From OPC server to OPC server. Possible ?

Hi.

I have an odd problem, that could possibly be solved if it is possible to exchange data between two OPC servers, each on its own PC. (if you want to know the background then look at the bottom)

In Simatic Net I can setup two PC Stations each with its own OPC server. And I can setup an S7 connection between the two.
Now, how do I setup symbols ?
What do the symbols point to ?
Is it all all possible to exchange data this way ?

Background:
We have a standard machine which we connect to a PC via OPC. On the PC there is amongs other things, an SQL database that logs data, stores production data etc. It is also intended to be the gateway for eventual customer data exchange.
Now we have a customer that wants to connect directly to our machine via Profibus and fetch the data from there. This we want to avoid at all costs, as it would mean that the machine would have to be "special" and not "standard".
The problem seems to be that he is not open to alternative methods, such as connecting via remote OPC or via SQL.
So, what if the customer could setup a Profibus connection to our PC+database, as if he was connected to the machine. If that is possible it could make everybody happy.

Hello Jesper;We were planning on implementing what is called "OPC bridging" in one of our bid projects where we needed to do something close to what you are planning. Didn't get the project finally, but this is one of the products we were looking into:
http://www.opcdatahub.com/Docs/dho-opcbridging.html

Maybe it could resolve your problem.
There is also a demo version of the software t download if you want to play around with it.
Hope this helps,
Daniel Chartier

Hi Daniel.

The problem is that it is two PCs, and the customer do not want to use Remote OPC. I could relatively easily do it if I had the mandate to use remote OPC or some databridging software (like OPC datahub) on my customers PC.
Problem is that he has gotten into his head that he wants to connect to the machine directly, and he ONLY wants to use a connection via Profibus. I think that the real issue is that he has a network layout via Profibus, and he cannot modify in any way (I dont know why). So it is the Profibus part that is important.

I could solve it if I can do something like this:
Database Client (PC1) <-- OPC Server (PC1) <-- Profibus --> OPC Server (PC2) --> Database Client (PC2)

At the moment, I have a "working" OPC connection setup between 2 PCs, but I have no clue as to what symbols or adresses I have to setup or how to set it up.

I found out of something that I find so useful that I think others should have the information too. Thats why I post it here.

Thanks to J_Bell on Siemens own forum, I got pointed to that there exists a "virtual" DB1 of 64 kBytes on the Simatic Net OPC server. It can be used for just such purposes as sending/retrieving from a PLC to the OPC server with PUT/GET for example.
The OPC syntax is "S7:[@LOCALSERVER]DB1, B0". There are no symbols, just a chunk of 64kB address area, but that is not such a big problem.
In the PLC you send a number of bytes to DB1 on the connection ID setup in NetPro.

Hello Jesper,

You can find instructions how to use symbols in Configuration Console - Simatic NET:




Then you can use them very easy when you set it up:

Hello krcedinac.

J_Bell plainly said to me that symbols are not possible with S7:[@LOCALSERVER]DB1.
But I will give it a look anyway.