I have a VT Scada realm configured with 9 applications. When I connect to this realm using the ODBC DSN, I only see the tags configured in the first application of the realm.

Do I need to create a new realm for each application? Can multiple VT Scada realms run on the same machine at the same time without issue?

What would be the best way to approach this kind of configuration? My goal is to query the VT Scada historical records using the ODBC DSN in Microsoft Excel.

It's possible to have more than one application in a realm, but not advised. Configuring a single application per realm is simply more robust from a security standpoint, or so our security experts tell me. For multiple applications, the first will be the default and you would need to refer specifically to the others as part of the address.

The Microsoft Support documentation suggests that it's possible to have more than one data connection in a workbook. (I haven't tried.) You would need separate queries for each application in any case. No single query will read from two applications.