Real-Time (Rt) And Isochronous Real-Time (Irt) Communication - Siemens SINAMICS G150 Operating Instructions Manual

Note
PROFINET for drive technology is standardized and described in the following document:
PROFIBUS profile PROFIdrive – Profile Drive Technology
Version V4.1, May 2006,
PROFIBUS User Organization e. V.
Haid-und-Neu-Straße 7,
D-76131 Karlsruhe
http://www.profibus.com,
Order Number 3.172, spec. Chp. 6
• IEC 61800-7
CAUTION
The cyclic process data channel for PROFIBUS DP is initially deactivated for a CU320-2
DP and inserted CBE20. However, it can be reactivated with parameter p8839 = 1 at any
time (see "Parallel operation of communication interfaces").
6.9.2.2

Real-time (RT) and isochronous real-time (IRT) communication

Real-time communication
When communication takes place via TCP/IP, the resultant transmission times may be too
long and non-deterministic to meet production automation requirements. When
communicating time-critical IO user data, PROFINET IO therefore uses its own real-time
channel, rather than TCP/IP.
Determinism
Determinism means that a system will react in a predictable ("deterministic") manner.
With PROFINET IO, it is possible to precisely determine (predict) transmission times.
PROFINET IO with RT (Real Time)
Real time means that a system processes external events over a defined period.
Process data and alarms are always transmitted in real time (RT) within the PROFINET IO
system. RT communication provides the basis for data exchange with PROFINET IO. Real-
time data are treated as a higher priority than TCP(UDP)/IP data. Transmission of time-
critical data takes place at guaranteed time intervals.
Converter cabinet units
Operating Instructions, 03/2012, A5E03263466A
6.9 Communication via PROFINET IO
Operation
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