If I have a historian that is external to PI (ex. a SQLServer db with I/O records from another collection system), can I integrate that data with my Pi historian data in Pi Vision?
I would suggest that you use the PI Interface for RDBMS.
It works very well and have a lot of features to configure the data flow just the way you want it. A one-time read of all data, or real-time transfer of data.
PI Vision can only use PI Data Archives and PI AF Servers as data sources. Tomas is correct in suggesting that you consider using the PI Interface for RDBMS to send data from your SQL server to the PI Data Archive.
Retrieving data ...