Description
User manual 55530_hdb_en_16
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3.2.4
MRP
Media redundancy
(MRP)
The Media Redundancy Protocol (MRP) according to IEC 62439 describes
the PROFINET redundancy with a typical reconfiguration time of <200 ms for
the communication lines with TCP / IP and RT frames after an error. The fault-
free operation of an automation system implies a Media Redundancy Manag-
er (MRM) and several Media Redundancy Clients (MRC) arranged in a ring.
Function of the Media
Redundancy Manager
(MRM)
The function of a Media Redundancy Manager consists in checking the ring
structure required by the configuration for its operability.
This is done by sending cyclic test telegrams. As long as the test telegrams
are received again by the MRM, the ring structure is intact.
An MRM uses this behavior to prevent circulation of telegrams and to convert
a ring structure into a line structure.
A
Media Redundance Client (MRC)
is a switch that functions only as a so-
called "forwarder" of telegrams and does normally not play an active role.
MRC must have two switch ports in order to connect to other MRCs or the
MRM in a single ring. The modules can be configured as MRCs.
