You probably need to look into some CAD/CAM software to produce your engraving code.
Have a look at CamBam (commercial licence
http://www.cambam.info/) or FreeCAD (open source
freecadweb.org/).
CamBam has versions for Windows and Linux while FreeCAD is crossplatform.
CamBam is straightforward although you will need to choose your fonts carefully.
FreeCAD has a longer learning curve as it is primarily designed as a sketch-based 3D CAD software with CAM capabilities.