BONFIGLIOLI ACTIVE Cube ACU 201-01 Operating Instructions Manual page 218

The behavior of the technology controller corresponds to a PID controller with the
components
− proportional component
− integral component
− differential component
The sign of the amplification determines the direction of control, i.e. with a rising
actual value and pos. sign of the amplification, the output frequency is reduced (e.g.
in pressure control). With a rising actual value and neg. sign of the amplification, the
output frequency is increased (e.g. in temperature control systems, refrigerating
machines, condensers).
The integral component can be used to reduce the steady-state control deviation
(deviation between actual value and reference value) over a period of time. If the
integral component is too dynamic
integral component is too passive
rected adequately.
Therefore the integral component must be adjusted installation-dependent.
1)
Dynamic behavior: fast correction of deviations.
2)
Passive behavior: slow correction of deviations.
In the factory setting
bled.
If the control behavior of the PI controller (or P controller) is too slow the setting of
the differential component (
ferential component is enabled the system tends to oscillate, so that the differential
component should be enabled and set carefully.
BONFIGLIOLI VECTRON recommends setting the values of
Derivative time
Parameter
output. This prevents oscillations of the system at steep acceleration ramps.
Via Parameter
range (hysteresis band) can be suppressed. This causes more passive behavior of the
technology controller. This can be helpful when the stator frequency cannot follow
the reference frequency of the Technology controller.
Rated frequency
The hysteresis acts as a limiter at the input of the integral part. Excessive differences
between the stator current and the output of the controller technology are so limited
and so prevent excessive integration of the integral value.
f
tech
Rated frequency
f
tech
Rated frequenz
218
Amplification
Integral time
Derivative time
Derivative time
Derivative time
618 higher than the sample time, which is 2 ms at the ACU device.
442 limits the frequency change at the controller
Max. P-Component
443 changes of the integral component outside a specified
Hysteresis
375, in most cases therefore 50 Hz.
−
f
≥
stator
Hysteresis
375
−
f
<
stator
Hysteresis 443
375
Operating Instructions ACU
444
445
618
1)
the system will be unstable and oscillates. If the
2)
the steady-state control deviation will not be cor-
618 = 0 ms the differential component is disa-
618) allows a faster control. If the dif-
Hysteresis
The deviation ∆ between Reference frequency
of the Technology Controller (f
443 frequency (f ) is too big. The Integrator is
stator
halted.
The Stator frequency (f
reference frequency of the technology control-
ler sufficiently. The deviation ∆ is mall
enough.
445 and
Integral time
443 is related to
) and Stator
tech
) can follow the
stator
06/13