Beckhoff EP8309-1022, Документация

Страница: 64 / 116

Commissioning and Configuration
EP8309-1022 64 Version: 2.0.0
Dithering
Dithering involves modulating a square wave signal on top of the actual output value. The modulated signal
results in continuous movement of a valve piston, for example.
This reduces static friction and prevents sudden "breakaway" of the piston.
The configuration required for this depends a lot on the particular application.
To activate dithering, the object
0x8060:03 [
}
83] ("Enable dithering") and the corresponding control bit must
be set.
Fig. 60: Enable dithering
The following parameters can be set:
Value Text Description
0x8060:1E
[
}
83]
Dithering frequency [Hz] Frequency of the applied dither in Hz
0x8060:1F
[
}
83]
Dithering amplitude [%] Amplitude of the applied dither (in % of the rated terminal
current)
The controller parameters themselves (K
p
,K
i
, and K
d
) also play a role.
In the diagrams a dither of 10 % of the rated current is shown as 100 Hz.
The controller has 5 ms for compensating a current pulse of 10 %. The steepness of the current rise is
limited by the controller parameters and the inductance.
The actual current should follow the set current. This is enabled through suitable settings of the controller
and dither parameters (frequency and amplitude).