Configuring Media Redundancy - Siemens SIMATIC ET 200AL System Manual

Functions
5.4 Media redundancy (ring topologies)
In order to ensure that an invalid MRP configuration does not result in the failure of the
network, delete the ring before loading.
Follow these steps:
1. Delete the ring.
2. Load the error-free and consistent MRP configuration from your project onto all the
devices involved and ensure that the devices are in data exchange mode (i.e. the
application relations (ARs) are set up).
3. Close the ring.
Boundary conditions
MRP and RT
RT operation is possible with the use of MRP.
Note
The RT communication is disrupted (station failure) if the reconfiguration time of the ring is
greater than the selected response monitoring time of the IO device. This is why you should
select a response monitoring time of the IO devices that is sufficiently large.
MRP and IRT
IRT mode is not possible together with MRP.
If you want to use media redundancy together with IRT in a ring, only use devices that
support MRPD.
MRP and TCP/IP (TSEND, HTTP, ...)
The TCP/IP communication with MRP is possible, because lost data packages are resent, if
applicable.
MRP and prioritized startup
If you configure MRP in a ring, you cannot use the "prioritized startup" function in PROFINET
applications on the devices involved.
If you want to use the "prioritized startup" function, then you must disable MRP in the
configuration (the device may also not be part of the ring).
5.4.2

Configuring media redundancy

Configuring MRP
Proceed as follows to create a PROFINET IO configuration with MRP in STEP 7:
1. Generate a ring via the port interconnections in the topology view. First interconnect the
devices to a line topology. Connect the unassigned port of the last device in the line with
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PROFINET with STEP 7 V15
Function Manual, 12/2017, A5E03444486-AH