Real-Time (Rt) And Isochronous Real-Time (Irt) Communication - Siemens SINAMICS DCM 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. Chapter 6
 IEC 61800-7
CAUTION
Inserting the CBE20 Communication Board deactivates the cyclic PZD channel for
PROFIBUS DP.
10.3.2.2

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

Real-time communication
When communication takes place via TCP/IP, the resulting 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.
Definition: Real time (RT) and determinism
Real time means that a system processes external events over a defined period.
Determinism means that a system responds in a predictable manner (deterministically).
In industrial networks, both these requirements are important. PROFINET meets these
requirements and is, therefore, implemented as a deterministic real-time network as follows:
● Transmission of time-critical data takes place at guaranteed time intervals. To achieve
● It is possible to predict the exact time at which data transmission will take place.
● Problem-free communication using other standard protocols is guaranteed within the
SINAMICS DCM DC Converter
Operating Instructions, 1.2012, C98130-A7066-A1-05-7619
this, PROFINET provides an optimized communications channel for real-time
communication: Real time (RT).
same network.
Descriptions of functions
10.3 PROFINET IO
371