Danfoss FC 300

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 accelera-
tion and deceleration. A linear ramp will give constant acceler-
ation during ramping. An S-ramp will give non-linear accelera-
tion, 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 re-
lated
[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 =
t
acc
s xn
M , N
(
par .1− 25
)
RPM
Δ ref RPM
3-72 Ramp 4 Ramp Down Time
Range: Function:
Size re-
lated
[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 gen-
erated 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 =
t
dec
s xn
M , N
(
par .1− 25
)
RPM
Δ ref RPM
3-75 Ramp 4 S-ramp Ratio at Accel. Start
Range: Function:
50%
*
[1 - 99%] Enter the proportion of the total ramp-up time (par. 3-71) in
which the acceleration torque increases. The larger the per-
centage value, the greater the jerk compensation achieved, and
thus the lower the torque jerks in the application.
2. How to Programme FC 300 Programming Guide
82 MG.33.M2.02 - VLT
®
is a registered Danfoss trademark
2