Wonderware Historian Tags

A tag in Wonderware Historian is the equivalent of a point or accumulator in ClearSCADA.

ClearSCADA automatically uses HCAL to create a new tag in Wonderware Historian when it first exports data for the point or accumulator. In order for ClearSCADA to export historic data:

The relevant Wonderware Historian must be specified as the historian application in the Export section of the point's or accumulator's configuration Form (see Define the Historic Export Details)
Data for the point or accumulator must subsequently be added to ClearSCADA's historian.

Tag creation is triggered when the first historic data for the point or accumulator is added to ClearSCADA's historian after the Wonderware Historian had been specified as the historian application to which the point or accumulator data is to be exported. Data is only added to ClearSCADA's historian if it meets the historic storage criteria for that point or accumulator. This includes meeting any Compression and/or Historic Data Filter criteria that might be configured for that point or accumulator. For more information see:

When ClearSCADA uses HCAL to create a new tag in Wonderware Historian, ClearSCADA gives the tag a name. The content that is included in the name depends on whether a Prefix is specified, and whether the Aggregate Name Suffix check box is selected on the Wonderware Historian Form (see Specify the Properties that are Associated with Tag Names).

The tag name has the following format:

[<prefix>.]<object name>[.<aggregate name>]

(where [<prefix>.] and [.<aggregate name>] are optional)

The tag name for a single point, named 'Internal Analog Point' in ClearSCADA, varies, depending whether the Prefix or Aggregate Name Suffix are used:

Internal Analog Point
(if neither the Prefix or Aggregate Name Suffix are used)

CS.Internal Analog Point
(if the Prefix is used, but the Aggregate Name Suffix check box is clear)

CS.Internal Analog Point.Historic
(if the Prefix is used and the Aggregate Name Suffix check box is selected)

Internal Analog Point.Historic
(if no Prefix is specified, but the Aggregate Name Suffix check box is selected)

A tag name can be a maximum of 256 characters in length. Ensure that the prefix and object names are not too long. For more about the tag name's Prefix and Aggregate Name Suffix, see Specify the Properties that are Associated with Tag Names.

Tags also have a description associated with them. By default, ClearSCADA sets the description to the class name and object ID of the point or accumulator. This is so that you can match tags in Wonderware Historian with items in the ClearSCADA database, for example, after renaming an item in ClearSCADA(see Troubleshooting Wonderware Historian Driver Operation). If you do not want to use the default description, you can change it by creating a custom ClearSCADA metadata field to configure the TagDescription property (see Configure Wonderware Historian Tag Properties from ClearSCADA and see TagDescription).

If you do one of the following in ClearSCADA:

Delete a point or accumulator
Disable historic storage on a point or accumulator

ClearSCADA will use HCAL to delete the tag from each Wonderware Historian server.

If you modify a point or accumulator to remove a historic export, ClearSCADA will use HCAL to delete the tag from the Wonderware Historian server for each removed export.

If you change the tag prefix in ClearSCADA, then ClearSCADA will only apply the new prefix to points or accumulators:

To which ClearSCADA has not yet exported any data
That you subsequently create.

All existing points and accumulators will retain their existing tag names, unless you use the RenameTag method to realign the tag names with the names of the points or accumulators with which those tags are associated.

If you move or rename points or accumulators in ClearSCADA (or a group containing points or accumulators) then these points or accumulators will retain their existing tag names. (However, with some versions of Wonderware Historian (as opposed to AVEVA Insight), you can use the RenameTag method to realign the two names. See the topic about the method for information about which versions of Wonderware Historian support the RenameTag method.)

To update the name of a tag in AVEVA Insight (formerly Wonderware Online) and older versions of Wonderware Historian, do one of the following:

Remove the historic export and then add the historic export back again (see Define the Historic Export Details in the ClearSCADA Guide to Core Point Configuration).
Disable historic storage and then enable historic storage again (see Enable or Disable Historic Data Storage in the ClearSCADA Guide to Core Point Configuration).

If you do either of these, ClearSCADA will use HCAL to:

Delete the existing tag from the Wonderware Historian server, along with all of its data
Create a new tag in Wonderware Historian with the current point or accumulator name and the current tag prefix.

NOTICE

LOSS OF EXPORTED HISTORIC DATA

If you follow the above procedure to update a tag name, you will lose all of the exported historic data associated with the tag.

Following the above procedure will result in the loss of exported historic data.

You can use the Status display to view the tag names associated with each point or accumulator (see Wonderware Historian Driver-Specific Status Display Attributes).