Monitor the Historian's Connection
You can use a VTScada expression to verify that any given Historian is connected to the data store on a given server. This expression may be created within an I/O and Calculation tag or as the condition for an Alarm tag.
Given an Historian named, "SystemHistorian" storing data on a server named "LogServer1" the expression to use is as follows:
Scope(\Code, "SystemHistorian")\GetServerStatus("LogServer1")
This expression will return a valid FALSE if disconnected. Invalid means that no data is available for that server, or it is a client, not a server.
By monitoring the connection, you can quickly raise an alarm if there is a loss of communication.
Historian Status Widget - Library object for monitoring all Historians in an application.
