Chapter 6. Redundant Media
GFK-2571N
May 2018
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6.2
Ring Topology with One Controller
The following diagram illustrates a simple ring topology with one RX3i CPU Node and three I/O Devices on the
same PROFINET network. In Figure 99, the PROFINET Controller module in the RX3i controller is configured to
be the Media Redundancy Manager and the I/O Devices, in this case PNS modules, are configured to be Media
Redundancy Clients.
Figure 99: Ring Topology with One Controller
As a Media Redundancy Manager, the PROFINET Controller detects when the network ring has been broken
and repaired. Each time the PROFINET Controller detects that the ring has been broken or repaired, a fault is
reported in the Local Log table and that condition is passed to the RX3i CPU to be registered in the CPU fault
table. In addition, the PROFINET Controller keeps a count of break/repair detections. In the PNC001-Ax module,
this may be viewed via the CLI
show
rdnmedia
command.
As a Media Redundancy Manager, the PROFINET Controller detects whether another Media Redundancy
Manager is on the same ring. If more than one Media Redundancy Manager is present on the same ring, the
PROFINET Controller logs an entry in its Local Log table and passes the fault to the RX3i CPU fault table. Upon
detecting that there are no longer multiple Media Redundancy Managers on the ring, the PROFINET Controller
logs a fault in the Local Log and passes this to the RX3i CPU to be registered in the CPU fault table. This
indicates that the previously invalid setup has subsequently been resolved.
