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Read Tags each n seconds

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11 Feb 2020 07:18 #8218 by support
Replied by support on topic Read Tags each n seconds
The answer is:
- Yes if the SourceTimestamp has changed (this is normally the case)
- Not to my knowledge, if the source timestamp has not changed.

You need to use "data change filter" and specify a triggering mode that is different form the default.

In principle, the code will be like the example here: opclabs.doc-that.com/files/onlinedocs/QuickOpc/Latest/User%2...e%20nodes%20with%20filter.html

except that you will use UADataChangeTrigger.StatusValueTimestamp.

Note that it is not necessary to use this approach just to "assure yourself" that the value is still coming from the server and has not changed. OPC UA and QuickOPC have enough mechanisms to assure that you either get the changed value, or an error indication.

Best regards

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10 Feb 2020 23:51 #8217 by alr1976
Hi!

it possible to Subscribe many tags and have value also if tags value is not changed?

For example i have 2000 tags and i need to have values for each 1 second also if value is not changed.

I can t use readmultiplevalues because i need some values for each 0.5 seconds and other values for each 3000 seconds and so on.

Br,Alessandro

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