Siemens SIMATIC S7 F, Manual

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Programming
Fail-Safe Systems
5-36
A5E00085588-03
5.3.10.3 Programming Communication Between the F User Program and
the Standard User Program
Available F Conversion Blocks
The following F conversion blocks are available:
Block Description
F_BO_FBO Converts from standard BOOL to F_BOOL
F_I_FI Converts from standard INT to F_INT
F_R_FR Converts from standard REAL to F_REAL
F_TI_FTI Converts from standard TIME to F_TIME
F_FBO_BO Converts from F_BOOL to standard BOOL
F_FR_R Converts from F_REAL to standard REAL
F_FI_I Converts from F_INT to standard INT
F_FTI_TI Converts from F_TIME to standard TIME
Rules for F Conversion Blocks
If data is to be exchanged between the F and the standard user programs, you
must not interconnect the inputs and outputs directly. Instead, you must use
separate F conversion blocks from the F library for these functions that can convert
to and from the safety data type.
Please comply with the following rules when you insert and interconnect F
conversion blocks:
•
The F-Blocks used to convert F-data types into standard data types
(F_FBO_BO, F_FR_R, F_FI_I or F_FTI_TI) must be placed in the standard
program.
•
The blocks used to convert standard data types to F-data types (F_BO_FBO,
F_I_FI, F_R_FR, F_TI_FTI) must be placed in the Safety Program.
•
You can only operate the Safety Program by means of F conversion blocks,
which you must insert explicitly.