Ramp-Function Generator - Siemens SINAMICS G120 Operating Instructions Manual

Advanced commissioning
6.19 Setpoint calculation
6.19.6

Ramp-function generator

The ramp-function generator in the setpoint channel limits the rate change of the speed setpoint
(acceleration). A reduced acceleration reduces the accelerating torque of the motor. In this
case, the motor reduces the load on the mechanical system of the driven machine.
You can select between two different ramp-function generator types:
● Extended ramp-function generator
The expanded ramp-function generator limits not only the acceleration but also the change
in acceleration (jerk) by rounding the setpoint. In this case, the torque does not rise suddenly
in the motor.
● Basic ramp-function generator
The basic ramp-function generator limits the acceleration, however not the rate the
acceleration changes (jerk).
Extended ramp-function generator
The ramp-up and ramp-down times of the extended ramp-function generator can be set
independently of each other. The optimum times that you select depend on your particular
application in question and can range from just a few 100 ms (e.g. for belt conveyor drives) to
several minutes (e.g. for centrifuges).
Initial and final rounding permit smooth, jerk-free acceleration and braking.
The ramp-up and ramp-down times of the motor are increased by the rounding times:
● Effective ramp-up time = p1120 + 0.5 × (p1130 + p1131).
● Effective ramp-down time = p1121 + 0.5 × (p1130 + p1131).
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Converter with the CU250S-2 Control Units
Operating Instructions, 04/2018, FW V4.7 SP10, A5E31759476B AG