Siemens SINUMERIK 840D sl Function Manual page 127

The effect of TCOFR is such that, when machining on an inclined surface, tool offsets are
considered implicitly as if the tool were standing vertically on the surface.
Note
The tool orientation is not bound strictly to the frame orientation. When a frame is active and G
command TCOABS is active, you can select a tool, whereby the orientation of the tool is
independent of the orientation of the active frame.
Following tool selection, you can change the frame, which does not affect the components of
tool length compensation. It is then no longer certain that the tool is positioned perpendicular
to the machining plane. You should therefore first check that the intended tool orientation is
maintained on an inclined surface.
When TCOFR, etc., is active, the tool orientation used in the tool length calculation is always
determined from the active frame each time the tool carrier is changed.
Tool carrier from G command of group 53
The G commands of group 53 (TOFRAME, TOROT, etc.) can be used to define a frame such that
an axis direction (Z, Y or X) in this frame is equal to the current tool orientation.
The G command of group 6 (G17 - G19), which is active at the time TOFRAME is called,
determines the tool orientation.
If no tool carrier is active, or if a tool carrier is active but does not cause the tool orientation to
change, the Z direction in the new frame is:
● The same as the old Z direction with G17.
● The same as the old Y direction with G18.
● The same as the old X direction with G19.
These directions are modified accordingly for rotating tool carriers. The same applies to the
new X and Y directions.
Instead of TOFRAME or TOROT, one of the G commands TOFRAMEX, TOFRAMEY, TOROTX, or
TOROTY can be used. The meanings of the axes are interchanged accordingly.
Group change
Changing the G command from group 42 (TCOABS, TCOFR, etc.) causes recalculation of the
tool length components.
The (programmed) angles of rotation stored in the tool carrier data is not affected, with the result
that the angles originally stored in the tool carrier data is reactivated on a change from TCOFR to
TCOABS.
Read rotary angle (α
The angles currently used to calculate the orientation can be read via system variable
$P_TCANG[n] where n = 1 or n = 2.
If two permissible solutions (i.e. a second valid pair of angles) are available for a particular
orientation, the values can be accessed with $P_TCANG[3] or $P_TCANG[4]. The number of
valid solutions 0 to 2 can be read with $P_TCSOL.
Tools
Function Manual, 06/2019, A5E47435126B AA
or α ):
1 2
2.8 Tool carriers with orientation capability
W1: Tool offset
127