Siemens SIMATIC ET 200AL System Manual page 336

Cycle times
The figure below shows the cycle times at ET-Connection based on the number of I/O
modules with a PN send clock of 0.5 ms.
Figure B-1
The cycle time at ET-Connection is synchronized with the PROFINET send clock. This means
that the input data of the I/O modules are transmitted via ET-Connection without further
delay (wait time in the interface module) via PROFINET. The output data from PROFINET is
also transmitted without further delay via ET-Connection to the I/O modules. Thus, the cycle
time of the ET-Connection, based on then number of I/O modules, is always a multiple of the
configured PROFINET send clock.
The chart shown above shows the trend for a send clock of 0.5 ms. With larger send clocks,
the gradation of the trend changes according to the send clock.
When using a larger number of IO-Link masters with a large I/O data configuration
(> 32 bytes), there may be a slight increase in the cycle time at the ET-Connection.
40
Cycle times
IM 157-1 PN (6ES7157-1AB00-0AB0)
Equipment Manual, 05/2021, A5E32347036-AE
B