PROFINET Designations

PROFINET CBA / PROFINET IO

PROFINET contains 2 different solutions:

  • PROFINET IO
  • PROFINET CBA (Component Based Automation)

PROFINET IO is used for communication with decentral periphery like IOs, drives, etc.

PROFINET CBA is a communication solution for autonomously acting partial units of machines or plants.

PROFINET IO and PROFINET CBA are using different kind of communications variations of PROFINET:

  • PROFINET NRT (non-real-time)
  • PROFINET RT (real-time)
  • PROFINET IRT (isochronous real-time)
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PROFINET CBA, PROFINET IO

PROFINET NRT

PROFINET NRT is used by PROFINET CBA and PROFINET IO for the exchange of non-critical data by using standard TCP/IP and UDP/IP transfer mechanism according to IEE 802.3.

PROFINET RT

PROFINET IO on RT is the real-time communication for time-critical process data between PLC and decentral periphery like I/O-devices, drives etc.

To reach the real-time behaviour, PROFINET RT does not use the addressing features and control mechanisms of TCP and UDP. PROFINET RT is using a separate real-time channel for transmission with a reduced overhead. If used for communication between different networks, the “RT over UDP” mode is available.

PROFINET IO based on RT can be used in separate and existing networks. The PROFINET communication runs in parallel to TCP/IP and TCP/UDP communication.

PROFINET IRT

PROFINET IRT is used for extremely time-critical applications (e. g. motion control). It uses hardware-aided real-time communication. To use PROFINET IRT, special hardware with cycle synchronisation is necessary.

Note

Real-time behaviour means that a process has to be executed in a predefined time. The duration of this predefined time interval does not matter; it is only necessary that the process is done during this time. Due to this predictability of this process it is possible (with aid of additional synchronisation methods) to cause chronologically adapted processes.