OI Roundtable

Fanuc Series -0 Alarms and Troubleshooting

Here is some good info from the Fanuc service manual, hopefully helps you guys out. Following is a list of alarms on applicable Fanuc Series:

FANUC Series 0- TC, 0- TC, FANUC Series 0- MC, 0- MC, FANUC Series 0- TF, 0- TF, FANUC Series 0- MF, 0- MF, Series 0- C, FANUC Series 0- TTC, 0- TTC, FANUC Series 0- GCC, 0- GCC, FANUC Series 0- GSC, 0- GSC, FANUC Series 0- TD, 0- TD Series 0, FANUC Series 0- MD, 0- MD, Series 0- D, FANUC Series 0- GCD, 0- GCD, Series 0- D, FANUC Series 0- GSD, 0- GSD, Series 0- D, FANUC Series 0- TD II, 0- TD II, Series 0- D, FANUC Series 0- MD II, 0- MD II, Series 0- D II, FANUC Series 0- GCD II, 0- GCD II, Series 0- D II, FANUC Series 0- GSD II, 0- GSD II, FANUC Series 00- TC 00- TC, FANUC Series 00- MC, 00- MC Series 00- C, Series 00, FANUC Series 00- GCC, 00- GCC, FANUC Series 0- Mate TC, 0- Mate TC, FANUC Series 0- Mate, MC 0- Mate, MC Series 0- Mate, C Series 0- Mate, FANUC Series 0- Mate, MF 0- Mate MF

• POWER CANNOT BE SWITCHED ON - Check the LED on the input unit or power supply unit AI, If no power supply alarm is detected (the red "ALM" LED does not light, Check the input fuse of the input unit or power supply unit AI.
  
  Measure the voltage across the R and S terminals on the screw-on terminal strip of the input unit or at the connector CP1 of the power supply unit AI using a volt-ohm-milliammeter, and check whether 200 VAC is available. If the 200 VAC cannot be detected at connector CP1, check the corresponding circuit in the machine.
  
  If both the fuse and power supply voltage are normal, the printed--circuit board of the input unit or the power supply unit AI may be defective.
• NO MANUAL OPERATION NOR AUTOMATIC OPERATION CAN BE EXECUTED - Execute the following procedure when no manual nor automatic operation is done: Check whether position display shows correct position, Check CNC status display, Check CNC internal status using diagnostic function
• JOG OPERATION CANNOT BE DONE - Check whether position display is operating, Check CNC status display, Check internal status using Diagnostic funciton.
• HANDLE OPERATION CANNOT BE DONE - Check another manual operation (JOG) is accepted, Check CNC status display.
• AUTOMATIC OPERATION CANNOT BE DONE - Check manual operation is possible, Check the status of cycle start LED on machine operator's manual, Check status of CNC.
  
  When manual operation is either impossible, perform countermeasure, based on the previous item "Jog operation cannot be done". Confirm that a correct mode isselected according to the mode selectstatus of CNC status display. Also, by confirming the automatic operation status it is possible to identify cycle operation, feed hold and cycle stop state
• CYCLE START LED SIGNAL HAS TURNED OFF - After cycle operation is started, then stopped, check as follows: Confirm cycle start LED on machine operator's panel, Confirm CNC's diagnostic function.
• NO DISPLAY APPEARS ON THE SCREEN WHEN THE POWER IS SWITCHED ON
• ALARM 85 (READER/PUNCHER INTERFACE ALARM) Parameters on reader/puncher interface are not correct. Check the following setting data and parameters. External I/O device or host computer is faulty. I/O board is faulty. Cable between NC and I/O device is faulty. Parameters on reader/puncher interface are not correct, Check the appropriate setting data and parameters.
• ALARM 86 (READER/PUNCHER INTERFACE ALARM) Parameters on reader/puncher interface are not correct. Check the following setting data and parameters. External I/O device or host computer is faulty. I/O board is faulty. Cable between NC and I/O device is faulty. Parameters on reader/puncher interface are not correct, Check the appropriate setting data and parameters.
• ALARM 87 (READER/PUNCHER INTERFACE ALARM) Parameters on reader/puncher interface are not correct. Check the following setting data and parameters. External I/O device or host computer is faulty. I/O board is faulty. Cable between NC and I/O device is faulty. Parameters on reader/puncher interface are not correct, Check the appropriate setting data and parameters.
• REFERENCE POSITION DEVIATES
• ALARM 90 (REFERENCE POSITION RETURN IS ABNORMAL) The CNC received one rotation signal at least one time when the axis is moving to the reference position at a speed higher than a speed equivalent
  to 128 pulses of position error amount(DGN800 to 807), note: When a pulse coder is used as the detection of the absolute position, the reference point can be established after the motor turns more than one rotation with the battery connected.
• ALARM 3n0 (REQUEST FOR REFERENCE POSITION RETURN) Absolute position data in the serial pulse coder was lost. (This alarm will be generated when serial pulse coder is exchanged or position feedback signal cable of the serial pulse coder is disconnected)
• ALARM 3n1 (ABSOLUTE PULSE CODER IS FAULTY) Absolute pulse coder, cable or servo module is faulty. Jiggle the feedback cable leading from the servomotor to the axis card. Note whether an alarm occurs. If an alarm occurs, replace the cable or replace the axis cable.
• ALARM 3n2 (ABSOLUTE PULSE CODER IS FAULTY) Absolute pulse coder, cable or servo module is faulty. Jiggle the feedback cable leading from the servomotor to the axis card. Note whether an alarm occurs. If an alarm occurs, replace the cable or replace the axis cable.
• ALARM 3n3 (ABSOLUTE PULSE CODER IS FAULTY) Absolute pulse coder, cable or servo module is faulty. Jiggle the feedback cable leading from the servomotor to the axis card. Note whether an alarm occurs. If an alarm occurs, replace the cable or replace the axis cable.
• ALARM 3n4 (ABSOLUTE PULSE CODER IS FAULTY) Absolute pulse coder, cable or servo module is faulty. Jiggle the feedback cable leading from the servomotor to the axis card. Note whether an alarm occurs. If an alarm occurs, replace the cable or replace the axis cable.
• ALARM 3n5 (ABSOLUTE PULSE CODER IS FAULTY) Absolute pulse coder, cable or servo module is faulty. Jiggle the feedback cable leading from the servomotor to the axis card. Note whether an alarm occurs. If an alarm occurs, replace the cable or replace the axis cable.
• ALARM 3N6 (ABSOLUTE PULSE CODER IS FAULTY) Absolute pulse coder, cable or servo module is faulty. Jiggle the feedback cable leading from the servomotor to the axis card. Note whether an alarm occurs. If an alarm occurs, replace the cable or replace the axis cable.
• ALARM 3n7 (ABSOLUTE PULSE CODER BATTERY IS LOW) This alarm is generated when absolute pulse coder battery becomes low. Replace the batteries in the battery box connected to the connector of axis
  cards (CPA9 for the 1st to 4th axis cards, CPA10 for the 5th/6th axis card, and CPA11 for the 7th/8th axis card) When a type B axis board is being used with a built-in absolute pulse coder and an "a" or "b" series amplifier, the battery is installed in the servo amplifier. In such a case, replace the battery as described in the appropriate manual supplied with the servo amplifier.
• ALARM 3n8 (ABSOLUTE PULSE CODER BATTERY IS LOW)  This alarm is generated when absolute pulse coder battery becomes low. Replace the batteries in the battery box connected to the connector of axis
  cards (CPA9 for the 1st to 4th axis cards, CPA10 for the 5th/6th axis card, and CPA11 for the 7th/8th axis card) When a type B axis board is being used with a built-in absolute pulse coder and an "a" or "b" series amplifier, the battery is installed in the servo amplifier. In such a case, replace the battery as described in the appropriate manual supplied with the servo amplifier.
• ALARM 3n9 (SERIAL PULSE CODER IS ABNORMAL) An error is generated in the control section of the serial pulse coder
• ALARM 400 (OVERLOAD) Amplifier or overheat of motor is detected. Confirm the detail by the diagnostic function of CNC.
• ALARM 401 (*DRDY SIGNAL TURNED OFF) Servo amplifier is not turned on or it turned off during operation.
• ALARM 402 (OVERLOAD)  Amplifier or overheat of motor is detected. Confirm the detail by the diagnostic function of CNC.
• ALARM 403 (*DRDY SIGNAL TURNED OFF) Servo amplifier is not turned on or it turned off during operation.
• ALARM 404 (*DRDY SIGNAL TURNED ON) DRDY signal is turned on before MCON signal is turned on. Or DRDY is not turned off after MCON signal is turned off. Possible servo amplifier is faulty, between servo amplifier and axis card is faulty, axis card is faulty.
• ALARM 405 (*DRDY SIGNAL TURNED ON) DRDY signal is turned on before MCON signal is turned on. Or DRDY is not turned off after MCON signal is turned off. Possible servo amplifier is faulty, between servo amplifier and axis card is faulty, axis card is faulty.
• ALARM 406 (OVERLOAD)  Amplifier or overheat of motor is detected. Confirm the detail by the diagnostic function of CNC.
• ALARM 490 (OVERLOAD)  Amplifier or overheat of motor is detected. Confirm the detail by the diagnostic function of CNC.
• ALARM 491 (*DRDY SIGNAL TURNED OFF) Servo amplifier is not turned on or it turned off during operation.
• ALARM 4n0 (EXCESSIVE POSITION ERROR AMOUNT DURING STOP)
• ALARM 4n1 (EXCESSIVE POSITION ERROR DURING MOVE) Position error amount during movement (DGN 800 to 807) execeeds a value set by parameter 504 to 507, 639, 640, 7504, 7505.
• ALARM 4n4 (DIGITAL SERVO SYSTEM IS ABNORMAL)
• ALARM 4n6 (DISCONNECTION ALARM) Position detection signal line is disconnected or short-circuited.
• ALARM 4n7 (DIGITAL SERVO SYSTEM IS ABNORMAL) Digital servo parameters are abnormal or are set incorrectly. Confirm the setting value of the following parameters: PRM 8n20 : Motor format number PRM 8n22 : Motor rotation direction PRM 8n23 : Number of pulses of velocity feedback PRM 8n24 : Number of pulses of position feedback PRM 0269 to 0274 : Servo axis number PRM 8n84 : Flexible feed gear ratio PRM 8n85 : Flexible feed gear ratio
• ALARM 700 (OVERHEAT AT CONTROL SIDE) Because an ambient temperature of the control unit becomes high, a thermostat mounted on the back panel of NC functions and informs an alarm
• ALARM 704 (SPINDLE SPEED FLUCTUATION DETECTION ALARM) This alarm indicates that the spindle speed has changed abnormally due to the load.
• ALARM 408 (THE SPINDLE SERIAL LINK DOES NOT START NORMALLY.) : Indicates that, in a system using serial spindles, the spindle amplifier does not start normally when power is applied. This alarm will not occur once the system (including the spindle control unit) has started. It can occur before the system starts during power turn-on processing. Once the system has started, an error is indicated as system alarm 945.
• ALARM 409 (SPINDLE ALARM) This alarm indicates, to the CNC, that in a system with serial spindles, an alarm has occurred in the spindle unit. The alarm is described using the AL-XX (where XX is a number) format Indicated on the spindle amplifier display. Setting bit 7 of parameter No. 0397 to 1 enables the display of the alarm number from the spindle on the alarm screen. This alarm is intended to indicate a failure in the spindle control unit. It is detailed below. The spindle should be repaired according to the procedure described for each alarm.
• ALARM 998 (ROM PARITY ERROR) A ROM parity error has occurred.
• ALARM 910 (RAM PARITY ERRORS) These alarms indicate RAM parity errors. RAM is provided with a check bit (parity bit). When data is written to RAM, the check bit is also written to the RAM by either setting it to 1 or resetting it to 0 so that the total number of 1 bits in the data, including the check bit, is even or odd. When the data is read from RAM, the check bit is used to ensure that the read data is correct.
• ALARM 911 (RAM PARITY ERRORS)
• ALARM 912 (RAM PARITY ERRORS)
• ALARM 913 (RAM PARITY ERRORS)
• ALARM 914 (RAM PARITY ERRORS)
• ALARM 915 (RAM PARITY ERRORS)
• ALARM 916 (RAM PARITY ERRORS)
• ALARM 920 (WATCH DOG OR RAM PARITY) The timer used to monitor the operation of CPU is called the watch dog timer. The CPU resets timer time every time a constant time has passed. When an error occurs in CPU or peripheral device, timer is not reset but the alarm is informed.
• ALARM 921 (WATCH DOG OR RAM PARITY) The timer used to monitor the operation of CPU is called the watch dog timer. The CPU resets timer time every time a constant time has passed. When an error occurs in CPU or peripheral device, timer is not reset but the alarm is informed.
• ALARM 922 (WATCH DOG OR RAM PARITY) The timer used to monitor the operation of CPU is called the watch dog timer. The CPU resets timer time every time a constant time has passed. When an error occurs in CPU or peripheral device, timer is not reset but the alarm is informed.
• ALARM 941 (INCORRECTLY INSTALLED MEMORY PRINTED--CIRCUIT BOARD) This alarm indicates the poor connection of a memory printed circuit board. Check that all connections are secure.
• ALARM 930 (CPU ERROR) CPU error (abnormal interrupt) has generated. Main CPU board is faulty An interrupt which will not occur during usual operation has generated. Peripheral circuit of the CPU may be abnormal. Change the main CPU board. If operation is performed normally by power off and on, noise may be a cause.
• ALARM 945 (SERIAL SPINDLE COMMUNICATION ERRORS)
• ALARM 946 (SERIAL SPINDLE COMMUNICATION ERRORS)
• ALARM 960 (SUB CPU ERROR) Sub-CPU printed circuit board defective. An interrupt that would not occur under a usual condition occurred. It is likely that a CPU peripheral circuit malfunctioned. Replace the sub-CPU printed circuit board. If a normal operation can be resumed by turning the power off and on again, the malfunction may have occurred due to noise
• ALARM 950 (BLOWN FUSE) The +24E fuse has blown. An overcurrent has flowed through the +24E line, which is a 24V line used for the I/O printed circuit board and machine power magnetics circuit. There may be a short circuit between the 24V line and 0V in the machine or I/O cable. After removing the cause, replace fuse in the power supply unit.

Thank you! Had ALARM 400 (OVERLOAD), simple problem and simple solution, turned out to be mechanical bind holding it back. Hint, keep your machines clean!

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