Coexistence Of Standard And Fail-Safe Components - Siemens SIMATIC S7 System Manual

Configuration Example for an S7 FH Systems F-System
The following figure illustrates an example of an S7 FH Systems system with redundant F-
CPU and shared, switched distributed I/O, as well as connection to a redundant system bus.
Figure 2-5
2.2.4

Coexistence of Standard and Fail-safe Components

Coexistence Is Possible
Standard, fault-tolerant (H-), and fail-safe (F-) components and systems can be used in
combination as follows:
• Standard systems, H-systems, F-systems, and FH systems can coexist in a system.
• In an F-system:
• In an F-system or FH-system, a standard user program can be executed along with the
Safety Engineering in SIMATIC S7
System Manual, 04/2006, A5E00109529-05
S7 FH Systems Fail-safe System
– Distributed I/O devices and systems can be operated with standard and fail-safe I/O,
such as ET 200S, ET 200pro and ET 200eco.
– S7-300 standard and fail-safe signal modules can be operated in safety mode both as
centralized modules (in S7 Distributed Safety only) and as decentralized modules in
ET 200M.
safety program.
Configurations and Help with Selection
2.2 Configuration of F-Systems
2-7