Description
User manual 55170_hdb_en_13
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3.3
PROFINET IRT
Isochronous Real Time
(IRT)
For PROFINET, an isochronous data exchange by the transmission of data
packages in regular time intervals of a few hundred milliseconds up to four mil-
liseconds is defined by the IRT (Isochronous Real Time) concept.
The beginning of a bus cycle is adhered to with the highest precision (jitter ≤1
µs). Each of the individual time intervals during the IRT communication is split
into an IRT interval and an open standard interval which requires the use of
special IRT switches.
For further information, refer to chap. 8.8 "Isochronous real time (IRT) config-
Communication cycle
with IRT and RT
Fig. 3-4: Division of communication cycle into IRT and RT