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  1. Forum
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  5. QuickOPC-Classic in .NET
  7. EasyDAMultipleItemsChangedEventArgs
× If you are developing in .NET, but are using the OPC-UA (OPC Unified Architecture), please post in the QuickOPC-UA category instead.

EasyDAMultipleItemsChangedEventArgs

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14 Sep 2023 11:43 #12129 by PythonByte
Replied by PythonByte on topic EasyDAMultipleItemsChangedEventArgs
I understand, it's an older application with multi components that inherited.

I will keep digging and hopefully I find something.

Thank you for your help

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14 Sep 2023 11:39 #12128 by support
Replied by support on topic EasyDAMultipleItemsChangedEventArgs
Hello.

Combining OPC server and client in one application is very difficult in terms of COM/DCOM security. And, doing so with two toolkit from different vendors even more so. Each toolkit may assume it has the right to control the COM/DCOM security, so conflicts are almost inevitable.

This is not the kind of setup we can help with.

Best regards

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14 Sep 2023 11:36 #12127 by PythonByte
Replied by PythonByte on topic EasyDAMultipleItemsChangedEventArgs
Yes, both are integrated into a single application. I am using SLIKDA server.

I was able to get further, my server is throwing an Access denied error when trying to connect with the ItemChanged method, if I comment it out, it connects just fine.

Thank you

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14 Sep 2023 11:17 #12125 by support
Replied by support on topic EasyDAMultipleItemsChangedEventArgs
I still do not understand your architecture.

On your side, is the client and server somehow integrated in a single application? QuickOPC only allows client development. If the server is integrated in the same application, what kind of server toolkit/library are you using?

Regards

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13 Sep 2023 16:43 #12119 by PythonByte
Replied by PythonByte on topic EasyDAMultipleItemsChangedEventArgs
Hello,

on my side, I have a client and a server, and on the other side they have a client and a server. My server handles their client requests and exchange info. It seems to be my server stops allowing their client to connect if I add the ItemChanged method and allows them to connect if I remove it.

I am looking into why this single method breaks communication between their client and my server...

Thank you

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13 Sep 2023 16:09 #12116 by support
Replied by support on topic EasyDAMultipleItemsChangedEventArgs
Hello, thanks.

I still do not get why you write " Siemens OPC server stops connecting to my OPC client ", I suppose in normal terminology it would be the other way round, so your client stops connecting to the Siemens OPC server? Please confirm.

Is your OPC client application connecting to multiple OPC servers? And one of them is affected and others are not?

And I do not get " the other OPC server is throwing is: Failed to connect to OPC server (80080005H)." Are you saying that when your clients tries to connect, the server shows this error? And what is the error on the client?

Regards

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13 Sep 2023 16:02 #12115 by PythonByte
Replied by PythonByte on topic EasyDAMultipleItemsChangedEventArgs

I will need some block diagram, or better explanation of parts involved. What you wrote makes no sense to me: " other OPC servers (Siemens OPC) stopped being able to connect to my OPC server" - OPC server do not connect to other OPC servers. Clients connect to servers.

Regards

sorry I mean Siemens OPC server stops connecting to my OPC client when I add that method (ItemChanged), If I comment it out, the server can connect to my client. In the older version (5.23) the OPC server connected to my client just fine using the MultipleItemsChanged method in my code, and with this method is gone in version 5.59, adding the ItemChanged method breaks the communication between the server and the client.


Thanks

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13 Sep 2023 15:47 #12114 by support
Replied by support on topic EasyDAMultipleItemsChangedEventArgs
I will need some block diagram, or better explanation of parts involved. What you wrote makes no sense to me: " other OPC servers (Siemens OPC) stopped being able to connect to my OPC server" - OPC server do not connect to other OPC servers. Clients connect to servers.

Regards

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13 Sep 2023 15:43 #12113 by PythonByte
Replied by PythonByte on topic EasyDAMultipleItemsChangedEventArgs
I have a very mysterious problem, everything was working in version 5.23. I started using the ItemChanged method and commented out the MultipleItemsChanged event, using this method:
Public Sub ItemChanged(sender As Object, e As EasyDAItemChangedEventArgs) Handles m_opcClient.ItemChanged
 
        Dim Tag As HQTag = CType(e.Arguments.State, HQTag)
 
        If e.Succeeded Then
            Tag.Value = e.Vtq.Value
        Else
            Tag.ServerError = e.Exception.GetHashCode.ToString
        End If
 
        RaiseEvent TagChanged(Tag)
 
    End Sub

Everything works, I get tags value being changed but other OPC servers (Siemens OPC) stopped being able to connect to my OPC server. If I comment out the event above ItemChanged, the other servers can connect to my OPC without issues...How can possibly this single method stops other OPC servers from connecting? The only error message the other OPC server is throwing is:
Failed to connect to OPC server (80080005H).

what do you think?

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13 Sep 2023 15:23 #12112 by support
Replied by support on topic EasyDAMultipleItemsChangedEventArgs
Hello.

The events that delivered multiple notifications at the same time were removed in later versions (together with their supporting event argument types).
The reason for the change was that they were not bringing the performance improvement they were intended for.

You can use the event that delivers single notification at a time, and remove the loop that iterated over multiple notifications.

Best regards

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