Run Sequence Of F-Blocks - Siemens SIMATIC PCS 7 Operating Manual

Configuring the safety program
7.2 Creating the safety program
Example: Structural element F_Real VHRANGE [STRUCT]"HIGH RANGE OF PROCESS VALUE"
You can change the structure comment to whatever you wish.
If you wish to change the value (default) of a block connection with an F data type, you may
only change the DATA component.
Changes to the input parameters of F blocks with F data types can be made as follows:
● Offline with the assistance of the CFC editor
● Online using CFC test mode with safety mode deactivated
Note
Values of PAR_ID and COMPLEM must not be changed.
If errors in the safety data format are detected during the execution of the safety program, an
F-STOP is triggered.
7.2.4

Run sequence of F-blocks

Defining the run sequence
You define the run sequence in the CFC editor in the same way as for a standard user
program. Changing the run sequence also changes the collective signature.
Correct run sequence of F-blocks
The sequence of the F-blocks within the F-shutdown group is relevant. The number of F-
runtime groups the F-shutdown group has been split into is of no relevance.
Essentially, the correct run sequence of the various F-block types is as follows:
1. Placed automatically:
– F module driver for F-signal modules with inputs or with inputs and outputs
– F-communications blocks and F-system blocks for receiving
– F blocks for data conversion from standard value to F-structure
– F modules with OS connection
2. F channel drivers for inputs
3. F blocks for user logic
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Compendium Part B - Process Safety (V8.2)
Operating Manual, 07/2016, A5E35031794-AB