10-17
10-4 Manual Tuning
OMNUC G5-Series AC Servo Drives Users Manual (Built-in MECHATROLINK-II communications type)
10
Adjustment Functions
Inertia guide
Pn100, Pn105 Position Loop Gain
This loop controls the number of pulses from encoder to be the designated number of pulses.
This is called an error counter, and when the pulse is equal to or lower than the specified value,
positioning is completed and the signal is output.
The ratio of maximum speed used and error counter is called a position loop gain.
For the position loop gain, use the inverse of Speed Loop Integral Time Constant 1 (Pn102) as
a guide for setting. Setting Pn102 to 100 ms results in 10 [1/s].
There will be no overshooting under this condition. To quicken positioning, increase the value
of position loop gain. If the value is too large, overshooting or vibration will occur. In such
cases, set the value smaller.
If the speed loop or the current loop is vibrating, adjusting the position loop does not eliminate
the vibration.
Response to the position loop gain adjustment is illustrated below.
If the position loop gain is high, an overshooting occurs.
If the position loop gain is low, positioning completion speed becomes slow.
The inertia is small.
5 times the rotor inertia max.
The inertia is medium.
5 to 10 times the rotor inertia max.
The inertia is large.
10 to 20 times the rotor inertia max.
Command maximum speed [pps]
Error counter accumulated pulse (P)
Position loop gain [1/s]
=
Actual operation
Command operation pattern
Speed
(r/min)
Time t
Actual operation
Command operation pattern
Speed
(r/min)
Time t
