Fail-Safe Blocks
Fail-Safe Systems
8-72 A5E00085588-03
8.6.9 F_SHUTDN
Function
The F_SHUTDN function block, which is a standard function block packaged in the
Failsafe Blocks library, provides new functionality to control and manage F-run-time
group shutdown and reinitialization.
The F_SHUTDN function block:
• is automatically placed by the compiler in a CFC named @F_ShutDn.
• interfaces to other blocks within the Safety Program.
• has two separate interfaces: shutdown logic interface and restart logic
interface.
• is connected to the shutdown logic through the RTG_LOGIC blocks to the
F_PLK, F_PLK_O, F_TEST, F_TESTC, and F_CYC_CO.
• is connected to the restart logic through the RTG_LOGIC connected to the
DB_INIT functionsstored in the @F_DbInit1.
• is placed in the slowest Organizational Block (OB3x) in a run-time group
named @F_ShutDn.
Note
No other logic shall be permitted to be placed within the @F_ShutDn CFC.
Connections may only be made to specified inputs and outputs of the F_SHUTDN
function block (see the table of I/Os below). Any logic placed within the
@F_ShutDn CFC will automatically be deleted during the compile.
I/Os
Name Data Type Explanation Default
Inputs:
RESTART BOOL Used to restart any F Run-time
group that is shutdown. A
rising edge will trigger the
reinitialization process that
may take several seconds to
complete. This input may be
connected to external logic.
0
FAILURE BOOL Combination of logical OR of
all F Run-time group
Shutdown requests (FAILED
output of F_PLK, F_TEST,
F_TESTC, and F_CYC_CO).
This input cannot be
connected to external logic.
0
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