Siemens SINAMICS S120 Series Function Manual page 130

Communication via PROFINET IO
5.2 RT classes for PROFINET IO
The table below specifies the reduction ratios which can be set between the send cycle and
the update times for IRT "high performance", IRT "high flexibility", and RT.
Table 5- 2 Settable send cycles and update cycles
Send cycle
Range 250, 500,
"even" 1000 µs
1)
2000 µs
4000 µs
Range 375, 625, 750, 875,
"odd" 1125,
3)
1250 µs ...
3875 µs
(increment
125 µs)
Explanations for the above table:
It is only possible to set send cycles from the "even" range when IO devices with real-time class "RT" are assigned to a
1)
synchronization domain. Likewise, only the reduction ratios from the "even" range can be set for a send cycle setting
from the "even" range.
It is generally only possible to set a reduction ratio of 1:1 between the update time and send cycle for IO devices
2)
(ET200S IM151-3 PN HS, SINAMICS S) which are operated in isochronous mode. In this case, the update cycle mode
must always be set to "fixed factor" (under IO device properties, "IO cycle" tab, "Mode" pulldown menu). This means
that STEP 7 will not automatically adjust the update cycle and thus the update cycle will always correspond to the send
cycle.
The send cycles from the "odd" range can be set only if a synchronization domain does not include any IO devices with
3)
real-time class "RT". Likewise, only the reduction ratios from the "odd" range can be set for a send cycle setting from the
"odd" range.
Isochronous operation is not compatible with IRT "high flexibility".
4)
Odd send cycles can be used only if the IO systems assigned to the synchronization domain do not include any RT or
5)
IRT "high flexibility" devices.
Furthermore, the send cycles which can actually be set are determined by the intersection of
the send cycles supported by all the devices in the synchronization domain.
The reduction ratio between the update cycle of an IO device and the send cycle is set in the
"Properties" of the PROFINET interface for the relevant device.
Note
There is no intersection between the send cycles for the "even" and "odd" ranges!
Send cycles for SINAMICS drive units
A SINAMICS drive unit with PROFINET interface which supports IRT permits send cycle
settings of between 0.25 ms and 4.0 ms in a 250 µs time frame.
128
Reduction ratios between update time and send cycles
RT
IRT "high flexibility"
4)
1, 2, 4, 8, 16, 32, 64, 128, 256, 512
1, 2, 4, 8, 16, 32, 64, 128, 256
1, 2, 4, 8, 16, 32, 64, 128
Not supported
5)
IRT "high performance"
1, 2, 4, 8, 16
2)
1, 2, 4, 8, 16
2)
1, 2, 4, 8, 16
2)
1
Function Manual, 12/2018, 6SL3097-5BD00-0BP0
Communication