Fanuc 16 and 18 Alarms and Error Codes

Fanuc 16 and 18 Alarms.

Please contact us if you need testing, a repair or an exchange part. Or if you need parts for your 16/18 control them visit our dedicated Fanuc Series 16 & 18 Page.

These alarm codes relate to Model A , B & C. 

(b) denotes model B additional alarms / (c) donotes model C additional alarms.

PMC Alarms

Alarm CodeDescription of Alarm/Fault
ALARM NOTHINGNormal Status
ER00 PROGRAM DATA ERROR (ROM)The sequence program in the ROM is not written correctly.
ER01 PROGRAM DATA ERROR (RAM)The sequence program in the debugging RAM is defective
ER02 PROGRAM SIZE OVERThe size of sequence program exceeds the maximum size of  LADDER (PMC-RC only)
ER03 PROGRAM SIZE ERROR (OPTION)The size of sequence program exceeds the option specification size.
ER04 PMC TYPE UNMATCHThe PMC model setting of the sequence program is not corresponding to an actual model.
ER05 PMC MODULE TYPE ERRORThe module type of the PMC engine is not correct.
ER06 PROGRAM MODULE NOTHINGBoth ROM for sequence program and the debugging RAM do not exist (PMC-RC only).
ER07 NO OPTION (LADDER STEP)There is no step number option of LADDER.
ER 16 RAM CHECK ERROR (PROGRAM RAM)The debugging RAM cannot be read/written normally.
ER17 PROGRAM PARITYThe parity error occured on the ROM for sequence program or the debugging RAM.
ER18 PROGRAM DATA ERROR BY I/OTransferring the sequence program from offline programmer was interrupted by the power off etc.
ER19 LADDER DATA ERROREditing the LADDER was interrupted by the power off or by the switch to the CNC screen by the function key etc.

Background Edit Alarm

Alarm CodeTypeDescription of Alarm/Fault
????BP/S alarmBP/S alarm occurs in the same number as the P/S alarm that occurs in ordinary program edit. ( 070, 071, 072, 073, 074, 085, 086, 087 etc)
140BP/S alarmIt was attempted to select or delete in the background of a program being selected in the foreground ( Note: Use background editing correctly)

Note: Alarm in background is displayed in the key input line of the background edit screen instead of the ordinary alarm screen and is resettable by any of the MDI key operation.

Absolute Pulse Coder (APC) Alarm

Alarm CodeTypeDescription of Alarm/Fault
300nth-axis origin returnManual reference position return is required for the nth axis (n=1-8)
301APM alarm: nth axis communicationnth axis (n=1-8) APC communications error. Failure in data transmission.
302APM alarm: nth axis over timenth axis (n=1-8) APC overtime error. Failure in data transmission.
303APM alarm: nth axis framingnth axis (n=1-8) APC framing error. Failure in data transmission.
304APM alarm: nth axis paritynth axis (n=1-8) APC parity error. Failure in data transmission.
305APM alarm:  nth axis pulse errornth axis (n=1-8) APC pulse error alarm. APC alarm.
306APM alarm: nth axis battery voltage 0nth axis (n=1-8) APC battery voltage has decreased to a low level so that the data cannot be held.
307APM alarm: nth axis battery low 1nth axis (n=1-8) APC battery voltage reaches a level where the battery must be renewed.
308APM alarm: ntha xis battery low 2nth axis (n=1-8) APC battery voltage has reached a level where the battery must be renewed. (including when the power is off).
309 (b) (c)
APC Alarm: n AXIS ZRN IMPOSSIBLReturn to the origin has been attempted without first rotating the motor one of more times. Before returning to the origin, rotate the motor one or more times then turn off the power.

Serial Pulse Coder (SPC) alarms

Alarm CodeTypeDescription of Alarm/Fault
350SPC ALARM: n AXIS PULSE CODERThe n axis ( axis 1-8) pulse coder has a fault.
351SPC ALARM: n AXIS COMMUNICATION n axis ( axis 1-8) serial pulse coder communciation error ( data transmission fault).

Servo Alarms

Alarm CodeTypeDescription of Alarm/Fault
400SERVO ALARM: n-TH AXIS OVERLOADThe n-th axis (axis 1-8) overload signal is on.
401SERVO ALARM: n-TH AXIS VRDYThe n-th xis (axis 1-8) servo amplifier READY signal (DRDY) went off.
404SERVO ALARM: n-TH VRDY ONEven 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.
405SERVO ALARM: ZERO POINT RETURN FAULTPosition control system fault. Due to an NC or servo system fault in the reference position return, there is the possiblity that the reference position return could not be executed correctly.
407SERVO ALARM: EXCESS ERRORThe difference in synchronous axis position deviation exceeded the set value.
409 (b) (c)
SERVO ALARM: n AXIS TORQUE ALARMAbnormal servo motor load has been detected. Alternatively, abnormal spindle motor load has been detected in Cs mode.
410SERVO ALARM: n-TH AXIS EXCESS ERRORThe position deviation value when the n-th axis( axis 1-8) stops is larger than the set value.
411SERVO ALARM: n-TH AXIS EXCESS ERRORThe position deviation value when the n-th axis( axis 1-8) moves is larger than the set value.
413SERVO ALARM: n-TH AXIS LSI OVERFLOWThe contents of the error register for the n-th axis ( axis 1-8) exceeded + or -2 31  power. This error usually occurs due to the result of incorrectly set parameters.
414SERVO ALARM: n-TH AXIS DETECTION RELATED ERRORN-th axis ( axis 1-8) digital servo system fault.
415SERVO ALARM: n-TH AXIS EXCESS SHIFTA 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 an improperly set CMR.
416SERVO ALARM: n-TH AXIS DISCONNECTIONPosition detection system fault in the n-th axis ( axis 1-8) pulse coder ( disconnection alarm).
417SERVO ALARM: n-TH AXIS PARAMETER INCORRECTThis 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 0r -111) is not set in parameter No 2022 (motor revolution direction).
  3. Illegal data ( a value below 0, etc) was set in parameter N0.2023 ( 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) contains a value out of the range from 1 to the number of axes, or an isolated value ( for example, 4 not preceeded by 3), was set in parameter No. 1023 ( servo axis number).
420 (b) (c)
SERVO ALARM: n AXIS SYNC TORQUE (M Series)During simple synchronous control, the difference between the torque commands for the master and slave axes exceded the value set in parameter No 2031.
421 (b) (c)
SERVO ALARM: n AXIS EXCESSER (D)The difference between the errors in the semi closed loop and closed loop has become excessive during dual positon feedback.

Over Travel Alarms

Alarm CodeTypeDescription of Alarm/Fault
500OVER TRAVEL:   +nExceeded the n-th axis ( axis 1-8) + side stored stroke limit I.
501OVER TRAVEL:     -n Exceeded the n-th axis ( axis 1-8) – side stored stroke limit I.
502OVER TRAVEL:    +n Exceeded the n-th axis ( axis 1-8) + side stored stroke limit II.
503OVER TRAVEL :    -n Exceeded the n-th axis ( axis 1-8) – side stored stroke limit II.
504OVER TRAVEL:     +n Exceeded the n-th axis ( axis 1-8) + side stored stroke limit III.
505OVER TRAVEL:     -n Exceeded the n-th axis ( axis 1-8) – side stored stroke limit III.
506OVER TRAVEL:     +n Exceeded the n-th axis ( axis 1-8) + side hardware OT.
507OVER TRAVEL:     -n Exceeded the n-th axis ( axis 1-8) – side hardware OT.
508INTERFERENCE : +n A tool moving in the positive direction along the n axis has fouled another tool post.
509INTERFERENCE:   -n A tool moving in the negative direction along the n axis has fouled another tool post.
510OVER TRAVEL:    +n Alarm for stroke check prior to movement. The end point specified in a block falls within the forbidden area defined with the stroke limit in the positive direction along the N axis. Correct the program.
511OVER TRAVEL:   -n Alarm for stroke check prior to movement. The end point specified in a block falls within the forbidden area defined with the stroke limit in the negative direction along the N axis. Correct the program.

Overheat Alarms

Alarm CodeTypeDescription of Alarm/Fault
700OVERHEAT: CONTROL UNITControl unit overheat
701OVERHEAT: FAN MOTORThe fan motor on top of the cabinet for the control unit is overheated.
704OVERHEAT: SPINDLESpindle overheat in the spindle fluctuation detection.

Rigid Tapping Alarms

740RIGID TAP ALARM: EXCESS ERRORThe positional deviation of the stopped spindle has exceeded the set value during rigid tapping.
741RIGID TAP ALARM: EXCESS ERRORThe positional deviation of the stopped spindle has exceeded the set value during rigid tapping.
742RIGID TAP ALARM: LSI OVERFLOWAn LSI overflow has occured for the spindle during rigid tapping.

Serial Spindle Alarms

Alarm CodeTypeDescription of Alarm/Fault
749 S-SPINDLE LSI ERROR It is serial communication error while system is executing after power supply on.
750SPINDLE SERIAL LINK START FAULT This alarm is generated when the spindle control unit is not ready for starting correctly when the power is turned on in the system with the serial spindle.
751FIRST SPINDLE ALARM DETECTION ( AL-XXX) This alarm indicates in the NC that an alarm is generated in the spindle unit of the system with serial spindle. The alarm is displayed in form AL-XX ( XX is a number).
752 FIRST SPINDLE MODE CHANGE This alarm is generated if the system does not properly terminate a mode change.
754SPINDLE 1 ABNORMAL TORQUE ALARM Abnormal first spindle motor load has been detected.
761SECOND SPINDLE ALARM DETECTION (AL-XXX) Refer to alarm No 751
762 SECOND SPINDLE MODE CHANGE FAULT Refer to alarm No 752
764 SPINDLE-2 ABNORMAL TORQUE ALARM Same as alarm No 754
771SPINDLE-3 ALARM DETECT (AL-XXX) Same as alarm No 751
772SPINDLE- 3 MODE CHANGE ERROR Same as alarm No 752
774SPINDLE 3- ABNORMAL TORQUE ALARM Same as alarm No 754

System Alarms ( These alarms cannot be reset with a reset key)

Alarm CodeTypeDescription of Alarm/Fault
900ROM PARITYROM parity error (CNC/OMM/Servo). Replace the number of ROM.
910ROM PARITY : (4N)RAM parity error in the tape memory RAM module. After this operation reset all the data including the parameters.
911ROM PARITY : (4N+1)RAM parity error in the tape memory RAM module.After this operation reset all the data including the parameters.
912ROM PARITY : (4N+2)RAM parity error in the tape memory RAM module. After this operation reset all the data including the parameters.
913ROM PARITY : (4N+3)RAM parity error in the tape memory RAM module. After this operation reset all the data including the parameters.
914 (b) (c)
SRAM PARITY: (2N)A RAM  parity error occured in RAM for part program storage or additional SRAM. Clear the memory, or replace the main CPU board or additional SRAM. Then set all data including  parameters again.
915 (b) (c)
SRAM PARITY: (2+1)A RAM  parity error occured in RAM for part program storage or additional SRAM. Clear the memory, or replace the main CPU board or additional SRAM. Then set all data including  parameters again.
916 (b) (c)
DRAM PARITYRAM parity error in DRAM module. Replace the DRAM module.
920SERVO ALARM (1/2 AXIS)Servo alarm (3rd or 4th axis). A wathdog alarm or RAM parity error in the servo module occured. Replace the servo control module on the main CPU board.
920 (b)
SERVO ALARM (1/2/3/4 AXIS)Servo alarm (1st to 4th axis). A wathdog alarm or RAM parity error in the servo module occured.
920 (c)SERVO ALARM (MAIN)Servo alarm (main CPU board). A watchdog alarm or a RAM parity error in the servo module occured. Replace the servo control module on the main CPU board.
921SERVO ALARM (3/4 AXIS)Servo alarm (3rd or 4th axis). A watchdog alarm or a RAM parity error in the servo module occured. Replace the servo control module on the main CPU board.
922SERVO ALARM (5/6 AXIS)Servo alarm (5th or 6th axis). A watchdog alarm or a RAM parity error in the servo module occured. Replace the servo control module on the option 2 board.
922 (b)SERVO ALARM (5/6/7/8 AXIS)Servo alarm (5th to  8th axis). A watchdog aalrm or a RAM parity error in the servo module occured.
922 (c)SERVO ALARM (OPT2)Servo alarm (option 2 board). A watchdog alarm or a RAM parity error in the servo module occured. Replace the servo control module on the option 2 board.
923SERVO ALARM (7/8 AXIS)Servo alarm (7th or 8th axis). A watchdog alarm or a RAM parity error in the servo module occured. Replace the servo control module on the option 2 board.
924SERVO MODULE SETTING ERRORThe digital servo module is not installed. Check that the serbo module or servo interface module on the main CPU or option 2 board is mounted securely.
926 (b)
SERVO ALARM (1/2/3/4/5/6/ AXIS)Servo alarm ( 1st to 6th axis). A watchdog alarm was issued, or a RAM parity error occured in the servo module.
930CPU INTERRUPTCPU error ( abnormal interrupt). The main CPC board is faulty.
945SERIAL SPINDLE COMMUNICATION ERRORCommunications error occured in the serial spindle. The optical fiber maybe be disconnected.
950PMC SYSTEM ALARMFault occured in the PMC. The PMC control module on the main CPU board or option 3 board may be faulty.
951PMC-RT WATCH DOG ALARMFault occured in the PMC-RC ( watchdog alarm). Option 3 board may be faulty.
970NMI OCCURED IN BOCRAM parity error or NMI occured in the RMC-RB or PMC-RA2 module.
971NMI OCCURED IN SLCAn alarm condition occured in the interface with an I/O unit. For PMC-RA1, PMC-RA2 and PMC-RB check that the PMC control module on the main CPU board is connected to the I/O unit securely. For PMC-RC, check that the PMC control module on the option 3 board is connected to the I/O unit is supplied with power and that the interface module is intact.
972NMI OCCURED IN OTHER MODULENMI occured in a  board other than the main CPU board.
973NON MASK INTERRUPTNMI occured for an unknown reason.
974 (b) (c)
F-BUS ERRORFANUC BUS is error.
975 (b) (c)
BUS ERROR (MAIN)MAIN CPU board is BUS error.