Siemens SINAMICS S120 Function Manual page 723

Furthermore, the send cycles which can actually be set are determined by the intersection of
the send cycles supported by all the devices in the synchronization domain.
The reduction ratio between the update cycle of an IO device and the send cycle is set in the
"Properties" of the PROFINET interface for the relevant device.
Note
There is no intersection between the send cycles for the "even" and "odd" ranges!
Send cycles for SINAMICS drive units
A SINAMICS drive unit with PROFINET interface which supports IRT permits send cycle
settings of between 0.25 ms and 4.0 ms in a 250 µs time frame.
Topology rules
Topology rules for RT
● A topology can be, but need not be configured for RT. If a topology has been configured,
● Otherwise, the wiring between devices is entirely optional.
Topology rules for IRT
● Mixed operation is not supported by STEP 7 V5.4 SP4, i.e. IRT "high performance"
● A synchronization domain with IRT "high performance" can contain a maximum of one
● IRT "high flexibility" is subject to the same topology rules as for IRT "high performance",
Device selection in HW Config
Hardware catalog:
The drive unit from the appropriate device family entry in the hardware catalog must be
configured. For the real-time class IRT, these are all entries as of firmware version V2.5.
GSDML:
GSDML files for devices which contain IRT as of firmware version V2.5.
Drive functions
Function Manual, (FH1), 04/2014, 6SL3097-4AB00-0BP4
the devices must be wired in accordance with the topology.
cannot be combined with IRT "high flexibility" in the same synchronization domain.
IRT "high performance" island. "Island" means that the devices must be interconnected to
match the configured topology. A synchronization master must be positioned in the
relevant island.
the only exception being that a topology does not need to be configured. However, if a
topology has been configured, the devices must be wired to match the topology.
11.3 Communication via PROFINET IO
Communication
723