Siemens SINUMERIK 840D sl Function Manual page 1459

TCOFR/TCOABS frame rotation
A frame rotation does not take place on activation and a rotation which is already active is not
changed. As in case T (only the tool can be rotated), the position of the rotary axes used for
the calculation is dependent on the G code TCOFR/TCOABS and determined from the rotation
component of an active frame or from the entries $TC_CARRn.
Activation of a frame changes the position in the workpiece coordinate system accordingly,
without compensating motion by the machine itself. The ratios are shown in the figure below:
Figure 18-43 Zero offset on activation of a rotary table with TCARR
Example
On the machine in the figure, the rotary axis of the table is pointing in the positive Y direction.
The table is rotated by +45 degrees. PAROT defines a frame, which similarly describes a
rotation of 45 degrees about the Y axis. The coordinate system is not rotated relative to the
actual environment (marked in the figure with "Position of the coordinate system after TCARR"),
but is rotated by -45 degrees relative to the defined coordinate system (position after PAROT).
If this coordinate system is defined with ROT Y-45, for example, and if the toolholder is then
selected with active TCOFR, an angle of +45 degrees will be determined for the rotary axis of
the toolholder.
Rotary table
With rotary tables (kinematic types P and M), activation with TCARR similarly does not lead to
an immediate rotation of the coordinate system (see figure), i.e. even though the zero point of
the coordinate system is offset relative to the machine, while remaining fixed relative to the
zero point of the workpiece, the orientation remains unchanged in space.
Basic Functions
Function Manual, 01/2015, 6FC5397-0BP40-5BA2
18.6 Toolholder with orientation capability
W1: Tool offset
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