is the innovative, open standard for industrial Ethernet in automation
technology. The PROFINET Standard is specified and published by PI
(PROFIBUS & PROFINET International – http://www.profibus.com).
PROFINET provides solutions for process automation, factory automation
and motion control. PROFINET enables the integration of existing
fieldbus systems, like PROFIBUS, Interbus, DeviceNet and other
technologies to an open Ethernet based network.
PROFINET uses Ethernet standard as well as TCP, UDP and IP as protocols
for communication, configuration and diagnosis in the network.
PROFINET standard defines three different performance levels which
cover the various requirements from different applications.
non-realtime applications, PROFINET NRT (Non Real Time) is defined. It
uses standard protocols as UDP/IP. With cycle times > 100 ms
PROFINET NRT targets for applications in process automation.
For applications with higher requirements on cycle time like factory
automation, PROFINET RT (Real Time) is the right choice. I/O data is
exchanged directly using the Ethernet protocol, while diagnosis and
configuration uses standard UDP/IP. PROFINET RT enables applications
with cycle times > 10 ms.
The highest requirements come from the control of complex drive systems
like packaging machines or robotics. With PROFINET IRT (Isochronous
Real Time) applications with cycle time < 1 ms and jitter < 1 Ás
are possible. This is accomplished by the usage of specific hardware
for the Ethernet interface.
On the application side three different device types are defined:
IO-Controller – the classic PLC (Master), which establishes connections
to the devices, exchanges data and controls the system, IO-Device – the
device (Slave) which is assigned to the controller to exchange data,
and IO-Supervisor – the interface for programming, commissioning and
diagnosis in the network.
communication and exchange of I/O data the PROFINET standard also
defines the topology and structure of the network. Guidelines for the
cabling, the selection of suitable connectors and topology components
facilitate the planning and the commissioning of a PROFINET network.
The user has the choice between aAugust 17, 2011 17:58the classical line structure used in PROFIBUS systems and tree structure which combines both principles.
The migration of existing PROFIBUS systems to PROFINET systems can
easily be achieved by using Proxies (Gateways) which enable the
communication and the data exchange between both networks.
The device profiles already known from the PROFIBUS world can also be
used for PROFINET. With PROFIdrive a powerful profile for the
implementation of high-performance drive solutions is available.
For safety-relevant applications, the PROFIsafe profile for PROFINET and PROFIBUS DP systems is defined.