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AFSDK AfValue timestamp precision

Question asked by salte on May 24, 2016
Latest reply on May 25, 2016 by salte



I'm making some integration tests with PI, and came across this issue with the time stamp precision. I suppose the root of the problem may be the level of precision supported by PI, but just thought I'd put it on here to clarify.


Basically, I'm writing some values to a specified PI tag, then I'm requesting the same value back. Every time there will be a difference of a few microseconds in the timestamp of the value written and the value read. The difference is not constant, I've seen variation from 1.5 to almost 8 microseconds.


One example:

Create new AfValue, with time stamp second value: 48.6397361

Write this value to pi using: server.UpdateValues(valueList, AFUpdateOption.InsertNoCompression, _afBufferOption);

Read the value back using:  piPoint.RecordedValues(afTimeRange, AFBoundaryType.Inside, string.Empty, false);

Now I get the correct value, but the time stamp second value is: 48.6397399, so roughly 3 microseconds difference.


Anyone know if this is expected?

If not, what may be the problem?