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BT_99800213-Newcomer
3-Newcomer
August 4, 2025
Solved

OPC-UA Client issues

  • August 4, 2025
  • 2 replies
  • 1036 views

Hello Everybody,

I'm trying to connect Kepware OPC-UA Client driver to remote OPC-UA Server to read about 50K tags.

It looks like the communication is too slow and other client, that connects to Kepware and read these tags experience read failures and doesn't read all of them and about 50% of tags signed with bad values. Event log of Kepware filled with lot of events like "The subscription id is not valid.",Status code = 0X80280000.(At the attached picture)

Is it anywhere recommendations about good configuration practice on OPC-UA Client driver?

And what are the sizing recommendations (amount of tags, devices and channels) for Kepware server?

Thanks a lot

Best answer by rajskumar

Hello,

 

When using the OPC Client Drivers within the Kepware project, each channel is a unique connection to the server and subsequently each device created under the channel is a unique OPC group to the target server

  • For each device/OPC group:
    • It is recommended to import/define no more than 5000 tags to be read from the target server at a requested update interval of 1000 ms
    • It is also recommended to only import/define only the necessary tags required from the target OPC server, not all tags available
      • Note: when launching the OPC Quick Client using the default setting to auto-build all tags available in the project, this will cause the client driver to request updates for all items at the update interval
      • Inefficient project configuration can cause this action to overwhelm the target OPC server and cause unexpected results, slow updates, or bad tag quality
  • Example:
    • If the target OPC server has 100,000 tags in the available namespace but the requesting client only needs 20,000 to satisfy the data needs, then the project file should be created with a single channel using an OPC Client driver configured with 4 devices under the channel with a maximum of 5000 tags imported under each device
  • NOTE: The 5000 tag limit per device is just an example
    • Some third-party target OPC servers may perform better with tag quantities between 2500 and 3500 per device (OPC group)

Let me know if you have any other questions or concerns.Thanks 

2 replies

R
rajskumar16-PearlAnswer
16-Pearl
August 4, 2025

Hello,

 

When using the OPC Client Drivers within the Kepware project, each channel is a unique connection to the server and subsequently each device created under the channel is a unique OPC group to the target server

  • For each device/OPC group:
    • It is recommended to import/define no more than 5000 tags to be read from the target server at a requested update interval of 1000 ms
    • It is also recommended to only import/define only the necessary tags required from the target OPC server, not all tags available
      • Note: when launching the OPC Quick Client using the default setting to auto-build all tags available in the project, this will cause the client driver to request updates for all items at the update interval
      • Inefficient project configuration can cause this action to overwhelm the target OPC server and cause unexpected results, slow updates, or bad tag quality
  • Example:
    • If the target OPC server has 100,000 tags in the available namespace but the requesting client only needs 20,000 to satisfy the data needs, then the project file should be created with a single channel using an OPC Client driver configured with 4 devices under the channel with a maximum of 5000 tags imported under each device
  • NOTE: The 5000 tag limit per device is just an example
    • Some third-party target OPC servers may perform better with tag quantities between 2500 and 3500 per device (OPC group)

Let me know if you have any other questions or concerns.Thanks 

    V
    vnamboodheriCommunity Manager
    Community Manager
    August 11, 2025

    Hello @BT_9980021,

     

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    Vivek N.
    Community Moderation Team.

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