Siemens SINAMICS G120 CU240B-2 - Ramp-Function Generator

Functions
7.5 Setpoint calculation
Inverter with CU240B-2 and CU240E-2 Control Units
Operating Instructions, 07/2010, FW 4.3.2, A5E02299792B AA
167
The maximum speed also acts as an important reference value for various functions (e.g. the
ramp-function generator).
Table 7- 11 Parameters for minimum and maximum speed
Parameter Description
P1080 Minimum speed
P1082 Maximum speed
7.5.2 Ramp-function generator
The ramp-function generator in the setpoint channel limits the speed of changes to the
speed setpoint. The ramp-function generator does the following:
● The soft acceleration and braking of the motor reduces the stress on the mechanical
system of the driven machine.
● Acceleration and braking distance of the driven machine (e.g. a conveyor belt) are
independent of the motor load.
Ramp-up/down time
The ramp-up and ramp-down times of the ramp-function generator can be set independently
of each other. The times that you select depend purely on the 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).
When the motor is switched on/off via ON/OFF1, the motor also accelerates/decelerates in
accordance with the times set in the ramp-function generator.
Table 7- 12 Parameters for ramp-up time and ramp-down time
Parameter Description
P1120 Ramp-up time
Duration of acceleration (in seconds)
from zero speed to the maximum
speed P1082
P1121 Ramp-down time
Duration of deceleration in seconds
from the maximum speed P1082 to
standstill
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For more information about this function, see the List Manual (function diagram 3060 and the
parameter list).