Siemens SIMATIC S7-1500 System Manual page 99

System overview
5.3 S7-1500 R/H-CPUs
Media redundancy
Media redundancy is a function for ensuring network and plant availability.
If the transmission link in the ring is interrupted at any point, e.g., due to interruption of the
PROFINET line or failure of a station, the redundancy manager immediately activates the
alternative communication path.
If you set up the S7-1500R/H redundant system in ring topology, then the two CPUs are
located in a PROFINET ring that uses the media redundancy method MRP. All PROFINET
devices in the PROFINET ring must support media redundancy (MRP).
In the case of the S7-1500H redundant system, you can also use switches to disconnect the
two H-CPUs from the PROFINET ring, in which case they are no longer included in the
PROFINET ring.
S7-1500R uses the PROFINET ring (via the PROFINET interfaces X1) for the synchronization of
the two CPUs. S7-1500H uses the redundancy connections over fiber-optic cables to
synchronize the two CPUs.
To set up a ring topology with media redundancy, you need to bring together the free ends of
a linear network topology in one device using 2 ports (ring ports, port label "R"). You specify
the ring ports in the device configuration.
With S7-1500H the two H-CPUs can also be located in different PROFINET rings. You can
connect the two PROFINET rings via MRP interconnection.
In the S7-1500R/H redundant system with ring topology the media redundancy role of both
CPUs must be configured to Manager (auto). For all other PROFINET devices in the PROFINET
ring, the media redundancy role Client must be configured. There is a communication
connection based on MRP between the redundancy manager and the redundancy clients. The
Media Redundancy Protocol (MRP) automatically reconfigures the data paths between the
individual devices if the ring is interrupted at any point.
You configure the media redundancy role for IO devices and other PROFINET devices in
STEP 7.
H-Sync forwarding
H-Sync forwarding enables a PROFINET device with MRP to forward synchronization data
(synchronization frames) of a S7-1500R redundant system only within the PROFINET ring.
In addition, H-Sync forwarding forwards the synchronization data even during
reconfiguration of the PROFINET ring. H-Sync forwarding avoids a cycle time increase if the
PROFINET ring is interrupted.
Note
Support of H-Sync forwarding
The technical specifications typically state whether a PROFINET device supports
H-Sync forwarding.
The GSD file will also indicate whether the device supports H-Sync forwarding. The device
supports H-Sync forwarding when the "AdditionalForwardingRulesSupported" attribute in the
"MediaRedundancy" element is set to "true".
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S7-1500R/H redundant system
System Manual, 01/2024, A5E41814787-AF