Real-Time (Rt) And Isochronous Real-Time (Irt) Communication - Siemens SINAMICS S120 Function Manual

Communication
11.3 Communication via PROFINET IO
Cyclic communication using PROFINET IO with IRT or using RT is possible on all drive units
equipped with a PROFINET interface. This means that error-free communication using other
standard protocols is guaranteed within the same network.
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 no. 3.172, spec. Section 6
• IEC 61800-7
Note
For CU320-2 DP with inserted CBE20, the cyclic PZD channel for PROFIBUS DP is
deactivated. When setting parameter p8839 = 1, the PZD channel can be reactivated (see
Section "Parallel operation of communication interfaces (Page 653)").
11.3.1.1

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 not defined to meet the production automation requirements. When communicating
time-critical IO user data, PROFINET IO therefore uses its own real-time channel, rather
than TCP/IP.
Real time means that a system processes external events over a defined period.
Determinism
Determinism means that a system will react in a predictable ("deterministic") manner.
With PROFINET IO with IRT, it is possible to precisely determine (predict) transmission
times.
PROFINET IO with RT (Real Time)
Real-time data is treated with a higher priority than TCP(UDP)/IP data. Transmission of time-
critical data takes place at guaranteed time intervals. RT communication provides the basis
for data exchange with PROFINET IO.
708
Function Manual, (FH1), 04/2014, 6SL3097-4AB00-0BP4
Drive functions