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2 Product description
2.1.8
Media redundancy protocol (MRP)
The MRP protocol according to IEC 62439 describes PROFINET redundancy
with a typical reconfiguring time of < 200 ms for communication paths with TCP/IP
and RT frames after a fault.
Error-free operation of an automation system involves a media redundancy
manager (MRM) and several media redundancy clients (MRC) arranged in a ring.
The function of a Media Redundancy Manager (MRM) 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 behaviour 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. It must have
two switch ports in order to connect to other MRCs or the MRM in a single ring.
SFB-PN modules can be configured as MRCs.
INFORMATION
Information about the configuration of the Media redundancy protocol (MRP)
can be found in the system manual of your engineering software.
Fault
in field bus
wiring
