Description of the Software Modules and Parameters
Parameter manual b maXX BM5800
Document No.: 5.16029.03
191
of 814
3
The calculation of the Ks factor is incorrect due to the friction forces. So that the friction
forces do not invalidate the Ks measurement the evaluated factor should (measured Ks
factor)
Z52.8– be made from the averaging between the evaluated Ks factors at the ac-
celeration procedure Z52.6– and the braking procedure Z52.7–.
Acceleration: Starting speed = N1, end speed = N2
Braking: Starting speed = N2, end speed = N1
The prerequisites for the Ks measurement are:
1 Current controller and motor control have correctly set parameters.
2 Set Value generator and ramp function generator have parameters set (ProDrive offers
recommended settings for both options).
3 Drive is running with speed control (or position control) with set value generator and
with provisionally set Ks factor and speed control parameters. As a recommended val
-
ue the speed controller can be preset with Kp = 60 1/s, Tn = 0.3 s and the parameter
Ks factor
Z18.40– can be preset with twice the estimated value or the experienced val-
ue.
4 After the successful measurement the measured Ks factor Z52.8– can be taken over
(copy in Z18.40–). At the same time Kp and Tn of the speed controller can be param-
eterized e. g. after symmetric optimum (for this ProDrive provides a calculation tool).
As by-product of the measurement of the drive inertia (Z52.11– "Inertia measured"), the
sliding friction factor (Z52.9– "Load friction factor") and the static friction coefficient
(Z52.10– "Load friction") are determined as well.
Ks measurement with FFT analyzer function
The Ks measurement by the FFT analyzer function is a lighter version of the control loop
analysis. Here, a noise signal, whose amplitude must be specified, is given to the current
additional set value, as well. Contrary to the control loop analysis here the Ks factor is
determined, only.
This method is suited especially for drives in machines with a limited travel plant, as it can
be carried out in position control, as well and for drives where the inertia torque is un
-
known. Concerning this, the drive can be operated in current control mode, so that the
drive carries out minimum movements, only. Thereby, the measured Ks-factor is a rough
setting, only; more accurate values can be calculated during movement, only.
The second and the third method use the FFT analyzer function of the controller. With the
controller-internal Ks-evaluation (method 2) the Ks value can be set for single mass sys
-
tems only, when having vibrancy-capable systems then a more detailed consideration of
the distance in ProDrive on the page control system analysis is required (method 3).
The Ks measuring via the FFT analysis can be executed in all operating modes where the
torque current controller (this means current control or higher operating modes such as
Ks
a
I
sq-Lim
---------------
Ks
measured
(P52.8) Ks
Accel.
Ks
Decel.
+2=
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