Description
User manual 55170_hdb_en_13
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Fig. 3-6: Malfunction
Function of a Media
Redundancy Manager
(MRM)
The function of a Media Redundancy Manager (MRM) is to check the opera-
bility of the ring structure specified by the configuration.
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 Redundancy 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.
When interrupted from the ring, Profinet communication will continue after re-
configuration.
For further information, refer to chap. 8.7 "Media redundancy (MRP) configu-