A client of mine has asked me to interface a linux system to a GE PLC using EGD but I have not been able to find any specs/docs on the protocol. Is it an open protocol? I see some vendors have EGD/OPC converters but I am just looking for the protocol def so I can implement my own simple client/consumer on a linux box.

 

That interesting....I was looking at document of that protocol and it's def.. last night and wondered how known is this info..

Hmmmmmm??

 

> That interesting....I was looking at document of that protocol and it's def..
> last night and wondered how known is this info..

so are you going to tease this poor guy or give him some help?

One of the friendly moderators here at Control.com

 

90 page note on EGD protocol:

http://tinyurl.com/ouhg4rs

 

David, thank you for this document but it is only a little bit of the protocol. There is an example of how some data types (floats/regs/etc) fit within the data portion of the EGD packet, but it does not show what a full EGD packet looks like (header, data, etc). Also need to know the UDP port used for EGD.

I have seen some references that indicate EGD has a 32-byte header, but nothing that describes the structure.

If you have that, I would very much appreciate it.

Ron

 

Hey..... I think I have got what you need.

I am putting some documents together. I got this from a GE vax down load of some protocals.

All hard copy....so give me time.


| LOCAL | Exchange | Local Adapter |
|Producer ID | ID | NAME |
|------------|------------|------------------
|------------|------------|-----------------|

| Consumer Consumer | Send |Producer
| Type Address | Type | Period |
|------------|------------|----------|---------|
|------------|------------|----------|---------|
|Reply | Status|
|Rate | Word |

Maybe

 

It's been many years but I remember my company having to sign a Non-Disclosure Agreement (NDA) with G.E. in order to get access to the EGD protocol documents. As far as I know, it's not a public protocol. Developing a product compatible with it would require, in my opinion, working hand in hand with G.E. engineers to validate and test the result.

I recommend you contact a suitable representative within G.E. and make your inquiry directly to them. Good luck!

 

Thank you very much. Do you think you can just scan it and post it?

 

GE no longer publishes the EGD protocol due to cyber security issues. You can possibly determine what the protocol is doing using Wireshark, it depends what class of EGD is implemented. EGD class 1 is cyclical data where the application determines the data content. EGD class 2 adds to class 1 with acyclical, programmed messages. EGD class 3 adds to class 2 with a fixed configuration server that defines the message content. EGD class 4 adds to class 3 with dynamically bound configuration. Most GE (now Emerson) PLCs support EGD class 1.