Communication Options
3.6 Safety-Related CPU-CPU Communication
Safety Engineering in SIMATIC S7
System Manual, 04/2006, A5E00109529-05
3-13
3.6
3.6
Safety-Related CPU-CPU Communication
Introduction
Both S7 Distributed Safety and S7 F/FH Systems allow safety-related communication
between safety programs in different F-CPUs. However, the communication mechanisms for
each are different:
Table 3-3
Overview of Communication between F-CPUs
F-System
Communication via ...
Communication between ...
PROFIBUS DP
DP master/DP master
PROFIBUS DP
DP-master/I-slave
PROFIBUS DP
I-slave/I-slave
PROFINET IO
I/O Controller / I/O Devices
S7 Distributed Safety
Industrial Ethernet (configured
S7 connections)
Not relevant
S7 F/FH Systems
Via PROFIBUS, MPI, Industrial
Ethernet, etc:
Configured standard or fault-
tolerant
S7 connections
Not relevant
3.6.1
S7 Distributed Safety: Safety-related Master-Master Communication
DP/DP Coupler
In S7 Distributed Safety, a DP/DP coupler (order number 6ES7 158-0AD01-0XA0) must be
used for safety-related communication between safety programs in different F-CPUs (DP
masters).
Each F-CPU is linked to the DP/DP coupler via its PROFIBUS DP interface.