3.15.2 Data transfer from standard user program to the safety program
Overview
It is only permissible that fail-safe data or fail-safe signals from the F-I/O and other safety
programs (in other F-CPUs) are processed in the safety program, as all variables from the
standard program are not secured.
If you have to process tags from a standard user program in the safety program, then you can
either evaluate bit memories from the standard user program, tags from a standard DB or the
process image of the inputs (PII) from the standard I/O in the safety program (see also the table
of the supported operand areas in: Restrictions in the programming languages FBD/LAD
(Page 63)).
However, note that structural changes to standard DBs, which are used in the safety program,
can result in inconsistencies of the safety program so that the password is possibly queried as
a consequence. In this case, the F-collective signature after compilation corresponds to the
original one. To avoid this effect, use "Coupling data blocks" between the standard user
program and the safety program.
WARNING
Unexpected machine motion when using non-failsafe data
Bit memories from the standard user program, variables of a standard DB or the process
image of inputs (PAE) of the standard I/O are not failsafe data. Hazardous states can occur in
the machine if you evaluate non-failsafe data in the safety program. This can put people in
dangerous situations or cause material damage.
● Check the standard data in the safety program for plausibility.
● If you use standard data in both F-runtime groups, then separately check the plausibility in
both F-runtime groups.
To make checking easier, when printing out the safety program, all PLC variables from the
standard user program, which are evaluated in the safety program, are printed out.
Bit memory
In order to process tags of the standard user program in the safety program, you can also read
bit memory in the safety program. However, read bit memory must not be written in the safety
program itself.
Safety program of the F-PLC
3.15 Data exchange between the standard user program and safety program
Safety Integrated (with SINAMICS S120)
90 Commissioning Manual, 02/2020, A5E46305916B AB
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