FANUC CNC systems are widely used in industrial automation, and alarms are an important part of system protection and diagnostics. Understanding the causes and solutions of common alarms can significantly reduce machine downtime and maintenance costs.
This guide covers frequently encountered FANUC alarms, including external alarms, servo alarms, pneumatic system issues, and maintenance-related questions.
1. What is FANUC Alarm 2003?
Cause
Alarm 2003 is typically an external alarm, often displayed as EX2003, followed by a detailed message defined by the machine tool builder.
For example:
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Insufficient lubrication
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Low pressure conditions
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External system faults
Solution
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Check the detailed alarm message following EX2003
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Refer to the machine builder’s documentation
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Contact the machine manufacturer for further clarification
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Inspect related systems such as lubrication or pneumatic units
2. How to Troubleshoot Low Air Pressure Alarm in 5-Axis CNC Machines?
Cause
Low air pressure alarms belong to machine builder-defined external alarms.
Troubleshooting Steps
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Check air supply source for stability
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Verify pressure gauge readings
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Inspect pneumatic circuits and valves
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Review electrical and pneumatic schematics
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Check ladder logic outputs (e.g., A-address signals)
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Confirm pressure switch signal status (should be ON when normal)
3. How to Fix FANUC Alarm 414?
Applicable Systems
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Series 16 / 18 / 21
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Series 0 / 0i-MA
Cause
Alarm 414 is a servo-related alarm, often linked to overcurrent or abnormal load.
Troubleshooting Steps
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Check servo amplifier display (e.g., codes 8, 9)
-
Inspect diagnostic parameters:
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DGN206
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DGN720–723 (Series 0)
-
-
Identify abnormal bits (value = 1)
Example:
-
DGN720#5 = OVC (Overcurrent)
Solutions
-
Check mechanical load
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Verify input voltage
-
Inspect motor power cables
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Test motor insulation
-
Replace faulty components if needed
4. How to Solve SV456 Alarm?
Cause
SV456 is usually related to HRV (High Response Vector) control mismatch or parameter errors.
Troubleshooting Steps
-
Check if HRV3 and HRV4 are set simultaneously
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Confirm system supports high-speed HRV
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Verify compatibility between:
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HRV settings
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Servo amplifier model (SVM)
-
-
Check parameter settings:
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P2004
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2013.0
-
2014.0
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2422.4
-
2590 / 2591
-
Additional Checks
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Servo motor code mismatch
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Amplifier version issues
-
Replace incorrect hardware
-
Initialize servo parameters if necessary
5. FANUC Fan Maintenance Guide
Maintenance Tips
Regular maintenance includes:
-
Cleaning cooling fans
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Replacing worn fans
-
Inspecting:
-
Servo amplifier fans
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Motor fans (servo & spindle)
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NC unit cooling fans
-
When Alarm Occurs
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Check alarm message details
-
Use diagnostic screens
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Replace faulty fan hardware
Recommendation
Keep commonly used fan spare parts in stock to minimize downtime.
6. How to Replace FANUC CNC Batteries?
Key Points
First, identify the battery type:
-
NC battery
-
Servo amplifier battery
Replacement Method
-
Replace under power ON (recommended)
-
Servo battery:
-
Replace within 10 minutes after power OFF
-
-
NC battery:
-
Pre-charge for 30 seconds
-
Replace within 30 minutes after power OFF
-
Best Practice
Always replace batteries while the system is powered ON to avoid data loss.
7. How to Fix SV409 Alarm?
Possible Causes
1. Mechanical Issues
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Excessive load
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Mechanical blockage
2. Machining Issues
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Improper cutting conditions
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Tool overload (e.g., tool jam)
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Incorrect tool or setup
3. Hardware Issues
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Servo amplifier failure
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Loose power cables
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Motor insulation problems
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Brake circuit faults
4. Parameter Issues
-
Incorrect parameter changes
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Motor replacement without reconfiguration
-
Improper load protection settings
Recommendation
-
Check machine builder settings for special machines
-
Adjust load detection parameters if necessary
8. Emergency Stop (E-Stop) Lift Parameters
Note
This involves complex configurations such as:
-
Gravity axis lift during E-stop
-
Stop distance optimization (Type 1 / Type 2)
-
Power-off recovery functions
Recommendation
Contact FANUC technical support or machine manufacturer for detailed configuration and on-site diagnosis.
9. How to Solve SV301 Alarm?
Troubleshooting Steps
1. Hardware Inspection
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Servo motor encoder
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Servo amplifier
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Fiber optic cables
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Feedback cables
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SDU and scale feedback lines
2. Parameter Check
-
Parameters:
-
1815
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1023
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11802
-
Solution
-
Restore factory parameters if needed
-
Re-set machine zero position
10. How to Fix SV436 Alarm?
Troubleshooting Steps
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Alarm at startup:
-
Check current parameters
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Initialize servo parameters
-
-
Check overload protection parameters:
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2062, 2063, 2065
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2161–2164
-
-
Brake motor:
-
Inspect brake circuit
-
-
Load analysis:
-
Evaluate cutting and mechanical load
-
-
Mechanical check:
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Disconnect motor from machine
-
Test motor independently
-
-
Motor condition:
-
Check wear or brake damage
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Reference Source: Beijing FANUC. This article is based on technical documentation provided by Beijing FANUC.
For More Fanuc CNC repair Cases and technical articles, please back to Fanuc Technical Support Center.
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- FANUC G/ M Code for a Machining Center
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- How to backup SRAM file
- How to backup All data
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