Multiple Rings - Siemens SIMATIC ET 200AL System Manual

The figure below shows the display of the redundancy levels in STEP 7 for the example
configuration.
Figure 5-38
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.
Several rings are possible. For example, the SCALANCE X414 as of firmware version 3.10
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 5-39
PROFINET with STEP 7 V15
Function Manual, 12/2017, A5E03444486-AH
Display of the redundancy levels in STEP 7
Configuration with several rings
5.4 Media redundancy (ring topologies)
Functions
169