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Updaterate 0

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11 Mar 2019 15:23 #7198 by support
Replied by support on topic Updaterate 0
The update rate in QuickOPC method calls loosely relates to dwRequestedUpdateRate in OPC AddGroup call. In AddGroup, 0 stands for the fastest practical rate the server can provide.

QuickOPC does not allow you to use 0 as update rate, this is by design, and there is no "workaround".

Because the real update rate cannot be true zero anyway, and 1 is the closest/smallest available update rate, using 1 is just what you should do if you have such requirement.

I would be very surprised if you could actually get update rates as fast as 1 millisecond working well anyway. These are extreme values that are not normally used by OPC applications.

Regards

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11 Mar 2019 13:50 #7197 by treams-gmbh
Updaterate 0 was created by treams-gmbh
Hi,

I have an very fast OPC-DA Item and the documentation tells me:

A very fast transfer rate is required for the measuring data. The "Data" item is notified when a modification occurs. Therefore, the "Update Rate" zero is required for the group that contains this item.

If i set the updaterate in the subscripeItem() function to zero I receive an exception. Currently I work with updaterate 1. It works but sometimes i miss data.

Is there a workearound to solve that problem.

Thanks and Regards
Tony

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