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.
Parameter 3-77 Ramp 4 S-ramp Ratio at Decel. Start
Table 248: Parameter 3-77 Ramp 4 S-ramp Ratio at Decel. Start
3-77 Ramp 4 S-ramp Ratio at Decel. Start
Parameter type: Range, 1 - 99%
Change during operation: True
Enter the proportion of the total ramp-down time (parameter 3-72 Ramp 4 Ramp Down Time) where the deceleration torque increa-
ses. The larger the percentage value, the greater the jerk compensation achieved, and thus the lower the torque jerks in the applica-
tion.
Parameter 3-78 Ramp 4 S-ramp Ratio at Decel. End
Table 249: Parameter 3-78 Ramp 4 S-ramp Ratio at Decel. End
3-78 Ramp 4 S-ramp Ratio at Decel. End
Parameter type: Range, 1 - 99%
Change during operation: True
Enter the proportion of the total ramp-down time (parameter 3-72 Ramp 4 Ramp Down Time) where the deceleration torque decrea-
ses. The larger the percentage value, the greater the jerk compensation achieved, and thus the lower the torque jerks in the applica-
tion.
5.4.9 3-8* Other Ramps
Parameter 3-80 Jog/Homing Ramp Time
Table 250: Parameter 3-80 Jog/Homing Ramp Time
3-80 Jog/Homing Ramp Time
Default value: Size related
Parameter type: Range, 0.01 - 3600 s
Change during operation: True
Enter the jog ramp time, that is the acceleration/deceleration time between 0 RPM and the rated motor frequency n
s
. Ensure that
the resulting output current required for the given jog ramp time does not exceed the current limit in parameter 4-18 Current Limit.
The jog ramp time starts after activation of a jog signal via the LCP, a selected digital input, or the serial communication port. When
jog state is disabled, then the normal ramping times are valid.
e30ba070.11
Time
P 3-80
RPM
P 4-13 RPM
high limit
P 1-25
Motor speed
Jog speed
P 3-19
P 3-80
Ramp up
(acc)
Ramp down
(dec)
t jog t jog
P 4-11 RPM
low limit
Illustration 53: Jog Ramp Time
Par . 3 − 80 = 
tjog s  × ns RPM
Δjogspeed par . 3 − 19  RPM
AU275636650261en-000101 / 130R0334150 | Danfoss A/S © 2022.12
Parameter Descriptions
VLT AutomationDrive FC 301/302
Programming Guide