Ramp-Function Generator - Siemens SINAMICS S150 NEMA Operating Instructions Manual

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Table of Contents

Setpoint channel and closed-loop control

7.2 Setpoint channel

Function diagram

Ramp-function generator

The ramp-function generator limits the rate at which the setpoint changes when the drive is

accelerating or decelerating. This prevents excessive setpoint step changes from damaging

the drive train. Additional rounding times can also be set in the lower and upper speed

ranges to improve control quality and prevent load surges, thereby protecting mechanical

components, such as shafts and couplings.

The ramp-up and ramp-down times each refer to the maximum speed (p1082). The rounding

times that can be set can prevent the actual speed value from being overshot when the

setpoint is approached, thereby improving control quality.

When final rounding set, a sudden reduction of the setpoint when ramping up can cause the

setpoint to overshoot, if continuous smoothing has been selected via p1134 = 0. The larger

the selected final rounding time, the larger the overshoot.

Rounding is also effective in the zero crossover; in other words, when the direction is

reversed, the ramp-function generator output is reduced to zero via initial rounding, the

ramp-down time, and final rounding before the new, inverted setpoint is approached via

initial rounding, the ramp-up time, and final rounding. Rounding times that can be set

separately are active in the event of a fast stop (OFF3). The actual ramp-up/ramp-down

times increase with active rounding.

The rounding type can be set using p1134 and separately activated/deactivated using

p1151.0 in the zero point.

Skip frequency bands and speed limiting

Maximum speed

CO: Speed limit in positive direction of rotation

CO: Speed limit positive effective

CI: Speed limit in positive direction of rotation

CO: Speed limit in negative direction of rotation

CO: Speed limit negative effective

CI: Speed limit in negative direction of rotation

CO: Ramp-function generator setpoint at the input

Operating Instructions, 12/2018, A5E36652151A

Enclosed Drives