If the EtherNet/IP Master is one whose scanlist is configured using RSNetworx, you will need at least a "stub EDS" file that defines the Identity of the device, and preferably also the I/O Assemblies.
While the scanner itself doesn't use EDS files, the RSNetworx software needs to know the basic identity and connection capabilities to create the Scanlist entries.
You can create a basic EDS by hand, just by determining the module identity using RSLinx Classic. The "EZ-EDS" software from ODVA makes it even easier to get the syntax correct.
If you can provide specifics about the Scanner and the Adapter device, Forum users may be able to give more specific advice.