Lenze PLC Designer PLC Designer (R3-1) - Manual (Page 935)

L-force | PLC Designer
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DMS 4.1 EN 03/2011 TD29 933
velocity ramp type:
The velocity ramp type defines the velocity profile for the velocity-generating one-axis
and the master/slave-modules. The associated libraries will provide up to three
different choices: trapezoid results in a trapezoid velocity profile (with constant
acceleration in each section), sin² results in a sin²-velocity profile (with continuous
acceleration), parabolic results in a parabolic velocity profile (with continuous
piecewise acceleration profile).
For the two latter modes the Jerk has to be defined in addition.
The following images demonstrate the effect of the different ramp types; the position
is displayed in green, the velocity in red and the acceleration in blue.
trapezoid
The velocity is piecewise linear, but continuous,
whereas the piecewise constant acceleration exhibits
jumps.
sin²
The sharp edges of the velocity function are smoothed
(by using a sin²-function instead of a line), so that the
jumps in the acceleration are eliminated.
As the motion sequence is clearly defined, in general
the jerk cannot be limited by the user. His limitation for
the jerk is valid only in case that the drive has an
acceleration different from 0 at the beginning. Then,
with respect to the jerk limit, the drive will be run to
zero, before the actual movement will be started.
Compared to the trapezoid velocity profile decelerating
will take more time now.
parabolic (not yet implemented)
The acceleration has a continuous, piecewise linear
profile, whose gradient is limited by the jerk. Therefore
the velocity has a continuous, piecewise parabolic
profile.
Actually this is the only profile the jerk can be limited
for.