R-Variables Read/Write speed degrading over time Siemens 840D NCK V4.5|OPC UA Implementation: Stacks, Tools, and Samples|Forum|OPC Foundation

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R-Variables Read/Write speed degrading over time Siemens 840D NCK V4.5
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Jeremy Pearson
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12/12/2023 - 18:16
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Hello and thank you in advance for reading. 

 

I am having an issue with a machine running Siemens 840D NCK V4.5, reading and writing R variables from OPC UC client, UAExpert. 

The problem is, that as time goes on in the sampling, the speed of the read/write of the variables slows down significantly over time. I am curious to know if there is any way to determine the exact cause of this, and to potentially improve the sampling rate. 

 

Thanks again for any advice. 

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Randy Armstrong
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12/13/2023 - 00:51
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You should be using subscriptions instead of periodically reading the same data.

That might help.

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Quincy Funk
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01/23/2024 - 00:58
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Would S7-Trace or S7-PLCSIM be used in this case?

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