Siemens SIMOTION Function Manual page 29

Note
Only a single cycle clock source is permitted on a SIMOTION device. For this reason:
If a SIMOTION device contains a PROFINET IO interface, a PROFIBUS DP interface can
no longer be operated as an isochronous DP slave.
The following figure shows cycle clock generation in PROFINET IO:
Figure 3-2 Cycle clock generation in a SIMOTION device in PROFINET IO
Synchronization in PROFINET IO
If the PROFINET IO interface has been configured as a Sync-Slave, the SIMOTION device
must be synchronized with the higher-level bus cycle clock. The synchronization behavior
Basic Functions for Modular Machines
Function Manual, 04/2014
Synchronizing SIMOTION devices with a higher-level bus cycle clock
3.1 General information about synchronizing a SIMOTION device with the bus cycle clock
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