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