Siemens Sinamics S120 Function Manual page 154

Vector control
4.3 Speed controller
The following relationships apply for optimization:
● If Kp is increased, the controller becomes faster, although overshoot is reduced. Signal
● If Tn is decreased, the controller still becomes faster, although overshoot is increased.
When speed control is set manually, it is easiest to define the possible dynamic response via
Kp (and actual speed value smoothing) first before reducing the integral time as much as
possible. When doing so, 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.
Function diagrams (see SINAMICS S120/S150 List Manual)
● 6040 Speed controller with/without encoder
Overview of important parameters (see SINAMICS S120/S150 List Manual)
● r0062 CO: Speed setpoint after the filter
● r0063[0...1] CO: Speed actual value
● p0340[0...n] Automatic calculation of motor/control parameters
● r0345[0...n] Rated motor starting time
● p1442[0...n] Speed controller actual speed smoothing time
● p1452[0...n] Speed controller actual value smoothing time (SLVC)
● p1460[0...n] Speed controller P gain lower adaptation speed
● p1462[0...n] Speed controller integral time lower adaptation speed
● p1470[0...n] Speed controller encoderless operation P gain
● p1472[0...n] Speed controller encoderless operation integral time
● r1482 CO: Speed controller I torque output
● r1508 CO: Torque setpoint before supplementary torque
● p1960 Rotating measurement selection
152
ripples and vibrations in the speed control loop, however, increase.
Function Manual, (FH1), 01/2012, 6SL3097-4AB00-0BP2
Drive functions