Guidelines For Setting The Load Inertia Ratio - YASKAWA SGM Series User Manual

speed reference falls within the positioning complete width. This shortens the positioning time
by reducing the number of pulses in the error counter.
Motor operation will become unstable if the bias is set too high. Adjust the bias while monitor-
ing the response because the optimum value will vary with the gain and the positioning com-
plete width.
Set Cn-001C to 0 if bias control will not be used.
Speed Speed
reference
Positioning
complete
(PSET)

5.9.4 Guidelines for Setting the Load Inertia Ratio

Adjustment guidelines are given below based on the rigidity and load moment of inertia of the
mechanical system. These values are given as guidelines only, and oscillation or poor response
may occur within the given ranges. Monitor the response (waveform) to optimize the adjust-
ment. Higher gain is possible with highly rigid machines.
J Machines with High Rigidity
Machines with high rigidity include ball screws and direct-drive machines.
Examples: Chip Mounters, IC Bonders, Precision Machine Tools
Load Inertia Ratio
2
(GD /GD
L
(Cn-0003) [%]
1× (100)
3× (300)
5× (500)
10× (1000)
15× (1500)
20× (2000)
30× (3000)
Note 1. For an inertia ratio of 10× or higher, slightly reduce the position loop gain and
speed loop gain below the values shown, and set the integration time constant
to a higher value before starting the adjustment.
2. Slightly increase the speed loop integration time constant for an inertia ratio
of 20× or higher.
3. As the inertia ratio increases, set the position loop gain and speed loop gain to
the lower limit of the range of values specified and increase the speed loop in-
tegration time constant.
"1" "0"
Position Loop Gain
2
) (Cn-001A) [0.01/s]
M
5000 to 7000
5 -25
Motor speed without bias control
Motor speed with bias control
Time
"1"
Speed Loop Gain Speed Loop
(Cn-004) [0.1 Hz] Integration Time
(Cn-005) [0.01ms]
500 to 700
5.9 Adjustments
5
Constant
500 to 2000