Advanced commissioning
7.4 Setpoint calculation
Converter with control units CU250D-2
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Operating Instructions, 04/2015, FW V4.7.3, A5E34261542B AB
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 on the motor.
3.
Evaluate your drive response.
–
If the motor accelerates too slowly, then reduce the ramp-up time.
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.
–
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.
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.
–
Extend the ramp-down time if the motor is braked too quickly or the converter goes
into a fault condition when braking.
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.
