Diagnose a FANUC High Current Alarm in 10-Steps

What is a FANUC 414 Servo Alarm?

A FANUC 414 servo alarm is generated by the CNC when it detects that an amplifier has a high current alarm 8, 9, or A. To determine the exact cause, you must go through the process of elimination. The high current alarm may be caused by the servo drives, amplifiers, modules, motor and/or cables.

In some instances, this alarm may indicate a short to ground. The short is causing too much current to flow through the power module inside the amplifier and will eventually cause it to break.

Here is the FANUC 414 Servo Alarm message:

Alarm Code

Message

Description

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. Look at the servo amplifier for alarm code.

How to Diagnose a FANUC 414 Servo Alarm:

Step 1 - Access the electronics cabinet with the power on (WARNING: Hazardous voltage inside).

Step 2 - Look for the amplifier unit displaying either FANUC servo alarm 8, 9, or A on the seven segment display.

Step 3 - Alarm 8, 9, and A are all the same problem. However, the different alarms identify which amplifier axis the alarm exists on.

Code

Message

Description

Alarm 8

Abnormal current alarm (L axis)

Located below the logic board, Alarm 8 indicates an abnormal current in the first axis on the amplifier which is labeled (L).

Alarm 9

Abnormal current alarm (M axis)

Located below the logic board, Alarm 9 indicates an abnormal current in the second axis on the amplifier which is labeled (M).

Alarm A

Abnormal current alarm (N axis)

Located below the logic board, Alarm A indicates an abnormal current in the third axis on the amplifier which is labeled (A). If your amplifier only controls two axes, your CNC should never display an Alarm Code A.

Step 4 - Turn on the main breaker of the machine and leave the CNC off.

a. If FANUC servo alarm 8, 9, or A appears when the CNC is off, disconnect the feedback connector to the amplifier axis indicated by the alarm and turn on the main breaker with the CNC off again.

i. If no alarm appears, there is an issue with the feedback cable or the pulse coder.

ii. If alarm 8, 9, or A appears with the feedback cable disconnected, the amplifier is most likely faulty and needs to be replaced.

b. If the alarm ONLY appears when the CNC is turned on, you need to troubleshoot the drive, motor, and power cable.

Step 5 - Disconnect the four motor leads from the bottom of the amplifier.

Step 6 - Turn on the CNC and release any emergency stop condition (if you’re removing the motor power with a vertical axis, physically prop up the axis or else it will fall when the emergency stop and servo motor brakes are released).

Step 7 - If an alarm 8, 9, or A still appears, the drive is probably faulty and needs to be replaced.

Step 8 - If an alarm doesn’t appear, the motor and/or power cable may be faulty and needs to be diagnosed.

Step 9 - With an ohm meter, check for shorts in the motor by measuring leg-to-leg and leg-to-ground on all three legs. An ohmmeter will tell you if your motor is shorted. Leg-to-leg readings should be low, but consistent, on all three legs. The leg-to-ground readings should be open (OL) on all three legs-to-ground.

Step 10 - With a megger, check each leg-to-ground. A megger will tell you if your motor is grounded. The reading should show infinity (or 500 MEG and above) at the 1000V setting. Check all three legs-to-ground because the problem can be in the power plug/terminal box of the motor or the power cables going from the drive to the motor.

FANUC Units We Service

If your CNC displays a FANUC high current alarm, Alarm 414, or Servo Alarm 8, 9, or A, Tennessee Industrial Electronics, LLC offers free tech support to help you diagnose the problem. TIE can also deliver fast, reliable repair services for your faulty servo amplifier, motor, drive, cable, or you can purchase a newly refurbished unit.

TIE has more than 100,000 FANUC parts in stock ready for same day shipping including:

Please contact us or call (615) 471-9450 to learn more about FANUC high current alarm. Alarm 414 and FANUC Servo Alarm 8, 9, and A.

Get your machine back up and running. TIE offers same day shipping on more than 100,000 FANUC parts in stock. We offer a 1 year in service warranty on all parts and repairs.

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Tennessee Industrial Electronics, LLC, Electronic Equipment & Supplies Wholesale & Manufacturers, La Vergne, TN
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