Siemens SINUMERIK 840D sl Programming Manual page 336

Coordinate transformation (FRAMES)
5.6 Frame calculation from three measuring points in space (MEAFRAME)
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 as from SW 6.3.
Example: chaining of frames "concatenation with ADDFRAME".
Further information for the parameters for ADDFRAME(FRAME, STRING) see
/FB1/ Function Manual Basic Functions; Axes, Coordinate Systems, Frames (K2), "FRAME
Chaining".
Example
Program code
DEF FRAME CORR_FRAME
Setting measuring points
Programming
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)
DEF REAL FIT_QUALITY = 0
DEF REAL ROT_FRAME_LIMIT = 5
DEF REAL FIT_QUALITY_LIMIT = 3
DEF REAL SHOW_MCS_POS1[3]
DEF REAL SHOW_MCS_POS2[3]
DEF REAL SHOW_MCS_POS3[3]
336
Comments
; Part program 1
Comments
; for test
; Permits max. 5 degrees rotation of
the part position
; Permits max. 3 mm offset between
the
ideal and the measured triangle
Programming Manual, 06/2009, 6FC5398-2BP20-0BA0
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