Siemens sinumerik 840D sl Function Manual page 70

Detailed description
2.8 Orientation
The following machine data specifies the conditions under which the rotary axis positions
may be modified:
MD21180 $MC_ROT_AX_SWL_CHECK_MODE
Value 0: No modification permitted (default, equivalent to previous behavior).
Value 1: Modification is only permitted if axis interpolation is active (ORIAXES or ORIMKS).
Value 2: Modification is always permitted, even if vector interpolation (large circle
interpolation, conical interpolation, etc.) was active originally.
Switch-over to axis interpolation
If the axis positions have to be changed from the originally determined value, the system
switches to rotary axis interpolation because the original interpolation path, e.g. large circle
interpolation or conical interpolation, can no longer be maintained.
Example
An example is shown in Chapter "Example for Generic 5-axis Transformation" for modifying
the rotary axis motion of a 5-axis machine with a rotatable tool.
2.8.3 Orientation compression
Introduction
Up to SW 6.2, the use of the compressors was subject to restrictions affecting orientation.
Some of these restrictions have been overcome by the options described below.
Extended function
Compressors COMPON, COMPCURV and COMPCAD have been extended so that NC
programs containing orientations programmed by means of direction vectors can also be
compressed to a definable tolerance.
Preconditions
The "Compressor for orientation" function is only implemented if the orientation
transformation option is available.
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Special functions: 3-Axis to 5-Axis Transformation (F2)
Function Manual, 11/2006, 6FC5397-2BP10-2BA0