PROFINET

PROFINET is an open and comprehensive concept for the vertical integration
of PROFIBUS. It allows for direct access from Office applications to the
process and automation systems and the field level. The use of IT and Ethernet
standards with transparent PROFIBUS access is in line with the trend towards
increasingly modular designs that are dominating intelligent automation systems.

PROFINET IO is a standard adopted by PROFIBUS International relating to the
communication of I/O controllers (PLC) with I/O devices (field equipment).
The technology is based on the Ethernet as the communication medium and serves
the purpose of transferring I/O data, parameters, alarms etc.

A difference is made between real-time applications (PROFINET RT) with
cycle times of 5 to 10 ms or PROFINET Isochronous Real-time (IRT) for
high-performance applica-tions with bus cycle times in the range of 1 ms.
For IRT applications, the I/O devices require switching functionality, i.e.
special chipsets must be used.