8 - 3
8. SPECIAL ADJUSTMENT FUNCTIONS
POINT
If the frequency of machine resonance is unknown, decrease the notch
frequency from higher to lower ones in order. The optimum notch
frequency is set at the point where vibration is minimal.
A deeper notch has a higher effect on machine resonance suppression but
increases a phase delay and may increase vibration.
The machine characteristic can be grasped beforehand by the machine
analyzer on the servo configuration software. This allows the required
notch frequency and depth to be determined.
Resonance may occur if parameter No. 58 59 is used to select a close
notch frequency and set a deep notch.
(b) Machine resonance suppression filter 2 (parameter No. 59)
The setting method of parameter No. 59 is the same as tha t of parameter No. 58. However, the
machine resonance suppression filter 2 can be set independently of whether adaptive vibration
suppression control is valid or invalid.
8.1.3 Adaptive vibration suppression control
(1) Function
Adaptive vibration suppression control is a function in which the servo amplifier detects m achine
resonance and sets the filter character istics automatica lly to suppress mechanical sy stem vibration.
Since the filter characteristics (frequency, depth) are set automatically, you need not be conscious of
the resonance frequency of a mechanical system. Also, while adaptiv e vibra tion sup pressio n contro l is
valid, the servo amplifier always detects machine resonance, and if the resonance frequency changes,
it changes the filter characteri stics in response to that frequ ency.
Mechanical
system
response
Mechanical
system
response
Machine resonance point Machine resonance poin t
Frequency Frequenc
y
Notch
depth Notch
depth
Notch frequency Notch frequency
Frequency Frequenc
y
When machine resonance is large and frequency is low When machine resonance is small and frequency is high
POINT
The machine resonance frequency which adaptive vibration suppression
control can respond to is about 150 to 500Hz. Adaptive vibration
suppression control has no effect on the resonance frequency outside this
range. Use the machine resonance suppression filter for the machine
resonance of such frequency.
Adaptive vibration suppression control may provide no effect on a
mechanical system which has complex resonan ce character istics or w hich
has too large resonance.
Under operating conditions in which sudden distu rbance to rque is imposed
during operation, the detection of the resonance frequency may malfunction
temporarily, causing machine vibration. In such a case, set adaptive
vibration suppression control to be "held" (par amete r N o. 60: 2 ) to fix
the characteristics of the adaptive vibr ation suppression control filter.