Siemens SINAMICS S120 Function Manual page 222

Vector control
6.4 Speed controller
T = 4 · T
n
K = 0.5 · r0345 / T
p
T = total of the short delay times (contains p1442 and p1452)
s
If vibration develops with these settings, reduce speed controller gain K
speed smoothing can also be increased (standard procedure for gearless or high-frequency
torsional vibration) and the controller calculation performed again because this value is also
used to calculate K
The following relationships apply for tuning:
● If K
signal ripples and oscillations in the speed control loop will increase.
● If T
When setting the speed control manually, you are advised to define the possible dynamic
response via K
subsequently be reduced as much as possible. Please note that the closed-loop control must
also remain stable in the field-weakening range.
To suppress any vibrations that occur in the speed controller, it is usually only necessary to
increase the smoothing time in p1452 for operation with an encoder or p1442 for operation
without an encoder or reduce the controller gain.
The integral output of the speed controller can be monitored via r1482 and the limited controller
output via r1508 (torque setpoint).
Note
In comparison with speed control with an encoder, the dynamic response of drives without an
encoder is significantly reduced. The actual speed is derived by means of a model calculation
from the converter output variables for current and voltage that have a corresponding
interference level. To this end, the actual speed must be adjusted by means of filter algorithms
in the software.
Speed controller response when a brake is opened
After a motor has been a magnetized, "Open brake" is controlled. The value that the BICO input
delivers defines the speed controller response:
● BICO input p1475 (torque setting value for the motor holding brake) supplies a value of 0:
– The speed controller I component is immediately enabled; this means that the system
– Depending on the parameter assignment, the speed setpoint remains inhibited until the
● BICO input p1475 (torque setting value for the motor holding brake) supplies a value ≠ 0:
– The speed controller I component is held at the specified setting value until the "Brake
– Only then are the speed controller I component and the speed setpoint enabled.
220
s
= 2 · r0345 / T
s
and T .
p n
is increased, the controller becomes faster and overshoot is decreased. However,
p
is reduced, the controller also becomes faster. However, this increases the overshoot.
n
(and actual speed value smoothing) first, so that the integral time can
p
can respond to a slipping load and establish a holding torque.
brake opening time has elapsed (p1275.6 = 0) - or until the brake feedback signal is
received (p1275.6 = 1).
open" feedback signal is received.
n
Function Manual, 06/2019, 6SL3097-5AB00-0BP2
manually. Actual
p
Drive functions