FANUC Servo Amplifier Alarm Codes List

FANUC Alarm Codes >> Servo Alarm Codes

Below is a list of FANUC servo amplifier alarms and faults with a short description briefly describing the source of each error code. Some point to the source of the problem itself, others point to the problem and do not identify the failing/malfunctioning component.

Servo Amplifiers We Service

  • FANUC Alpha, Alpha i series & Alpha is series
  • FANUC AC Digital and Analog
  • FANUC AC Serial Interface
  • FANUC AC Series i & S

Tri Star CNC Services can provide you with more information on the meaning of your alarms. We will provide a fault diagnosis and a dependable 1-year warranty if you require servo repairs or parts replacement

Fanuc Servo Amplifer Alarms

Alarm Code Message Description
1   Internal cooling circuit faulty
1 6066, 6089, 6090 DC voltage of
the main circuit power supply is abnormally
high.
1 Beta The battery voltage of the absolute pulse coder is low. (warning)
11 Beta When the absolute pulse coder is used, the motor has not yet rotated through more than one turn after the first power–up.
2   Inverter: control power supply undervoltage
2 Beta The battery voltage of the absolute pulse coder is low.
2   The control power
voltage is abnormally low.
3 Beta The motor has overheated (OHAL).
3 6066, 6089, 6090 DC voltage of the main circuit power supply is abnormally
low or the circuit breaker is tripped.
4 6066, 6089, 6090 Regenerative discharge energy is too high.
–The regenerative discharge circuit is
abnormal.
5   Inverter: DC link undervoltage
5, S Beta A communication error for the serial pulse coder was detected.
5 6066, 6089, 6090 Average regenerative discharge energy is too high(too frequent acceleration/deceleration)–The transformer overheats.
6   Inverter: overheat
7 6066, 6089, 6090 Relay contacts for the dynamic brake is faulty.
8   Abnormal current alarm (L axis)
8. (dot)   Inverter: IPM alarm (L axis)
9   Abnormal current alarm (M axis)
9 Beta Reference position setting cannot be executed normally
9. (dot)   Inverter: IPM alarm (M axis)
A   Abnormal current alarm (N axis)
A.   Inverter: IPM alarm (N axis)
b   Abnormal current alarm (L axis)
b 6066, 6089, 6090 Abnormally high current in the L–and M–axis motors
b. 6066, 6089, 6090 IPM alarm for L–and M–axis axes.
c Beta An overcurrent alarm or IPM alarm
C Beta Faulty cooling circuit
d   Abnormal current alarm (N axis)
E Beta An error was detected in the RAM write/read test at power–up.
F   External cooling circuit faulty
J Beta The regenerative discharge unit has overheated
L   FSSB communication error
P   Communication error between amplifier and module
P Beta DC link low voltage alarm
U   FSSB communication error
U Beta A parameter that requires power–down has been specified.
u Beta A first to third reference position return cannot be executed because the reference position has not yet been established.
Y Beta DC link overvoltage alarm

Fanuc Servo Amplifier 400 Alarm Codes

Alarm Code Message Description
400 SERVO ALARM: n–TH AXIS OVERLOAD The n–th axis (axis 1–8) overload signal is on. Refer to diagnostic display No. 201, 720 or 721 for details.
401 SERVO ALARM: n–TH AXIS VRDY OFF The n–th axis (axis 1–8) servo amplifier READY signal (DRDY) went off.
402 SERVO ALARM 3, 4TH AXIS OVERLOAD 3-axis, 4-axis overload signal is on. Refer to diagnostic display 722 or 723 for details.
404 SERVO ALARM: n–TH AXIS VRDY
ON
Even though the n–th axis (axis 1–8) READY signal (MCON) went off,
the servo amplifier READY signal (DRDY) is still on. Or, when the power
was turned on, DRDY went on even though MCON was off.
Check that the servo interface module and servo amp are connected.
405 SERVO ALARM: (ZERO POINT RETURN
FAULT)
Position control system fault. Due to an NC or servo system fault in the
reference position return, there is the possibility that reference position
return could not be executed correctly. Try again from the manual reference
position return.
407 SERVO ALARM: EXCESS ERROR The difference in synchronous axis position deviation exceeded the set
value.
409 SERVO ALARM: n AXIS TORQUE ALM Abnormal servo motor load has been detected. Alternatively, abnormal
spindle motor load has been detected in Cs mode.
410 SERVO ALARM: n–TH AXIS – EXCESS
ERROR
The position deviation value when the n–th axis (axis 1–8) stops is larger
than the set value.
411 SERVO ALARM: n–TH AXIS – EXCESS
ERROR
The position deviation value when the n–th axis (axis 1–8) moves is
larger than the set value.
413 SERVO ALARM: n–th AXIS – LSI
OVERFLOW
The contents of the error register for the n–th axis (axis 1–8) exceeded
 231 power. This error usually occurs as the result of an improperly set
parameters.
414 SERVO ALARM: n–TH AXIS –
DETECTION RELATED ERROR
N–th axis (axis 1–8) digital servo system fault. Refer to diagnosis display
No. 200 and No.204 for details. Also look at the servo amlifier for alarm code.
415 SERVO ALARM: n–TH AXIS – EXCESS
SHIFT
A speed higher than 511875 units/s was attempted to be set in the n–th
axis (axis 1–8). This error occurs as the result of improperly set CMR.
416 SERVO ALARM: n–TH AXIS – DISCONNECTION Position detection system fault in the n–th axis (axis 1–8) pulse coder
(disconnection alarm). Refer to diagnosis display No. 201 for details.
417 SERVO ALARM: n–TH AXIS – PARAMETER
INCORRECT
This alarm occurs when the n–th axis (axis 1–8) is in one of the conditions
listed below. (Digital servo system alarm)
1) The value set in Parameter No. 2020 (motor form) is out of the
specified limit.
2) A proper value (111 or –111) is not set in parameter No.2022
(motor revolution direction).
3) Illegal data (a value below 0, etc.) was set in parameter No. 2023
(number of speed feedback pulses per motor revolution).
4) Illegal data (a value below 0, etc.) was set in parameter No. 2024
(number of position feedback pulses per motor revolution).
5) Parameters No. 2084 and No. 2085 (flexible field gear rate) have not been set.
6) A value outside the limit of {1 to the number of control axes} or a non–continuous value (Parameter 1023 (servo axis number) con
tains a value out of the range from 1 to the number of axes, or an
isolated value (for example, 4 not prceded by 3).was set in parame
ter No. 1023 (servo axisnumber). 7) The amplifier in use does not support the HC alarm avoidance function.
If you want to use this amplifier, reset the
function bit 2209#4 to 0.
If you want to use the HC alarm avoidance function, use an amplifier that supports it.
420 SERVO ALARM: n AXIS SYNC
TORQUE
(M series)
During simple synchronous control, the difference between the torque
commands for the master and slave axes exceeded the value set in parameter
No. 2031.
421 SERVO ALARM: n AXIS EXCESS
ER (D)
The difference between the errors in the semi–closed loop and closed
loop has become excessive during dual position feedback. Check the
values of the dual position conversion coefficients in parameters No.
2078 and 2079.
422 SERVO ALARM: n AXIS In torque control of PMC axis control, a specified allowable speed
has been exceeded.
423 SERVO ALARM: n AXIS In torque control of PMC axis control, the parameter–set allowable
cumulative travel distance has been exceeded.
430 n AXIS : SV. MOTOR OVERHEAT A servo motor overheat occurred.
431 n AXIS : CNV. OVERLOAD 1) PSM: Overheat occurred.
2) β series SVU: Overheat occurred.
432 n AXIS : CNV. LOWVOLT CON. 1) PSM: The control power supply voltage has dropped.
2) PSMR: The control power supply voltage has dropped.
3) β series SVU: The control power supply voltage has dropped
434 n AXIS : INV. LOWVOLT CONTROL SVM: The control power supply voltage has dropped.
435 n AXIS : INV. LOWVOLT DC LINK SVM: The DC link voltage has dropped.
436 n AXIS : SOFTTHERMAL (OVC) The digital servo software detected the soft thermal state (OVC).
437 n AXIS : CNV. OVERCURRENT POWER PSM: Overcurrent flowed into the input circuit.
438 n AXIS : INV. ABNORMAL CURRENT 1) SVM: The motor current is too high.
2) α series SVU: The motor current is too high.
3) β series SVU: The motor current is too high.
439 n AXIS : CNV. OVERVOLT POWER 1) PSM: The DC link voltage is too high.
2) PSMR: The DC link voltage is too high.
3) α series SVU: The C link voltage is too high.
4) β series SVU: The link voltage is too high.
440 n AXIS : CNV. EX DECELERATION
POWER
1) PSMR: The regenerative discharge amount is too large.
2) α series SVU: The regenerative discharge amount is too large. Alternatively, the regenerative discharge circuit is abnormal.
441 n AXIS : ABNORMAL CURRENT
OFFSET
The digital servo software detected an abnormality in the motor currentdetection circuit.
442 n AXIS : CNV. CHARGE FAILURE 1) PSM: The spare discharge circuit of the DC link is abnormal.
2) PSMR: The spare discharge circuit of the DC link is abnormal.
443 n AXIS : CNV. COOLING FAN FAILURE 1) PSM: The internal cooling fan failed.
2) PSMR: The internal cooling fan failed.
3) β series SVU: The internal cooling fan failed.
444 n AXIS : INV. COOLING FAN FAILURE SVM: The internal cooling fan failed.
445 n AXIS : SOFT DISCONNECT ALARM The digital servo software detected a broken wire in the pulse coder.
446 n AXIS : HARD DISCONNECT ALARM A broken wire in the built–in pulse coder was detected by hardware.
447 n AXIS : HARD DISCONNECT (EXT) A broken wire in the separate detector was detected by hardware.
448 n AXIS : UNMATCHED FEEDBACK
ALARM
The sign of feedback data from the built–in pulse coder differs from
that of feedback data from the separate detector.
449 n AXIS : INV. IPM ALARM 1) SVM: IPM (intelligent power module) detected an alarm.
2) α series SVU: IPM (intelligent power module) detected an alarm.
453 n AXIS : SPC SOFT DISCONNECT
ALARM
Software disconnection alarm of the α pulse coder.
Turn off the power to the CNC, then remove and insert the pulse coder cable. If this alarm is issued again, replace the pulse coder.
456 ILLEGAL CURRENT LOOP The current control cycle settings (parameter No. 2004, bit 0 of parameter
No. 2003, and bit 0 of parameter No. 2013) are incorrect.
Possible problems are as follows.
– For the two axes whose servo axis numbers (settings of parameter
No. 1023) are an odd number followed by an even number (a
pair of axes 1 and 2 or axes 5 and 6, for example), a different
current control cycle is set for each of the axes.
– The requirements for slaves needed for the set current control
cycle, including the number, type, and connection method of
them, are not satisfied.
457 ILLEGAL HI HRV (250US) Use of high–speed HRV is specified although the current control
cycle is 200 μs.
458 CURRENT LOOP ERROR The current control cycle setting does not match the actual current
control cycle.
459 HI HRV SETTING ERROR Of two axes having adjacent servo axis numbers (parameter No.
1023), odd number and even number, high–speed HRV control can
be performed for one axis and not for the other.
460 n AXIS : FSSB DISCONNECT FSSB communication was disconnected suddenly. The possible
causes are as follows:
1) The FSSB communication cable was disconnected or broken.
2) The power to the amplifier was turned off suddenly.
3) A low–voltage alarm was issued by the amplifier.
461 n AXIS : ILLEGAL AMP INTERFACE The axes of the 2–axis amplifier were assigned to the fast type interface.
462 n AXIS : SEND CNC DATA FAILED Because of an FSSB communication error, a slave could not receive
correct data.
463 n AXIS : SEND SLAVE DATA FAILED Because of an FSSB communication error, a slave could not receive
correct data.
464 n AXIS : WRITE ID DATA FAILED An attempt was made to write maintenance information on the amplifier maintenance screen, but it failed.
465 n AXIS : READ ID DATA FAILED At power–up, amplifier initial ID information could not be read.
466 n AXIS : MOTOR/AMP COMBINATION The maximum current rating for the amplifier does not match that for
the motor.
467 n AXIS : ILLEGAL SETTING OF AXIS The servo function for the following has not been enabled when an
axis occupying a single DSP (corresponding to two ordinary axes) is
specified on the axis setting screen.
1. Learning control (bit 5 of parameter No. 2008 = 1)
2. High–speed current loop (bit 0 of parameter No. 2004 = 1)
3. High–speed interface axis (bit 4 of parameter No. 2005 = 1)
468 HI HRV SETTING ERROR(AMP) Use of high–speed HRV is specified for a controlled axis of an amplifier
which does not support high–speed HRV.

Fanuc Servo Amplifier 600 Alarms

Alarm Code Message Description
600 n AXIS: INV. DC LINK OVER CURRENT DC link current is too large.
601 n AXIS: INV. RADIATOR FAN FAILURE The external dissipator cooling fan failed.
602 n AXIS: INV. OVERHEAT The servo amplifier was overheated.
603 n AXIS: INV. IPM ALARM(OH) The IPM (intelligent power module) detected an overheat alarm.
604 n AXIS: AMP. COMMUNICATION
ERROR
Communication between the SVM and the PSM failed.
605 n AXIS: CNV. EX. DISCHARGE POWER PSMR: Regenerative power is too large.
606 n AXIS: CNV. RADIATOR FAN FAILURE PSM: The external dissipator cooling fan failed.
PSMR: The external dissipator cooling fan failed.
607 n AXIS: CNV. SINGLE PHASE FAILURE PSM: Input voltage is in the open–phase condition.
PSMR: Input voltage is in the open–phase condition.
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Did you know this?
Setting Zero Return on Fanuc machines or any CNC Machine can sometimes be difficult. Each builder has their own way to set zero return through their own side of the control.

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