OPC Server DA dll - Retrieve tags value in bulk|Classic OPC: DA, A&E, HDA, XML-DA, etc.|Forum|OPC Foundation

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OPC Server DA dll - Retrieve tags value in bulk
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Koon Seng Chong
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09/10/2019
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09/10/2019 - 09:51
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Hi,

I’m using OPCSiemensDAAutomation dll with C# .NET to retrieve tag’s value from OPC Server. I managed to retrieve the values using QueryAvailableProperties() and GetItemProperties(), but the objective is to retrieve 500k tags value per request.

I have tested with 100 tags and the code finished it in 45 seconds, with multi threading resulted in a small improvement of 30 seconds for 100 tags. It’ll requires more than 4 hours to achieve the targeted tags volume with current speed. Is there any way that I can retrieve the tags value in bulk with better performance? Thanks.

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Randy Armstrong
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09/12/2019 - 01:36
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GetItemProperties is a metadata method in COM DA and it can be very slow.

The only way to access data efficiently is to use the Read or set up a a Subscription.

Some servers provide ItemIDs for Properties which allows you to use the Read method.

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