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  5. QuickOPC-UA in .NET
  7. Reading, Writing, Subscriptions
  9. Wrong values returned from ReadMultiple

Wrong values returned from ReadMultiple

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21 Mar 2019 09:12 #7250 by veda
Replied by veda on topic Wrong values returned from ReadMultiple
Made a new post about the subscription issue here: www.opclabs.com/forum/ua-reading-writing-subscriptions/2630-...disconnect-subscription-update

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20 Mar 2019 10:13 #7237 by veda
Replied by veda on topic Wrong values returned from ReadMultiple
This is correct. Sorry about that. This is about subscription. The only relevans might (or not) be some kind of cache setting....

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19 Mar 2019 15:04 #7229 by support
Replied by support on topic Wrong values returned from ReadMultiple
Your original post was about Reads. This new one seems to be about Subscribes only. Is that correct? If so, I will move it to a different forum thread. There is no relation between the two then.

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19 Mar 2019 14:58 #7228 by veda
Replied by veda on topic Wrong values returned from ReadMultiple
We see an issue with some subscribed variables/values not being updated after the client has been running for some hours/days. If I start a second instance of the same client code on a different machine this client will receive update of subscription updates. So I end up with two identical clients running on two servers connected to the same OPC Server. The client that has been running for a long time will stop reporting updates (only some values, not all), while the newely started client will work as expected.

Additional note: The OPC server we see the problem realted to has very seldom updates of values.

Are there any more cache/maximum age parameters hidden in the EasyUAClient that we should adjust (related to subscriptions)? We use the EasyUAClient.SubscribeMultipleMonitoredItems functions with an array of EasyUAMonitoredItemArguments.

I find this kind of issues a bit worrying. We need to be certain that we can trust the values reported by the EasyUAClient or client will report updates. If we need to adjust some cache parameters to be able to trust the client this should be clearly highlighted in the documentation (as you know we also have some server reconnect issues).

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05 Mar 2019 13:19 #7170 by veda
Replied by veda on topic Wrong values returned from ReadMultiple
Thank you for a quick response. The fault is quite random, but will verify the your suggestion once we see the fault again.

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05 Mar 2019 12:28 #7167 by support
Replied by support on topic Wrong values returned from ReadMultiple
Hello.

The UAReadArguments objects has a ReadParameters property of type UAReadParameters, and in it, there is a MaximumAge property. This is set to CacheMaximumAge (Int32.MaxValue) by default, with the meaning "The maximum age value that denotes reading from the cache.". See the reference documentation. Set it to DeviceMaximumAge (0.0d) and repeat the tests.

Best regards

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05 Mar 2019 07:38 #7163 by veda
Wrong values returned from ReadMultiple was created by veda
We have an application where we have an array of "UAReadArguments". We pass this array to EasyUAClient.ReadMultiple. When we examine the result of this call, the values returned are not correct even though we get UAAttributeDataResult.Succeeded and UAAttributeDataResult.AttributeData.HasValue (we compare with the values shown in Siemens OPC Scout client). I have not found any definitive pattern, but it looks like the values are old, and not updated correctly. Is this a known issue? Any idea how to fault find this?

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  5. QuickOPC-UA in .NET
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  9. Wrong values returned from ReadMultiple
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