Single-Channel I/O (S7 Distributed Safety) - Siemens SIMATIC S7 System Manual

Configurations and Help with Selection
2.3 Configuration Variants for Fail-safe Systems According to Availability Requirements
Further information about PROFIBUS and Industrial Ethernet
PROFIBUS or Industrial Ethernet is described in the SIMATIC NET hardware manuals
PROFIBUS Networks
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)
Figure 2-6
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.
2-10
Industrial Twisted Pair and Fiber Optic Networks
and
S7 Distributed Safety with Single-channel I/O (Centralized Configuration)
, respectively.
Safety Engineering in SIMATIC S7
System Manual, 04/2006, A5E00109529-05