HBK TIM-PN Montageanleitung Seite 74

You can configure domain management, I/O devices and RT classes in the Network view
under Properties. RT (Real Time) and IRT (Isochronous Real Time) options are available
for the RT classes. Once the RT classes have been assigned, the send clock of the bus
cycle time can be selected.
TIM-PN
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PROFINET CONFIGURATION WITH THE TIA PORTAL