Siemens SIMATIC ET 200AL, System Manual

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Functions
5.4 Media redundancy (ring topologies)
PROFINET with STEP 7
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Function Manual, 05/2021, A5E03444486-AL
5.4.4 Multiple rings
Multiple rings
Use multiple rings to achieve higher availability for PROFINET IO networks with star topology.
In a multiple ring configuration, several PROFINET lines lead from a switch (star topology).
The individual PROFINET lines lead from IO device to IO device. Redundant PROFINET cables
run back to the switch from the last IO device on each individual line.
The switch operates as a manager. The manager must have two ring ports for each ring.
Multiple rings are possible. The SCALANCE X414 as of firmware version 3.10, for example,
supports up to 4 rings.
The manager monitors all the rings individually: It checks for each particular ring (an MRP
domain) whether the transmission path is intact. To do this, it uses an MRP instance in each
case. An MRP instance is required for each connected ring (set up automatically by STEP 7).
Figure 5-42 Configuration with several rings
Requirements
• SCALANCE X414 as of version 3.10
• SCALANCE X300 as of version 4.0 (configured via GSD file)