Has anybody ever ..

Hi List

in our equipment integration project at AMD, Dresden (the ones producing
all the Athlons and Opterons etc.) we stepped over a communication
infrastructure called OPC, which translates to 'OLE for Process Control'
(http://www.opcfoundation.org ). There are two, lets say, approaches or
architectures, one is based on COM, the newer one on Web Services.

Now the question is, has anybody written an OPC Client or Server for the
COM-based variant? Was it difficult? Did COM-Connect help, was it
sufficient?

Thanks for any answer!

Roland
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Tel: x49-231-9 75 99-26   Fax: x49-231-9 75 99-20
Georg Heeg eK Dortmund
Handelsregister: Amtsgericht Dortmund  A 12812

If anyone would know, it'll be Mike Hales, he did quite a bit with OPC
over COM, I believe. He's a frequent visitor to this list, you can
easily get his email direct if he doesn't respond here.

Hope this helps,

-Boris

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> -----Original Message-----
> From: Roland Wagener [mailto:[hidden email]]
> Sent: Wednesday, November 07, 2007 1:08 PM
> To: vwnc
> Subject: Has anybody ever ..
>
> Hi List
>
> in our equipment integration project at AMD, Dresden (the ones
producing
> all the Athlons and Opterons etc.) we stepped over a communication
> infrastructure called OPC, which translates to 'OLE for Process
Control'
> (http://www.opcfoundation.org ). There are two, lets say, approaches
or
> architectures, one is based on COM, the newer one on Web Services.
>
> Now the question is, has anybody written an OPC Client or Server for
the

Hey Roland, we use a third party dll purchased from WinTech for both  
OPC client and server.  I built an External interface class wrapping  
it and some basic Objects modeling servers, groups and items.  Unless  
you are really COM savvy, I would not recommend using COM-connect to  
build your own OPC client, I would buy a third party SDK that gives  
you a C api. That greatly simplifies things.  With ours, I do load the  
COM-Automation parcel so I get support for VARIANT structures for free  
which is how COM passes the data back and forth.  There are a number  
of vendors selling sdk's including a couple which have bridges to  
linux as well.

Also of note is the OPCXMLDA package in the Cincom public store which  
has the server implementation of the Web Services approach to OPC.  
This was Randy Coulman's work from Key which he was kind enough to  
publish.

Also note that the OPC foundation is in the process of rolling out the  
OPC "Unified Architecture" which will include a Web-Services based, as  
well as platform independent binary protocol.  They promise ansi-C  
dynamic libraries for multiple platforms.  This will be a while before  
it is widely adopted in the industry though.

Your best be is getting a C library and wrapping it, which isn't hard,  
the COM-Connect parcels from Cincom can help with 2 big things, GUID's  
and VARIANT's which most C libraries assume you can deal with.

Mike


On Nov 7, 2007, at 2:08 PM, Roland Wagener wrote:

Thank you everybody for your comments, they were very helpful in
deciding which direction to take.

Thanks Mike for the not so obvious tricks.

Roland
--
Roland Wagener * Senior Consultant * [hidden email]
Tel: x49-231-9 75 99-26   Fax: x49-231-9 75 99-20
Georg Heeg eK Dortmund
Handelsregister: Amtsgericht Dortmund  A 12812