State Industries GFK-0827 manual Basic Hot Standby Operation, Control Strategy

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a47000

PRIMARY UNIT

SECONDARY UNIT

RACK 0

RACK 0

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U

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31

30

*TERMINATED I/O CABLE

REMOTE DROP

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LOCAL I/0

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CAN BE IN

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RACKS

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RACK 1

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*I/O CABLE WITH BUILT-IN TERMINATION

IC697CBL811 (10 FEET (3m))

IC697CBL826 (25 FEET (7.5m)

*TERMINATED I/O CABLE

Figure 1. Example of a Local I/O Configuration with Expansion Racks in a

Hot Standby CPU Redundancy System

Control Strategy

Control strategy refers to the type of redundancy alternative that may be used. For the Hot Standby CPU Redundancy product, the control strategy is referred to as Genius Hot Standby (GHS). The control strategy must be selected when configuring the system with the Logicmaster 90-70 programming Software Configurator function.

Basic Hot Standby Operation

In a basic Genius Hot Standby CPU Redundancy system, Genius blocks receive outputs from two PLCs (Primary PLC and Secondary PLC), but they are normally controlled directly by the Genius Bus Controller at serial bus address 31 (Genius Bus Controller in the Primary PLC). If no output data is available from bus address 31 (the preferred data)

GFK-0827 Chapter 1 Introduction 5