Profinet Industrial Ethernet Protocol Overview

High level Ethernet protocol


PROFINET is the innovative open standard for Industrial Ethernet, development by Siemens and the Profibus User Organization (PNO). With PROFINET, solutions can be implemented for factory and process automation, for safety applications, and for the entire range of drive technology right up to clock-synchronized motion control. PROFINET is standardized in IEC 61158 and IEC 61784. Profinet products are certified by the PNO user organization, guaranteeing worldwide compatibility.

PROFINET is based on Ethernet and uses TCP/IP and IT standards and complements them with specific protocols and mechanisms to archive a good Real Time performance. PROFINET enables the integration of existing Fieldbus systems like PROFIBUS, DeviceNet, and Interbus, without changes to existing devices. That means that the investments of plant operators, machine and system builders, and device manufacturers are protected.

Real-Time classes
PROFINET offers a scalable performance with three performance levels:

TCP/IP: for non Real Time applications
Real Time (RT): for Real Time transfer of time-critical process data
Isochronous Real Time (IRT): for motion control applications

PROFINET Modes
PROFINET includes two modes and allows to combine distributed automation and distributed I/O.

PROFINET IO
Distributed I/O (Remote I/O) is connected through PROFINET IO. Here, the familiar I/O view of PROFIBUS is retained, in which the user data from the field devices are periodically transmitted into the process model of the control system. PROFINET IO describes a device model, consisting of places of insertion (slots) and groups of I/O channels (subslots). The technical characteristics of the field devices are described by the GSD (General Station Description) on an XML basis.

PROFINET CBA
This variation is an advanced concept for industrial automation which fulfills the requirements of plant builders and operators for an system-wide and manufacturer-spanning engineering process. The PROFINET component model sees its real use in distributed automation systems. It is ideally suited for intelligent field devices with programmable functionality as well as controllers. PROFINET CBA is based on the object-oriented modelling of technological modules. Based on the object model, machines and installations are structured in PROFINET in the form of technological modules. The functionality of the technological modules is encapsulated in uniform PROFINET components. From the outside, PROFINET components are accessed through uniformly defined interfaces. They can be arbitrarily connected in this way.

Configuration with GSD-Files
During the setup phase of the PROFINET network, the Profinet Controller must be configured with a special configuration tool such as Step7 from Siemens. The configuration process is based on electronic device data sheets (GSD-Files) which are required for each Profinet device. GSD-Files are provided by the device manufacturer and contain electronic descriptions all relevant communication parameter of the Profinet device.

PROFINET FACTS
Network Type:	Scalable Ethernet based advanced communication system
Topology:	Very flexible with Line, Bus, Star or Tree topology depending on physical media
Installation :	Switched Ethernet transmission with shielded twisted pair cables and RJ45 or M12 connectors. Alternatively Fiber Optic Media.
Data Rate :	100 Mbit/s
max. Stations:	Almost unlimited
Data :	each node: up to 1.500 bytes per telegram frame Total: nearly unlimited
Network Features :	Scalable communication system based on switched Fast Ethernet technology with good real time performance and advanced configuration, diagnosis and alarm handling.
User Organization:	Profibus International

HMS is an active member of the Profibus User Organization and participates actively in the further standardization of the Profinet technology. HMS offers a broad range of Profinet products.