Siemens SINUMERIK 828D Function Manual page 165

Profile for limit velocity
The use of a velocity profile for rounding in compliance with defined tolerances is controlled via the hundreds
position in MD20480:
Value Description
< 100: A profile of the limit velocity is calculated within the rounding area, based on the defined
maximum values for acceleration and jerk on the participating axes or path.
This can lead to an increase in the path velocity in the rounding area and therefore to the
acceleration of the participating axes.
≥ 100: A profile of the limit velocity is not calculated for rounding blocks with G641/G642. A
constant velocity limit is specified instead.
This prevents the participating axes being accelerated into the rounding area during
rounding with G641/G642. However, in certain cases, this setting can cause the
rounding blocks to be traversed too slowly, especially in large rounding areas.
1xx: No velocity profile for G641
2xx: No velocity profile for G642
Note
MD28530 $MC_MM_PATH_VELO_SEGMENTS (number of memory elements for limiting
the path velocity)
Constraints
Restriction for protection zones with active radius compensation and tool orientation:
Although tool radius compensation is applied for a tool orientation, which is not perpendicular to one of the three
datum planes of the basic coordinate system, the protection zones are not rotated onto the corresponding plane.
For G643 the following must apply:
MD28530 $MC_MM_PATH_VELO_SEGMENTS > 0 (number of memory elements for limiting the path velocity)
If this condition is met, then it must be applicable for all axes:
MD35240 $MC_ACCEL_TYPE_DRIVE = FALSE (acceleration characteristic line DRIVE for axes on/off)
Basic Functions
Function Manual, 09/2011, 6FC5397-0BP40-2BA0
B1: Continuous­path Mode, Exact Stop, LookAhead
3.3 Continuous-path mode
165