23 January 2021
Configuring an ATV61 or ATV71 drive for 2 part dual rampProduct Line:
Altivar 61 and Altivar 71 Environment:
All models, All serial numbersCause:
Application requires the motor to ramp to a minimum speed in a short amount of time and then ramp from this minimum speed to full speed at a much slower rate.Resolution:
The ATV61 and ATV71 drives have a split ramp function in Menu 1.7APPLICATION FUNCTIONS, Sub-menu RAMP. Define the acceleration and deceleration in 2 steps, split at a certain output frequency. The following parameters are involved:
ACC = Acceleration for the lower part of the ramp.
DEC = Deceleration for the lower part of the ramp.
AC2 = Acceleration for the upper part of the ramp.
DE2 = Deceleration for the upper part of the ramp.
FRT = Ramp 2 threshold, the speed, in Hz. at which the drive switches between ramp 1 (ACC,DEC) parameters and ramp 2 (AC2,DE2) parameters.
ACC = 10sec
DEC = 10sec
AC2 = 60sec
DE2 = 30sec
FRT = 30Hz
When the drive starts the motor with a 60Hz speed reference, it will ramp up from 0Hz to 30Hz in 5sec because ACC = 10s so 0Hz to 30Hz is half of the 10s. Then, it will ramp up from 30Hz to 60Hz in 30sec because AC2 = 60s. Total ramp up time is 35sec. When stopping, it will ramp down from 60Hz to 30Hz in 15sec and then 30Hz to 0Hz in 5sec. Total ramp down time is 20sec.
Note that the ACC/AC2 times are defined as time to go from 0Hz to motor rated frequency(FrS) 60Hz. DEC/DE2 is time to go from FrS to 0Hz.