Excessive Jerk For Block Transitions Without Constant Curvature (Axis-Specific); General Information; Parameterization; Velocity-Dependent Jerk Adaptation (Axis-Specific) - Siemens SINUMERIK 840D sl Function Manual

B2: Acceleration
5.2 Functions
5.2.16

Excessive jerk for block transitions without constant curvature (axis-specific)

5.2.16.1

General Information

Overview
In the case of block transitions without constant curvature (e.g. straight line > circle), the
programmable controller has to decelerate movement of the geometry axes significantly in
order to ensure compliance with the parameterized axis dynamics. For the purpose of reducing/
avoiding deceleration in connection with block transitions without constant curvature, a higher
level of axis-specific jerk can be enabled.
The excessive jerk is parameterized using a dedicated axis-specific maximum value.
5.2.16.2

Parameterization

The excessive jerk for block transitions without constant curvature is parameterized using the
axis-specific machine data:
MD32432 $MA_PATH_TRANS_JERK_LIM
(excessive jerk for block transitions without constant curvature)
5.2.17

Velocity-dependent jerk adaptation (axis-specific)

Function
The dynamic path response results from the parameterized, constant axial maximum values
for velocity, acceleration and jerk of the axes involved in the path:
● MD32000 $MA_MAX_AX_VELO (maximum axis velocity)
● MD32300 $MA_MAX_AX_ACCEL (maximum axis acceleration)
● MD32431 $MA_MAX_AX_JERK (max. axial jerk for path motion)
For contours with non-constant curvature (torsion), as for example in connection with free-form
surfaces, fluctuations in the path velocity, particularly in the upper velocity range, can result
mainly due to the axial jerk. The fluctuations of the path velocity lead to adverse affects in the
surface quality.
The influence of the axial jerk on the path velocity is decreased for contours with non-constant
curvature through a velocity-dependent increase of the permissible axial jerk. Fluctuations in
the path velocity can be avoided with the appropriate parameterization.
The velocity-dependent increase of the permissible axial jerk has no effect on the maximum
possible path acceleration and path jerk. These result from the constant axial maximum values
parameterized in the in the machine data even when jerk adaptation is active.
As both curvature and torsion are zero in the case of linear motion, the velocity-dependent jerk
adaptation has no effect with linear motions.
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Function Manual, 01/2015, 6FC5397-0BP40-5BA2
Basic Functions