Rotate the coordinate system in the plane (G68/G69)

Release Note

This function is available as of CNC Build V3.1.3079.33.

This function rotates a coordinate system in the current plane (G17/G18/G19). Contours programmed in the machine coordinate system can be adapted quickly and easily to workpieces in offset positions.

Contour rotation acts directly on the programmed axis coordinates (contour) before all other contour-influencing functions, i.e. all offsets and mirroring operations are not influenced by the rotation and can be used as before (*).

Rotation may also be applied within an already rotated coordinate system (#(A)CS).

A change of plane with G17/ G18/ G19 automatically deselects an active contour rotation and a warning is output.

As a alternative to G68/ G69, contour rotation can be programmed using #ROTATION.

Syntax (example in G17):
G68 R.. X.. Y..	Select contour rotation	modal
G69	Deselect contour rotation	modal, initial state

R..

Rotation angle in degrees [°], absolute. If no angle is specified, the value 0° is set. The rotation angle has no influence on already programmed circle radii.

X.. Y..

Absolute coordinates of the centre of rotation in [mm, inch] in the main axes of the current plane.

The following applies: G17 - X and Y, G18 - Z and X, G19 - Y and Z

With coordinates that are not programmed, the current actual position is set as the centre of rotation.

Significance of rotation parameters in the main plane (example G17):

a: X..

b: Y..

c: R..

The programmed rotation parameters can be read with the following variables:

V.G.ROT_ACTIVE	Contains the value 1 if a rotation is active
V.G.ROT_ANGLE	Rotation angle
V.G.ROT_CENTER1	Offset of the first main axis relative to the centre of rotation
V.G.ROT_CENTER2	Offset of the second main axis relative to the centre of rotation

Notice

(*) It makes no difference whether the offsets (e.g. G54, G92 etc. ) were programmed before or after G68; they always act in the axis directions of the basic coordinate system of the machine (MCS).

In addition, tool offsets always act independently of P-TOOL-00010 in the axis directions of the MCS.

Programing Example

Rotation in a plane (contour rotation)

%L part

N10 G0 G90 X0 Y0

N30 G1 F5000 Y50

N40 X75

N50 G2 Y-50 R50

N60 G1 X0

N70 Y0

N80 M29

%ang1.nc

N100 G53 G17

N110 LL part

N130 G68 R-45 X10 Y100

N140 LL part

N150 G21 (mirroring of X coordinates)

N160 LL part

N170 G69

M30