Dimensional Notation (G90, G91)

G90 absolute dimensions

Command	G90 (default setting)
Cancellation	G91

Switches to absolute coordinates. X, Y, Z are interpreted as absolute PCS (program coordinate system) coordinates. This adjustment is the default. The switch becomes active in its own block.

G91 relative dimensions

Command	G91
Cancellation	G90

Switches to relative coordinates. X, Y, Z are interpreted to be relative to the current point, i.e. the next point is computed as the sum of [X,Y,Z] and the current point. The switch has an effect for its own block.

	Implement Offsets Manually Using `G91` and in this way switching to relative coordinates any Tool Offsets and Zero Shifts that have been defined earlier are not evaluated within these coordinates and therefore have to be defined and implemented manually within the framework of the `G91`-Code.

Example:

The path of the following example is shown in Figure “ExampleG90G91”. The switch to G90/ G91 takes effect immediately.

N10 G90 G01 X10 Y20 F6000
N20 X20 Y10
N30 G91 X10 Y10
N40 X10 Y-10
N50 G90 X50 Y20
M02

Figure “ExampleG90G91”.