Siemens Sinamics G120P Operating Instructions Manual page 355

Setting the extended ramp-function generator
Procedure
Proceed as follows to set the extended ramp-function generator:
1. Enter the highest possible speed setpoint.
2. Switch the motor on.
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
4. Switch the motor off.
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 inverter goes into
6. Repeat steps 1 ... 5 until the drive behavior matches the requirements.
Inverter cabinet units
Operating Instructions, 12/2014, A5E32923362A
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.
rounding.
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 inverter either reaches the motor current, or the DC-link voltage in the
inverter becomes too high. Depending on the inverter setting, the real braking time
exceeds the set ramp-down time, or the inverter goes into a fault condition when
braking.
a fault condition when braking.
Another possibility is to limit the maximum DC-link voltage, see Limiting the maximum
DC link voltage (Page 369).
Functions
7.4 Setpoint calculation
355