Danfoss MCO 305 Design Manual page 51

MCO 305 Design Guide
__ Functions and Examples __
This chart is similar to the previous example except
that it begins with a positive acceleration. In this
case, the curve must start with an acceleration
ramp-down segment (using JERKMIN2). Once the
acceleration reaches 0, then the curve can continue
as before.
The chart below shows a movement that begins with a negative constant velocity and changes direction to a
positive constant velocity. The curve must start by slowing down the speed so that it can 'turn around'. Hence
the curve begins with a deceleration ramp-up segment (using JERKMIN3) until it reaches maximum deceleration.
The deceleration continues at maximum decele-
ration until it reaches 0 velocity. Note that there is
no deceleration ramp-down segment because the
movement is not stopping. At exactly 0 velocity,
the direction reverses and the movement is now
accelerating in the other direction. But since maxi-
mum acceleration is higher than maximum decele-
ration for this example, the curve is now able to
include an acceleration ramp-up segment (using
JERKMIN). The curve finishes in the normal way
with a constant acceleration segment and an
acceleration ramp-down segment to constant
velocity (using JERKMIN2).
Moving to a Specified Position
The chart below shows a 'normal' movement from being stopped at one position and then moving forward
to stop at another position. The curve starts with an acceleration ramp to maximum velocity. This portion of
the curve will be similar to the first of the examples shown in "Changing to a Constant Velocity". The curve
is simply changing to a constant velocity where the constant velocity is the maximum velocity.
Hence, the curve will consist of an acceleration ramp-
up segment (using JERKMIN), a constant acceleration
segment at maximum acceleration, and then an
acceleration ramp-down segment to maximum velo-
city (using JERKMIN2). The movement then proceeds
at maximum velocity until it needs to start the dece-
leration ramp that will stop the movement at the
desired position. The deceleration ramp is identical to
the first of the examples shown in "Stopping". The
curve will consist of a deceleration ramp-up segment
(JERKMIN3), followed by a constant deceleration
segment (at maximum deceleration), and finally a
deceleration ramp-down segment to 0 velocity (using
JERKMIN4) stopping at the desired position.
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