ProfiNet, Modbus/TCP or Ethernet/IP

S
"I might agree that Ethernet I/P is not as open as one might want it to be, but it is about as "open" as it gets in the industrial control arena."

Both pro-EIP and anti-EIP posters in this thread have described it as less open than Modbus/TCP, and it's more plentiful as well.
 
In reply to bob peterson: People really can do what they want on the Internet. There is nobody enforcing any rules. Usually, what people want is for their stuff to work, so they do tend to follow standards and conventions. It's entirely voluntary however. That voluntary cooperation however works a lot better than anything we've seen come out of industry.

As for whether AB Ethernet I/P is "'open' as it gets in the industrial control arena", there are other common protocols that unlike EIP you are free to implement without restriction. At best you might be able to say that EIP isn't as bad as the worst of the others, but then some of the others are a pretty bad lot.

We had a discussion on this a couple of years ago. Here's the URL:
http://www.control.com/thread/1026244726
Go have a look at that discussion, which includes numerous quotes from the ODVA contract. How is any of that "open"?

Let's go back to the Internet analogy. How come I can view any web site anywhere in the world with any web browser that I have, but I can't plug an AB PLC into a Siemens PLC and have them talk to each other?

How come I can write my own web server (which I have done more than once), and it will talk with any web browser, but writing a server that can talk with an AB or Siemens PLC is almost impossible?

I'm not saying that the Internet is perfect. I'm just saying that if industrial networks were as good as the Internet people would be satisfied with that.
 
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