Siemens SINUMERIK 840DE Programming Manual page 361

Determine tool length compensation from the orientation of the toolholder, TCOABS
TCOABS calculates the tool length compensation from the current orientation angles of the
toolholder; stored in system variables $TC_CARR13 and $TC_CARR14.
For a definition of toolholder kinematics with system variables, see
References: /PGA/Programming Guide, Advanced, Chapter "Toolholder kinematics"
In order to make a new calculation of the tool length compensation when frames are
changed, the tool has to be selected again.
Tool direction from active frame
It is possible to set the orientating toolholder such that command
• TCOFR or TCOFRZ points in Z direction.
• TCOFRY points in Y direction.
• TCOFRX points in X direction.
If there is a switchover between TCOFR and TCABS, the tool length compensation is
calculated again.
Request toolholder, TCARR
With TCARR, the toolholder number m is requested with its geometry data (offset memory).
With m=0, the active toolholder is deselected.
The geometry data of the toolholder only become 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 parts program via the
corresponding system variables.
Recalculation of tool length compensation, TCOABS with frame change
In order to make a new calculation of the tool length compensation 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 compensation 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, the rotation angle values stored in the system variables must at least
correspond approximately to the mechanically set rotation angles.
Fundamentals
Programming Manual, 10.2004 Edition, 6FC5 298-7AB00-0BP1
8.14 Tool length compensation for orientable toolholders (TCARR, TCOABS, TCOFR)
Tool offsets
8-65