Allen-Bradley ControlNet PLC-5 User Manual page 50

B-8 Backup States
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ControlNet Backup Configuration and Status file - This
checksum is only calculated when the PLC-5 system goes
through qualification. Since this checksum cannot change
when the PLC-5 system is in Run mode, this checksum does
not change after qualification. The ControlNet Backup
Configuration and Status File checksum is only calculated on
the first 3 words of the ControlNet Backup Configuration and
Status File.
Force Tables - This checksum is calculated for all I/O force
tables and for force control words, and continues to be
calculated when the backup system is qualified. This allows
status to be available regarding whether the Force Table
checksums differ for a qualified backup system. Included in
the Force Tables checksum are:
• I/O Force Table values
• Extended Force Table values
• Force Status (is forcing enabled and are forces present)
No SFC information is included in the Force Tables
checksum. Also, note that you cannot perform forcing on
DIF or DOF files.
Status File - This checksum is calculated for various
configured words in the Status File, and continues to be
calculated when the backup system is qualified. This allows
status to be available regarding whether the Status File
checksums differ for a qualified backup system. The
different words included in the Status File checksum for
equivalence checking are:
• Watchdog Set Point
• Fault Routine Number
• STI Set Point
• STI Routine Number
• I/O RESET Bits
• I/O INHIBIT Bits
• PII Routine Number
• PII Word Number
• PII AND Mask
• PII Polarity Mask
• PII Counter Preset
• Data Table Protection File Number
• ControlNet Backup Configuration and Status File
Number
• ControlNet PLC-2 File Number
• MCP I/O Disable Word
• MCP INHIBIT Word
• MCP File Numbers