Nt_Pole_Limit - Siemens SINUMERIK 840DE sl Function Manual

K12 transformation definitions with kinematic chains
4.2 Commissioning
<n>:
<PoleTolAngle>:
Example
A pole angle of 2.54° is set for the first transformation:
Program code
N100 $NT_POLE_LIMIT[1] = 2.54
4.2.5.6

$NT_POLE_LIMIT

Function
The maximum permitted angle by which the C axis can deviate from its programmed position
during a large circle interpolation at the end of a block is entered in the system variable.
End angle
In the 5-axis transformation, the two orientation axes of the tool span a spherical coordinate
system, consisting of meridians and parallels.
If a traversing movement is programmed that is not to pass exactly through the pole, but within
the area near to the pole defined by MD 24530 ($MC_TRAFO5_NON_POLE_LIMIT_n), the
movement will deviate from the specified path because the interpolation runs exactly through
the pole point. As a result, the position at the end point of the fourth axis (pole axis) deviates
from the programmed value.
The system variable specifies the angle by which the pole axis for the 5-axis transformation can
deviate from the programmed value if there is a switchover from the programmed interpolation
to the interpolation through the pole point.
If a large deviation results, an error message is displayed (Alarm 14112) and the interpolation
is not carried out.
For a conventional 5 or 6-axis interpolation, a pole position is identified by the fact that the tool
orientation does not change during a rotation of a rotary axis. If a programmed path then runs
in the vicinity of the pole, extremely high traversing speeds can result for individual rotary axes
to maintain the orientation. If the programmed path runs exactly through the pole, this problem
may not arise under certain circumstances.
308
System variable or transformation index
Data type: INT
Range of val‐ 1, 2, ... (MD18866 $MN_MM_NUM_KIN_TRAFOS - 1)
ues:
Tolerance value
Data type: REAL
Comment
; 1st transformation,
; pole angle
Function Manual, 06/2019, A5E47435470B AA
Transformations