State Industries FANUC GFK-0827 - Manual (Page 39)

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28 Series 90-70 Hot Standby CPU Redundancy User’s Guide – December 1993 GFK-0827
Redundancy System Requirements
For a redundant CPU configuration using the Hot-Standby Redundancy scheme to be
valid, the following requirements must be true in both the Primary Unit and the
Secondary Unit in the redundancy system.
H One configuration must be set to Primary; the other to Secondary.
H The control strategy configurable parameter must be set to ”GHS”.
H An RCM must be configured in rack 0 of each system. There can be no empty slots
between the RCM and the CPU. For a given unit, the Local RCM is the one
configured in that unit; the Remote RCM is not configured by the user, but is
automatically configured by the system to be in slot 1 of rack 7.
H All Genius Bus Controllers in the system must be configured for RED CTRL
Redundancy with the redundant pair set for EXTERNAL, or they must be
configured for no redundancy.
H If a Genius Bus Controller is set to redundant in a redundant CPU configuration, all of
its bus blocks must also be set redundant; if a Genius Bus Controller is set
non-redundant in a redundant CPU configuration, all of its bus blocks must also be set
non-redundant.
H If the primary/secondary configurable item is set to PRIMARY, all Genius Bus
Controllers configured for RED CTRL redundancy must have Serial Bus Address 31.
If the primary/secondary configurable item is set to SECONDARY, all Genius Bus
Controllers configured for RED CTRL redundancy must have Serial Bus Address 30.
H The Shared I/O selections must match exactly between Primary and Secondary PLCs.
Basic Redundancy System Setup
H Assemble each PLC system and cable the last rack of each system to the RCM of the
other PLC using the terminated I/O cable. If there are no expansion racks in the
system, cable each BTM to the RCM in the other PLC.
Logicmaster 90 Configuration
H Set the primary CPU to PRIMARY.
H Set the secondary CPU to SECNDARY.
For both Primary and Secondary CPUs, do the Following:
H Select Data Transfer (SHARED I/O) parameters (up to 20 Kbytes Input data, up to 28
Kbytes Output data).
H Configure the SBA for all Redundancy Genius Bus Controllers (SBA 31 for the
Primary; SBA 30 for the Secondary), and Redund Mode to ”RED CTRL”.
H Select fail-wait time. The default value of 60 ms should suffice for most applications.
H Select watchdog timer. Allow for worst case scan time plus data transfer time plus
two fail-wait times (plus a generous margin). Setting this value too small could
cause the standby unit to time out during a failure of the active unit.
H Select the programmer window. Set to about 10% of the normal scan time (if scan
time is unknown, use default time (do not exceed the fail wait time).
H Select Fault Actions.
I/O System Configuration
H Configure your I/O system as required for your application.