Siemens SIMATIC S7 F, Руководство пользователя

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Programming
Fail-Safe Systems
5-10
A5E00085588-03
5.3 Inserting and Interconnecting Fail-Safe Blocks
5.3.1 Inserting Fail-Safe Blocks
Blocks are inserted in the chart by dragging and dropping them from the F User
Blocks folder of the Failsafe Blocks library. Each block can be inserted as often
as you want.
Note
If a block type has already been inserted from the library, it can be inserted more
quickly the next time from the "CFC Catalog". Note that although fail-safe blocks
and conversion blocks that convert F-data types to standard data types are
distributed to the usual block groups, they are easy to recognize because they are
colored yellow and their names always begin with F_.
Rules for Fail-Safe Blocks
•
Fail-safe blocks must be inserted in separate charts in which there must not be
any standard blocks.
•
The F blocks in the F Control Blocks folder are automatically inserted when
the chart is compiled; you must not insert these blocks. Exception: Manual
insertion of the F module drivers.
•
Fail-safe block’s instances must not be placed in multiple F-run-time groups.
This may occur due to an F-run-time group being copied to or inserted in
another task.
•
You must not use the names of the fail-safe blocks for other blocks or rename
the fail-safe blocks.
!
Safety Note – Symbol Table Entries for F-Blocks cannot be changed
The names of the fail-safe blocks in the "Symbol" column of the symbol table of
your user program must not be changed or deleted.
If a change to the block names in the symbol table is detected, the compilation of
the Safety Program is rejected with the following error message:
"Block type ’xxx’ does not correspond to the standard in the "Fail-safe Blocks
library [Import the block again from the "Fail-safe Blocks" library into the block
catalog and the chart folder of the program]
This also applies to changes in the symbol table assigned to the "Fail-safe Blocks"
block library.
If changes to F-Block names are detected, you can correct the names of the fail-
safe blocks in the symbol table. You can find the correct names in the "Name
(Header)" text box on the "General" tab in the "Object Properties" dialog box for the
block.
See Also
Fail-Safe Blocks