Siemens SIMOTION D4x5-2 Commissioning And Hardware Installation Manual page 232

Commissioning (software)
7.5 Additional information on configuring the SINAMICS Integrated
Figure 7-34 SINAMICS time synchronization diagnostic buffer entry
Error correction
If problems occur with time synchronization, this may be due to deactivated symbolic
assignment to incorrect configuration information (Fast IO configuration).
For more information, see Section Message frame configuration (Page 271).
Compensation of runtime deviations
To compensate for deviations between the SIMOTION and SINAMICS clocks, the time of day
is automatically resynchronized at regular intervals.
The following behavior must be taken into consideration when setting the SIMOTION time:
● "Time/date to be set" is later than "Time/date on SINAMICS": Time and date are corrected
on the SINAMICS.
● "Time/date to be set" is earlier than "Time/date on SINAMICS": The SINAMICS clock must
be stopped until the SINAMICS "Time/date" has caught up with "Time/date to be set".
Adopting this procedure ensures that the sequence of SINAMICS diagnostic buffer entries
remains the same, even when the runtime differences are aligned.
The SINAMICS clock operates with a resolution of 1 ms. A synchronization accuracy of 1 ms
can be achieved for all bus cycle clocks that can be divided exactly by 1 ms (e.g. 1 ms, 2 ms,
3 ms, etc.).
Due to system considerations, a slightly lower synchronization accuracy is achieved for all bus
cycle clocks that cannot be divided exactly by 1 ms (e.g. 1.25 ms).
If the drive unit does not have an isochronous connection on SIMOTION, this can result in
runtime differences of milliseconds (depending on the set cycle clock ratios).
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Commissioning and Hardware Installation Manual, 03/2018, A5E33441636B
SIMOTION D4x5-2