
26 Publication LOGIX-AP008B-EN-P - June 2008
Chapter 1 Hardware Conversion
Profinet
Profinet provides for similar Profibus DP functionality on an Industrial
Ethernet with the same programming overhead requirements. A network using
Profinet is similar to Profibus except for different cable and connectors, and
use Ethernet field interface modules rather than Profibus. Controllers with a
built-in Profinet interface or a communication processor that is equipped for
Profinet are used to connect to the network.
Alternatively, an existing Profibus DP network can be bridged to Profinet,
either with a proxy or by using the Profibus DP port of a Profinet-equipped
controller.
Some Profinet field interface modules have multiple RJ45 ports with an
integrated switch, to allow a Profibus-type line bus topology, if required.
Profinet provides these three communication possibilities:
• Profinet CBA (Component Based Automation), which is primarily used
for controller to controller communication and uses standard Ethernet
hardware and the TCP/IP software stack.
• Profinet IO for scheduled transfers such as Drives or I/O modules and
uses standard Ethernet hardware, but bypasses the TCP/IP software
stack.
• Profinet IRT (Isochronous Real Time) for motion control applications
which uses Profinet specific hardware and also bypasses the TCP/IP
software stack and must exist on a protected network segment.
If the Profinet CBA framework is used, then Profibus, Profinet and Industrial
Ethernet networks can be integrated by graphical configuration, with reduced
need for additional programming. Rockwell Automation EtherNet/IP
networks provide this functionality using standard hardware and the standard
TCP/IP software stack utilizing built-in functions like the Message (MSG)
instruction and produced/consumed tags.
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