Tag History Splitter

Tag History Splitter Provider

Some users prefer to have data recorded by the Tag Historian sent to multiple databases: project specifications require redundant logging, or users at another facility would like to have a copy of the data in their local database. In cases like this, the Tag History Splitter Provider is ideal. A Splitter provider simply logs tag history into multiple database connections. This requires that the gateway the tags reside in have multiple database connections configured. Should one of the database connections fault, the Store and Forward system will kick in to maintain the data on the faulted connection. Since each database connection has it's own Store and Forward engine, the data is always forwarded to the correct database.

To use the tag history splitter

Once the module is installed, to create the additional tag history provider, do the following steps:

  1. Go to the Configure section of the Gateway, and choose Tags>History from the menu on the left.

  2. Go to the bottom of the Database Tag History Providers page, and click Create new Historical Tag Provider.
    The Add Historical Tag Provider Step 1: Choose Type page is displayed.

  3. Select Tag History Splitter and click Next.
    The New Historical Tag Provider page is displayed.

  4. Enter a name for the Provider Name, and from the dropdown choose a database for the First Connection (for the primary data) and one for the Second Connection (for secondary data).

  5. Click Create New Historical Tag Provider.
    Now the splitter tag provider is created and you can use it to log the tag history data in the Designer.
    Check this by going back to the Designer, selecting a tag and then right-clicking to select the Edit tags. On the Tag Editor window go to the History tab and see the new splitter provider in the dropdown of the History Provider.

Tag History Splitter Provider Properties

Below are the properties available on the Historical Tag Provider.

Main

Provider Name

Name of the connection.

Enabled

Enables and disables the connection.

Description

Description of the connection. The description appears on the Historical Tag Providers page of the Gateway.

Storage

First Connection

Data is stored to both connections equally. However, all tag history queries (tag history bindings, system.tag.queryTagHistory() calls, reporting tag historian queries, etc.) execute against the first connection, unless a limit is imposed using the settings below, or the first connection is unavailable.

Second Connection

The second connection to store tag history.

Querying

Limit First Connection Query

If enabled, only queries that are within the time frame specified below will be executed against the first connection. Queries that go further back will execute against the second connection.

Limit Length and Units

The unit and length of the time frame limitation mentioned above.

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