Danfoss VLT AutomationDrive FC 301 Programming Manual page 77

Parameter Descriptions
3-68 Ramp 3 S-ramp Ratio at Decel. End
Range: Function:
50 % [1 - 99. Enter the proportion of the total ramp-down
*
%] decel time (parameter 3-62 Ramp 3 Ramp down
Time) where the deceleration torque decreases.
The larger the percentage value, the greater
the jerk compensation achieved, and thus the
lower the torque jerks in the application.
3.4.7 3-7* Ramp 4
Configure ramp parameters, see parameter group 3-4*
Ramp 1.
3-70 Ramp 4 Type
Option: Function:
Select the ramp type, depending on
requirements for acceleration and deceleration.
A linear ramp gives constant acceleration
during ramping. An S-ramp gives non-linear
acceleration, compensating for jerk in the
application.
[0] Linear
*
[1] S-ramp Accelerates with lowest possible jerk.
Const Jerk
[2] S-ramp S-ramp based on the values set in
Const parameter 3-71 Ramp 4 Ramp up Time and
Time parameter 3-72 Ramp 4 Ramp Down Time.
NOTICE
If [1] S-ramp Const Jerk is selected and the reference
during ramping is changed, the ramp time may be
prolonged to realize a jerk-free movement, which may
result in a longer start or stop time.
More adjustments of the S-ramp ratios or switching
initiators may be necessary.
3-71 Ramp 4 Ramp up Time
Range: Function:
3.00 [0.01 - Enter the ramp-up time, which is the
s 3600.00 s] acceleration time from 0 RPM to the rated
*
motor speed n
that the output current does not exceed the
current limit in parameter 4-18 Current Limit
during ramping. The value 0.00 corresponds
to 0.01 s in speed mode. See ramp-down
time in parameter 3-72 Ramp 4 Ramp Down
Time.
Par . 3 − 71 =
3-72 Ramp 4 Ramp Down Time
Range: Function:
3.00 [0.01 - Enter the ramp-down time, which is the
s 3600.00 s] deceleration time from the nominal motor
*
MG33MO02
Programming Guide
. Select a ramp-up time such
s
t s x n RPM
acc s
ref RPM
Danfoss A/S © 01/2018 All rights reserved.
3-72 Ramp 4 Ramp Down Time
Range: Function:
speed n to 0 RPM. Select a ramp-down time
s
such that no overvoltage occurs in the
inverter due to regenerative operation of the
motor, and such that the generated current
does not exceed the current limit set in
parameter 4-18 Current Limit. The value 0.00
corresponds to 0.01 s in speed mode. See
ramp-up time in parameter 3-71 Ramp 4
Ramp up Time.
t
dec
Par . 3 − 72 =
3-75 Ramp 4 S-ramp Ratio at Accel. Start
Range: Function:
50 % [1 - 99. Enter the proportion of the total ramp-up time
*
%] (parameter 3-71 Ramp 4 Ramp up Time) in
which the acceleration torque increases. The
larger the percentage value, the greater the
jerk compensation achieved, and thus the
lower the torque jerks in the application.
3-76 Ramp 4 S-ramp Ratio at Accel. End
Range: Function:
50 % [1 - 99. Enter the proportion of the total ramp-up time
*
%] (parameter 3-71 Ramp 4 Ramp up Time) in
which the acceleration torque decreases. The
larger the percentage value, the greater the
jerk compensation achieved, and thus the
lower the torque jerks in the application.
3-77 Ramp 4 S-ramp Ratio at Decel. Start
Range: Function:
50 % [1 - 99. Enter the proportion of the total ramp-down
*
%] time (parameter 3-72 Ramp 4 Ramp Down Time)
where the deceleration torque increases. The
larger the percentage value, the greater the
jerk compensation achieved, and thus the
lower the torque jerks in the application.
3-78 Ramp 4 S-ramp Ratio at Decel. End
Range: Function:
50 % [1 - 99. Enter the proportion of the total ramp-down
*
%] time (parameter 3-72 Ramp 4 Ramp Down Time)
where the deceleration torque decreases. The
larger the percentage value, the greater the
jerk compensation achieved, and thus the
lower the torque jerks in the application.
s x n RPM
s
ref RPM
75
3 3