I understand now - but I cannot help, this is a j-interop issue.

And yes, it is almost self-evident that j-interop always uses the "remote" channel. It implements the "wire protocol" of DCOM, so even when locally, it needs to go over the network loopback. J-interop does not "hook into" local COM objects directly.

If the issue is in j-interop and related permission etc., OPC UA has nothing to do with, and cannot help here.

Regards

I see.

There are only 2 ways to use QuickOPC: With .NET, or with COM. QuickOPC is mainly written in .NET, and it provides the "best" interface and biggest amount of features. COM layer is implemented on top of the .NET code, and is a bit limited (although sufficient for most purposes).

So, if the J-interop and COM do not work well with you (can you give some details?), the only remaining option with QuickOPC is .NET.

The whole QuickOPC documentation is full of examples in .NET, and they are also installed with the product.

But, you need a tool/language that can consume .NET. If your requirement is Java, you would need some Java-to-.NET interop. This is not my area of expertise. See e.g. stackoverflow.com/questions/6378022/java-net-interop .

You still have not explained what's the issue with PHP. In our experience it works relatively well with QuickOPC over COM.

Regards

OK thanks,
I think it is much clearer now.

Now, I do not understand what actually is the problem here: "The issue we have is in point 3, because another our app (in PHP, same computer) communicate with 4 via COM correctly.". Another application, including PHP, can use (4) QuickOPC too, why not? [The PHP app must be on Windows, though]

And, coming back to your original question: QuickOPC is also OPC UA client. Therefore, if you replace (6) with OPC UA server (or the server is both OPC "Classic" and OPC UA server), (4) QuickOPC will be able to use OPC UA communication (usually "opc.tcp") in place of (5) (instead of COM/DCOM).

In this case, your Java applicaton, or PHP application, can still communicate with (4) QuickOPC over COM. But, it needs to use another set of QuickOPC objects and methods (for start, it needs to instantiate the EasyUAClient object and not the EasyDAClient object). The API is somewhat different, although you would recognize that the main principles remained.

Best regards

OK this will still take some time to clarify.

First of all, let's explain some terms. "DCOM" (Distributed COM) is an extension of Microsoft COM (Component Object Model). COM by itself only works locally (server and client on the same machine). DCOM also allows remoting.

When somebody (you) uses the term DCOM, it can therefore mean two things:
a) The whole, broad meaning - DCOM can be either remote or local
b) it is used *in contrast* to the term COM - that is, by saying DCOM, you are basically saying "I am doing things remote".

I do not know for sure which of the above meaning you have in mind.

Then, there are some more questions that come with the fact that you are using J-interop. This means that if you Java code is using QuickOPC, it is using it via COM interface (as opposed to the .NET interface which is how QuickOPC is primarily written). So that's the FIRST usage of COM. And then, if OPC "Classic" (not OPC UA) is used, QuickOPC communicates with the server using COM or DCOM - so that is the SECOND usage of COM. So, my current understanding of your architecture is as follows:

(1) Java application ->
(2) J-interop ->
(3) COM ->
(4) QuickOPC ->
(5) COM/DCOM ->
(6) OPC "Classic" server.

Can you please confirm the above. And, if it is correct, please tell me how many "boxes" (computers) are involved, so make clear to me where the remoting is used, and, on which of these the components (1), (4) and (6) reside. So, for example, I would expect that most likely answer is that there are 2 computers, say A and B, and that (1) and (4) reside on A, and (6) resides on B. Please confirm.

If you have placed (1) and (4) on different computers, and used "true" (remoting) DCOM in place of (3), that would be quite unusual scenario.

Only after all of this is clarified, I can go back to your original question.

Regards

We will resolve it... just need to keep clarifying.

Which programming language or tool you are using?

Regards