Chapter 4 Parameters
4-56
With Auto acceleration / deceleration it is possible to reduce vibration and shocks during
starting/stopping the load.
When Pr.01.16 is set to 3 Auto acceleration / deceleration (set by load):
During Auto acceleration the torque is automatically measured and the drive will accelerate to
the set frequency with the fastest acceleration time and the smoothest starting current.
During Auto deceleration, regenerative energy is measured and the motor is smoothly stopped
with the fastest deceleration time.
When this parameter is set to 4 Auto acceleration / deceleration (set by Accel/Decel Time
setting): the actual accel/decel time will be equal to or more than parameter Pr.01.09
~Pr.01.12.
When this parameter is set to 5(Linear Accel. controlled by current, linear Decel.)/6(Linear
Accel. controlled by current, auto Decel.): the current value when the drive performs over-
current stall prevention can be kept within the setting of stall prevention level. For example, if
the setting of stall prevention level is 100%, it will perform deceleration as the current exceeds
100% during operation and keep the current around 100%. Besides, it will perform
deceleration no matter over-current occurs during deceleration or constant speed. (The
present over-current stall prevention during acceleration is used to keep the output frequency
and prevent from the drive overload (OL).
When this parameter is set to 5(Linear Accel. controlled by current, linear Decel.): the drive will
perform the linear deceleration by the setting of deceleration time. When this parameter is set
to 6 (Linear Accel. controlled by current, auto Decel.), the drive stop the motor by the fastest
deceleration time after auto-distinguish load regenerative energy.
Ov er-c ur rent
level
Speed
Output
cur rent
Output
frequency
Auto acceleration/deceleration makes the complicated processes of tuning unnecessary. It
makes operation efficient and saves energy by acceleration without stall and deceleration
without brake resistor.
In applications with brake resistor or brake unit, the deceleration time is the shortest. It is NOT
recommended to use Auto deceleration function, or it will extend the deceleration time.
Related parameters: Pr.01.09(Accel Time 1), Pr.01.10(Decel Time 1), Pr.01.11(Accel Time 2)
and Pr.01.12(Decel Time 2).
01.17
Acceleration S-Curve
Unit: second
01.18
Deceleration S-Curve
Unit: second
Factory Setting: 0.0/0.00
Settings
0.0
S-curve
disabled
0.1 to 10.0/0.01 to 10.00
S-curve enabled (10.0/10.00 is the smoothest)
This parameter is used to ensure smooth acceleration and deceleration via S-curve.
The S-curve is disabled when set to 0.0 and enabled when set to 0.1 to 10.0/0.01 to 10.00.
Setting 0.1/0.01 gives the quickest and setting 10.0/10.00 the longest and smoothest S-curve.
The AC motor drive will not follow the Accel/Decel Times in Pr.01.09 to Pr.01.12.
The diagram below shows that the original setting of the Accel/Decel Time is only for reference
when the S-curve is enabled. The actual Accel/Decel Time depends on the selected S-curve
(0.1 to 10.0).
