SourceTimestamp and ServerTimestamp with MonitoredItem and bad status in notification | OPC UA Standard | Forum

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SourceTimestamp and ServerTimestamp with MonitoredItem and bad status in notification
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Mark Rice
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06/26/2020 - 06:40
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I have a client that creates monitored items and requests both SourceTimestamp and ServerTimestamp. I really only utilize the SourceTimestamp. Under normal conditions, everything works as expected.

However, there is a specific use case that I am trying to determine what the proper behavior should be. My client is connecting to a certain UA server. It starts monitoring a tag and receiving data notifications with the value and SourceTimestamp. Then the tag is removed from the UA server while still monitoring. Then the client receives a notification with a status of Bad_NodeIdUnknown as expected. The problem my client has is that the SourceTimestamp is null. Only the ServerTimestamp is filled out.

Is this the expected behavior from the UA server? Do I need to use the ServerTimestamp if the SourceTimestamp is null and the status is bad? Are there other cases where I might get a null SourceTimestamp and I need to use the ServerTimestamp with monitored items?

Thanks.

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Randy Armstrong
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06/26/2020 - 14:10
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https://reference.opcfoundatio.....rt4/7.7.3/

In the case of a bad or uncertain status sourceTimestamp is used to reflect the time that the source recognized the non-good status or the time the Server last tried to recover from the bad or uncertain status.

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Mark Rice
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06/26/2020 - 18:37
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Thanks for the clarification Randy. I had read that before, but I wasn't sure if it was saying the server is required to include the sourceTimestamp. You have clarified that it should in fact do this.

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