dl-breadcrumbs__homedl-breadcrumb-item__separatorConfiguration and programmingdl-breadcrumb-item__separatorConfiguration in Automation Builderdl-breadcrumb-item__separatorPLC devices and componentsdl-breadcrumb-item__separator...dl-breadcrumb-item__separatorPROFINET IO Configuratordl-breadcrumb-item__separatorPROFINET IO controllerdl-breadcrumb-item__separatorFunctions dl-breadcrumb-item__separatorMedia Redundancy (MRP)
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Media Redundancy (MRP)

Media redundancy (based on MRP – Media Redundancy Protocol) is a function for increasing the system availability by means of redundant communication paths. Standard Ethernet allows for only a single, unique data path (line and star topologies) to one network participant. MRP allows for the physical closing of a line topology to one ring. As a result, the participant can be reached over two paths.

All participants of an MRP ring (also: "MRP domain") have to be configured as a media redundancy client (MRC) and at least one of them as a media redundancy manager (MRM). If there is no physical malfunction of the rings, then the MRM interrupts the ring to prevent an infinite loop of Ethernet data. When a malfunction is detected, the MRM opens the ring and the participants in the disconnected network segment can be reached again.

Media redundancy can be combined with other redundancy mechanisms such as system redundancy. It is possible to configure multiple rings and (if the devices support it) also multiple configured rings. Devices that do not support MRP themselves can be attached to an MRP ring as passive participants (from an MRP perspective). One example is an MRP ring of switches to which the remaining participants are attached as in a classic star topology. Media redundancy is negotiable for standard Ethernet protocols and therefore not limited to PROFINET communication.

Configuration / Commissioning:

  1. In the topology editor, configure the port switching of the PROFINET Devices.

    In the simplest case, a real existing line topology, which is not yet closed to the ring, can also be imported into the project using the import function. Then close the ring in the configuration.

    Result:

    _pnio_img_topology.png

  2. Activate the ring and configure a participant as the “Manager” or multiple participants as “Manager_Auto”.

    On the “Media Redundancy” tab, a closed ring with the participants is displayed.

    _pnio_img_media_redundancy.png

  3. Download the project to the controller.

    The PROFINET Devices are parameterized with the MRP configuration at start-up.

    As long as the ring has not been closed physically, the MRM displays a diagnosis "MRP Ring open".

  4. After successful configuration, you can now close the ring physically.

NOTICE

NOTICE
NOTICE
NOTICE

NOTICE

NOTICE

In the case that the ring is interrupted, the reconfiguration of the ring may cause a temporary interruption of the PROFINET communication. This is the case when the interruption is longer than the watchdog time set for the PROFINET connection. This time depends on the number of devices (maximum of 50 devices per ring) as well as the type of device. The total time is always less than 200ms and can also be significantly shorter.