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Historian Playback Tool - Output Column Values <=> Measumrent Type (header) mismatch

Developer
Feb 16, 2012 at 6:37 PM
Edited Feb 16, 2012 at 6:38 PM

Hi,

    I would appreciate your advice in an unusual task.

    We have to track down an issue of mismatching titles (metadata) on extracted with HistorianPlayback tool archives.

            Metadata displays                       Historian Playback output column (.csv).

           (null:1):TVA_BULLRUN:F (Hz)      ->      245589,003 (Kv) 

           (null:10):TVA_BULLRUN:S (flag) ->     -100.03 (looks like v)       etc...

    This is just an example and seems like all other collumn are not assigned to the right output.

    Next I've tried to find solution to extract Historian IDs directly form *.D files... but documentation (OpenPDC Archive File Format overview) indicates only time related DataPointer  (BlockTypeID -> BaseTimeStamp -> OffsetTimeStamp ) and there is no sign of HistorianID at all.

    My questions:

                        - Is there any way to extract HistorianIDs without metadata files (from what I've seen in code "no" but I can be wrong)?

                       - What would be a way to approach mismatching data <=> metadata issue?

  Thank you,

denis.

Coordinator
Feb 16, 2012 at 7:54 PM

There is a metadata file (e.g., ppa_dbase.dat) that is always associated with a setup of historian files. This contains the "definitions" of the point ID's as of the last metadata refresh. However, this doesn't track metadata history - just the most current set of point definitions.

Even so, metadat from the openPDC is pushed into this file, not the other way around - that is, the "ActiveMeasurement" view is the metadata master and this file is the slave.

If you have some historical .D files you are trying to load and the ActiveMeasurement ID's no longer match - then your best bet will be to load the .DAT file.

Normally if you use the playback utility to browse to a folder full of .D files with a .DAT, you can see all the metadata loaded from this file along with the original ID's. Note that to do this one of the .D files must be considered "active", i.e., a file named like ppa_archive.d msy exist. If you do not have a file suffixed with _archive.d you will need to rename the newest file in the folder to "nnn_archive.d" where "nnn" is the archive name (e.g., PPA, STAT or DEVARCHIVE).

You can look at the open source tools to see how they "load" metadata from the .DAT files...

Hope that helps!
Ritchie

Developer
Feb 17, 2012 at 1:10 AM
Edited Feb 17, 2012 at 1:12 AM

Thank you Ritchie,

      Your explanation helped me to understand what is going on, I just wasn't sure if am I on a right track to accomplish this task or misunderstood something. I assume metadata "history" had changed with time that's why I'm getting this output.

With best regards,

denis. 

 

Jul 3, 2012 at 10:42 AM
Edited Jul 3, 2012 at 10:44 AM

I perhaps have a very trivial question:

In order to be able to use the historian playback utility - what are the files which are necessary? It seems you can't just take a .d file and point the playback utility to it. So, which other files must also be present in that directory to provide enough metadata for the tool to successfully work? Thanks much, --S

 

Coordinator
Jul 4, 2012 at 2:48 PM

Minimum files needed in the folder are:

  • An active archive file (e.g, stat_archive.d)
  • The metadata file (e.g., stat_dbase.dat)

If all of your .D historical data files are timestamped (e.g., stat_archive_2011-03-08 00!48!50.743_to_2011-09-25 01!22!15.424.d) and you don't have an active archive, then just rename the newest timestamped .D file to the active archive file name (e.g., stat_archive.d)

That should do it...

Thanks!
Ritchie

Jul 18, 2014 at 11:43 AM
can we see the historian trending for a month?? pls suggest me...
Coordinator
Jul 18, 2014 at 1:16 PM
Certainly - but with very high resolution, such as synchrophasors streaming in at 30 times per second, a months worth of data for one measurement can be 80,352,000 individual values. Because of this the trending tool has a "Chart resolution" setting that will determine how many maximum points to display on the trend.

Note this is for the display only - if you export data for a month you will get all 80,352,000 values.

Thanks,
Ritchie