888 HEIDENHAIN Technical Manual MANUALplus 620
Maximum values for parameter MP_iCtrlDiffFreqFF as a function of the PWM
frequency:
Adjustment of the current controller if increased current controller
factors are active over MP_iCtrlAddInfo:
If PDT
1
feedforward or the increase of the current controller factors is
activated, you must keep in mind that the noise in the current increases when
the bandwidth is increased. You have to find a compromise between the
increase of the current controller bandwidth and
the development of noise in the drive.
To adjust the increased current controller factors, proceed as follows:
In the corresponding parameter set of the axis MP_iCtrlAddInfo, set bit
0 = 1 to activate the function.
Readjust the current controller with TNCopt (Bode diagram function; see
TNCopt User's Manual).
PWM frequency Maximum value for MP_iCtrlDiffFreqFF
3333 Hz 800 Hz
4000 Hz 960 Hz
5000 Hz 1200 Hz
6666 Hz 1600 Hz
8000 Hz 1920 Hz
10000 Hz 2400 Hz
For standard drives, it is usually not necessary to increase the current
controller bandwidth. In general, the increase is only useful if the drives are
connected directly without an interconnected gear.
If you activate the PDT
1
feedforward by entering a value in the
MP_iCtrlDiffFreqFF parameter, it is not necessary to readjust the current
controller. The PDT
1
feedforward does not have a noticeable effect on the
current control loop but rather only on the superimposed speed control
loop. For axes with rigidly connected mechanics, you attain higher
controller factors in the speed control loop if the PDT
1
feedforward is
activated.
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