Communication Via A Point-To-Point Cp On The Et200M - Siemens SIMATIC S7-400H System Manual

11.6.3

Communication via a point-to-point CP on the ET200M

Connection via ET200M
Links from fault-tolerant systems to single-channel systems are often possible only by way of
point-to-point connections, as many systems have no other connection alternatives.
In order to make the data of a single-channel system available to CPUs of the fault-tolerant
systems as well, the point-to-point CP (CP 341) must be installed in a distributed rack along
with two IM 153-2 modules.
Configuring connections
Redundant connections between the point-to-point CP and the fault-tolerant system are not
necessary.
Figure 11-12 Example of linking of a fault-tolerant system and a single-channel third-party system
Reaction to failure
Double errors in the fault-tolerant system (in other words CPUa1 and IM153-2) and single
errors in the third-party system lead to a total failure of communication between the systems
involved (see previous figure).
The point-to-point CP can also be inserted centrally in "H system a". However, in this
configuration even the failure of the CPU, for example, will cause a total failure of
communication.
S7-400H
System Manual, 09/2007, A5E00267695-03
11.6 Communication via S7 connections
Communication
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