Siemens SINAMICS DCM Manual page 478

Example:
● Synchronization domain IRT: SIMOTION2 with SINAMICS
● SINAMICS, which is assigned to the IO system of SIMOTION1, is arranged in the
topology in such a way that its RT communication must be established through the IRT
synchronization domain.
Figure 10-45 RT communication across the limits of synchronization domains
Update cycles and send cycles for RT classes
Definition of the update time / send cycle:
If we take a single IO device in the PROFINET IO system as an example, this device has
been supplied with new data (outputs) by the IO controller and has transferred new data
(inputs) to the IO controller within the update time. The send cycle is the shortest possible
update cycle.
All cyclic data is transferred within the send cycle. The actual send cycle that can be set
depends on various factors:
● Bus load
● Type of devices used
● Computing capacity available in the IO controller
● Supported send clocks in the participating PROFINET devices of a synchronization
domain. A typical send cycle is, e.g. 1 ms.
The table below specifies the reduction ratios which can be set between the send cycle and
the update times for IRT "high performance", IRT "high flexibility", and RT.
SINAMICS DCM DC Converter
Operating Instructions, 02.2015, A5E34763375/RS-AA/001
ac.maher.co.ir
Descriptions of functions
10.5 Communication via PROFINET IO
479