you determine which component failed. When you have replaced  
that component, you must cycle power, with one exception. After cycling power, if  
the backplane is now operating, it assumes the Standby role. If the failure was in the  
fiber cable, the backplane may return to Standby mode without cycling power.  
If replacing the component does not solve the problem, call Schneider Electric  
customer support at 1-800-468-5342 for further directions.  
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Maintenance  
Detecting Failures in the Primary Backplane  
Troubleshooting  
Components  
To determine which component failed, compare the status of the controller, Hot  
Standby module and RIO head to the chart below:  
Controller  
CHS 110  
RIO Head  
Failure Type  
Description  
Stops  
All LEDs off  
except READY  
OR COM ACT  
displays error  
pattern  
All LEDs off except  
READY  
READY on and  
COM ACT blinks  
four times  
The Interface error patterns  
are described in Com Act  
Error Patterns, p. 209  
Runs as offline  
All LEDs off  
except READY  
OR COM ACT  
displays error  
pattern  
All LEDs off except  
READY  
CHS 110  
RIO Head  
The Com Act error patterns  
are described in (See Com  
Act Error Patterns, p. 209)  
Stops  
Stops  
All LEDs off  
All LEDs off except  
READY OR COM  
ACT displays error  
pattern  
The Com Act error patterns  
are described in Com Act  
Error Patterns, p. 209  
except READY  
All LEDs off  
READY on and COM RIO CableFailure at In a dual cable system, if only  
except READY  
ACT blinks four times Primary End  
one cable fails, the Error A or  
Error B indicator on the RIO  
head lights instead and the  
system continues to operate.  
When the RIO cable fails at  
the Primary end, input data  
may be reset to 0 for one  
scan because the  
communication failure to the  
drop occurs before the  
broken link is detected.  
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Maintenance  
Detecting Failures in the Standby Backplane  
Troubleshooting  
Components  
To determine which component failed, compare the status of the controller, Hot  
Standby module and RIO head to the chart below.  
Controller  
CHS 110  
RIO Head  
Failure  
Description  
Stops  
All LEDs off except  
All LEDS off except Controller  
The Interface error  
patterns are described in  
Com Act Error Patterns,  
p. 209  
READY OR COM ACT READY OR  
displays error pattern  
READY on and  
COM ACT blinks  
once a second  
Runs as offline  
Stops  
COM ACT displays  
error pattern  
READY on and  
COM ACT stops  
blinking  
CHS 110  
The Com Act error  
patterns are described in  
Com Act Error Patterns,  
p. 209  
All LEDs off except  
READY  
COM ACT displays RIO Head  
error pattern  
After you have replaced  
the module and cycled  
power, you must perform a  
program update, to ensure  
that the controllers have  
identical programs. Error  
codes for a blinking Com  
Act indicator are listed in  
Com Act Error Patterns,  
p. 209  
Stops  
All LEDs off except  
READY  
READY on and  
COM ACT blinks  
four times  
RIO Cable  
Failure at  
In a dual cable system, the  
RIO head gives no  
indication if only one cable  
has failed.  
Standby End  
Runs as offline  
READY and COM ACT COM ACT stops  
on blinking  
Failure of Fiber  
Link from  
Standby  
Transmit to  
Primary Receive  
Runs as offline  
READY and COM ERR COM ACT stops  
on blinking  
Failure of Fiber  
Refer to following  
Link from Primary description.  
Transmit to  
Standby Receive  
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Maintenance  
Failure of Fiber Link from Primary Transmit to Standby Receiver  
Fiber Optic Cable Replace the cable and restart the controller. The unit should return to Standby  
mode. If it does not, cycle the power on the Standby unit.  
If the cable has been connected improperly (i.e., the transmit port of the Primary is  
linked to the transmit on the Standby), two error patterns are possible.  
If the program has already been loaded in the Standby controller and both  
controllers are running, then the Ready and Com Err indicators light on the  
Standby CHS 110 module.  
If the program has not yet been loaded in the Standby and you attempt to load it  
using the program update procedure, then the Ready indicator lights and the  
Standby blinks.  
If both fiber links fail, the Com Err indicator lights on the Standby CHS 110. Again,  
replace the cable and restart the controller. The unit should return to Standby mode.  
If it does not, cycle the power on the Standby unit.  
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Maintenance  
10.4  
Replacement  
Introduction  
Purpose  
This section describes replacing a Hot Standby module.  
This section contains the following topics:  
What’s in this  
Section?  
Topic  
Page  
193  
Replacing a Hot Standby Module  
Changing the Program and Performing a Program Update  
Updating PLC System Executives in a 984 HSBY System  
Updating PLC System Executives in an IEC HSBY System  
194  
198  
200  
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Maintenance  
Replacing a Hot Standby Module  
HotSwapandthe Hot swapping any key module in the Primary or Standby backplane forces that  
Hot Standby  
System  
backplane offline. When the module is in the Primary backplane, this causes  
switchover.  
Key modules include the controller, remote I/O head processor and the Hot Standby  
module.  
Any time you hot swap a module, you must cycle power to the backplane to ensure  
proper system initialization. If you have hot swapped the controller, you must also  
perform a program update, using the proper procedure.  
You may replace a CHS 110 module while the Hot Standby system is running, as  
long as the module is in the current Standby backplane and you follow the procedure  
below  
CAUTION  
Primary Backplane Hazard  
Do not attempt to hot swap the CHS 110 module in the Primary  
backplane.  
Failure to follow this precaution can result in injury or equipment  
damage.  
Hot swapping any key module in the Primary or Standby backplane forces that  
backplane offline. When the module is in the Primary backplane, this causes  
switchover.  
Replacement  
Procedure  
The following table shows the replacement procedure.  
Step  
Action  
1
Power down the backplane.  
2
Disconnect the fiber optic cable from the module and remove it from the  
backplane.  
3
4
Install the new module and reconnect the fiber optic cable.  
Restore power to the backplane.  
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Maintenance  
Changing the Program and Performing a Program Update  
Updating the  
Primary and  
Standby  
The program includes the configuration table, I/O map, configuration extensions,  
segment scheduler, all .EXE loadables and the entire state RAM, including user  
logic.  
Note: Program downloads:  
Change program means: a complete program change.  
Update program means: to update the user logic  
If you reprogram your Primary controller or replace the Standby controller, you may  
use the update feature to copy the full program of the Primary controller to the  
Standby. This feature not only saves time, but also ensures that the controllers have  
identical user logic.  
If program changes include any of the above, or replacing the Standby controller,  
the Standby must be in dim awareness before a keyswitch update can be performed  
Note: A program update can only be performed from the Primary controller to the  
Standby. The Standby controller cannot update the Primary.  
Note: To put the Standby into dim awareness, remove the battery for at least 5  
minutes.  
CAUTION  
Battery Hazard  
Whenever installing a new controller, be sure its battery has been  
disconnected for at least five minutes.  
Failure to follow this precaution can result in injury or equipment  
damage.  
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Maintenance  
CAUTION  
Program Change Hazard  
To change the program, you must stop both controllers and take the  
Standby controller Off Line.  
Failure to follow this precaution can result in injury or equipment  
damage.  
Before You  
Begin:  
To download a new program to your Primary controller, you must stop the Standby  
controller as well.  
The Standby CHS 110 module must be in Off Line mode. Make any changes to the  
program. Then follow the steps below to copy the new program to the Standby  
controller.  
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Maintenance  
Updating  
Standby  
Procedure  
The following table demonstrates how to update the Standby procedure.  
Step  
Action  
1
Put the Primary controller in Run mode. Be sure the Standby controller is still  
stopped and Off Line.  
2
3
Push the update button on the Standby unit. Hold the button down.  
Turn the key on the Standby CHS 110 module to Xfer. This prepares the  
Standby unit to receive the update  
Updating Standby  
Off  
Off  
Line  
Line  
Xfer  
Run  
Xfer  
Run  
Slide switches must be  
set in opposite positions.  
Update Button  
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Maintenance  
Step  
Action  
4
Turn the key to the mode you want the Standby unit to be in after the update,  
Run or Off Line.  
Result:  
The amber Standby indicator begins to blink.  
Updating Standby  
Off  
Off  
Line  
Line  
Xfer  
Run  
Xfer  
Run  
Slide switches must be  
set in opposite positions.  
Update Button  
5
Release the update button.  
Result  
The Primary controller begins copying its full program to the Standby.The  
Standby indicator on the Standby unit continues to blink as the module  
processes the update. When the update is completed, the CHS 110 Hot  
Standby module instructs the Standby controller to return to the mode you have  
set, Run or Off Line. If the Standby unit is in Run mode, the Standby and Com  
Act lights are lit. If the Standby unit is offline, neither indicator is lit.The Standby  
now has an program identical to the Primary unit.  
6
Remove the key and store it in a secure place.  
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Maintenance  
Updating PLC System Executives in a 984 HSBY System  
Updating PLC  
System  
Bit 12 in the Hot Standby command register can be set to 1 to facilitate an executive  
upgrade while one of the controllers in the Hot Standby system continues to operate  
Executives  
CAUTION  
Overriding the Safety Checking Protection Hazard  
Setting bit 12 to 1 overrides the safety checking protections between  
the Primary and Standby controllers in your Hot Standby system. It is  
important to reset the bit to 0 as soon as the executive upgrade  
operation is complete.  
Failure to follow this precaution can result in injury or equipment  
damage.  
Even if it is possible to have this command register parameter be prepared for this  
operation, it is strongly recommended not to have it set by configuration extension  
and to set it only when needed. To do this, you can either use a Zoom screen on a  
CHS instruction block in ladder logic or call up the Hot Standby command register  
in the Reference Data Editor (RDE).  
Upgrading the  
PLC executives  
while Hot  
Standby system  
is running  
If you want to access the command register via a Zoom screen, make sure that a  
CHS instruction has been inserted in ladder logic before the system is powered up.  
While the Hot Standby system is running, connect to the Primary controller with  
Concept. Go to the LL984 Editor and call up the Zoom screen when having the CHS  
instruction inserted.  
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Maintenance  
StepstoUpgrade Zoom or RDE  
PLC executives  
Step  
Action  
while Hot  
Standby is  
running  
1
Call up the Hot Standby command register, either in a Zoom screen or in the  
RDE. If you are using the Zoom screen, select the Without Stopping option for  
bit 12. If you are using the RDE, set the value of bit 12 in the Hot Standby  
command register to 1.  
2
3
4
Disconnect from the PLC and start the Firmware Loader Utility.  
Perform a firmware download to the standby controller.  
Do a program update from the Primary to the Standby controller as described in  
Using a Quantum 984 HSBY System, p. 67 or Using a Quantum IEC Hot  
Standby System , p. 109. At this point, you have a new system executive in the  
Standby controller with the correct ladder logic and state RAM values.  
5
6
7
Initiate a Hot Standby switchover.  
Perform a firmware download to the new Standby controller.  
Refer to Concept V 2.2 User’s Manual, 840 USE 483 00. Now both the Primary  
and the Standby controllers have the new system executive installed, and both  
are running the same logic program with the same state RAM values. If you  
initiate another switchover, the controller that was originally the Standby  
becomes the Standby again.  
Note: Some Exec upgrades may be because of new versions of Concept and  
in certain cases the project may have to be converted before downloading.  
8
Reconnect to the Primary controller and reset bit 12 of the Hot Standby  
command register back to 0 via either the Zoom screen or the RDE.  
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Maintenance  
Updating PLC System Executives in an IEC HSBY System  
Updating PLC  
System  
Executives  
In a Pre Concept 2.5 IEC Hot Standby System it’s not possible to update the PLC  
system executives without shutting down the process. Instead you must follow the  
steps in the table below.  
Concept 2.5 IEC Hot Standby System allows the upgrading of the controllers  
executives without shutting down the system. See Advanced Options, Section  
B122.  
CAUTION  
Executing the Steps Hazard  
Following the procedural steps in order is critical for the safety and  
reliability of your Hot Standby system.  
Failure to follow this precaution can result in injury or equipment  
damage.  
QuantumIECHot The following table shows the steps in a Quantum IEC Hot Standby Controller Exec  
Standby  
Upgrade Procedure.  
Controller Exec  
Upgrade  
Procedure  
Step  
Action  
1
Stop the process being controlled.  
Stop both controllers.  
2
3
4
Load the new Execs in both controllers.  
Download the project to the primary controller. Note: Some Exec upgrades may  
be because of new versions of Concept and in certain cases the project may  
have to be converted before downloading. Note: The Primary controller must be  
started.  
5
6
Load the project into the Standby Controller via the fiber optic CHS link in  
Transfer mode.  
Start the Standby Controller. Note: You can do this by using the CHS fiber optic  
update procedure, without using Concept.  
Result: The IEC Hot Standby System will now come up and run in Normal  
Recommended Operation.  
200  
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Maintenance  
10.5  
Testing  
Forcing a Switchover  
Testing a Hot  
Standby  
To test your Hot Standby system, you may force a switchover manually or through  
software.  
Switchover  
Note: In systems with scan times of 200 ms or greater and more than 15 RIO  
drops, it is recommended that the drop holdup time be increased to 1.5 seconds to  
ensure that communication with remote drops is maintained during switchover.  
Forcing a  
Switchover  
Manually  
Take the following steps to force a switchover manually.  
Step  
Action  
1
Be sure that the Standby controller has been fully programmed.  
2
Place the function keyswitch on the CHS 110 Hot Standby module in the Run  
position.  
3
4
Observe that the Standby indicator on the CHS 110 module is steady amber.  
Be sure that the designation slide switch on one Hot Standby module is in  
position A and that the switch on the other Hot Standby module is in position B.  
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Maintenance  
Step  
Action  
5
Confirm that the keyswitch on both Hot Standby modules has not been  
overridden by software.  
After Taking the Primary Controller Offline  
Primary  
Standby  
6
7
Turn the key on the Primary Hot Standby module to Off Line.  
Result: Standby should now be functioning as the Primary controller.  
Check to see that all LED indicators are normal and all application devices are  
functioning properly. The Standby indicator should be extinguished and the  
Primary indicator should be a steady green.  
202  
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Maintenance  
Step  
Action  
8
Return the key on the original Primary unit to the Run position. The Standby  
indicator should come on.  
Bringing the Original Primary Unit Back Online  
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Maintenance  
Forcing a  
Switchover  
Through  
You can force a switchover using the RDE or, if you have programmed a CHS  
instruction in ladder logic, a Zoom screen. The instructions are the same; however,  
in the RDE you are working with the command and status registers, while in the  
Zoom screen you are working with the command and status pages.  
Software  
Step  
Action  
1
Addressing the Primary controller: Check the status register or page to be sure  
one unit is designated A and the other is B. Be sure that both the Primary and  
the Standby controllers are in run mode and that the function keyswitch override  
has been enabled.  
2
3
In the command register or on the command page, take the Primary controller  
offline.  
If you are operating on a Modbus Plus network, the programming panel is  
automatically communicating with the Primary controller. If you are operating via  
the Modbus or Modbus Port directly connected to the original primary controller,  
you must reconnect the programming cable to the new Primary controller and  
then log in again, due to the port address swap.  
Result: The status should now show that the original Primary controller is offline  
and that the Standby is now functioning as the Primary unit. Refer to Command  
Register, p. 76.  
4
5
Check the LED displays on the Hot Standby modules to confirm that the  
switchover has taken place. The Primary indicator on the original Primary unit  
should be extinguished, while the Primary indicator on the original Standby unit  
should be a steady green.  
In the command register or on the command page, return the original Primary  
unit to RUN mode. The status register or page and the LED display on the front  
panel of the Hot Standby module should now show that unit in Standby mode.  
204  
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Specifications for CHS 110 Hot  
Standby  
11  
Specifications  
Specifications  
for CHS 110 Hot  
Standby  
Electrical  
Electrostatic Discharge (IEC 801-2)  
RFI Immunity (IEC 801-3)  
8 kV air/ 4 kV contact  
27 - 1000 MHz, 10 V/m  
700 mA  
Bus Current Required (Typical)  
Operating Conditions  
Temperature  
0 to 60° C  
Humidity  
0 to 95% Rh noncondensing  
@ 60C  
Altitude  
15,000 ft. (4500 m)  
Vibration  
10 - 57 Hz @ 0.075 mm d.a.  
57 - 150 Hz @ 1 g  
Storage Conditions  
Temperature  
Humidity  
-40 to +85° C  
0 to 95% Rh noncondensing  
@ 60° C  
Free Fall  
1 m unpackaged  
Shock  
3 shocks/axis, 15 g, 11 ms  
Agency Approvals  
Electrical  
UL 508  
CE  
CSA 22.2-142  
FM Class I Div 2 pending  
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Specifications for CHS 110 Hot Standby  
206  
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Appendices  
Appendices for Quantum Hot Standby Planning and Installation Guide  
At a Glance  
The appendices for the Quantum Hot Standby Planning and Installation Guide are  
included here.  
What’s in this  
Appendix?  
The appendix contains the following chapters:  
Chapter  
Chapter Name  
Page  
209  
A
B
C
Com Act Error Patterns  
Fiber Optic Cable Guide  
ProWORX Nxt Configuration  
213  
217  
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Appendices  
208  
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Com Act Error Patterns  
A
At a Glance  
Purpose  
This Appendix describes error patterns for the HSBY.  
This chapter contains the following topics:  
What’s in this  
Chapter?  
Topic  
Page  
CHS 110 Hot Standby Module Error Patterns  
CRP Remote I/O Head Processor Error Patterns  
210  
211  
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Com Act Error Patterns  
CHS 110 Hot Standby Module Error Patterns  
CHS 110 Error  
Patterns  
The following table shows the number of times the Com Act indicator blinks for each  
type of error and the codes possible for that group (all codes are in hex).  
Number Blinks  
Code  
6900  
6801  
6802  
6803  
6804  
6604  
6605  
6503  
6402  
6301  
C101  
C102  
C103  
C200  
Error  
1
2
2
2
2
4
4
5
6
7
8
8
8
8
error in additional transfer calculation  
ICB frame pattern error  
head control block error  
bad diagnostic request  
greater than 128 MSL user loadables  
powerdown interrupt error  
UART initialization error  
RAM address test error  
RAM data test error  
PROM checksum error  
no hook timeout  
read state RAM timeout  
write state RAM timeout  
powerup error  
210  
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Com Act Error Patterns  
CRP Remote I/O Head Processor Error Patterns  
Error Patterns  
The following table shows error patterns.  
Number  
Blinks  
Code  
Error  
Slow (steady) 0000  
requested kernel mode  
hcb frame pattern error  
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
3
4
4
4
4
4
5
6
7
7
8
6820  
6822  
6823  
682A  
682B  
682C  
6840  
6841  
6842  
6843  
6844  
6845  
6846  
6847  
6849  
684A  
684B  
684C  
6729  
6616  
6617  
6619  
681A  
681C  
6503  
6402  
6300  
6301  
8001  
head control block diag error  
mod personality diag error  
fatal start IO error  
bad read IO pers request  
bad execute diag request  
ASCII input xfer state  
ASCII output xfer state  
IO input comm state  
IO output comm state  
ASCII abort comm state  
ASCII pause comm state  
ASCII input comm state  
ASCII output comm state  
building 10 byte packet  
building 12 byte packet  
building 16 byte packet  
illegal IO drop number  
984 interface bus ack stuck high  
coax cable initialization error  
coax cable dma xfer error  
coax cable dumped data error  
coax cable DRQ line hung  
coax cable DRQ hung  
RAM address test error  
RAM data test error  
PROM checksum error (exec not loaded)  
PROM checksum error  
kernel PROM checksum error  
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Com Act Error Patterns  
Number  
Blinks  
Code  
Error  
8
8
8002  
8003  
flash prog / erase error  
unexpected executive return  
212  
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Fiber Optic Cable Guide  
B
At a Glance  
Purpose  
This Appendix describes specifications for the fiber optic cable.  
This chapter contains the following topics:  
What’s in this  
Chapter?  
Topic  
Page  
Fiber Optic Cable  
Other Tools  
214  
216  
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Fiber Optic Cable Guide  
Fiber Optic Cable  
Recommen-  
dations  
Schneider Electric recommends the use of up to 1 km of 62.5/125 graded index,  
duplex, multimode glass fiber for all applications. Most 62.5/125 cables are rated at  
3.5dB loss per km.  
We recommend using a 3 mm diameter cable for your hot Standby system, because  
the fiber cable clasps used to maneuver the cable into the ports are designed to be  
used with 3 mm cable.  
The following cable meets these recommendations.  
Vendor  
AMP  
Part Number  
502086-1  
Description  
Black  
AMP  
502908-1  
Beige  
Connectors  
You need four ST bayonet-style connectors per cable. Suggested connectors  
include:  
Vendor  
AMP  
AMP  
AMP  
3M  
Part Number  
503571-1  
503415-1  
501380  
Description  
Epoxy, -20 to +75C  
Epoxy, -20 to +75C  
Epoxy, -30 to +705C  
Epoxy, -40 to +805C  
Hot Melt, -40 to +605C  
6105  
3M  
6100  
Termination Kits  
Suggested kits include:  
Vendor  
Part Number  
Description  
AMP  
501258-7  
501258-8  
8154  
Epoxy, 110 Vac, only for AMP  
connectors  
AMP  
3M  
Epoxy, 220 Vac, only for AMP  
connectors  
Epoxy, 110 or 220 Vac, only for 3M  
connectors  
3M  
6150  
Hot Melt, 110 or 220 Vac, only for 3M  
connectors  
214  
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Fiber Optic Cable Guide  
Other Tools  
Suggested Tools include:  
Vendor  
Part Number  
Description  
3M  
9XT  
Optical Source Driver (hand-held,  
requires light source)  
(photodyn  
e)  
3M  
1700-0850-T  
Optical Light Source (850 nm, ST  
connectors, for 9XT)  
(Photody  
ne)  
3M  
3M  
17XTA-2041  
7XE-0660-J  
Power Meter (hand-held)  
Optical Light Source (660 nm, visible,  
for 9XT: use to troubleshoot raw fiber,  
requires FC/ST patch cord)  
3M  
3M  
BANAV-FS-0001  
8194  
FC/ST Patch Cord (connects FC  
connector on 7XE to ST)  
Bare Fiber Adapter, ST compatible  
(permits use of above source and  
meter to test raw fiber; two required)  
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Fiber Optic Cable Guide  
Other Tools  
Other Tools  
Suggested tools include  
Vendor  
Part Number  
Description  
3M  
9XT  
Optical Source Driver (hand-held,  
requires light source)  
(Photody  
ne)  
3M  
1700-0850-T  
17XTA-2041  
7XE-0660-J  
Optical Light Source (850 nm, ST  
connectors, for 9XT)  
(Photody  
ne)  
3M  
Power Meter (hand-held)  
Photodyn  
e
3M  
Optical Light Source (660 nm, visible,  
for 9XT: use to troubleshoot raw fiber,  
requires FC/ST patch cord)  
3M  
3M  
BANAV-FS-0001  
8194  
FC/ST Patch Cord (connects FC  
connector on 7XE to ST)  
Bare Fiber Adapter, ST compatible  
(permits use of above source and  
meter to test raw fiber; two required)  
216  
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ProWORX Nxt Configuration  
C
ProWORX Nxt Hot Standby Configuration Extension  
Description  
Use the Hot Standby Configuration Extension dialog to specify Hot Standby  
configuration parameters for a Quantum Hot Standby System. It allows the type of  
state ram to be transferred between primary and standby PLC, the non-transfer area  
(Ver. 2.xx Quantum PLCs with CHS loadable) and the command register. It is  
activated from the Network Editor. Select Config Extension on the Configuration  
menu and select HSBY Extension from the Tree Control.  
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ProWORX Nxt Configuration  
Configuration  
Extensions  
Go to the ProWORX Configuration Extensions Dialog Screen. In the left window  
pane, highlight <config extensions> <Hot Standby (Quantum)>  
Dialog Screen  
Configuration Extension  
Config Extensions  
Quantum Hot Standby Configuration  
Hot Standby (Qua  
Non-Transfer Area:  
Start Address:  
Area Length:  
Command Register  
Command/Status Registers  
State RAM Transferred:  
Routine Transfer Table:  
Routine and Extra  
Extra Transfer Table:  
0x  
1x  
3x  
4x  
00001-00016  
10001-10016  
30001-30016  
40001-40016  
0x  
1x  
3x  
4x  
00017-00032  
10017-10032  
30017-30032  
40017-40032  
Words Used: 00018/00255  
Descriptor:  
Scans to Transfer:  
Help  
OK  
Cancel  
218  
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ProWORX Nxt Configuration  
Field and  
functions  
The following table describes the functions of the fields of the <config extensions>  
<Hot Standby (Quantum)> dialog screen  
Field  
Function  
Command Register  
Use to specify the 4x register that will be used as the command register.  
Use this register to control various parameters of the Hot Standby system  
Non-Transfer Area; Start Address  
Non-Transfer Area; length  
State RAM Transferred  
Use to specify first 4x register of a group of registers that will not be  
transferred from primary to standby PLC.  
Use with the start address to specify the number of 4x registers that will  
not be transferred  
Use to select State Ram transfer options:  
All State Ram: all configured state ram transferred  
Routine only: all state ram defined in routine transfer table  
Default (12K):  
All 0x and 1X discretes up to 8192 each transferred  
All 3x and 4x registers configured transferred if combined they total  
less than 10000  
1000 3x and all 4x registers (up to combined total of 1000)  
transferred, if configured combined total of 3x and 4x registers is  
greater than 1000  
Routine and Extra: all state ram defined in routine transfer table and  
extra transfer table  
Routine Transfer Table  
Extra Transfer Table  
Use to define the state ram (0x,1x,3x,4x) to be transferred every scan.  
Each input must be a multiple of 16 and 4x requires minimum of 16.  
Use to define the state ram (0x,1x,3x,4x) to be transferred in multiple  
scans. Each input must be a multiple of 16.  
Scans to Transfer: Used to specify the number of scans in which to  
transfer the extra state ram  
Description  
The Command/Status Registers dialog is used to control or monitor various  
parameters of a Quantum Hot Standby system.  
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ProWORX Nxt Configuration  
Command/  
Go to the ProWORX Command/Status Registers Dialog Screen.  
Status Registers  
dialog screen  
Command/Status Registers  
Initial Command Register  
Status Register  
Command Register  
Initial Command Register Setting  
Controller Mode:  
Swap Port Addresses:  
OffLine  
Controller A Mode  
Yes  
Yes  
Yes  
Swap Port 1  
Swap Port 2  
Controller B Mode OffLine  
Standby Mode  
(on logic mismatch)  
Swap Port 3  
Yes  
Executive  
Upgrade Switch  
Keyswitch  
Override  
Enabled  
Cancel  
Disabled  
Help  
OK  
220  
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ProWORX Nxt Configuration  
Field and  
functions  
The following table describes the functions of the fields of the Command/Status  
Registers dialog screen:  
Field  
Function  
Swap Port 1  
Use to specify if Modbus Port 1 address on  
primary PLC will change to the standby PLC  
Modbus Port 1 address when a switchover  
from primary to standby occurs. The 2  
options for this field are:  
Yes - address changes on switchover  
No - address does not change on  
switchover  
Swap Port 2  
Use to specify if Modbus Port 2 address on  
primary PLC will change to the standby PLC  
Modbus Port 2 address when a switchover  
from primary to standby occurs. The 2  
options for this field are:  
Yes - address changes on switchover  
No - address does not change on  
switchover  
Swap Port 3  
Use to specify if Modbus Port 3 address on  
primary PLC will change to the standby PLC  
Modbus Port 3 address when a switchover  
from primary to standby occurs. The 2  
options for this field are:  
Yes - address changes on switchover  
No - address does not change on  
switchover  
Controller A Mode  
Use to specify the operating mode for the  
PLC at startup when the keyswitch override  
is enabled. There are 2 options for this field:  
Offline  
Run  
Controller B Mode  
Use to specify the operating mode for the  
PLC at startup when the keyswitch override  
is enabled. There are 2 options for this field:  
Offline  
Run  
Standby Mode (on logic mismatch)  
Use to specify Standby PLC’s state if a  
mismatch is detected between its logic  
program and the Primary PLCs logic  
program. The 2 state options are:  
Yes – Online Standby with logic mismatch  
No – Offline with logic mismatch  
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ProWORX Nxt Configuration  
Field  
Function  
Executive Upgrade Switch  
Use to specify if the PLC has to be stopped  
to download new executive to PLC. The 2  
options are:  
Yes – PLC has to be stopped  
No – PLC does not have to be stopped  
Keyswitch Override  
Use to specify if the keyswitch on CHS 110  
modules is disabled (command register  
controls online/offline state of PLCs). The 2  
options are:  
Disabled – keyswitch controls online/  
offline state  
Enabled – control register controls online/  
offline state  
222  
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B
configuration extension  
Numerics  
984 HSBY, 27, 67  
controlling the Hot Standby system, 72  
dialog screen, 218  
using configuration extension screens,  
115  
connectors, 214  
A
CRP Remote I/O, 211  
C
cable  
D
diagrams, 59  
distances, 56  
topologies, 58  
DFB instance  
data, 44  
reducing, 161  
startup, 104  
CHS instruction, 70  
coaxial cable  
diagrams, 58  
coaxial splitters  
E
error patterns, 210  
Exec, 44  
required in RIO network, 58  
Com Act  
indicator, 139  
LED, 105  
command register  
diagram, 118  
must not be in nontransfer area, 77  
complex data structures, 162  
F
fiber optic cable  
connecting, 24  
permissible lengths, 56  
fiber optic repeaters  
for extending coaxial cable in RIO  
network, 56  
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Index  
H
N
health message, 180  
Hot Standby  
nontransfer area of state RAM  
command register must not be placed in  
the nontransfer area, 76  
Hot Standby kit, 24  
Hot Standby system  
installation, 61  
O
off line mode, 21  
normal operation, 108  
planning guidelines, 56  
startup, 104  
timing, 173  
topology, 166  
P
primary controller, 16, 28  
program data, 44  
hot swapping, 193  
HSBY, 13  
R
reduce scan time, 36  
reference data editor, 121  
remote I/O network  
I
IEC heap, 44, 128  
IEC HSBY, 28  
IEC logic, 114  
cable requirements, 56  
diagrams, 58  
IP address, 128  
hardware required, 58  
run mode, 22  
K
keyswitch, 20  
override, 119  
S
L
scan time, 142  
ladder logic, 72  
slide switch, 20  
LED display  
during normal operation, 105  
recognizing errors, 181  
logic scan, 32, 46  
failure, 108  
Standby LED, 105  
startup error, 184  
state RAM, 30  
M
IEC HSBY, 46  
MAC address, 128  
stages of transfer, 32  
state RAM transfer  
automatic, 108  
maximum IEC heap size, 44  
224  
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Index  
state RAM transfer area  
defined, 76  
status register, 94  
switchover  
automatic, 108  
system scan time, 33, 47  
T
time-of-day clocks  
synchronizing, 106  
timing  
diagram, 33  
transfer  
buffer, 53  
transfer mode, 21  
transfer process, 32  
troubleshooting, 184  
trunk terminator  
required in RIO network, 58  
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Index  
226  
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