
8. ALARM LIST
539
No.
LED
display
Description Countermeasure
411
The servo position error dur-
ing movement is larger than
the value specified in
parameter(*) 182.
Determine the mechanical
cause of the large position
error. If no mechanical
cause is found, apply any of
the following countermea-
sures:
S Specify a larger value for
the parameter(*).
S Specify a lower feedrate.
S Increase the time
constants.
[SVU–12, SVU–20]
An overcurrent alarm is
issued.
This alarm is issued when
an excessively large current
flows in the main circuit.
412
(1) Check whether a valid motor number is specified in pa-
rameter(*) 30.
(2) Check whether the standard values are specified in the
current control parameters(*) for servo control.
Correct current control is possible only when the stan-
dard values are specified for the following parame-
ters(*):
No.70, 71, 72, 78, 79, 84, 85, 86, 87, 88, 89, 90
(3) Disconnect the power line from the servo amplifier unit
connector. Then, release the emergency stop state.
– If the overcurrent alarm continues to be issued,
replace the servo amplifier unit.
– If no overcurrent alarm is issued, go to (4).
(4) Check the insulation between the ground and each of
U, V, and W.
³ If the insulation is satisfactory, go to (5). If a short–
circuit is detected, disconnect the power line from
the motor connector. Then, check the insulation
between the ground and each of U, V, and W of the
motor.
³ If a short–circuit is found between the ground and U,
V, or W of the motor, replace the motor.
³ If the insulation is satisfactory, replace the power
line.
(5) Connect the power line. Observe the waveform of the
motor current (IR, IS) while the motor is accelerating or
decelerating.
³ If the motor current (IR, IS) does not exhibit a normal
sine wave, replace the servo amplifier unit.
(6) Check if the motor current (IR, IS) waveforms include
noise.
³ When noise is included, take an action such as
making a connection to shield ground.
³ When noise is not included, replace the servo am-
plifier unit.
(7) If (1) to (6) above are not the cause of the alarm, the
pulse coder, or command cable may be defective.