Siemens SINUMERIK 840D sl Programming Manual page 645

<quality>:
Note
Quality of the measurement
In order to map the measured coordinates onto the ideal coordinates using a rotation and a
translation, the triangle formed by the measured points must be congruent to the ideal triangle.
This is achieved by means of a compensation algorithm that minimizes the sum of squared
deviations needed to reshape the measured triangle into the ideal triangle.
Since the effective distortion can be used to judge the quality of the measurement, MEAFRAME
returns it as an additional variable.
Note
The frame created by MEAFRAME can be transformed by the ADDFRAME function into
another frame in the frame chain (see example "Chaining with ADDFRAME").
Examples
Example 1:
Part program 1:
Program code
...
DEF FRAME CORR_FRAME
Setting measuring points:
Program code
DEF REAL IDEAL_POINT[3,3]=
SET(10.0,0.0,0.0,0.0,10.0,0.0,0.0,0.0,10.0)
DEF REAL MEAS_POINT[3,3]=
SET(10.1,0.2,-0.2,-0.2,10.2,0.1,-0.2,0.2,9.8)
NC programming
Programming Manual, 12/2019, 6FC5398-2EP40-0BA0
Variable with which information on the quality of the FRAME calculation is
returned
Type: VAR REAL
Value: -1 The ideal points are almost on a straight line: The
frame could not be calculated. The returned
FRAME variable contains a neutral frame.
-2 The measuring points are almost on a straight line:
The frame could not be calculated. The returned
FRAME variable contains a neutral frame.
-4 The calculation of the rotation matrix failed for a
different reason.
≥ 0.0 Sum of distortions (distances between the points),
that are required to transform the measured triangle
into a triangle that is congruent to the ideal triangle.
Work preparation
3.8 Coordinate transformations (frames)
Comment
; For test.
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