14.4 Troubleshooting Based on the Operation and Conditions of the Servomotor
14-61
Large Motor
Speed
Overshoot
on Starting
and Stop-
ping
The servo gains are not bal-
anced.
Check to see if the servo
gains have been cor-
rectly tuned.
Perform autotuning
without a host refer-
ence.
page 8-23
The setting of Pn100 (Speed
Loop Gain) is too high.
Check the setting of
Pn100.
The default setting is Kv =
40.0 Hz.
Set Pn100 to an appro-
priate value.
−
The setting of Pn102 (Posi-
tion Loop Gain) is too high.
Check the setting of
Pn102.
The default setting is Kp
= 40.0/s.
Set Pn102 to an appro-
priate value.
−
The setting of Pn101 (Speed
Loop Integral Time Con-
stant) is not appropriate.
Check the setting of
Pn101.
The default setting is Ti =
20.0 ms.
Set Pn101 to an appro-
priate value.
−
The setting of Pn103
(Moment of Inertia Ratio or
Mass Ratio) is not appropri-
ate.
Check the setting of
Pn103.
Set Pn103 to an appro-
priate value.
−
The torque reference is satu-
rated.
Check the waveform of
the torque reference.
Use the mode switch.
−
The force limits (Pn483 and
Pn484) are set to the default
values.
The default values of the
force limits and Pn483 =
30% and Pn484 = 30%.
Set Pn483 and Pn484
to appropriate values.
page 6-17
Absolute
Encoder
Position
Deviation
Error (The
position
that was
saved in the
host con-
troller when
the power
was turned
OFF is dif-
ferent from
the posi-
tion when
the power
was next
turned ON.)
Noise interference occurred
because of incorrect Encoder
Cable specifications.
Turn OFF the power sup-
ply to the servo system.
Check the Encoder Cable
to see if it satisfies speci-
fications.
Use a shielded twisted-
pair wire cable or a
screened twisted-pair
cable with conductors of
at least 0.12 mm
2
.
Use cables that satisfy
the specifications.
−
Noise interference occurred
because the Encoder Cable
is too long.
Turn OFF the power sup-
ply to the servo system.
Check the length of the
Encoder Cable.
• Rotary Servomotors:
The Encoder Cable
length must be 50 m
max.
• Linear Servomotors:
Make sure that the
Serial Converter Unit
cable is no longer
than 20 m and that
the Linear Encoder
Cable and the Sensor
Cable are no longer
than 15 m each.
−
Noise interference occurred
because the Encoder Cable
is damaged.
Turn OFF the power sup-
ply to the servo system.
Check the Encoder Cable
to see if it is pinched or
the sheath is damaged.
Replace the Encoder
Cable and correct the
cable installation envi-
ronment.
−
Continued on next page.
Continued from previous page.
Problem Possible Cause Confirmation Correction Reference
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