Siemens CU240B-2 Operating Instructions

6.17.6 Ramp-function generator
The ramp-function generator in the setpoint channel limits the rate change of the speed setpoint
(acceleration). A reduced acceleration reduces the accelerating torque of the motor. As a
consequence, the motor reduces the stress on the mechanical system of the driven machine.
The extended ramp-function generator not only limits the acceleration, but by rounding the
setpoint, also acceleration changes (jerk). This means that the motor does not suddenly
generate a torque.
Extended ramp-function generator
The ramp-up and ramp-down times of the extended ramp-function generator can be set
independently of each other. The optimum times that you select depend on your particular
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).
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Initial and final rounding permit smooth, jerk-free acceleration and braking.
The ramp-up and ramp-down times of the motor are increased by the rounding times:
● Effective ramp-up time = p1120 + 0.5 × (p1130 + p1131).
● Effective ramp-down time = p1121 + 0.5 × (p1130 + p1131).
Table 6-42 Additional parameters to set the extended ramp-function generator
Parameter Description
p1120 Ramp-function generator, ramp-up time (factory setting depends on the Power Module)
Duration of acceleration (in seconds) from zero speed to maximum speed P1082
p1121 Ramp-function generator, ramp-down time (factory setting depends on the Power Mod‐
ule)
Braking time in seconds from the maximum speed down to standstill
Advanced commissioning
6.17 Setpoint calculation
Converter with the CU230P-2 Control Units
Operating Instructions, 09/2017, FW V4.7 SP9, A5E34257946B AE 271

Siemens CU240B-2 Specifications

General

Brand	Siemens
Model	CU240B-2
Category	Inverter
Language	English