Could you explain "Timed Data" a little more?
Timed data is a way to retrieve "Archive" values for PI Point(s) at at particular times (specified in an array of time stamps). I say "Archive" because the values that are being returned may not be exactly the values that you have stored in your archive files if no actual measurement exists at that particular time. Since timed data is asking for values at specific times, it may actually be returning an interpolated value from the surrounding two archived values. Overall, it's a way of getting actual (if an value exists in the archive for the exact time stamp) or interpolated (if there is no exact match) sample values for your data item.
It is particularly helpful if you have two different tags and you want to see if\how their values are correlated. For example, in the following I have a tag, BA:Phase.1, that tells me what phase my process is in. By retrieving the compressed (raw) values from my archive, I can see when my transition between Phases occurred. If I was then interested in what my process temperature, BA:TEMP.1, was at those exact same transition moments, I would want to use the Time Data function. This would allow me to retrieve the value of my temperature at the exact times of the phase transitions.
For instance, in the image below I made a spreadsheet with the actual values from my archive for tag PA:PHASE.1 in columns A and B. I then used the Times Data function in column D for tag BA:TEMP.1, selecting the array of time stamps in column A. Thus, each row has the value of my phase (column B) and temperature (column D) at the same times. If I look at the actual values for the temperature in my archives (columns G and H), I can see that the time that the time stamps for my temperature values (column G) do not exactly match the same times that the phase tag (column A) was recorded. Hence, the values from the Timed Data (column D) function are actually interpolated values of my temperature tag at the time stamps provided by the archived values of my phase tag.
You can also find more information about the Time Data function on our Live Library: https://livelibrary.osisoft.com/LiveLibrary/content/en/Clients-v1/GUID-A8A6782B-3288-4DFE-87F3-11E6BAD9D781
As well as another example: https://livelibrary.osisoft.com/LiveLibrary/content/en/Clients-v1/GUID-99192C72-98EE-412A-9376-224A5D6EA80C
Please let me know if that helps clarify Timed Data!!!