PROFIBUS Power Hub Segment Coupler 3 (SK3)
Basic Redundancy Concepts
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Basic Redundancy Concepts
The following redundancy concepts have become established on the market: Flying
redundancy and system redundancy. These redundancy implementations are described in the
following sections.
Flying Redundancy
This concept connects both slave and master instances to the same physical bus, so only
1 PROFIBUS DP cycle exists. The address of the primary slave incremented by 64 is assigned
to the backup slave:
Figure 8.1
Flying redundancy
The concept has the disadvantage that in the event of a fault on the bus, all communication is
interrupted. If redundancy link modules (RLM) are used, this can be avoided through socalled
media redundancy. As the following topology illustrates, a fault is only relevant to the
corresponding bus:
