You can configure additional settings of the driver using the INI file. This allows you to configure how you map external axes.
When you run the driver for the first time, it will generate a file containing flags for configuring advanced parameters of the driver such as external axes mapping. The location of this settings file can be found at the beginning of the driver's log on the line that starts with Loading settings.
You can open this file with any text editor, and you’ll find a list of axes used by RoboDK and the corresponding axes on the Fanuc robot controller side. Additionally, you can enable extra debug printing and change the number of motion groups that will be used.
If, for example axis 8 in RoboDK corresponds to axis 9 on the robot controller you would simply change the number on the right-hand side to the correct value, you can see the configured mapping in the startup message below the Loading settings message.
Axes 0-9 are Motion group 1 and Axes 10-17 are motion group 2, thus if your external axis is in the second motion group, it corresponds to axes 10 in the configuration file.