Panasonic MINAS A5-series Operating Instructions Manual page 253

4. Manual Gain Tuning (Basic)
Suppression of Machine Resonance
How to Check the Resonance Frequency of the Machine
(1) Start up the Setup Support Software, "PANATERM" and bring the frequency charac-
teristics measurement screen.
(2) Set up the parameters and measurement conditions. (Following values are standard.)
• Set up Pr1.01 (1st gain of velocity loop) to 25 or so. (to lower the gain and make it
easy to identify the resonance frequency)
• Set up the amplitude to 50 (r/min) or so. (not to saturate the torque)
• Make the offset to 100 (r/min) or so. (to increase the speed detecting data and to
avoid the measurement error in the vicinity of speed-zero)
• Polarity is made positive direction with "+" and negative direction with "–".
• Setup the sampling rate to 0. (setup range to be 0 to 7.)
(3) Execute the frequency characteristic analysis.
Remarks
• Make sure that the revolution does not exceed the travel limit before the measurement.
Standard revolutions are,
Offset (r/min) × 0.017 × (sampling rate +1)
Larger the offset, better measurement result you can obtain, however, revolutions may
be increased.
• Set up Pr2.00 (Setup of adaptive filter mode) to 0 while you make measurement.
Note
• When you set a larger value of offset than the amplitude setup and make the motor run
to the one direction at all time, you can obtain a better measurement result.
• Set up a smaller sampling rate when you measure a high frequency band, and a larger
sampling rate when you measure a low frequency band in order to obtain a better mea-
surement result.
• When you set a larger amplitude, you can obtain a better measurement result, but
noise will be larger. Start a measurement from 50 [r/min] and gradually increase it.
Relation of Gain Adjustment and Machine Stiffness
In order to enhance the machine stiffness,
(1) Install the base of the machine firmly, and assemble them without looseness.
(2) Use a coupling designed exclusively for servo application with high stiffness.
(3) Use a wider timing belt. Belt tension to be within the permissible load to the motor
shaft.
(4) Use a gear reducer with small backlash.
• Inherent vibration (resonance frequency) of the machine system has a large effect
to the gain adjustment of the servo.
You cannot setup a higher response of the servo system to the machine with a low
resonance frequency (machine stiffness is low).
Note
Please download the Setup support software "PANATERM"from our web site anduse after
install to the PC.
Related page
• P.7-26 "Outline of Setup support software "PANATERM"
http://industrial.panasonic.com/jp/i/fa_motor.html
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