Setting The Ramp Times Of The Ramp-Function Generator - Siemens SIMOTRAS 6SG7050 Operating Instructions Manual

01.04
• The following settings affect the speed control loop:
P225: Controller gain Kp
Setting too low a gain results in an inaccurate speed correction to the setpoint (remaining
control deviation)
Setting too high a gain may result in speed instability. The drive will tend to vibrate.
Increase the gain using P225 until the first signs of instability occur, then slightly reduce
the value of P225.
P226: Reset time Tn
The control response becomes "sharper" by shortening the reset time.
P200: Smoothing of actual speed value (tachometer voltage) factory setting: 10 ms.
Excessive smoothing can produce instability in the speed control loop.
• After optimizing the speed controller, reset to master switch setpoint P625=170
• Other:
P158: Smoothing of current setpoint (speed controller output)
P157 = 0: Smoothing (P158) only active following torque direction reversal
P157 = 1 Smoothing (P158) always active
P227: Droop
The speed controller is not inflexible, i.e. it does permit small deviations to the setpoint as
the load increases.
At a load level that produces the rated converter current, a control deviation according to
the percentage set in P227 will be permitted
e.g.
50 %
n
set
(K0190)
0
z.B.
50 %
n
t
ac
(K0167)
0
Fig. 7.6.10.2

7.6.11 Setting the ramp times of the ramp-function generator

• Increase the speed setpoint in stages.
• Set the ramps for the ramp-function generator to provide optimum drive acceleration.
Set the transition roundings for the ramp-function generator such that there are no jerking
motions when reaching or leaving the setpoint.
SIEMENS AG 6SG7000-0BA76
SIMOTRAS HD Operating Instructions
HR...Acceleration ramp
Step response of speed control loop with ramp-function generator
Speed setpoint ramp
Time
Actual speed value curve
Time
Start-up
7-13