EthernetIP

[engsatapex]

EthernetIP is emerging of which I know little about. I've been told its like devicenet where you map an area of memory that can be accessible to read and write btw devices using ethernet cables OR once it is set up does it use socket messaging? Is it easy to install? Is it reliable? Is it faster than devicenet? Is it cheaper to set up than dnet? Is there a good article on this topic?

Many Thanks in advance?

 

[Logicon]

EthernetIP was developed by Rockwell Automation (Allen-Bradley) about 10 years ago or a little more. It has been released to a national standards management board however it has taken a while to migrate beyond the AB world. Several non-AB automation vendors now offer compatible devices or PLCs on ethernetIP now.

It is faster than DNET and in my experience a LOT easier to setup. With EthernetIP being layered on the typical Ethernet that we all know and love, as ethernet improves and speeds up, the EthernetIP device abilities do the same. Recently AB has also begun to include daisy chain abilities in some of their components which eliminates the large amount of ethernet cables you have in a control panel. That was the plus to Devicenet, the daisy chain saved wiring.

AB has their own sales pitch for you if you'd like to read more. See link below my signature.




Marc Whitney
www.thelogicongroup.com

 

[engsatapex]

Thanks Logicon,

Another question. Does EIP map a read and write data area btw devices like devicenet?

 

[Logicon]

I can only answer that relative to the Allen-Bradley controllers as I have not used EIP on any other platform PLC yet.

Answer = Sort of

For AB devices you have a predefined module you add to the IO tree and NAME which becomes you tag in the database that includes input, output, and config information.

For NON-Ab devices, you would add a GENERIC ETHERNET MODULE to the IO tree, set the IP address and enter the INPUT, OUTPUT, and CONFIG assembly size information and give that module a name. That name will appear in your controller tags with the mapped data in it. The only trick then is to determine which words in the mapping correspond to the specific data you need to access. A neat trick with Logix 5000 is to use a UDT that already has the defined structure you want to use, then map the physical tag from ETHERNET into a new tag of TYPE "your UDT name". This will allow you to place the data into meaningfully named and structured places for use in the code.




Marc Whitney

http://www.thelogicongroup.com

 

[djs]

EthernetIP is very communications intensive. This becomes an issue when using radio communications. A typical EthernetIP data request can reult in 10 or more TCP exhanges. On a high speed network this is not a problem.