Siemens SINUMERIK 840D sl Programming Manual page 784

Work preparation
3.13 Tool offsets
Further information
Determine tool length offset from the orientation of the toolholder (TCOABS)
TCOABS calculates the tool length offset from the current orientation angles of the toolholder;
saved in the system variables $TC_CARR13 and $TC_CARR14.
For a definition of toolholder kinematics with system variables, see "Toolholder kinematics
(Page 777)".
In order to make a new calculation of the tool length offset when frames are changed, the tool
has to be selected again.
Tool direction from active frame
The toolholder with orientation capability is set so that the tool points in the following directions:
● With TCOFR or TCOFRZ in the Z direction
● With TCOFRY in the Y direction
● With TCOFRX in the X direction
The tool length offset is re-calculated when changing over between TCOFR and TCOABS.
Request toolholder (TCARR)
With TCARR, the toolholder number m is requested with its geometry data (compensation
memory).
With m=0, the active toolholder is deselected.
The geometry data of the toolholder only becomes active after a tool is called. The selected tool
remains active after a toolholder change has taken place.
The current geometry data for the toolholder can also be defined in the part program via the
corresponding system variables.
Recalculation of tool length offset (TCOABS) for a frame change
In order to make a new calculation of the tool length offset when frames are changed, the tool
has to be selected again.
Note
The tool orientation must be manually adapted to the active frame.
When the tool length offset is calculated, the angle of rotation of the toolholder is calculated in
an intermediate step. With toolholders with two rotary axes, there are generally two sets of
rotation angles, which can be used to adapt the tool orientation to the active frame; therefore,
784
Programming Manual, 12/2019, 6FC5398-2EP40-0BA0
NC programming