G functions

A complete list of G functions is contained in the overview of commands in the Appendix under G functions (G..).

"G” functions describe the type of feed motion, interpolation type and measuring method. They switch time-related influences and activate certain operation states. The syntax consists of the letter G combined with an identifier. The identifier is assigned a fixed validity and can be optionally preceded by a 0:

G <expr>

Various distinguishing features must be considered with G functions:


There are G functions that only retain their validity after programming for a specific block ( non-modal) and G functions that retain their validity the first time they are programmed until they are explicitly deselected ( modal).


Certain G functions mutually exclude each other. For example, G01 (linear interpolation) and G02 (circular interpolation) cannot be selected simultaneously. Therefore, the functions summarised in these groups may not be programmed in the same NC block.

A modal function is automatically deselected if a different function in the same group is selected in a following block.

Programing Example


G functions


N50 G01 X100 Y200                ;linear interpolation effective

N60 G41 X200 Y200                ;linear interpolation effective

N70 X300 Y250                    ;linear interpolation effective

N80 X100 Y50                ;linear interpolation effective

N90 G02 X100 Y50 I100            ;circular interpolation effective


Initial position:

During switching, after RESET or at program end, the controller is in initial position. In initial position, several G functions are active without being explicitly selected.