3-24
3-5-6 Bias Function: Position Control
The bias function shortens positioning time by adding the bias rotational speed to the
speed command when the residual pulses in the deviation counter exceed the position-
ing completion range.
H
Function
•
When the residual pulses in the deviation counter exceed the positioning completion range (Cn-1b),
this function adds the bias rotational speed (Cn-1C) to the speed command. When the pulses are
within the positioning completion range, it stops adding the bias rotational speed.
H
Parameters to be Set
PRM No.
Parameter name
Factory
setting
Unit
Setting
range
Explanation
Cn-1b
Positioning completion
range
3
Com-
mand
units
1 to 250
Sets the range for positioning
completion signal output.
Cn-1C
Bias rotational speed
0
r/min
0 to 450
Sets position control bias.
Note
1. When not using the bias function, set the bias rotational speed to “0.”
Note
2. As the bias rotational speed increases, Servomotor rotation becomes more unstable. The optimal val-
ue changes depending on the load, gain, and positioning completion range, so observe the response
while making the adjustment. Start with the bias rotational speed set to 0 and slowly increase it.
H
Operation
•
When the residual pulses in the deviation counter exceed the positioning completion range (Cn-1b),
the bias rotational speed (Cn-1C) is added to the deviation counter output (speed command).
•
When the pulses are within the positioning completion range, the bias rotational speed is no longer
added to the speed command.
•
For internal processing block configuration, refer to the position loop block diagram in
3-7-2 Manual
-
ly Adjusting Gain.
OFF
Speed command
(Frequency of
command pulse
train)
Servomotor speed without
bias function
Servomotor speed when
bias function is used
ON
Positioning
completion
+r/min.
Time
Time reduced
INP
Motor speed
Operation
Chapter 3
