bnp-b2365(eng)b.pdf - 第212页

4. Servo Adjustment 4 - 13 (2) Jitter compensation (Vibration control w hen motor is stopped.) The load inertia becomes much sm aller than usual if the motor po sition enters the machine backlash when the motor is stopp …

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4. Servo Adjustment
4 - 12
(1) Notch filter
This servo drive unit mounts 5 notch filters. Measure the resonance frequency with the current
feedback analog output function, and set that frequency in parameter.
However, if the notch filter is set to a particularly low frequency, another resonance frequency that
did not vibrate initially may occur. If the notch filter's depth compensation (SV033, nfd1, nfd2) is
adjusted so that the filter does not operate unless necessary, the servo control will be stabilized.
Notch filter 3 is a filter with frequency fixed to 1125Hz, and has no depth compensation.
<Setting method>
[1] Set the resonance frequency in the notch filter frequency (1, 2, 4, 5).
[2] If the machine starts to vibrate at another frequency, raise (make shallower) the notch filter
depth compensation value, and adjust to the optimum value at which the resonance can be
eliminated.
[3] When the vibration cannot be completely eliminated, use also another notch filter for this
frequency.
No. Abbrev. Parameter name Explanation Setting range
FEDCBA98765 4 3 2 10
hvx svx nfd2 nf3 nfd1 zck
bit Meaning when "0" is set Meaning when "1" is set
1 Set the filter depth for Notch filter 1 (SV038).
2 nfd1 Value 000 001 010 011 100 101 110 111
3
Depth (dB)
DeepÅ
Infntly
deep
-18.1 -12.0 -8.5 -6.0 -4.1 -2.5 -1.2
ShallowÆ
4 nf3 Notch filter 3 stop Notch filter 3 start (1125Hz)
5 Set the filter depth of Notch filter 2 (SV046).
6 nfd2 Value 000 001 010 011 100 101 110 111
SV033 SSF2
Servo function
selection 2
7
Depth (dB)
DeepÅ
Infntly
deep
-18.1 -12.0 -8.5 -6.0 -4.1 -2.5 -1.2
ShallowÆ
SV038 FHz1
Notch filter frequency
1
Set the vibration frequency to suppress if machine vibration occurs.
(Valid at 36 or more) When not using, set to "0".
0 to 9000
(Hz)
SV046 FHz2
Notch filter frequency
2
Set the vibration frequency to suppress if machine vibration occurs.
(Valid at 36 or more) When not using, set to "0".
0 to 9000
(Hz)
FEDCBA98765 4 3 2 10
hvx svx nfd2 nf3 nfd1 zck
bit Meaning when "0" is set Meaning when "1" is set
1 Set the filter depth for Notch filter 4 (SV038).
2 nfd4 Value 000 001 010 011 100 101 110 111
3
Depth (dB)
DeepÅ
-
∞
-18.1 -12.0 -8.5 -6.0 -4.1 -2.5 -1.2
ShallowÆ
5 Set the filter depth for Notch filter 5 (SV046).
6 nfd5 Value 000 001 010 011 100 101 110 111
SV083 SSF6
Servo function
selection 6
7
Depth (dB)
DeepÅ
-∞
-18.1 -12.0 -8.5 -6.0 -4.1 -2.5 -1.2
ShallowÆ
SV087 FHz4
Notch filter
frequency 4
0 to 2250
(Hz)
SV088 FHz5
Notch filter
frequency 5
Set the vibration frequency to suppress if machine vibration occurs.
(Valid at 141 or more) When not using, set to "0".
To use this function, set to not "0" (normally "1") when turning the power
ON. This function cannot be used with adaptive filter.
0 to 2250
(Hz)
4. Servo Adjustment
4 - 13
(2) Jitter compensation (Vibration control when motor is stopped.)
The load inertia becomes much smaller than usual if the motor position enters the machine
backlash when the motor is stopped. Because this means that an extremely large VGN1 is set for
the load inertia, vibration may occur.
Jitter compensation can suppress the vibration that occurs at the motor stop by ignoring the
backlash amount of speed feedback pulses when the speed feedback polarity changes.
Increase the number of ignored pulses by one pulse at a time, and set a value at which the
vibration can be suppressed. (Because the position feedback is controlled normally, there is no
worry of positional deviation.)
When jitter compensation is set to an axis that is not vibrating is set, vibration could be induced, so
take care.
(3) Adaptive filter
The servo drive unit detects the machine resonance point and automatically sets the filter constant.
Even if the ball screw and table position relation changes causing the resonance point to change,
the filter will track these changes. If the sensitivity to detect the vibration is insufficient and the
effect of the filter is not apparent, increase the sensitivity (SV027/bitC, D). The filter coefficient is
recalculated when the power is turned ON again, so vibration may occur temporarily.
Notch filter 4 and notch filter 5 cannot be used together.
No. Abbrev. Parameter name Explanation
SV027 SSF1
Servo function
selection 1
F E D C B A 9 8 7 6 5 4 3 2 1 0
aflt zrn2 afse ovs lmc omr zrn3 vfct upc vcnt
<Jitter compensation> Removal of vibration when motor is stopped
bit Explanation
4 Set the number of compensation pulses of the jitter compensation.
5
vfct
00: Jitter compensation invalid 10: Jitter compensation 2 pulses
01: Jitter compensation 1 pulse 11: Jitter compensation 3 pulses
<Adaptive filter>
bit Meaning when "0" is set Meaning when "1" is set
C 00: Adaptive filter sensitivity standard
D
afse
11: Adaptive filter sensitivity increase (Set 2bits at a time)
E zrn2 Set to "1".
F aflt Adaptive filter stop Adaptive filter start
POINT
Jitter compensation vibration suppression is only effective when the motor is
stopped.
4. Servo Adjustment
4 - 14
(4) Variable speed loop gain control
If vibration occurs when the motor is rotating at a high speed, such during rapid traverse, or if
disturbing noise occurs, the state can be improved by lowering the speed loop gain during
high-speed rotation. The low-speed region speed loop gain used for cutting feed (G1 feed), etc., is
maintained at a high level, so the vibration can be improved without dropping the machining
accuracy.
No. Abbrev. Parameter name Explanation Setting range
SV005 VGN1 Speed loop gain 1 Set the speed loop gain.
Set this according to the load inertia size.
The higher the setting value is, the more accurate the control will be,
however, vibration tends to occur.
If vibration occurs, adjust by lowering by 20 to 30%.
The value should be determined to be 70 to 80% of the value at the
time when the vibration stops.
1 to 999
VGN1
VGN2
VCS VLMT
SV006 VGN2 Speed loop gain 2 If the noise is bothersome at high
speed during rapid traverse, etc, lower
the speed loop gain.
As in the right figure, set the speed
loop gain of the speed 1.2 times as
fast as the motor’s rated speed, and
use this with SV029 (VCS).
When not using, set to "0".
0
(Rated speed × 1.2)
-1000 to 1000
SV029 VCS Speed at the change
of speed loop gain
If the noise is bothersome at high speed during rapid traverse, etc,
lower the speed loop gain.
Set the speed at which the speed loop gain changes, and use this with
SV006 (VGN2). (Refer to SV006.)
When not using, set to "0".
0 to 9999
(r/min)