Synchronization Modules; Synchronization Modules For S7-400H - Siemens SIMATIC S7-400H System Manual

Synchronization modules

15.1

Synchronization modules for S7-400H

Function of the synchronization modules
Synchronization modules are used for communication between two redundant S7-400H
CPUs. You require two synchronization modules per CPU, connected in pairs by fiber-optic
cable.
The system supports hot-swapping of synchronization modules, and so allows you to
influence the repair reaction of the fault-tolerant system and to control the failure of the
redundant connection without stopping the plant.
If you remove a synchronization module in redundant mode, there is a loss of
synchronization. The standby CPU changes to the TROUBLESHOOTING mode. The other
CPU remains master and continues operation in single mode. Once you have inserted the
new synchronization module and re-established the redundancy link, the standby CPU links
up and updates.
Distance between the S7-400H CPUs
Two types of synchronization module are available:
Order number
6ES7 960–1AA04–0XA0
6ES7 960–1AB04–0XA0
Long synchronization cables may increase cycle times by up to 10 % per cable kilometer.
Note
A fault-tolerant system requires four synchronization modules of the same type.
S7-400H
System Manual, 09/2007, A5E00267695-03
Maximum distance between the CPUs
10 m
10 km
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