4-45
•
Sets the speed loop integral time constant.
•
The higher the setting, the lower the response, and the lower the resiliency to external force. There is a
risk of oscillation if the setting is too low.
Servomotor
speed (speed
monitor)
Time
When speed loop integration
constant is long.
Overshoots when speed loop integration constant is short.
Pn102
Position loop gain (Position, speed with position lock)
Setting
range
1 to 2000
Unit
1/s
Default
setting
40
Restart
power?
No
•
Adjust the position loop response to suit the mechanical rigidity.
•
The position loop gain is enabled in speed control only if using the position lock function. Use servo-
lock power adjustment during position lock.
•
Servo system response is determined by the position loop gain. Servo systems with a high loop gain
have a high response, and positioning is fast. To raise the position loop gain, you must improve me-
chanical rigidity and raise the specific oscillation. This 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 production robots.
The default position loop gain is 40 (1/s), so be sure to lower the setting for machines with low rigidity.
•
Raising the position loop gain in systems with low mechanical rigidity or systems with low specific os-
cillation may result in machine resonance, causing an overload alarm to occur.
•
If the position loop gain is low, you can shorten the positioning time using feed forward. You can also
shorten the positioning time using the bias function.
Position loop gain is generally expressed as follows:
Position loop gain (Kp) =
Command pulse frequency (pulses/s)
Deviation counter residual pulses (pulses)
(1/s)
When the position loop gain is manipulated, the response is as shown in the diagram below.
Servomotor
speed (speed
monitor)
Time
When position loop gain is low
When position loop gain is high
Operation
Chapter 4
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