Tuning CDHD
212 User Manual
To achieve t he fast est response t im e of the HD cont r ol loop, the low pass filter
can be adjusted manually. The goal is to use the m aximum value for
NLFI LTDAMPI NG and the m inim um value for NLFILTT1.
1 . I ncrease NLFI LTDAMPI NG until noise and/ or oscillations of I CMD are
observed, then reduce by 10% .
2 . Decrease NLFI LTT1 until noise and/ or oscillat ions of I CMD are observed,
then increase by 20% and at least 0.05 m s.
If the plant to be controlled has resonances at relatively high frequencies,
NLFI LTT1 can be applied on the current output. NLFI LTT1 efficiently reduces
acoustical noise, but also reduces control bandwidth and the potential stiffness of
t he syst em .
NLFI LTDAMPI NG minimizes the negative effects of the low pass. NLFI LTDAMPI NG
m ay be set independently of NLFI LTT1 t o provide an overshoot response.
Com bined with t he low pass characteristic of the m echanical system , it helps in
achieving a higher bandwidth of the control.
NLFI LTDAMPI NG
at 0% 40% 80%
NLFI TT1
value too low
NLFI TT1
selected value
Figur e 9 - 2 3 . Low Pass Filte r s
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