Siemens SIMOTION D4x5-2 Commissioning And Hardware Installation Manual page 147

These two ports are marked with an "R" in the module rack in HW Config.
Note
Only devices with MRP-capable ports may be inserted in an MRP ring. If MRP-capable ports
are not used, the reconfiguration times can be in the seconds range.
Bumpless media redundancy (MRPD)
Requirement for SIMOTION D4x5-2:
● SIMOTION SCOUT as of V4.3
● SIMOTION SCOUT TIA as of V4.5
MRPD is a procedure for bumpless media redundancy for PROFINET IO with IRT. MRPD also
requires MRP.
The combination of MRP with MRPD provides bumpless PROFINET operation for short cycle
times in the event of a fault in the ring. MRPD is based on IRT and ensures bumpless operation
by the provider sending the cyclic data in both directions which the consumers then receive
twice. If the ring is interrupted somewhere (e.g. through the failure of a ring node), receipt of
the cyclic data via the fault-free side of the ring is still guaranteed.
Bumpless media redundancy MRPD always requires the activation of MRP in the individual
rings.
A maximum of two Ethernet nodes may be between the sync master and the redundant sync
master. If the redundant sync master is used together with MRPD, it is recommended that the
redundant sync master be connected directly to the sync master and the two nodes located
in a shared cabinet so that the cable connection between both nodes is protected.
If there is an interruption in the link between the sync master and the redundant sync master,
the system continues to run without bumps, but after switching off and on again faults can
occur.
Too high a network load or too-rapid coming and going of faults can also result in unfavorable
cases in the failure of the PROFINET connection with activated MRPD because of delayed or
incomplete switchover actions of MRP/MRPD.
For example, with two consecutive faults at different points in the ring, bumpless operation is
only ensured when there is approx. three seconds between the two faults.
Additional information
You will find additional information about media redundancy in the
Communication System Manual.
SIMOTION D4x5-2
Commissioning and Hardware Installation Manual, 03/2018, A5E33441636B
Parameter assignment / addressing
6.5 Configuring PROFINET IO
SIMOTION
147