YASKAWA Sigma-7 SGD7S Series

9.14.2 Tuning the Servo Gains
Encoder
+
-
M
PG
+
-
+
-
Tf
Position control loop
Speed control loop
Servomotor
Speed
Speed pattern
Movement
reference
Time
Position loop
Deviation
counter
Position
loop gain Kp
Speed
reference
Speed loop
Speed control
section
Kv and Ti
Current loop
Current
control
section
Power
converter
SERVOPACK
Kp: Position loop gain (Pn102)
Kv: Speed loop gain (Pn100)
Ti: Speed loop integral time constant (Pn101)
Tf: First stage first torque reference filter time constant (Pn401)
Host controller
(Not provided by Yaskawa)
Fig. 298: Tuning the Servo Gains
In order to manually tune the servo gains, you must understand the configuration and
characteristic of the SERVOPACK and adjust the servo gains individually. In most cases,
if you greatly change any one parameter, you must adjust the other parameters again. To
check the response characteristic, you must prepare a measuring instrument to monitor
the output waveforms from the analog monitor.
The SERVOPACK has three feedback systems (the position loop, speed loop, and cur-
rent loop), and the response characteristic must be increased more with the inner loops.
If this relationship is not maintained, the response characteristic will suffer and vibration
will occur more easily.
A sufficient response characteristic is ensured for the current loop. There is never a need
for it to be adjusted by the user.
You can use manual tuning to set the servo gains in the SERVOPACK to increase the
response characteristic of the SERVOPACK. For example, you can reduce the posi-
tioning time for position control.
Use manual tuning in the following cases.
n When tuning with autotuning without a host reference or autotuning with a host refer-
ence does not achieve the desired results
n When you want to increase the servo gains higher than the gains that resulted from
autotuning without a host reference or autotuning with a host reference
n When you want to determine the servo gains and moment of inertia ratio yourself
You start manual tuning either from the default parameter settings or from the gain set-
tings that resulted from autotuning without a host reference or autotuning with a host ref-
erence.
You can monitor the servo gains with the SigmaWin+ or with the analog monitor.
Vibration may occur while you are tuning the servo gains. We recommend that you
enable vibration alarms (Pn310 = n.2) to detect vibration. Refer to the following sec-
tion for information on vibration detection.
Ä Chap. 7.12 ‘Initializing the Vibration Detection Level’ page 246
Vibration alarms are not detected for all vibration. Also, an emergency stop method is
necessary to stop the machine safely when an alarm occurs. You must provide an emer-
gency stop device and activate it immediately whenever vibration occurs.
Servo Gains
Outline
Applicable Tools
Precautions
Sigma-7 Series SERVOPACKs
Tuning
Manual Tuning > Tuning the Servo Gains
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