Safety Notes For Programming; Compiler Generated Values Off-Limits - Siemens SIMATIC S7 F Manual

Programming
5.2.2

Safety Notes for Programming

•
A Safety Program can only be compiled to be executable under an F-capable
CPU (e.g. CPU 417-4H).
•
The Safety Program must be created in CFC using special F-Blocks from the
Failsafe Blocks library. The name of the library must not be changed.
•
During compilation the Safety Program is changed automatically, and F-
specific sections are added. These are modified parameter values and
additional blocks. These modifications are visible in the CFC chart.
Safety Note – Compiler Generated Values off-limits
!
Placements, interconnections and parameter assignments of F-Blocks
automatically executed during compilation must not be changed!
•
The COMPLEM and PARID structural components of F-data types must not be
manipulated.
•
Control blocks inserted automatically must not be changed.
•
Parameters not visible in F blocks and parameters marked as non-
interconnectable (UDA s7_visible, s7_link) must not be interconnected or
parameterized.
Fail-safe blocks must not be manipulated (deleted, inserted) offline or online in the
block container.
Online modifications of the fail-safe I/Os in SIMATIC Manager made, for example,
by controlling variables or forcing are not permissible and will result in a Safety
Progam disable if fail-safe blocks (V1.2) or greater is used.
You must not operate Safety Programs directly when safety mode is activated! You
can enter safety parameters for unconnected inputs:
•
from the standard program, using fail-safe conversion blocks with an
additional plausibility check
•
in CFC test mode and with safety mode deactivated.
If you don't comply with these safety guidelines, you also risk the Safety Program
becoming disabled.
Fail-Safe Systems
A5E00085588-03
5-5