Archiving

The history of object values and events is kept in archives — the Server’s historical databases. For an object’s values to be archived, create an archive with a suitable retention depth and assign it to the object. Graphs, summaries, the Data table and the event journal build their past periods from these archives.

Everything on this page needs the Configure right.

WARNING: in version 2.6, archiving cannot yet be set up from the Client. In version 2.6 the archives are kept by a separate process, scada-historian (see Server processes), and on an installation made with scada-setup:

  • creating an archive and assigning one to an object from the Client are refused by the Server;
  • values coming from devices are not written to the archive;
  • the Databases window stays empty.

To set up archiving on a version 2.6 site, contact Telecontrol (mail@telecontrol.ru). The Client procedure below is how it works on a Server running as a single process.

The Server’s archives

Archives are listed in the More -> Databases window (or the Databases section of the Administration mode). Each shows its retention depth and its write state — see Databases.

There is always a system archive, shown as «Системная база данных»: it keeps every Server event for 30 days, and cannot be changed or deleted.

Creating an archive

  1. Open the Databases window.
  2. In its context menu, choose Create -> Database. The archive is created at once, named “Database”, and its properties window opens.
  3. Set its name (for example “Measurements, 1 year”) and its retention depth — the Depth, days property. A new archive starts with a depth of 1 day, so set it straight away.

An archive is renamed with Rename or the Name field in its properties.

Once a minute the Server deletes data older than the archive’s depth; reducing the depth deletes the excess at once. The formula under Historical databases helps estimate the disk space needed.

Assigning an archive to objects

In the properties of a data object, under Archiving, choose the archive in the Value archive field. The list holds every archive and ** — do not archive.

A device’s events are stored in the archive chosen in its Event archive property (Devices).

A common practice is several archives with different depths — say, one for fast-changing measurements and one for rare events — each assigned to the objects it suits.

What happens to the data

  • Changing an object’s archive — its history is deleted from the previous archive, and new values go to the new one.
  • Deleting an object — its history is deleted from the archive.
  • Clearing a device’s event archive — events already written stay in the previous archive until its depth expires.
  • Deleting an archive — all of its data is deleted.

Checking

After assigning an archive, open the object’s Graph or Data for a past period: values written since the assignment should show. In the Databases window, an archive’s Measurement count shows how many objects write to it.