Siemens SIMATIC PCS 7 Function Manual page 41

Hardware components
Communication processors
Setup
Racks
The following racks are available for installing the S7-400H. Normally, the UR2-H rack is used.
Type
Rack UR2‑H
Rack UR2
Rack UR1
Rack CR3
Central processing units
There are two CPUs in an H-system. The two CPUs are connected to one another using
synchronization modules and fiber-optic cables.
Power supply
A separate power supply module from the standard S7-400 series is needed for each
subsystem of the S7-400H. Two power supply modules can be used in each subsystem to
increase the availability of the fault-tolerant system. In this case, use the following power supply
modules that can be used for redundancy.
Power supply modules for 24 VDC as well as for 120/230 VAC nominal input voltages with
output currents of 10 and 20 A.
Fault-tolerant Process Control Systems (V8.1)
Function Manual, 11/2014, A5E34878832-AA
Communication processor CP 443-5 Extended
Communication processor CP 443-1
Slots Special feature
2 x 9 Installation of two separate subsystems each with nine
modules. The two subsystems are electrically isolated
(not mechanically).
It is not possible to replace a rack in runtime.
1x 9 Two racks are required for an S7-400H .
You can replace a rack in runtime.
1x 18 Two racks are required for an S7-400H .
You can replace a rack in runtime.
1x 4 Two racks are required for an S7-400H .
You can replace a rack in runtime.
Fault-tolerant Solutions in PCS 7
3.2 Solutions for automation systems
41