F Control Blocks - Siemens SIMATIC S7 F Manual

Fail-Safe Blocks
8.6

F Control Blocks

To ensure that a Safety Program is executable, the F control blocks are necessary
to check the program execution time. These F control blocks are automatically
inserted and interconnected at compilation of CFC charts.
Block
F_CYC_CO
F_M_DI8
F_M_DI24
F_M_DO8
F_M_DO10
F_M_AI6
F_PLK
F_PLK_O
F_SHUTDN
F_TEST
F_TESTC
F_TESTM
DB_RES
DB_INIT
FAIL_MSG
RTG_LOGIC
Integration in Block Types
The control blocks must not be integrated in block types.
Fail-Safe Systems
A5E00085588-03
Description
F cycle time monitoring
F module driver for 8-channel digital input
F module driver for 24-channel digital input
F module driver for 8-channel digital output
F module driver for 10-channel digital output
F module driver for 6-channel analog input
Program execution monitoring before output blocks
Program execution monitoring after output blocks
Manage F-run-time group shutdown and restart in the
event shutdown errors occur.
Self-test for commands not backed up by diversity
Control block for the background self-test of the CPU
Activate/deactivate safety mode
Support of the startup characteristics for cold
restart/warm restart
FC used to restart (cold start) shutdown one or more
F-run-time groups
FC used to report a shutdown F-run-time group.
Logic used to interface between F_SHUTDN,
DB_INIT, and the F-run-time groups.
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