VDO ACTUATORS - FOR CENTRAL LOCKING SYSTEMS V3.1 Manual de usuario descargar pdf (Pagina 6)

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Introduction to PROFINET, EtherNet/IP and Ethernet

About Industrial Ethernet

The use of Ethernet in IT for connecting various

terminals is widespread, especially in local area

networks (LAN). Since 1985, the Institute of

Electrical and Electronics Engineers (IEEE) has

used the Ethernet technology developed by Dr.

Metcalfe as its ofcial standard (802.3). This

standard remains the basic technology used in

an effective data transfer system that continues

to be developed (Fast Ethernet, 10-Gigabit

Ethernet, switching, full duplex data transfer,

wireless LAN).

One Standard, Many Protocols.

Generally speaking, Ethernet is also suitable

for automation applications. Nevertheless, the

requirements of industrial communication are

more rigorous with regard to the mechanical

and electrical characteristics of the devices and

media used.

Two examples that can be named here are

ambient conditions and real-time behavior.

In addition, no uniform application protocol

exists that is tailored to meet the needs of

automation technology. A host of different

organizations have dened higher application

protocols that can be embedded in the standard

Ethernet data package. As a result, different

protocols and specications are currently in use.

Neither protocols are compatible with

one another:

TCP/IP (“Ofce” Ethernet Protocol)

EtherNet/IP (ODVA)

PROFINET (Probus user organization)

Modbus/TCP (Modbus-IDA Group)

In addition, other manufacturer-specic

approaches exist such as EtherCat, Ethernet-

Powerlink, and JetSync. Lumberg Industrial

Ethernet products have been designed for

use with TCP/IP, EtherNet/IP, PROFINET, and

Modbus/TCP systems.

Data Transfer Technology

While there are different approaches to

real-time communication, all of them have a

common core, which comprise the established

standards of Layers 1-2 as well as the Ethernet

data transfer technology and bus access

procedure (CSMA/CD, Layer 2). All systems

support industrial IT functions such as Web

servers, le transferring, and e-mail. For IT

functions such as these, the Internet protocol

(Layer 3) as well as TCP and UDP protocol (Layer

4) are used. In addition, other IT standards can

be used such as Hypertext Transfer Protocol

(http) and File Transfer Protocol (FTP).

Carrier Sense Multiple Access with

Collision Detection (CSMA/CD)

MA-Multiple Access All devices in an Ethernet

network are equal and can exchange data with

other devices at any time. Devices access media

together. Ethernet does not rely on a master/

slave procedure of the type used with eld

busses, where communication is controlled by a

central device.

CS-Carrier Sense

If a device wants to send a data package, it rst

checks to see whether the medium is available

or communication is already in progress. If

the medium is busy, the device will wait for

completion of the current data transfer and will

only send data when the medium is no

longer busy.

CD-Collision Detection

While sending data, the device monitors the

medium to detect collisions with data packages

sent by other devices. If a collision has been

detected, the devices involved stop sending

data and wait for a specic amount of time to

elapse before restarting the sending procedure.

The system assumes that a data package has

been sent successfully if no collisions occur.

In this process, the transfer time depends

greatly on the power supply load and cannot

be predetermined. For this reason, this data

transfer procedure is only suitable for certain

types of industrial automation.

The performance of an Ethernet network can

be improved through the use of switches and

Ethernet interfaces with full duplex operation.

The CSMA/CD procedure is deactivated during

full duplex device operation (simultaneous data

package sending and receiving).

Industrial Ethernet Media

Cordsets, Connectors

and Switches with Plug-

N-Play Features Reduce

Overall Installation and

Maintenance Costs.

1 2 3 4 5 6 7 8 9 10 11 ... 95 96

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