Ramp-Function Generator - Siemens SINAMICS G150 Operating Instructions Manual

Setpoint channel and closed-loop control
7.2 Setpoint channel
Parameters
• p1082
• p1083
• r1084
• p1085
• p1086
• r1087
• p1088
• r1119
7.2.5

Ramp-function generator

Description
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 start
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.
The ramp-up time (p1120) can be scaled using connector input p1138, the ramp-down time
(p1121) using connector input p1139. Scaling is deactivated in the factory setting.
372
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
Converter cabinet units
Operating Instructions, 03/2012, A5E03263466A