11/03 Setpoint Channel and Closed-Loop Control
SINAMICS G150
Operating Manual
7-5
7.2.4 Ramp Generator
Description
The ramp 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. You can also set additional rounding times 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 relate 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.
Caution: if rounding times are too long, this can cause the setpoint to be overshot if
the setpoint is reduced abruptly during ramp-up. Rounding is also effective in the
zero crossover; in other words, when the direction is reversed, the ramp generator
output is reduced to zero via start rounding, the ramp-down time, and end rounding
before the new, inverted setpoint is approached via start rounding, the ramp-up
time, and end rounding. Rounding has no effect in the event of an emergency stop
(OFF3). The actual ramp-up/ramp-down times increase with active rounding.
Signal Flow Diagram
p1131p1130p1131p1130
t
f
RG.T_Ramp_Up
0.00...999999.00 s
p1120 (10.00)
RG.T_Ramp_Down
0.00...999999.00 s
p1121 (10.00)
RG.T_FInRnd
0.00...30.00 s
p1131 (0.00)
RG.T_InitRnd
0.00...30.00 s
p1130 (0.00)
nSetbefore_RG
r1119
nSetp_after_RG
r1150
Fig. 7-3 Signal flow diagram: Ramp generator
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