Danfoss MCO 305 Design Manual page 49

MCO 305 Design Guide
A Limited-jerk movement can be used in three different situations:
1. Stopping from the current velocity and acceleration (where the final position is not important).
2. Changing from the current velocity and acceleration to a specified constant velocity (where the positions
are not important).
3. Moving from the current position (and the current velocity and acceleration) and stopping at a specified
position.
Examples
In the following examples, maximum acceleration has been set to a value higher than maximum decelera-
tion so the motor can speed up faster than it can slow down. As well, JERKMIN has been set smaller than
JERKMIN2, JERKMIN2 smaller than JERKMIN3, and JERKMIN3 smaller than JERKMIN4. This was done so
that the various segments of the curves can be visually distinguished in the charts. The four JERKMIN
values have been labeled simply J1, J2, J3, and J4.
Stopping
This chart shows a stopping movement that begins
from a positive constant velocity. The curve
consists of a deceleration ramp-up segment (using
JERKMIN3), followed by a constant deceleration
segment (at maximum deceleration), and finally a
deceleration ramp-down segment to 0 velocity
(using JERKMIN4).
This chart shows a stopping movement that begins
from a positive velocity and a positive acceleration.
Since the initial acceleration is positive, the curve
must start with an acceleration ramp-down
segment to 0 acceleration (using JERKMIN2). This
will then be followed by a deceleration ramp-up
segment (using JERKMIN3), a constant
deceleration segment, and a deceleration ramp-
down segment to 0 velocity (using JERKMIN4).
__ Functions and Examples __
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MG.33.L4.02 – VLT is a registered Danfoss trademark
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