Technical data
Communication   
9.4 Communication via PROFINET IO 
  Function Manual 
664  Function Manual, 06/2012, 6SL3097-4AB10-0BP4 
Set the RT class 
The RT class is set by means of the properties of the controller interface of the IO controller. 
If RT class IRT "high performance" is set, it is not possible to operate any IRT "high 
flexibility" devices on the IO controller and vice versa. IO devices with RT can always be 
operated, regardless of the IRT class setting. 
You can set the RT class in the HW Config for the associated PROFINET device. 
1. In HW Config, double-click on item PROFINET interface in the module. 
The "Properties" dialog box is opened. 
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". 
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. 
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Figure 9-41  RT communication across the limits of synchronization domains 










