IAI America PCON-CA - Manual (Page 202)

Chapter 7 I/O Parameter
POWER CON
PCON-CA/CFA
194
7.3 Servo Adjustment
The parameters are preset at the factory before shipment so that the actuator operates stably
within the rated (maximum) transportable weight.
However, the preset setting cannot always be the optimum load condition in the actual use. In
such cases, servo adjustment may be required.
This section describes the basic servo adjustment method.
ᴾ
No.
Situation that requires
adjustment
How to Adjust
Takes time to finish
positioning
Positioning accuracy is
not appropriate
1
Shorter takt time is
desired
Ɣ Set “parameter No.55 “Position command primary filter time
constant”” to “0” if it is set.
Ɣ Increase the value of “parameter No.7 “Servo gain number””. By
setting a larger value, the following ability to the position
command becomes better. Set the value to any of 3 to 10
roughly or up to 15 at the maximum. If the value is too large, an
overshoot is caused easily and may cause noise or vibration.
If the value of “parameter No.7 “Servo gain number”” is
increased, also adjust the “parameter No.31 (Note 1) “Velocity loop
proportional gain”” in increasing direction to ensure the stability
in the control system.
To increase the value of “parameter No.31 (Note 1) “Velocity loop
proportional gain”” by about 20% of the default. Prior to the
setting, adjust “parameter No.7 “Servo gain number””.
2 Vibration is generated at
acceleration/deceleration
Ɣ The cause of the problem is excessive
"acceleration/deceleration setting" or vulnerable structure of the
unit on which the actuator is installed. If possible, reinforce the
unit itself, first.
Ɣ Decrease the values of “acceleration/deceleration setting”.
Ɣ Decrease the number of “parameter No.7 “Servo gain number””.
If the “parameter No.7 “Servo gain number”” is too low, it takes
long time to finish the positioning.
Speed is uneven during
the movement
3
Speed accuracy is not
appropriate
Ɣ Increase the value of parameter No.31 (Note 1) “Velocity loop
proportional gain”. By setting a larger value, the follow-up ability
to the speed command becomes better.
Setting too large value makes the mechanical components easy
to vibrate. As a reference for the setting, increase the value little
by little by 20% from the initial setting.
Note 1 For the actuators (RCP4) available for high output, set four sets of Velocity Loop
Proportional Gain and select a parameter to use. [Refer to Item [88] in 7.2 Detail
Explanation of Parameters for the details.]
Caution: Rapid and excessive settings are dangerous. They may cause devices
including the actuator to be damaged and/or people to be injured. Take
sufficient note on the setting.
Record settings during servo adjustment so that prior settings can always be
recovered.
When a problem arises and the solution cannot be found, please contact IAI.