Glossary - Siemens SIMATIC S7-1200 Safety Programming Manualline

5 Glossary

Glossary
5
Coded processing
To meet the normative requirements in terms of redundancy and diversity, all
SIMATIC F-CPUs use the "coded processing" principle. In coded processing, the
safety program is processed twice by a single processor.
To this end, the compiler generates a diverse (encoded) safety program that is
referred to as the protection program.
The first program run processes the unmodified safety program of the user. After
that, the protection program is processed. Then the F-CPU compares the results. If
processed correctly, the safe outputs are written. If there are differences between
the two program parts (e.g., due to data corruption), the F-CPU goes to stop and
generates an entry in the diagnostic buffer.
Figure 5-1: Safety program processing sequence
Main Safety
(F-CALL)
Zeit
Data corruption
Data corruption means that data of the safety program has been tampered with by
external influences (e.g., EMC influences) or illegal write access.
F-CPU
An F-CPU is a controller suitable for safety-related tasks.
PROFIsafe
PROFIsafe is a protocol for fail-safe communication via PROFINET.
Cross-circuit
Cross-circuit detection is a diagnostic function of an evaluation unit that detects
short-circuits or cross-circuits between two input channels (sensor circuits).
A cross-circuit can be caused, for example, by a squashed light plastic-sheathed
cable. Without cross-circuit detection, this would result in, for example, a two-
channel emergency stop circuit not tripping even though only one normally closed
contact is faulty (secondary error).
Safety Programming Guideline
Entry ID: 109750255, V1.0,
F-PAE lesen (F_CTRL_1)
Sicherheitsprogramm bearbeiten
Absicherungsprogramm bearbeiten
Ergebnisse vergleichen
F-PAA schreiben (F_CTRL_2)
10/2017
F-Ablaufgruppe
45