Siemens SINUMERIK 840DE Programming Manual page 227

Plane change
Warning
If you program a change of plane (G17 to G19) after a rotation, the angles of rotation
programmed for the axes are retained and continue to apply in the new working plane. It is
therefore advisable to deactivate the rotation before a change of plane.
Deactivate rotation
For all axes: ROT (without axis parameter)
Caution
In both cases, all frame components of the previously programmed frame are reset.
Substituting instruction, ROT X Y Z
The coordinate system is rotated through the programmed angle around the specified axes.
The center of rotation is the last specified settable zero offset (G54 to G599).
Fundamentals
Programming Manual, 10.2004 Edition, 6FC5 298-7AB00-0BP1
6.4 Programmable rotation (ROT, AROT, RPL)
Frames
6-19