Siemens SIMATIC S7 F Manual page 116

Programming
5.3.10.2 Programming Communication Between F-Run-Time Groups
Within a CPU
Rules for Communication Between F-Run-Time Groups
•
If data has to be exchanged between two F-run-time groups, you cannot
interconnect the inputs and outputs directly. Instead, you must use separate
fail-safe blocks for these functions.
•
Sequence: See Defining the Run Sequence.
Available Fail-Safe Blocks
You must use the following fail-safe blocks for data exchange between F-run-time
groups:
Block
F_S_R / F_R_R
F_S_BO / F_R_BO
Procedure
1. Insert an F-Block of the type F_S_x (F_S_R or F_S_BO) in the F-run-time
group from which data is to be transferred.
2. Insert an F-Block of the type F_R_x (F_R_R or F_R_BO) in the F-run-time
group to which data is to be transferred.
3. Interconnect the SD_R_xx input of the F_S_R or the SD_BO_xx input of the
F_S_BO with the send data.
4. Interconnect the RD_R_xx outputs of the F_R_R or the RD_BO_xx outputs of
the F_R_BO with the inputs of the F-Blocks for further processing of the
received data.
5. Interconnect the S_DB output of the send block with the S_DB input of the
corresponding receive block.
6. Assign parameter to the TIMEOUT inputs of the F_R_R and F_R_BO receive
blocks with the desired monitoring time.
You can find information on how to calculate this in the section entitled
"Configuring the Monitoring Times for S7 F/FH Systems".
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Description
Safe transfer of 5 parameters of the F-data type F_REAL
Safe transfer of 10 parameters of the F-data type F_BOOL
Fail-Safe Systems
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