Siemens SINUMERIK 840D sl Programming Manual page 403

General structure of an NC block that be compressed
The general structure of an NC block that can be compressed can therefore look like this:
N... X=<...> Y=<...> Z=<...> A3=<...> B3=<...> C3=<...> THETA=<...> F=<...>
or
N... X=<...> Y=<...> Z=<...> A2=<...> B2=<...> C2=<...> THETA=<...> F=<...>
Note
The position values can be entered directly (e.g. X90) or indirectly via parameter settings
(e.g. X=R1*(R2+R3)).
Programming tool orientation using rotary axis positions
Tool orientation can be also specified using rotary axis positions, e.g. with the following
structure:
N... X=<...> Y=<...> Z=<...> A=<...> B=<...> C=<...> THETA=<...> F=<...>
In this case, compression is executed in two different ways, dependent on whether large
radius circular interpolation is executed. If no large radius circular interpolation takes place,
then the compressed change in orientation is represented in the usual way by axial
polynomials for the rotary axes.
Contour accuracy
Depending on the selected compression mode (MD20482 $MC_COMPRESSOR_MODE)
either the configured axis-specific tolerances (MD33100 $MA_COMPRESS_POS_TOL) or
the following channel-specific tolerances – set using setting data – are effective for the
geometry axes and orientation axes for compression:
SD42475 $SC_COMPRESS_CONTUR_TOL (maximum contour deviation)
SD42476 $SC_COMPRESS_ORI_TOL (maximum angular deviation for tool orientation)
SD42477 $SC_COMPRESS_ORI_ROT_TOL (maximum angular deviation for the angle of
rotation of the tool) (only available on 6-axis machines)
References:
Function Manual Basic Functions; 3 to 5-Axis Transformation (F2),
Chapter: "Compression of the orientation"
Job Planning
Programming Manual, 06/2009, 6FC5398-2BP20-0BA0
6.6 Compression of the orientation (COMPON, COMPCURV, COMPCAD)
Transformations
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