Jerk Limiting Along The Path Through Velocity Reduction - Siemens SINUMERIK 802D sl Function Manual

Continuous Path Mode, Exact Stop and LookAhead (B1)
3.4 Continuous-path mode
Overload factor
The overload factor restricts step changes in the machine axis velocity at the block transition.
To ensure that the velocity jump does not exceed the maximum load on the axis, the jump is
derived from the acceleration of the axis. The overload factor indicates the extent by which
the acceleration of the machine axis, which is set in MD32300 MAX_AX_ACCEL (axis
acceleration), may be exceeded for an IPO cycle.
The velocity jump is the product of:
axis acceleration * (overload factor-1) * interpolator cycle. The overload factor is 1.2.
Factor 1.0 means that only tangential transitions with finite velocity can be traversed. For all
other transitions, the velocity is reduced to zero by changing the setpoint.
Selection and deselection of velocity reduction
Continuous-path mode with velocity reduction according to overload factor can be selected
modally in every NC part program block by means of program code G64 (BRISK active, not
SOFT).
Continuous path mode G64 can be
● interrupted non-modally when exact stop G9 is selected,
● de-selected when exact stop G60 is selected.
3.4.3

Jerk limiting along the path through velocity reduction

Introduction
With the jerk limiting along the path, another method of influencing the continuous-path
mode is introduced. While the "Velocity reduction according to overload factor" function limits
the rate of velocity change, the "Jerk limitation on path" function described here limits the
acceleration changes (jerks).
When sections of the contour consisting of blocks (e.g. circle straight line transitions) are
machined, step changes in the acceleration rate occur at the block transition in continuous
path mode.
Reducing jerk
The severity of such jerks can be reduced by decreasing the path velocity at transitions
between blocks containing different degrees of curvature. A smoother transition is thus
achieved between the contour sections.
Jerk limit
The user specifies the maximum jerk, which may occur on a path axis during a block
transition, with MD32432 PATH_TRANS_JERK_LIM (maximum axis-specific jerk of a path
axis at the block transition).
64
Turning, Milling, Nibbling
Function Manual, 11/2012, 6FC5397-1CP10-5BA0