4 Replies Latest reply on Aug 9, 2018 8:49 PM by vkaufmann

    PI Archive Value : Retrieval Modes Auto and Exact Time.

    alanR

      Hi ,

      Im running pi data link 2015 in excel ,im pulling tag data using archive value function in excel for some of the rows it is displaying “No events Found”. This is only showing for Archive Values from 28-July-2018 to 02-Aug-2018. The screenshot below is showing the client time timestamp. When i use the retrieval method "auto " it works , but when i use the retrieval method "exact time".  It does not work?

       

       

      This screenshot below is showing the Archive Value timestamp for only one of the tags and it clearly has data and so do the other tags that are not shown in the screenshot.

       

      They both have the same date and time values but are not showing ? Im puzzled to as why they are not showing.

       

      Thanks,

        • Re: PI Archive Value : Retrieval Modes Auto and Exact Time.
          André Åsheim

          Hi,

          Is the PI Data Archive and the client in the same timezone?

           

          Secondly, not sure if it applies but can you check if there is sub-second timestamps on the values. In SMT click view->Settings-->Time format

          Check for "PI Time format" and select the number of sub-seconds

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          • Re: PI Archive Value : Retrieval Modes Auto and Exact Time.
            Lal_Babu_Shaik

            Hi Alan

             

            Archive Retrieval method uses below modes determine the returned values

            • previous Returns the value that exactly matches or precedes the specified time stamp.
            • previous only Returns the value that precedes the specified time stamp.
            • interpolated Returns the interpolated value at the specified time.See Interpolated values.
            • auto Returns the interpolated value at the specified time, or follows the previous method. (Uses the previous method for data items with step attributes.)
            • next Returns the value that exactly matches or follows the specified time stamp.
            • next only Returns the value that follows the specified time stamp.
            • exact time Returns only a value that exactly matches the time stamp, or returns No events found if no value exists at that time stamp.

             

            Thanks,

            Lal Babu

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            • Re: PI Archive Value : Retrieval Modes Auto and Exact Time.
              VasanthakumarR

              Hi Alan,

              I have tested your scenario for the ArchiveValues Datalink function, below are my test results and comments,

               

              Scenario 1:

              I have given the Timestamp as 02-Aug-2018 00:00:00 and data retrival methods as Auto, Exact Time and Interpolated Values,

              Archive1.png

              In this case, the given timestamp does have any values, so the 'Exact time' gives results as "No Events Found".

              If the Data is not available in the given timestamp Auto retrieval method will gives the interpolated values, you will get the same data when you select 'interpolated data' retrieval method.

               

              Scenario 2:

              I have given the timestamp  where the Data is available.

              Archive2.png

              In this scenario you will get the straight forward results as we have data for the particular timestamp.

               

              So the issue in your case is you are giving the timestamp where there is no data, so the 'Exact time' returns  "No Events Found" and 'Auto' returns the interpolated values.

               

              Refer the below screenshot for the details about Retrieval Modes in Archive Value,

              Archive Value.JPG

               

              -Vasanth.

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