Allen-Bradley ControlNet PLC-5 User Manual page 52

B-10 Backup States
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All elements of all data table files are crossloaded in the
Qualification Data Table crossload, with the exception of the
following files. These files cannot be crossloaded because they
contain processor-specific configuration and status information.
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Though the complete Status File is not crossloaded, there are six
words in this file that are transferred from the primary system to
the qualifying system. These six words are the real-time clock.
The Qualification Data Table crossload does not occur if the Data
Table Structures are not the same. If you want to ensure that a
Qualification Data Table crossload occurs, you must enable
equivalence checking for the Data Table structure area.
If, for some reason, the Qualification Data Table crossload fails,
qualification also fails and a major fault is declared for the
qualifying system. (Refer to Chapter 4 for descriptions of
specific major fault codes.)
• Transition to Run mode
Once the complete Data Table crossload is complete, the
qualifying PLC-5 system transitions into Run mode. Although
the PLC-5 system is now in Run mode, the PLC-5 processor is
not through with qualification and is still in the No Control
backup state. Also note that any outputs in the qualifying
processor that are not ControlNet redundant connections are now
controlled by the PLC-5 processor. This includes any local
resident chassis outputs, remote I/O channel outputs, and
non-redundant I/O connections on the ControlNet channel.
• State data table crossload
Even though a Qualification Data Table crossload has occurred,
some of the crossloaded data may have become stale. For
example, if the Qualification Data Table crossload takes 10
seconds, the data in the original data table file that was
transferred is 10 seconds old. In order to bring certain state
information in the data table up to date, a Qualification State Data
Table crossload is performed.
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Status File
ControlNet Backup Configuration and Status File
ControlNet Data Input File (DIF)
ControlNet Data Output File (DOF)
ControlNet Configuration File
ControlNet I/O Status File
ControlNet Diagnostic File