Siemens SINAMICS DCM Operating Instructions Manual page 352

Descriptions of functions
10.3 PROFINET IO
RT class
Maximum switching depth
(number of switches in one
line)
For possible send cycles, see subitem "Send cycles and update times for RT classes" in table "Adjustable send cycles and
update times"
Set the RT class
The RT class is set by means of the IO controller interface properties. 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 for the relevant PROFINET device in HW Config.
1. In HW Config, double-click the PROFINET interface item in the module.
2. Select the RT class under "RT class" on the "Synchronization" tab.
3. Once you have selected "IRT", you can also choose between "high flexibility" and "high
4. Confirm with "Update".
Synchronization domain
Taken as a whole, all of the devices that are to be synchronized form a synchronization
domain. The entire domain must be set to a single, specific RT class (real-time class) for
synchronization, meaning that mixed operation of RT classes IRT and IRT* is not
permissible. Different synchronization domains can communicate with one another via RT.
With IRT* and IRT, all IO devices and IO controllers must be synchronized with a common
synchronization master.
IRT* drive units can be replaced with IRT drive units in HW Config. This conversion from
IRT* to IRT and vice versa is not performed automatically, but instead must be carried out
manually.
The HW Config consistency check ascertains whether modules communicating with one
another within a single synchronization domain are all configured to use the same RT
classes: All modules use either IRT* or IRT.
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 subnetwork.
Example:
● Synchronization domain IRT*: SIMOTION 1 with SINAMICS
● Synchronization domain IRT: SIMOTION 2 with SINAMICS
● SINAMICS, which is assigned to the IO system of SIMOTION 1, is arranged in the
352
RT
10 at 1 ms
The "Properties" dialog opens.
performance".
topology in such a way that its RT communication must be conducted through the IRT
synchronization domain.
IRT "high flexibility"
61
Operating Instructions, 06.2010, C98130-A7067-A1-02-7619
IRT "high performance"
32
SINAMICS DCM Control Module