Siemens SINAMICS Series Operating Instructions Manual page 504

Descriptions of functions
10.5 Communication via PROFINET IO
You can set the RT class in the HW Config for the associated PROFINET device.
1. In HW Config, double-click item PROFINET interface in the module.
The "Properties" dialog box opens.
2. Select the RT class under RT class on the "Synchronization" tab.
3. Once you have selected "IRT", you can also choose between option "high flexibility" and
"high performance".
Note
The "high performance" option must not be selected for SINAMICS DCM, otherwise an
error message is issued.
4. Confirm with "OK".
Synchronization domain
The sum of all devices to be synchronized form a synchronization domain. The whole
domain must be set to a single, specific RT class (real-time class) for synchronization.
Different synchronization domains can communicate with one another via RT.
For IRT, all IO devices and IO controllers must be synchronized with a common
synchronization master.
RT allows an IO controller to communicate with a drive unit outside a synchronization
domain or "through" another synchronization domain. As of version 5.4 SP1, STEP 7
supports multiple synchronization domains on a single Ethernet subnet.
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 10-40 RT communication across the limits of synchronization domains
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SINAMICS DCM DC Converter
Operating Instructions, 12/2018, A5E34763375A