Siemens SINUMERIK 840Di Function Manual page 189

Special cases of LookAhead
Axis-specific feed stop and axis-specific axis disable are ignored by LookAhead.
If an axis is to be interpolated that should on the other hand be made stationary by axis-
specific feed stop or axis disable, LookAhead does not stop path movement before the block
in question but decelerates in the block itself.
If this response is not wanted, an axis-specific feed stop can be transferred to a channel via
the PLC to stop the path immediately.
See also: /FB1/, A3, Axis clamping.
2.5 NC block compressor COMPON, COMPCURV, -CAD
2.5
COMPON, COMPCURV
The modal G code COMPON or COMPCURV can be used to activate an "NC block
compressor".
This function collects a series of linear blocks during linear interpolation (the number is
limited to 10) and approximates them within a tolerance specified in machine data via a 3rd
degree (COMPON) or 5th degree (COMPCURV) polynomial.
One larger traversing block is processed by the NC instead of a large number of small
blocks.
COMPCAD
The COMPCAD G code can be used to select a further compression, which optimizes the
surface quality and velocity. The interpolation accuracy can again be specified in machine
data.
COMPCAD is processor and memoryintensive. It should only be used if surface quality
enhancement measures cannot be incorporated in the CAD/CAM program.
The programming procedure is described in:
References:
/PGA/ Programming Guide, Advanced.
The compressor for orientation transformation is described in:
References:
/FB3/ Description of Functions, Special Functions; 3 to 5-axis transformation (F2).
Continuous-Path Mode, Exact Stop, LookAhead (B1)
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0
2.5 NC block compressor COMPON, COMPCURV, -CAD
Detailed Description
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