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Chapter 10 Adjustment
10–9
(4) Adjusting the settling time
The settling time is the time required for
the position droop to enter the in-position
width after the feed command (F∆T) from
the CNC reaches 0.
The settling time can be shortened by
raising the position loop gain or using
SHG control. However, a sufficient
response (sufficiently large VGN1 setting)
for the speed loop is required to carry out
stable control.
The settling time during normal control
when the CNC is set to linear acceleration/
deceleration can be calculated using the
following equation. During SHG control,
estimate the settling time by multiplying
PGN1 by
2
.
Settling time (ms) = −
10
3
PGN1
×
λ
n
F
×
10
6
60
×
G0tL
×
PGN1
2
× 1 − exp −
PGN1
×
G0tL
10
3
PGN1 : Position loop gain1 (SV003) (rad/s)
F : Rapid traverse rate (mm/min)
G0tL : Rapid traverse linear acceleration/
deceleration time constant (ms)
INP : In-position width (SV024) (µm)
Example of speed/current command waveform during acceleration/deceleration
INP
Position
droop
Time
Positioning
time
In-position
0
0
F∆T
F
G0tL
0
0
3000
200
–200
–3000
Time
Time
Speed command
(r/min)
Current command
(Rated current %)