3-66 Ramp 3 S-ramp Ratio at Accel. End
Range:
Function:
50%
*
[1 - 99%]
Enter the proportion of the total ramp-up time (par. 3-61) 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.
3-67 Ramp 3 S-ramp Ratio at Decel. Start
Range:
Function:
50%
*
[1 - 99%]
Enter the proportion of the total ramp-down time (par. 3-62) 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.
3-68 Ramp 3 S-ramp Ratio at Decel. End
Range:
Function:
50%
*
[1 - 99%]
Enter the proportion of the total ramp-down time (par. 3-62) 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.
2.6.7. 3-7* Ramp 4
Configure ramp parameters, see 3-4*.
3-70 Ramp 4 Type
Option:
Function:
Select the ramp type, depending on requirements for acceleration and deceleration. A linear ramp will give
constant acceleration during ramping. An S-ramp will give non-linear acceleration, compensating for jerk in the
application
[0]
*
Linear
[1]
S-ramp Const Jerk
Accelerates with lowest possible jerk.
[2]
S-ramp Const Time
S-ramp based on the values set in par. 3-71 and 3-72.
NB!
If S-ramp [1] is selected and the reference during ramping is changed the ramp time may be prolonged in order to realize a jerk free
movement which may result in a longer start or stop time.
Additional adjustment of the S-ramp ratios or switching initiators may be necessary.
3-71 Ramp 4 Ramp up Time
Range:
Function:
Size related [0.01 - 3600.00 s]
Enter the ramp-up time, i.e. the acceleration time from 0 RPM to the rated motor speed n
M,N
(par. 1-25). Choose
a ramp-up time such that the output current does not exceed the current limit in par. 4-18 during ramping. The
value 0.00 corresponds to 0.01 sec. in speed mode. See ramp-down time in par. 3-72.
Par. 3
−
71 =
tacc s x nM, N (par. 1
−
25)
RPM
Δ
ref RPM
3-72 Ramp 4 Ramp Down Time
Range:
Function:
Size related [0.01 - 3600.00 s]
Enter the ramp-down time, i.e. the deceleration time from the rated motor speed n
M,N
(par. 1-25) to 0 RPM.
Choose a ramp-down time such that no over-voltage arises in the inverter due to regenerative operation of the
motor, and such that the generated current does not exceed the current limit set in par. 4-18. The value 0.00
corresponds to 0.01 s in speed mode. See ramp-up time in par. 3-71.
Par. 3
−
72 =
tdec s x nM, N (par. 1
−
25)
RPM
Δ
ref RPM
2. How to Programme
FC 300 Programming Guide
70
MG.33.M3.02 - VLT
®
is a registered Danfoss trademark
2
