Tag Archives: fanuc troubleshooting

FANUC Controls Alarms

FANUC CNC Troubleshooting – Frequently Asked Questions

MRO Electric stocks new and refurbished FANUC products, and also offers reliable FANUC repairs. Please call 800691-8511 or email sales@mroelectric.com for a quote.

What is the proper method to test a motor for a short?
The proper way to test a FANUC motor for a short is to first lock out the machine, remove the cable from the drive, and test all three motor phases to ground with a megohmmeter. This will test both the motor and the cable for problems.

Why am I getting errors when I connect to my FANUC drive’s RS-232 port?
There are a number of explanations for these errors. The RS-323 port is a high-fail component on a FANUC drive as it is very susceptible to electrical surges. However, the RS-232 cable is also another high-fail item. Ensure that you are using a cable that is known to be functional when communicating. Otherwise when you attempt to read-in or punch-out a cable, you will get an 086 alarm that is going to indicate that the cable is incorrect, or that the port has failed.

To test whether the cable or the port has failed, take a known good cable and insert it into the RS-232 port. Next, set your machine up to receive a file. The screen should being to flash “READ”. Next, transmit your file into the machine tool. If the machine continues to flash “READ” (or “LSK” on modern controls) but never receives the file, you have a defective communications port on either the memory board or the master board. These boards or your machine will need to be sent in for repair.

What is an Axis Communications Error?
An Axis Communications Error indicates a communications problem between the motor encoder and the CNC control. This can be caused by the motor encoder itself,  the cable going to the encoder, or the axis control card the cable is plugged into.

What is an Excess Error Alarm and why is it caused?
Generally, an Excess Error means that the machine has moved beyond its allowable tolerance. The CNC has told the servo drive to make a move, the servo drive moves the motor,  which in turn moves the encoder. As the machine moves, there will be some deviation. This deviation is known as the Excess. The parameters set how much deviation/excess should be allowed.

These errors can be caused by a variety of problems. For example, a dull tool can caused the axis to be pushed out of position which results in a deviation error. Debris build up can cause deviations while the machine is stopped. Additionally, a failed servo drive can also cause deviation errors.

What is FANUC Alarm 401?
Alarm 401 is a very generic alarm. It simply means that the servo’s did not obey. The CNC, which is in charge of the servos, tells the servo drives to turn on and remain on. If for whatever reason the servo drive turns itself off without the permission from the CNC, the CNC will generate a 401 alarm. This alarm will usually occur with other alarms, such as the 414 Alarm.

What is FANUC Alarm 414?
The 414 Alarm is an alarm issued by the CNC that says a problem has been found in either the servo drive or the feedback system. The alarm will show which axis is causing the problem. To identify the specifics of this alarm, you must go into the CNC diagnostics page. Diagnostics number 200 on the 16th row will indicate what is causing the problem.

What is the difference between a High-Current Alarm and an Over-Current alarm?
A high current is an abnormal current that can be caused by noise. When the system detects this, it will generally shut the machine down and generate a High-Current Alarm. This alarm is usually caused by defective servo drive or cooling contamination inside of the motor windings or cable.

An Over-Current Alarm indicates that too much current has flowed through the DC link. This is usually caused by a short in the system, an unplanned contact, a defective transistor module, or dull tooling attempting to make a cut. 

Why do I get a Soft Overtravel Alarm when I try to reference a newly installed motor?
When the CNC power down, it remembers its last known position. When you restart the machine, an incremental encoder will ask that the machine be re-positioned. When you try to do a re-reference of the machine tool, and it doesn’t agree with where the last known position was, the machine with automatically go into a default that indicates a Soft Overtravel Alarm. These alarms can occur as any point in the travel of the machine. To bypass this alarm, power the machine down and hold down the key with the letter “P” on it as well as the “Cancel” button (at the same time). Then power the machine up while you continue to hold down both of these buttons. If you do this, the machine will ignore all Soft Overtravels until the first zero referenced position has been done on that axis, and will clear the Soft Overtravel Alarms.

I unplugged my AC or DC FANUC motors, and now I am getting a 300APC Alarm. What is that?
A 300APC Alarm indicates that you are using an absolute pulse coder. The difference between an absolute pulse coder and a incremental pulse coder deals in the memory retention of the position. Using a CNC control with an incremental pulse coder, you must reference the machine every time you turn the machine back on.

With an absolute pulse coder, there is a battery backed memory that retains the position of the machine tool when it powers down. When the CNC machine turns back on, it asks the encoder its position, and the encoder then responds back with its current position. If it is within tolerance of where it was when it shut down, the CNC will continue to run the program. However, if you lose the memory retention due to an encoder cable being unplugged, you will end up with the 300 level APC alarms. These alarms simply signify that the machine must be re-referenced. The re-referencing procedure is determined by the machine tool builder – consult your machine tool builder manual for the proper operation.

Fanuc Spindle Amp Alarm Codes for Alpha Series

fanuc spindle amp

Fanuc Spindle Amp Alarm Codes for Alpha Series

Fanuc Spindle Amp Alarm codes for amplifiers that start with part number A06B-6088, A06B-6102, and A06B-6078.

“A” Program Rom abnormality (Not Installed)

AL-01 Motor Overheat

AL-02 Excessive speed deviation

AL-03 DC Link fuse blown

AL-04 Input fuse blown

AL-05 Control power supply

AL-06 Over Speed

AL-07 Excessive Speed

AL-08 High Input Voltage

AL-09 Excessive load on main circuit section

AL-10 Low input voltage

AL-11 Over-voltage in DC link section

AL-12 Over-current in DC link section

AL-13 CPU Internal data memory abnormality

AL-15 Spindle switch/output switch alarm

AL-16 RAM Abnormality

AL-18 Program ROM checksum error

AL-19 Excessive U phase current detection circuit offset

AL-20 Excessive V phase current detection circuit offset

AL-24 Serial transfer data error

AL-25 Serial transfer data stopped

MRO Electric and Supply maintains a comprehensive stock of new and used FANUC CNC parts including FANUC Spindle Amps. If you need a replacement part, please call 800-691-8511 or email sales@mroelectric.com.

AL-26 Disconnection of speed detection signal for C’s contouring control

AL-27 Position coder signal disconnection

AL-28 Disconnection of position detection signals for C’s contouring control

AL-29 Short-time overload

AL-30 Input circuit over current

AL-31 Speed detection signal disconnection motor restraint alarm

AL-32 Abnormality in RAM internal to LSI for serial data transfer

AL-33 Insufficient DC link section charging

AL-34 Parameter data setting beyond allowable range of values

AL-35 Excessive gear ratio data setting

AL-36 Error counter overflow

AL-37 Speed detector parameter setting error

AL-39 Alarm for indicating failure in detecting 1-rotation signal for C’s contouring control

AL-40 Alarm for indicating 1-rotation signal for C’s contouring control not detected

AL-41 Alarm for indicating failure in detecting position coder 1-rotation signal

AL-42 Alarm for indication position coder 1-rotation not detected

AL-43 Alarm for indicating disconnection of position coder signal for differential speed mode

AL-46 Alarm for indicating failure in detecting position coder 1 rotation signal in thread cutting operation

AL-47 Position coder signal abnormality

AL-48 Position coder 1-rotation signal abnormality

AL-49 The converted differential speed is too high

AL-50 Excessive speed command calculation value in spindle synchronization control

AL-51 Under voltage at DC link section

AL-52 ITP signal abnormality 1

AL-53 ITP signal abnormality 2

AL-54 Overload current alarm

AL-55 Power line abnormality in spindle switching/output switching

AL-56 Cooling fan error.

Fanuc Spindle Alarms for Troubleshooting

A06B-6079-H106

Alarm # Led Display Content of FANUC SPINDLE Alarms
8 4 2 1

1

o

Motor Overheat

2

o

Speed deviates from commanded speed

3

o

o

Regenerative fault

6

o

o

Excess Motor Speed Analog

7

o

o

o

Excess Motor Speed Digital

8

o

Voltage higher than specified

9

o

o

Radiator for power semiconductor overheat

10

o

o

+15Volt Supply is low

11

o

o

o

DC Link voltage is high

12

o

o

DC Link current is high

13

o

o

o

CPU and peripheral parts are defective

14

o

o

o

ROM is defective

Alarm List for A06B-6044-Hxxx

Alarm List for the following Drives:

Alarm # Led Display Content of Alarms
8 4 2 1

1

o

Motor Overheat

2

o

Speed deviates from commanded speed

3

o

o

Fuse F7in DC link is blown out.

4

o

Fuses F1,F2,F3 for AC input blown out.

5

o

o

Fuses AF2 or AF3 on PCB are blown out.

6

o

o

Excess Motor Speed Analog

7

o

o

o

Excess Motor Speed Digital

8

o

Voltage higher than specified (24v)

9

o

o

Radiator for power semiconductor overheat

10

o

o

+15Volt Supply is low

11

o

o

o

DC Link voltage is high

12

o

o

DC Link current is high

13

o

o

o

CPU and peripheral parts are defective

14

o

o

o

ROM is defective

15

o

o

o

o

Option circuit fault.

Digital AC Spindle Drive

Alarm List for A06B-6055-Hxxx

Alarm List for the following drives:

  • Model 3 thru 22    A06B-6055-Hxxx

 

Alarm Display Alarm Content

AL-01

Motor Overheated

AL-02

Speed deviates from commanded speed

AL-03

Fuse F7in DC link is blown out.

AL-04

Fuses F1,F2,F3 for AC input blown out.

AL-06

Excess Motor Speed Analog

AL-07

Excess Motor Speed Digital

AL-08

Voltage higher than specified (24v)

AL-09

Radiator for power semiconductor overheat

AL-10

+15v power supply is abnormally low

AL-11

DC Link voltage is high

AL-12

DC Link current is high

AL-13

Data memory for CPU abnormal

AL-16

RAM in NVRAM is abnormal

AL-17

ROM in NVRAM is abnormal

AL-18

Check sum alarm of ROM

AL-19

Excessive alarm of U phase current detection circuit offset

AL-20

Excessive alarm of V phase current detection circuit offset

AL-21

Excessive alarm of velocity command circuit offset.

AL-22

Excessive alarm of velocity detection circuit offset.

AL-23

Excessive alarm of ER circuit offset.

AL-14

ROM is abnormal

AL-15

Spindle selection control circuit is abnormal.

Alarm List for A06B-6059-Hxxx

Alarm List for the following drives:

  • Model 1S thru 3S   A06B-6059-Hxxx

 View Fanuc Spindle Amp Alarm Codes for Alpha Series here. 

Alarm # Meaning

AL-01

Motor Overheat

AL-02

Speed deviates from commanded speed

AL-03

24v Fuse is blown. (before PCB edition 09A)

AL-04

AL-05

AL-06

Excess Motor Speed Analog

AL-07

Excess Motor Speed Digital

AL-08

Over voltage

AL-09

Overheat of radiator

AL-10

Low voltage of input power.

AL-11

Excessive high voltage of DC link

AL-12

Abnormal current of DC link

AL-13-15

AL-16-23

Defective arithmetic circuit and peripheral circuit

No indication

Defective ROM

Alarm List for A06B-6059-Hxxx

Alarm List for the following drives:

  • Model 6S-26S    A06B-6059-Hxxx
Alarm # Meaning

AL-01

Motor Overheat

AL-02

Speed deviates from commanded speed

AL-03

24v Fuse is blown. (before PCB edition 09A)

AL-04

Open phase of input power.

AL-05

AL-06

Excess Motor Speed Analog

AL-07

Excess Motor Speed Digital

AL-08

Over voltage

AL-09

Overheat of radiator

AL-10

Low voltage of input power.

AL-11

Excessive high voltage of DC link

AL-12

Abnormal current of DC link

AL-13

Defective arithmetic circuit

AL-14

Defective ROM

AL-15

Defective optional circuit.

AL-16-23

Defective arithmetic circuit and peripheral circuit

No indication

Defective ROM

Rebuild a Fanuc Motor – Model A06B-0131-B075 Process

Gallery of pictures showing the process that it takes to rebuild a Fanuc motor, part number A06B-0128-B675#7008.

Original pictures of the motor. Fan is dirty, all sides show significant use.

fanuc motor repair
fanuc motor repair

Upon disassembling the FANUC servo motor, the residue was found in the stator prompting the removal of the motor shaft. This would have caused a short in the stator once running.

The finished product, after the motor is rebuilt and fully tested.

rebuild a fanuc motor
fanuc servo motor repair
MRO Electric stocks new and refurbished FANUC CNC Motors. We also provide pre-priced Control Techniques repairs. For more information or to request a quote, please call 800-691-8511 or email sales@mroelectric.com.