The SAP RFC connector allows you to connect via the RFC connection layer to your on premise SAP system.
The SAP RFC connecitvity is performed through SAP's librfc32.dll.
If you want to use the SAP RFC connector, make sure your hub and also the machine where you use the AppBuilder has this dll's in place.
LibRfc32 Installation on a 32 Bit OS
Copy the LibRfc32.dll (32 Bit Version, also installed when you install SAP GUI/SAP Logon) into the C:\Windows\System32 Folder.
LibRfc32 Installation on a 64 Bit OS
Copy the LibRfc32.dll (64 Bit Version, Download via SAP SDN) into the C:\Windows\System32 Folder.
Copy the LibRfc32.dll (32 Bit Version, also installed when you install SAP GUI/SAP Logon) into the C:\Windows\SysWOW64 Folder (this Folder means System Windows on Windows 64)
The LibRfc32 requires the Visual C++ 2005 Runtime. Please make sure this is installed on the given machine
RFC's can be accessed through this connectors. The only requirement is, that the given function modules has the processing type marked as a "Remote-Enabled Module" in SAP.
SAP tables can also be accessed through the connector (read only). Since tables are by default not accessible from outside SAP, internally the standard SAP RFC "RFC_READ_TABLE" supports the connector to consume SAP tables.