Mango can read from an external database using the SQL data source. Out of the box it can connect to a MySQL database, but others can be implemented by finding the appropriate driver (usually just a jar file that you can add to WEB-INF/lib).
If you are on a Windows platform, it is possible to use an ODBC/JDBC driver to connect Mango to and ODBC data source. In Windows you can then set up various things - like flat files, Excel spreadsheets, Access databases - as your ODBC sources. Might be worth a try. By finding the appropriate drivers (which are typically easy to find), you can also connect Mango directly to Oracle, MS SQL Server, Postgres, etc.
Your alternative to having a database intermediary is to connect directly to your A/D converter processing board, assuming it supports some communications protocol like Modbus, BACNet, 1-wire, etc. Do you know?
Once you've decided on a connectivity strategy, i can help you with the details.