Omron SMARTSTEP 2 R88M-G Series User Manual page 221

 Gain Parameters
Position Loop Gain
Pn10
Setting range 0 to 32767
 Set this parameter to adjust the position loop response according to the mechanical rigidity.
 The responsiveness of the servo system is determined by the position loop gain. Servo systems
with a high loop gain have a high response and can make positioning faster. To increase the
position loop gain, you must improve mechanical rigidity and increase the specific oscillation
frequency. The value should be 50 to 70 (1/s) for ordinary machine tools, 30 to 50 (1/s) for general-
use and assembly machines, and 10 to 30 (1/s) for industrial robots. Since the default position loop
gain is 40 (1/s), be sure to lower the setting for machines with low rigidity.
 Increasing the position loop gain in systems with low mechanical rigidity or systems with low
specific oscillation frequencies may cause machine resonance, resulting in an overload alarm.
 If the position loop gain is low, you can shorten the positioning time by using feed forward.
 This parameter is automatically changed by executing realtime autotuning function. To set it
manually, set the Realtime Autotuning Mode Selection (Pn21) to 0.
 Position loop gain is generally calculated as follows:
Position loop gain (Kp) =
When the position loop gain is changed, the response is as shown in the following diagram.
Servomotor
speed
When the speed loop gain is low.
 If the speed loop gain and position loop gain are optimally set, the Servomotor operation for the
command will be delayed 2/Kp at acceleration and delayed 3/Kp at deceleration.
2
Kp
Servomotor
Position
speed
command
Servomotor operation
Unit 1/s
Command pulse frequency (pulses/s)
Deviation counter accumulated pulses (pulses)
When the position loop gain is high
Time
3
Kp
5-10 User Parameters
Default setting 40
Power OFF → ON
(1/s)
Time
Position
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