Configurations and Help with Selection
2.3 Configuration Variants for Fail-safe Systems According to Availability Requirements
Safety Engineering in SIMATIC S7
2-10
System Manual, 04/2006, A5E00109529-05
Further information about PROFIBUS and Industrial Ethernet
PROFIBUS or Industrial Ethernet is described in the SIMATIC NET hardware manuals
PROFIBUS Networks and Industrial Twisted Pair and Fiber Optic Networks, respectively.
2.3.1
Single-channel I/O (S7 Distributed Safety)
Characteristics of Single-channel I/O
In a single-channel configuration, fail-safe I/O are not redundant. The fail-safe I/O is
addressed by one F-CPU.
Required Hardware Components for S7 Distributed Safety
The hardware component requirements depend on whether the F-System is configured as a
centralized system or as a decentralized system and whether the PROFIBUS DP is
configured with a copper cable or a fiber-optic cable. The F-I/O is not redundant.
Centralized Configuration of S7 Distributed Safety
Centralized configuration of S7 Distributed Safety requires the following elements:
•
One CPU 31xF-2 DP or CPU 31xF-2 PN/DP
•
F-SMs and, if necessary, standard SMs
•
Safety protector (required for SIL3/Category 4 applications only)
Configuration Example of S7 Distributed Safety: Single-channel I/O (Centralized Configuration)
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Figure 2-6
S7 Distributed Safety with Single-channel I/O (Centralized Configuration)
S7 Distributed Safety with Stand-Alone IM 151-7 F-CPU
Note
Unlike IM 151-1 HIGH FEATURE, for example, the IM 151-7 F-CPU is an intelligent
preprocessing device (I-slave) and can also be used as a DP master. An IM 151-7 F-CPU
can therefore exercise full and, if necessary, independent control over a technological
functional unit and can be used as a stand-alone CPU or F-CPU. The IM151-7 F-CPU
represents an addition to the line of F-CPUs for S7 Distributed Safety.