• Not Answered

Deltav Historian trend gab

Dear All,

I' working on issue a PHV trends , where the operator cant go back in trends for any parameters for 2 months back but for some reason the trend history before more than 2 months available in PHV so there is a gab in the trends.

when i checked the Historian setting for the workstation the maximum historian size  to 600 MB and minimum time span enabled to 60 days but the data set time span not enable. The data set size was 600 MB and the data set export enabled.the historical data entry was not enabled. i have several questions:

  1.  only one work station not the pro-plus was configured for historian, are all work station should configured the same?
  2. The Administrative historian tool not working is that need a licence?
  3. whats the procedures to fill gabs in old trends to make it continues with new history data? 

thanks 

3 Replies

  • Not sure what version you are on, and whether you are using DeltaV Continuous Historian or Legacy Historian/Advanced Historian (which are both based on OSI PI). The Historian Administration tool in DeltaV is used for the native Continuous Historian, so I'll assume you have that. And that has not changed much over the last 7 revisions.

    Although Continuous Historian is installed and available on every workstation for 250 history tags (no additional licensing required), only the Application Station supports the Scale up licenses to expand the History tag capacity to 30250 tags total. Recently, Emerson released support to allow up to 3250 tags on Workstations, matching this feature on PK Standalone HMI's. These require licensing. per workstation, similar to Application station.

    History is stored in the Active Data Set, which you define the size of in the Continuous Historian Properties, along with rules for creating new data sets and what happens to Current Data sets when the History Storage space is filled. The Administration Tool allows you to manage these Current Data Sets, export them and convert the data to Extended Data sets. The Admin tool connects to the local historian on the computer you access it on.

    In Admin tool, you can view all data sets with their Start and End Times. If there is a gap in data, that should be evident by the end time of one Dataset not corresponding to the start time of the next. From what you describe, your Active Dataset is collecting data and you may have one or more Current Data sets covering data up to 2 months back, and then a gap is seen, with the older files, which may be Current or Extended Data sets.

    To fill this gap, you would need a Data set with start and end times that do not overlap with the existing data sets. If you have an export of this data from this Historian, it would fit this requirement. If you have a separate Historian that also collected this data at the same time, you would only be able to use that data if the Data sets Dates do not conflict/overlap.

    There are no tools to extract a subset of tags or time window from one Dataset to create another that fits into a Gap in history. Not natively.

    As I mentioned, if you have an export file for this historian or a current dataset from a backup of the node, you will need to create an Extended Data set from the Backup and register this to make the data available. If you have a back up you would need to recover the back up and then extract the needed data set and either export it to create an Extended Data set, or copy this to the system and register it via History admin tools.

    The Continuous Historian data sets can be registered on any server to view the data, as long as there is no conflict in time spans. You can use an offline system to confirm you have a valid dataset with the data and then move this to the online system.

    You might want to consider getting some assistance from a local service provider who has experience with DeltaV historian.

    Andre Dicaire

  • In reply to Andre Dicaire:

    Thanks Andre your input was valuable to me.

    I did create extended data set in continuous historian administrative tool that filling the gab for the required period but when i checked the PHV to see if the data gab filled , it still the same gab do i miss something ? I notice you mention registration of data set ? How can i do that?

    In other site when i try open the continues historian administrative tool in workstation it not open and shows me message :

    “ “The Continuous Historian server is not available please start the Continuous Historian server and try again””

    Whats the possible reason and how can be solved?

    Thanks
  • In reply to Haitham:

    When you create the Extended Data set, it will appear in the list of data sets shown in the Administration tool indicating the type is Extended and Backup Status is Backed Up.  

    If it does not appear in the list, it would have indicated a message as to why the Extended data set was not created.  Note on the left that the Primary location where the Active, Current and Extended Data sets reside.  Your Export files are likely in a backup location. 

    When configurating the Historian, you define the "max" size of the history space on the hard drive with a maximum size of 10Gb, (10,000 Mb).  Along the bottom of the Admin tool, it indicates the number of objects and the Free Space for datasets. The Free space value is based on your configured max size minus the Active and Current datasets.  The extended Datasets don't apply to this free space limit.  In the example above, the Active dataset is 23 Mb and my max size is 600 Mb on this computer, and the free space is 600 - 23 = 577 Mb.  So adding an Extended Data set will not fail due to the configured history size.  When free space approaches 0, the oldest Current Data set will be exported to allow a new Active Dataset to be created as needed. Your overall disk space on the computer is managed by you and should be verified prior to creating extended data sets to ensure there is enough disk space. 

    If you were successful in creating the data set, verify the "size" is consistent with your other data sets.  Compare the time span to other data sets and the Size should be proportional to the size based on time span.  If your new Extended dataset has a very small size, it may not contain the data you expect and so you still observe a gap at runtime.

    As for the message you see on the other system, that is consistent with the Historian not being enabled on the computer you were running the Admin tool on.  Check in Explorer that the computer has the Historian enabled and that it is the continuous Historian.  If the system has the Advanced Historian or the Legacy historian, these are PI data  historians and are managed with external PI Administrative tools, which are mostly command line level.

    Andre Dicaire