Mrpd - Siemens SIMATIC NET System Manual

Network structures and network configuration
2.3 Media redundancy
Depending on the connection status of the interconnection ports, the MIC sends status
messages (Link up or Link down) to the MIM. Interconnection ports are ports that are
connected over the primary or secondary connection. This means the MIM is always
informed about the connection status between the Primary MIC and the Primary Coupled
MIC ("primary connection") as well as its own connection to the Secondary Coupled MIC
("secondary connection"). In regular operation, the data exchange between the two rings is
via primary connection and the MIM blocks its interconnection port. If a Link down of the
primary connection is signaled to MIM, it switches its interconnection port to the "Forwarding"
status, and the data exchange between the two rings is via secondary connection between
MIM and Secondary Coupled MIC.
Note
Suitable devices for MRP Interconnection
The Interconnection Manager, the Interconnection Client and all other devices in the rings
must support MRP Interconnection. This is the case for the following devices:
• SCALANCE XM-400 as of firmware version V6.2
• SCALANCE XR-500 as of firmware version V6.2
2.3.5

MRPD

MRPD - Media Redundancy with Planned Duplication
The MRPD procedure is specified in IEC 61158 Parts 5 and 6 type 10 "PROFINET". It allows
bumpless redundant linking of devices.
The cyclic IRT frames are duplicated and the PROFINET devices connected to the ring send
their data in both directions. The devices receive this data at both ring ports, and this
reduces the reconfiguration time of the ring. As with MRP, a redundancy manager prevents
circulating data frames.
Requirements
● Devices with ERTEC hardware support.
– SCALANCE X-200IRT as of firmware version 5.0
● STEP 7 as of version V5.5 SP1
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System Manual, 09/2019, C79000-G8976-C242-10
Industrial Ethernet