Siemens SINUMERIK 840D sl Function Manual page 183

MD20462
Whether the programmed feedrate should also be taken into consideration during the
smoothing is determined by the machine data:
MD20462 $MC_LOOKAH_SMOOTH_WITH_FEED (path smoothing with programmed
feedrate)
If the MD is set to 1 (default), the smoothing factor is observed with particular precision if the
override is set to 100%.
MD32440
The following machine data contains a smoothing frequency for LookAhead:
MD32440 $MA_LOOKAH_FREQUNECY (smoothing frequency for LookAhead)
Acceleration and braking processes running at a frequency higher than parameterized in this
MD are smoothed or reduced in their dynamic response depending on their parameterization
in the machine data:
MD20460 $MC_LOOKAH_SMOOTH_FACTOR (smoothing factor for LookAhead)
MD20465 $MC_ADAPT_PATH_DYNAMIC (adaptation of the dynamic path response)
The minimum value for all axes involved in the path is always calculated.
If vibration is excited in the mechanical system of this axis and if the corresponding
frequency is known, this MD should be set to a value smaller than this frequency.
The required resonance frequencies, for example, can be calculated using the built-in
measuring functions.
The minimum value for this MD32440 is calculated as
in the path.
For the smoothing, only those acceleration processes in which the start and end velocity of
this motion are reached within the time below are taken into consideration:
t = t2-t1 = 2/
is reached again.
Note
The smoothing of the path velocity does not lead to contour errors. Variations in axis velocity
due to curvatures in the contour at constant path velocity may continue to occur and are not
reduced at this point.
Variations in path velocity due to the input of a new feedrate are not changed either. This
remains the responsibility of the programmer of the subprogram.
Basic logic functions: Continuouspath Mode, Exact Stop, LookAhead (B1)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0
fPath
Detailed description
2.3 Continuous -path mode
fPath
on the basis of the axis involved
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