Siemens SINAMICS S120 System Manual page 151

I component
The integral-action component can be deactivated by setting the integral time to zero
(p1463). For a negative P gain setting, the integral time is interpreted as a negative value so
that the compensation always acts as negative feedback.
The integrator can be activated/deactivated from the PLC. The current status is returned to
the PLC.
Integrator feedback
The integrator of the velocity controller loop is reduced to a 1st order low-pass response with
the configured time constant (p1494) using weighted feedback.
● Effect:
The output of the velocity controller integrator is limited to a value proportional to the
difference between setpoint and actual values (steady-state proportional action).
● Applications:
Machining motion for position setpoint zero and dominant stiction can be suppressed, but
result in a permanent distance-to-go, e.g., oscillation of the position-controlled axis at
zero speed (stick-slip effect) or overshoot for the μm-step method.
● Setting note:
Optimize this data starting from a high value until you find the best compromise.
Integrator feedback threshold
Velocity below which the integrator feedback takes effect (p1495).
The integrator feedback function is mainly used when stiction problems are encountered, i.e.
to suppress undesirable movements caused by stiction (slip-stick effect) in position-
controlled operation and at zero speed.
p1495 can be used to ensure that the integrator feedback is activated only for low velocity
setpoints and stabilizes the axis at zero speed. At high velocities, however, the effect of the I
component is not restricted.
D component (acceleration feedback)
A derivative-action component (acceleration feedback) is implemented in the controller in
addition to the P component. This derivative-action component is located in the feedback
branch. The setting is realized using the derivative-action time (p1465, p1466 and p1467). It
can be negative or positive. No D component is active if 0 is entered.
Similar to the P component setting, it is possible to set a D component at the A and B sides
of the cylinder.
Since precise differentiation is not possible, an additional denominator component must be
provided. This component is set using a smoothing time constant (p1464). If the D
component is deactivated, then the smoothing constant also becomes inactive.
Hydraulic Drive
System Manual, 04/2015, 6SL3097-4BA00-0BP1
Drive functions
5.3 Closed-loop velocity control
151