Difference between Industrial Ether net and Ethernet

Dear Sir,
I'm interested to know the difference between the Industrial Ethernet and Ethernet can someone able to explain in detail.

Ethernet is a very generic term that broadly covers the how data is shifted from one computer using either TCP or UDP protocols. But Ethernet does not define the meaning of the data. ie if TCP delivers a packet of data into my PC, what is it for, which application is it intended for and how is it used in that application?

Common application layers are web browsing, email, ftp, etc. Industrial Ethernet builds on the basic Ethernet data transport layers to define a set of application layers useful for Industrial Automation purposes, eg Control data, Configuration data and Data Collection.

The application to do this originated within Rockwell Automation and is called CIP (Control and Information Protocol). It first appeared in DeviceNet and has been migrated for use in ControlNet (plus the ControlLogix chassis backplane) and Industrial Ethernet.

In essence these networks all share the identical CIP Application Layer; they just use different transport/media layers underneath. Typically the Control Data is an IO connection between say a logic processor and an IO module. In Industrial Ethernet this is handled as a UDP (User Datagram Protocol) that is best suited for fast, low overhead connections on a local segment. By contrast messages for configuration and data collection between devices, eg RSLinx polling for processor tags, is done using a TCP (Transmission Control Protocol) connection that allows for bridging and routing between network segments.

In a nutshell, Ethernet is the pipe; Industrial Ethernet defines the contents of the pipe. Have a look around the Rockwell site and I am sure you will find more info and pretty pictures.

Philip,

The term "Industrial Ethernet" doesnt necasserily imply the Rockwell type of Industrialised Ethernet.

Siemens actually used (and partially still use) "Industrial Ethernet" as a name for their version of Industrialised Ethernet - todays name of Siemens Ethernet solutions is "ProfiNet".

The Rockwell/CIP type of inndustrialised Ethrenet uses the name "Ethernet/IP"

In addition to the names/types influenced by Rockwell and Siemens there are also Modbus/TCP and Foundation Fieldbus on Ethernet (dont remember the exact name). And there are probably other types of industrialised Ethernet.

I dont disagree with the other things you write, but it is a little limiting only to talk about Rockwells Ethernet/IP when bringing up "Industrial Ethernet".

Jesper ..yes I agree. The term "Industrial Ethernet" is wider than just the Rockwell version. I thought about this about one hour and one minute after I posted..

It is my impression that the Seimens (Profibus), Schneider (Modbus) and Rockwell (CIP) are the major "Industrial Ethernet" players in the market. So after a decade of progress towards "Open Systems" we will be able to plug three PLC's, one from each of the above big boy's, into one Ethernet switch....and still not get meaningful data to transfer.

The good news is that at least the source codes and protocols are now open to third parties and linking between systems is nowhere near the drama it was 15 years ago...but still in ones' heart of dark little hearts'...it would have been nice if they had managed to choose just one "Industrial Ethernet"....no?

Powerlink

Has anyone come across Powerlink yet?

http://www.ethernet-powerlink.org/

The term “Industrial Ethernet” also is used to describe some new hardware that is now out. It is basically the normal hardware (cable, switches, routers, connectors) that are sealed and rugged for the industrial application. It is made to withstand greater shock as well. The price can be four times as much for the hardware. The cat 5 and cat 6 industrial connectors are a slick way to get cable into and out of a box. They are also great for wall plates. I think that Hubbell and Leviton are both making Industrial Ethernet equipment now.


Charlie

Has anyone come across Powerlink yet?

Click to expand...

Looking at the site you have linked to at first blush it appears to have almost magical performance...200 uS cycle times with 1uS of jitter!! But the catch is that to achieve this the network segment must be "protected" ie separated. If you need to share the network with normal Ethernet nodes, then it has to run in "Open" mode, in which case cycle times deteriorate to the normal millisecond range expected with standard TCP/IP performance.

From what I can read PowerLink appears to use standard Ethernet hardware, BUT completely substitutes it's own protocol stack...in answer to a question comparing PowerLink to EthernetIP:

"EthernetIP is based on the complete TCP/IP protocol stack whereas Powerlink is substituting it with its own protocol stack."

For very high speed applications demanding submillisecond throughputs I can see the case for PowerLink, but frankly by entirely substituting the standard TCP/IP stack with it's own, PowerLink more or less looses the right to call itself "Ethernet". This fact alone will probably relegate it to a minority status; although it looks like a superior technology in some aspects, that alone may not sufficient to ensure that it gains critical mass. (On the other hand who knows? Maybe it is poised to take over the world tommorrow and I haven't noticed just yet.)

And thanks for the link derek, it's an interesting read.