I'm kinda new in this subject, but I'm in a project where we want to control a 4-axis SCARA robot with Mach3. We also are using The Geckodrive G100 and G340 motor drivers. I'd like to know if exist a module or plugin of Mach3 to control this tipe of robots and able to work in this type of coordinates (angles of rotation of each joint). I saw that Mach3 can be programed but I'm not sure that it can be configured to convert cartesian coordinates in to the coordinate of the robot. I'd be glad if someone give me information or suggestions about.

Just set up the steps per unit in motor control to equal one degree.   Then you can have xyza all in "degrees"

Works great on my robot.