Siemens SIMATIC S7 F, Manual

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Configuration
Fail-Safe Systems
4-4
A5E00085588-03
4.4 Parameter Assignment of F-I/Os
Additional options are available for parameter assignment of F-I/Os that are not
available for parameter assignment of comparable standard SMs:
•
You can select between safety mode (different levels to a certain extent) and
standard mode.
•
You can operate F-I/Os redundantly in safety mode to increase availability
(fault tolerance). Redundant modules can be inserted either in the same
mounting rack or in different ones for increased availability. Note: redundancy
is only available in modules which support it.
An F-I/O cannot be addressed directly in safety mode. It can only be addressed via
the fail-safe driver blocks.
Only in the F-I/O can you choose between Safety and Standard-Mode, but not in
the ET 200S F modules.
Dynamic parameter assignment by means of SFC calls is only possible in standard
mode for the F-SM. It is not possible to change to safety mode in this way.
You can find more information on the parameter assignment of F-I/Os in manual /1/
(refer to the references in Appendix B) and in the context-sensitive help information
in HWCONFIG.
Symbolic Names
Note
Enter a symbolic name for each input or output channel of the configured F-I/Os.
In the case of F-I/Os in safety mode, in CFC you must assign the symbolic name of
the associated channel to the VALUE input of each F channel driver block.
This enables automatic assignment between the module parameters configured in
HWCONFIG (addresses, monitoring times, etc.) and the I/Os of the associated F
channel driver blocks in CFC.
If you configure 1oo2 sensor evaluation for the digital input modules, we
recommend that you mark the channels that are unavailable (4 to 7 in the SM 326;
DI 8 x NAMUR and 12 to 23 in the SM 326; DI 24 x DC 24 V and the
corresponding channel in the 4/8 F-DI 24 VDC PROFIsafe) as reserved in the
symbol table.