Siemens SINAMICS G120 Operating Instructions Manual page 266

Advanced commissioning
6.16 Setpoint calculation
3. Evaluate your drive response.
– If the motor accelerates too slowly, then reduce the ramp-up time.
– If the motor accelerates too fast, then extend the ramp-up time.
– Increase the initial rounding if the acceleration is jerky.
– We recommend that you set the final rounding to the same value as the initial rounding.
4. Switch off the motor.
5. Evaluate your drive response.
– If the motor decelerates too slowly, then reduce the ramp-down time.
– Extend the ramp-down time if the motor is braked too quickly or the converter goes into
6. Repeat steps 1 ... 5 until the drive behavior meets the requirements of the machine or plant.
You have set the extended ramp-function generator.
Basic ramp-function generator
When compared to the extended ramp-function generator, the basic ramp-function generator
has no rounding times.
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An excessively short ramp-up time means that the motor will reach its current limiting
when accelerating, and will temporarily not be able to follow the speed setpoint. In this
case, the drive exceeds the set time.
The minimum ramp-down time that makes sense depends on your particular application.
Depending on the Power Module used, for an excessively short ramp-down time, the
converter either reaches the motor current, or the DC link voltage in the converter
becomes too high. Depending on the converter setting, the real braking time exceeds
the set ramp-down time, or the converter goes into a fault condition when braking.
a fault condition when braking.
Converter with the CU240B-2 and CU240E-2 Control Units
Operating Instructions, 01/2017, FW V4.7 SP6, A5E34259001B AD