No. LED display Description Countermeasure
[SVU-40, SVU-80]
An overcurrent alarm or IPM alarm is issued.
This alarm is issued in the following cases:
• This alarm is issued when an excessively
large current flows in the main circuit.
• This alarm is issued when an error
(overcurrent, overheat, low IPM control
power supply voltage) is detected in the IPM
(semiconductor driving the motor).
412
(1) Check whether a valid motor number is specified in parameter No.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 standard values are specified for the
following parameters:
No.70, 71, 72, 78, 79, 84, 85, 86, 87, 88, 89, 90
(3) Turn off the servo amplifier unit for about ten minutes, then release the emergency stop
state. If no overcurrent alarm is issued, The IPM protection function (against overheat)
may be operating. Possible causes of overheat include a high ambient temperature and a
too severe motor operating condition. Check the cause.
- If an overcurrent alarm is issued, go to (4).
(4) Disconnect the power line from the servo amplifier unit connector. Then, release the
emergency stop state.
- If an overcurrent alarm is issued, the IPM protection function (against overcurrent, low
control power supply voltage, overheat) may be operating or defective. Replace the
IPM or servo amplifier unit.
- If no overcurrent alarm is issued, go to (5).
(5) Disconnect the power line from the amplifier connector. Check the insulation between the
ground and each of U, V, and W.
- If a short-circuit is found between the ground and U, V, or W of the motor, replace the
motor.
- If the insulation is satisfactory, replace the power line.
(6) Connect the power line. Observe the waveform of the motor current (IR, IS) while the motor
is accelerating or decelerating.
- If the motor current (IR, IS) does not show a normal sine wave, replace the servo
amplifier unit.
(7) Check whether the waveform of the motor current (IR, IS) contains noise.
- If it contains noise, take appropriate measures against noise, such as grounding the
shield.
- If it does not contain noise, replace the servo amplifier unit.
(8) If (1) to (7) above are not the cause of the alarm, the pulse coder, command cable, or
internal hardware of the CNC may be defective.
A DC link overvoltage alarm is issued. This alarm is issued when the DC voltage of
the main circuit power is too high.
413
(1) When SVU-12 or SVU-20 is used, and a separate regenerative discharge unit is not used,
check the specification to see if regenerative energy per one time does not exceed the
allowable regenerative energy of the servo amplifier unit.
(2) For the SVU-40 and the SVU-80, when the separate regenerative discharge resistor is not
used, check whether the CX23 connector is short-circuited with a dummy connector.
(3) The supply voltage for dynamic power may exceed the rated value. Check the voltage. If the
voltage is too high, reduce the voltage to an appropriate level.
(4) The regenerative discharge unit may not be properly connected. Check the connection.
(5) The resistance of the separate regenerative discharge unit may be abnormal. Disconnect
the separate regenerative discharge unit, then check the resistance. If the resistance is not
within ±20% of the predetermined resistance, replace the separate regenerative discharge
unit.
(6) If (1) to (5) are not the cause of the alarm, replace the servo amplifier unit.
EDIT
DATE DISIGNE
DESCRIPTION
TITLE
DRAW
ALARM FOR FANUC SERVO MOTOR β series I/O Link Option
(FANUC Series 16i/18i/160i/180i/160is/180is–MA OPERATOR’S
MANUAL),(FANUC Series
16i/160i/160is–MB,18i/180i/180is–MB5,18i/180i/180is–MB
B-63014EN/02-8, B-63534EN/02-1
SHEET
6/8
APPROV.
FANUC LTD