2 Replies Latest reply on Mar 31, 2015 12:00 AM by kholstein

    Creating Basic Reports with PI DataLink Online Course March 2015 Run- Videos, Exercises, and Final Project Discussion


      Hi Everyone,


      I have created this new topic for discussing the video lectures and exercises as part of the Creating Basic Reports with PI DataLink Online Course.


      • Do you have a question or comment about one the videos you watched?
      • Would you like to share an idea you have for one of the exercises?
      • Are you stuck trying to figure out how to obtain current and archived values for a tag, or retrieve compressed and sampled data?


      This is the place for you to ask questions, share thoughts, and even answer other students' questions with your own suggestions!




          • Re: Creating Basic Reports with PI DataLink Online Course March 2015 Run- Videos, Exercises, and Final Project Discussion

            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.


            timed data explaination.png


            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!!!