Increase Of Plant Availability, Reaction To Errors - Siemens SIMATIC CPU 410 System Manual

I/O configuration variants
6.3 Fault-tolerant automation systems (redundancy operation)
Single-channel switched I/O
In single-channel switched configuration, there is one of each of the input/output modules. In
redundant operation, these modules can addressed by both subsystems. The single-channel
switched I/O configuration is recommended for system components which tolerate the failure
of individual modules.
See also
Connection of two-channel I/O to the PROFIBUS DP interface (Page 80)
6.3.2

Increase of plant availability, reaction to errors

System-wide integration
The CPU 410 and all other SIMATIC components, such as the SIMATIC PCS 7 control
system, are matched to one another. The system-wide integration, ranging from the control
room to the sensors and actuators, is implemented as a matter of course and ensures
maximum system performance.
Graduated availability by duplicating components
The redundant structure of the S7-400H ensures requirements to reliability at all times. This
means: all essential components are duplicated.
This redundant structure includes the CPU, the power supply, and the hardware for linking
the two CPUs.
You yourself decide on any other components you want to duplicate to increase availability
depending on the specific process you are automating.
Redundancy nodes
Redundant nodes represent the fail safety of systems with redundant components. A
redundant node can be considered as independent when the failure of a component within
the node does not result in reliability constraints in other nodes or in the overall system.
The availability of the overall system can be illustrated simply in a block diagram. With a 1-
out-of-2 system, one component of the redundant node may fail without impairing the
operability of the overall system. The weakest link in the chain of redundant nodes
determines the availability of the overall system
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CPU 410 Process Automation/CPU 410 SMART
System Manual, 05/2017, A5E31622160-AC