Siemens sinumerik 840D sl Function Manual page 33

2.1.5 Singular positions and handling
Extreme velocity increase
If the path runs in close vicinity to a pole (singularity), one or several axes may traverse at a
very high velocity.
Alarm 10910 "Irregular velocity run in a path axis" is then triggered. The programmed
velocity is then reduced to a value, which does not exceed the maximum axis velocity.
Behavior at pole
Unwanted behavior of fast compensating movements can be controlled by making an
appropriate selection of the following machine data (see following Figure):
MD24530 $MC_TRAFO5_NON_POLE_LIMIT_1 (definition of pole area for 5-axis
transformation 1)
MD24630 $MC_ TRAFO5_NON_POLE_LIMIT_2 (definition of pole area for 5-axis
transformation 2)
MD24540 $MC_TRAFO5_POLE_LIMIT_1 (closing angle tolerance for interpolation by pole
for 5-xis transformation)
MD24640 $MC_TRAFO5_POLE_LIMIT_2 (closing angle tolerance for interpolation by pole
for 5-xis transformation)
Note
Singularities are dealt with differently in SW 5.2 and higher: There is now only one relevant
machine data $MC_TRAFO5_POLE_LIMIT (see Chapter "Singularities of Orientation" or
"Programming Manual Work Preparation").
$MC_TRAFO5_NON_POLE_LIMIT
This machine data identifies a limit angle of the 5th axis of the first MD24530
$MC_TRAFO5_NON_POLE_LIMIT_1 or the second MD24630
$MC_TRAFO5_NON_POLE_LIMIT_2 5-axis transformation with the following properties:
If the path runs past the pole at an angle lower than the value set here, it crosses through
the pole.
With the 5-axis transformation, a coordinate system consisting of circles of longitude and
latitude is spanned over a spherical surface by the two orientation axes of the tool.
If, as a result of orientation programming (i.e. the orientation vector is positioned on one
plane), the path passes so close to the pole that the angle is less than the value defined in
this MD, then a deviation from the specified interpolation is made so that the interpolation
passes through the pole.
Special functions: 3-Axis to 5-Axis Transformation (F2)
Function Manual, 11/2006, 6FC5397-2BP10-2BA0
Detailed description
2.1 5-axis transformation
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