Siemens SINUMERIK 840DE sl Function Manual page 192

F2: Multi-axis transformations
3.9 Orientation
Definition by the orientation of the active tool
The basic orientation is determined by the tool, if:
● it has not been defined by specifying a direction vector in the transformation call
and
● a tool is already active.
The orientation of a tool is dependent on the selected plane. It is parallel to Z at G17, parallel
to Y at G18 and parallel to X at G19.
It can be modified arbitrarily by orientable toolholders, see:
Further information
Function Manual Tools; Tool offset, orientable tool carriers
If the tool is changed when a transformation is active, the basic orientation is also updated. The
same applies if the orientation of a tool changes as the result of a change in plane (plane
changes are equivalent to tool changes, as they also alter the assignment between tool length
components and individual axes).
If the tool is de-selected, thereby canceling the definition of tool orientation, the basic
orientation programmed in machine data becomes operative.
Definition using a machine data
If the basic orientation is not defined by either of the two variants described above, it is specified
with reference to the following machine data:
$MC_TRAFO5_BASE_ORIENT_n (basic tool orientation)
This machine data must not be set to a zero vector or else an alarm will be generated during
control run-up when a transformation is active.
If a basic orientation is programmed in machine data $MC_TRAFO5_BASE_ORIENT_n when
a transformation is active and a tool is subsequently activated, the basic orientation is re-
defined by the tool.
Note
The range of settable orientations depends on the directions of the rotary axes involved and the
basic orientation. The rotary axes must be mutually perpendicular if all possible orientations are
to be used. If this condition is not met, "dead" ranges will occur.
Examples:
1. Extreme example: A machine with rotatable tool has a C axis as its first rotary axis and an
A axis as its second. If the basic orientation is defined in parallel to the A axis, the orientation
can only be changed in the X-Y plane (when the C axis is rotating), i.e. orientation with a Z
component unequal to zero is not possible in this instance. The orientation does not change
when the A axis rotates.
2. Realistic example: A machine with nutator kinematics (cardan head) with an axis inclined at
less than 45
a semi-circle: The top semi-circle with basic orientation towards +Z and the bottom with
basic orientation towards -Z.
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in a basic orientation parallel to the Z axis can only assume orientations within
o
Function Manual, 06/2019, A5E47435470B AA
Transformations