Siemens SINUMERIK 840D sl Function Manual page 207

Activation
The function is only effective:
● In AUTOMATIC
● In the "Acceleration with jerk limit (SOFT)" mode
Parameterization
Working memory
The memory for the "Free-form surface mode: Extended function" is configured via the
machine data:
MD28533 $MC_MM_LOOKAH_FFORM_UNITS = <value>
The required memory depends on the part program, the block lengths, the axis dynamic
response, as well as on an active kinematic transformation.
The following setting applies as a guideline for processing free-form surfaces: MD28533 = 18
Note
Due to the additional storage requirements, MD28533 should only be set for the channels in
which free-form surfaces are being processed.
Number of NC blocks in the IPO buffer
It is generally advisable to significantly increase the configured number of NC blocks in the
interpolation buffer when using the "Free-form surface mode: Extension function":
MD28060 $MC_MM_IPO_BUFFER_SIZE > 100
If the block memory capacity is too low, this may diminish the uniformity of the path-velocity
profile.
Activation/deactivation
The function can be switched on or off independently for every dynamic response mode (see
Section "Dynamic response mode for path interpolation (Page 222)"):
MD20443 $MC_LOOKAH_FFORM[<n>]= <value>
Index <n>
Basic Functions
Function Manual, 01/2015, 6FC5397-0BP40-5BA2
Dynamic response mode
0 Standard dynamic response set‐
tings (DYNNORM)
1 Positioning mode, tapping
(DYNPOS)
2 Roughing (DYNROUGH)
3 Finishing (DYNSEMIFIN)
B1: Continuous-path mode, Exact stop, Look Ahead
<value> Free-form surface mode: Extension
function
0 Off
1 On
0 Off
1 On
0 Off
1 On
0 Off
1 On
4.3 Continuous-path mode
207