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OPC DA Group Subscription
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Harivishnu B
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10/08/2020
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03/04/2021 - 19:59
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Hi Team,

I am working on developing an Opc client app with .net. I have around 55000k tags with different refresh rates. I tried with Group read with (ABB 800Xa(ABB.AfwOpcDaSurrogate.1) system but it is taking around 4min to complete. I would like to know about the Subscription-based group read. Is there any limit for number of groups that we can create for subscription-based group read?

Which is the best way to improve the performance of reading taglines (Subscription-based group read or group read) or is there any alternative?

Thanks in advance,

Vishnu

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Randy Armstrong
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05/30/2017
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03/04/2021 - 20:41
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The NET API will create 1 group for each refresh rate, however, you may find performance improves if you explicitly create groups/subscriptions for each refresh rate you support and add those.

You can then experiment with multiple groups for the same refresh rate.

You should also be depending on datachanges for updates rather than read. Change based updates are a core optimization of OPC which you lose if you simply try to read large numbers of tags.

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