The Tag History Module has a provider type called the Tag History Splitter. Like the Remote History Provider, it doesn't store history on it's own, it relies on having other providers already set up. A Splitter provider simply logs Tag History into multiple existing History Providers.
Some users prefer to have the data that is recorded by the Tag Historian sent to multiple databases. For example, project specifications require redundant logging and users at another facility may like to have a copy of the data in their local database. In cases like this, the Tag History Splitter Provider is ideal.
The Gateway that these Tags reside in must have multiple Tag History Providers configured. Should one of the providers fault, the Store and Forward system will kick in to maintain the data on the faulted connection. Since each database connection has its own Store and Forward engine, the data is always forwarded to the correct database.
To create the additional Tag History provider, do the following steps:
Below are the properties available on the Historical Tag Provider.
|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.|
|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.|
|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.|