Siemens SIMATIC CPU 410 System Manual page 29

Power supply
You require a power supply module from the standard system range of the S7-400 for each
of the two subsystems of the S7-400H.
To increase availability of the power supply, you can also use two redundant power supplies
in each subsystem. In this case, you use the power supply modules PS 405 R / PS 407 R.
A combination (PS 405 R with PS 407 R) can also be used.
Synchronization modules
The synchronization modules are used to link the two CPUs. They are installed in the CPUs
and interconnected by means of fiber-optic cables.
Two types of synchronization modules are available:
● Synchronization modules for synchronization cables up to 10 meters long
● Synchronization modules for synchronization cables up to 10 kilometers long
You must use 4 synchronization modules of the same type in a fault-tolerant system. For a
description of the synchronization modules, refer to the section Synchronization modules for
the CPU 410. (Page 239).
Fiber-optic cable
The fiber-optic cables are used to interconnect the synchronization modules for the
redundant link between the two CPUs. They interconnect the upper and lower
synchronization modules in pairs.
You will find the specification of the fiber-optic cables you can use in an S7-400H in the
section Selecting fiber-optic cables (Page 245).
Operation
You need a system expansion card for operation of a CPU 410. The system expansion card
specifies the maximum number of process objects that can be loaded to the CPU and saves
the license information in case of a system expansion. The system expansion card forms a
hardware unit with the CPU 410. In redundant operation, each CPU 410 must have a system
expansion card with identical quantity framework and scope of functions.
CPU 410 Process Automation/CPU 410 SMART
System Manual, 05/2017, A5E31622160-AC
Introduction to the CPU 410
2.4 The basic system for redundant operation
29