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FANUC Servo Drive βISVSP A06B Maintenance Guide: Troubleshooting No Display Issues


FANUC servo drives, specifically the βISVSP A06B series, are widely used in various automated equipment, providing efficient and precise motor control. However, in practical use, various faults may arise, with one of the most common being the lack of display. A non-functional display is often caused by power issues, control circuit problems, or hardware malfunctions. This article explores the maintenance approach for resolving no display issues in FANUC servo drives, focusing on troubleshooting steps and solutions.

I. Fault Phenomenon: No Display

The no display fault in FANUC servo drives refers to a situation where the device powers on, but the panel displays no information. The indicator lights might be completely off, or the screen may be unresponsive, suggesting that there could be problems with the control circuits, display module, or power supply module inside the drive. If not addressed in a timely manner, this issue could prevent the device from starting or executing control instructions, which can negatively impact production efficiency.

II. Troubleshooting Approach

When encountering a no display issue in a servo drive, it’s essential to systematically check the device. Below are the common troubleshooting steps:

1. Check Power Supply Input

The first step is to verify if the power supply to the servo drive is functioning correctly. Power is the foundation for all electronic devices, and any instability or interruption in the power supply can prevent the drive from functioning properly.

  • Check the Power Voltage: Use a multimeter to check the voltage at the input terminals of the servo drive, confirming that it falls within the specified range. The FANUC servo drive typically requires a three-phase AC input voltage within a certain range.
  • Check Power Connections: Verify that the power supply cables are correctly connected and not damaged or disconnected. Poor power contact can lead to unstable voltage supply, which can result in no display issues.

2. Check Fuses and Circuit Breakers

Servo drives are equipped with fuses or circuit breakers to prevent damage from excessive current. If a fuse blows or the circuit breaker trips, the device will fail to operate properly.

  • Check the Fuse: Open the servo drive and inspect the fuses in the power section. If the fuse is blown, replace it with one of the same rating.
  • Check the Circuit Breaker: Some servo drives come with an internal circuit breaker that trips in case of voltage abnormalities or overcurrent. If the circuit breaker has tripped, reset it manually.

3. Check the Main Control Circuit

If the power supply is fine, the next step is to inspect the servo drive’s main control circuit. The control circuit acts as the brain of the servo drive, and any malfunction in this area could result in a non-responsive display.

  • Check the Control Chip: The control chip is usually located centrally on the circuit board and is responsible for processing input signals and controlling the operation of the drive. Look for signs of overheating, burning, or damage around the chip. Use an oscilloscope or multimeter to check the power supply voltage and signal output of the chip to ensure it’s functioning properly.
  • Check Circuit Connections: The circuit board in the servo drive is connected to various modules via connectors. Check if any connectors are loose or disconnected, as poor connections can prevent signals from transmitting correctly.

4. Check the Display Module and Signal Transmission

The display module is responsible for showing system status information to the operator. If the display module fails, it could lead to a no display situation.

  • Check the Display Screen: Inspect the power supply input terminals and signal transmission lines to the display screen to ensure they are properly connected. If the display module itself is faulty, it may need to be replaced.
  • Check Signal Transmission: If the display module appears intact, the issue could lie with the signal transmission. Inspect the signal lines between the main control board and the display module to ensure that signals are properly transmitted.

5. Check Capacitors and Power Filtering Circuits

Capacitors and filtering circuits help stabilize the voltage supply, especially for high-frequency currents. If the capacitors are damaged, the power supply could become unstable, affecting the drive’s operation.

  • Check the Capacitors: Look for signs of bulging, leakage, or aging in the capacitors. If a capacitor is faulty, it should be replaced with one of the same model.
  • Check the Filtering Circuits: The components in the filtering circuits may also be damaged, which can cause unstable voltage output. Inspect these components and replace them as necessary.

III. Common Fault Analysis and Solutions

1. Unstable Power Supply Leading to No Display

An unstable power supply voltage can prevent the drive from starting properly. In this case, check the stability of the power supply and ensure the voltage is within the specified range. If issues are found with the power supply, it may be necessary to replace the power module or reconnect the power supply.

2. Control Circuit Malfunction

A malfunctioning control circuit can prevent the system from starting or lead to a no display issue. Typically, this fault requires replacing damaged components. Commonly damaged components include control chips, integrated circuits, and resistors.

3. Display Module Failure

If the display module itself is faulty, it could be due to issues with the backlight, circuit board, or the display screen. Inspect the power input terminals and signal transmission lines to confirm the issue. If the display screen is damaged, replacing the display module will likely resolve the problem.

4. Capacitor or Filtering Circuit Issues

Damaged capacitors can cause unstable power, affecting the drive’s operation. Replacing faulty capacitors or repairing the filtering circuits should solve this issue.

IV. Conclusion

The no display issue in FANUC servo drives βISVSP A06B series is typically related to power problems, control circuit failures, or display module malfunctions. Through systematic troubleshooting and careful inspection, the problem can usually be pinpointed and resolved. During maintenance, special attention should be paid to power stability, circuit connections, and the condition of critical components. For more complex issues, professional diagnostic tools may be required, and damaged components should be replaced to restore the device to normal operation. Timely and effective maintenance ensures the long-term stability and performance of FANUC servo drives, helping to maintain production efficiency.

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The Meaning and Solutions for AL-24 Alarm on FANUC αi Series Spindle Amplifiers

In the maintenance and repair of CNC machine tools, fault alarms are a common occurrence. For equipment using FANUC αi series spindle amplifiers, the AL-24 alarm is a typical code. This article will explore the meaning of this alarm, possible causes, and solutions, providing theoretical support and practical guidance for CNC servo system repairs.


AL-24

1. Meaning of the AL-24 Alarm

According to FANUC’s official documentation, the AL-24 alarm indicates that the serial communication data between the CNC (Computer Numerical Control system) and the spindle amplifier module contains errors. This alarm typically occurs when there is an abnormality in the communication link between the CNC and the spindle amplifier. It is important to note that this alarm does not necessarily indicate hardware failure; in most cases, it is caused by communication issues or external interference.

Scenarios Triggering the Alarm

  • The CNC is powered off while the spindle amplifier remains energized.
  • Serial communication is disrupted, causing data transmission errors.
  • Communication cables are loose, damaged, or poorly connected.

2. Possible Causes of the AL-24 Alarm

When diagnosing the AL-24 alarm, the investigation should focus on the communication link, cable conditions, and hardware status. Common causes include:

1. Communication Noise Interference

Serial data transmission between the CNC and the spindle amplifier may be disrupted by external electromagnetic noise, resulting in data errors and triggering the AL-24 alarm.

2. Cable Issues or Connection Problems

The communication cable is a critical link between the CNC and the spindle amplifier. Possible issues include:

  • Cable aging or internal breakage.
  • Loose or improperly secured connectors.
  • In the case of fiber optic communication, damaged optical connectors or modules.

3. Bundling of Communication and Power Cables

When communication cables are bundled with spindle or servo motor power cables, high-frequency currents may cause electromagnetic interference, affecting communication stability.

4. Hardware Malfunction

Hardware-related issues that may trigger the AL-24 alarm include:

  • Faulty internal circuit boards in the spindle amplifier module (SPM).
  • Damaged communication interface boards or modules in the CNC control system.

5. Parameter Configuration Issues

Incorrect communication parameter settings in the spindle amplifier or CNC can also lead to communication failures.


A06B-6140-h055

3. Solutions for the AL-24 Alarm

When addressing the AL-24 alarm, follow these steps for systematic troubleshooting:

1. Verify CNC Power Status

Check whether the CNC is properly powered. If the CNC is off, the spindle amplifier cannot establish communication, which is a normal reason for the alarm.

  • Action: Ensure the CNC is fully powered and there are no additional alarm codes.

2. Inspect Communication Cables

Communication cables are crucial for the connection between the CNC and the spindle amplifier. Diagnosing cable issues is a key step.

  • Steps:
    • Inspect the cable’s exterior for damage or aging.
    • Ensure connectors are securely plugged in.
    • For fiber optic communication, check the cleanliness of the optical connectors and the condition of the optical modules.
  • Actions:
    • Replace the communication cable and reconnect.
    • If optical modules are faulty, contact the supplier for replacement.

3. Address Noise Interference

Communication stability can be compromised by noise interference, particularly when communication cables are bundled with power cables.

  • Steps:
    • Check the routing of communication cables to ensure they are separated from power and servo cables.
    • Use well-shielded cables or add shielding to existing cables.
  • Actions: Separate communication cables from power cables to maintain a safe physical distance.

4. Examine the SPM Module

The internal circuit board of the spindle amplifier (SPM) may fail due to aging or external impact.

  • Actions:
    • Inspect the SPM module for physical damage or burn marks.
    • Contact FANUC support for repair or replacement if the module is faulty.

5. Validate CNC Hardware

If the SPM is functioning correctly, check the communication interface boards or modules on the CNC side.

  • Actions:
    • Replace the relevant communication boards and test.
    • Check the CNC’s alarm log for related issues.

6. Correct Parameter Settings

Incorrect communication parameters may prevent successful communication between the CNC and the SPM.

  • Actions:
    • Reconfigure communication parameters based on the equipment model and manual.
    • Ensure communication speed, protocols, and other settings match between the SPM and CNC.

4. Preventive Measures

To reduce the likelihood of AL-24 alarms, consider the following preventive measures:

  1. Regular Cable Inspection:
    • Ensure communication cables are free from aging, breakage, or damage.
    • Use durable, high-quality shielded cables.
  2. Optimize Cable Routing:
    • Keep communication cables separate from power lines to avoid interference.
  3. Routine Hardware Maintenance:
    • Inspect the SPM and CNC hardware regularly and replace aging components promptly.
    • Clean amplifier and cable interfaces to prevent dust accumulation.
  4. Environmental Control:
    • Minimize strong electromagnetic interference around the equipment.
    • Provide adequate cooling for amplifiers and control cabinets.

Conclusion

The AL-24 alarm, a common fault code in FANUC αi series spindle amplifiers, primarily reflects communication abnormalities between the CNC and the spindle amplifier. By understanding its meaning, identifying causes, and following a structured troubleshooting process, maintenance personnel can quickly resolve the issue. Additionally, implementing preventive measures can significantly reduce the occurrence of such alarms, ensuring long-term stability and performance of the equipment.

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Comprehensive Guide to FANUC Servo System Troubleshooting and Repair(DB DELAY FAILURE)

FANUC servo systems, widely used in industrial automation, are renowned for their reliability and precision. However, like any sophisticated equipment, they can experience faults that require systematic diagnosis and repair. This guide focuses on two common faults: “NEED REF RETURN” (Absolute Pulse Coder Alarm) and “DB RELAY FAILURE” (Dynamic Brake Relay Issue), along with general troubleshooting techniques.


DB DELAY FAILURE

1. “NEED REF RETURN” Alarm

Fault Description

The “NEED REF RETURN” alarm indicates that the absolute position data of the encoder is lost or the axis requires a reference return operation. This typically happens when:

  • The encoder battery voltage is low or the battery has failed.
  • The system loses its absolute position data due to a power interruption or improper initialization.

Repair Process

  1. Check the Encoder Battery:
    • Replace the battery if its voltage is below the specified threshold (typically 3.6V for FANUC systems).
    • Ensure the battery is replaced with the power ON to prevent loss of encoder data.
  2. Perform Reference Return:
    • Access the machine’s control interface and initiate the reference return operation for the affected axes.
    • Follow the machine tool builder’s specific procedures for homing operations.
  3. Inspect Encoder Wiring:
    • Verify that the encoder cables are securely connected and free from damage.
    • Check for continuity and signal integrity using a multimeter or oscilloscope if necessary.
  4. Reset the Alarm:
    • Once the reference return is completed, reset the alarm via the machine control panel.

A06B-6240-H105

2. “DB RELAY FAILURE” Alarm

Fault Description

The “DB RELAY FAILURE” alarm indicates an issue with the Dynamic Brake (DB) relay, responsible for safely braking the motor during stop or emergency stop conditions. Possible causes include:

  • A malfunctioning DB relay (burnt coil or damaged contacts).
  • Faults in the relay driver circuit.
  • Open or damaged connections in the DB circuit.

Repair Process

  1. Visual Inspection:
    • Open the servo amplifier and inspect the relay for signs of burning, discoloration, or physical damage.
    • Check the PCB for any visible defects such as burnt traces or damaged components.
  2. Test the DB Relay:
    • Use a multimeter to measure the resistance of the relay coil. A functional relay typically has a specific resistance value (e.g., tens to hundreds of ohms). If open or short-circuited, the relay needs replacement.
    • Inspect the relay contacts for proper operation and absence of welding or pitting.
  3. Inspect the Driver Circuit:
    • Check the transistors or ICs driving the DB relay for shorts or open circuits.
    • Use an oscilloscope to verify the control signal to the relay during operation.
  4. Verify DB Resistor and Wiring:
    • Ensure the dynamic braking resistor is intact and its connections are secure.
    • Measure the resistor’s value and compare it with the specifications.
  5. Replace Faulty Components:
    • Replace the relay or driver components if faults are detected.
    • Ensure replacement parts are genuine and match the original specifications.
  6. Reset and Test:
    • After repairs, reset the system and perform operational tests to confirm the alarm is cleared and the DB relay functions correctly.

A06B-6079-H207

3. General Troubleshooting Techniques

LED Indicators

  • Check the LED status on the servo amplifier front panel. LED patterns often provide diagnostic information about the amplifier’s status and errors.

Error Codes

  • Refer to the system’s maintenance manual for detailed descriptions of error codes.
  • FANUC manuals, such as the GFZ-65195EN/01, provide comprehensive troubleshooting steps for each alarm code.

Electrical Checks

  • Measure power supply voltages to ensure they are within specified ranges.
  • Inspect connectors, cables, and PCB traces for continuity and integrity.

Parameter Verification

  • Confirm that the servo parameters are set correctly. Incorrect parameters can lead to operational issues and alarms.

4. Preventive Maintenance Tips

  1. Regular Battery Replacement:
    • Schedule periodic checks and replacements for the encoder battery to avoid position loss.
  2. Keep Components Clean:
    • Clean the servo amplifier and surrounding areas to prevent dust and debris accumulation.
  3. Inspect Wiring:
    • Regularly inspect cables and connectors for wear, corrosion, or loose connections.
  4. Follow Manufacturer Guidelines:
    • Always adhere to FANUC’s maintenance and operational guidelines for optimal system performance.

A06B-6079-H207 power board and fault relay location

Conclusion

By understanding the causes and systematic repair methods for alarms like “NEED REF RETURN” and “DB RELAY FAILURE,” maintenance engineers can ensure minimal downtime and enhanced reliability of FANUC servo systems. Regular preventive maintenance further helps in avoiding recurring issues and extending the life of these critical components.

Comprehensive Guide to FANUC Servo System Troubleshooting and Repair

FANUC servo systems, widely used in industrial automation, are renowned for their reliability and precision. However, like any sophisticated equipment, they can experience faults that require systematic diagnosis and repair. This guide focuses on two common faults: “NEED REF RETURN” (Absolute Pulse Coder Alarm) and “DB RELAY FAILURE” (Dynamic Brake Relay Issue), along with general troubleshooting techniques.


1. “NEED REF RETURN” Alarm

Fault Description

The “NEED REF RETURN” alarm indicates that the absolute position data of the encoder is lost or the axis requires a reference return operation. This typically happens when:

  • The encoder battery voltage is low or the battery has failed.
  • The system loses its absolute position data due to a power interruption or improper initialization.

Repair Process

  1. Check the Encoder Battery:
    • Replace the battery if its voltage is below the specified threshold (typically 3.6V for FANUC systems).
    • Ensure the battery is replaced with the power ON to prevent loss of encoder data.
  2. Perform Reference Return:
    • Access the machine’s control interface and initiate the reference return operation for the affected axes.
    • Follow the machine tool builder’s specific procedures for homing operations.
  3. Inspect Encoder Wiring:
    • Verify that the encoder cables are securely connected and free from damage.
    • Check for continuity and signal integrity using a multimeter or oscilloscope if necessary.
  4. Reset the Alarm:
    • Once the reference return is completed, reset the alarm via the machine control panel.

2. “DB RELAY FAILURE” Alarm

Fault Description

The “DB RELAY FAILURE” alarm indicates an issue with the Dynamic Brake (DB) relay, responsible for safely braking the motor during stop or emergency stop conditions. Possible causes include:

  • A malfunctioning DB relay (burnt coil or damaged contacts).
  • Faults in the relay driver circuit.
  • Open or damaged connections in the DB circuit.

Repair Process

  1. Visual Inspection:
    • Open the servo amplifier and inspect the relay for signs of burning, discoloration, or physical damage.
    • Check the PCB for any visible defects such as burnt traces or damaged components.
  2. Test the DB Relay:
    • Use a multimeter to measure the resistance of the relay coil. A functional relay typically has a specific resistance value (e.g., tens to hundreds of ohms). If open or short-circuited, the relay needs replacement.
    • Inspect the relay contacts for proper operation and absence of welding or pitting.
  3. Inspect the Driver Circuit:
    • Check the transistors or ICs driving the DB relay for shorts or open circuits.
    • Use an oscilloscope to verify the control signal to the relay during operation.
  4. Verify DB Resistor and Wiring:
    • Ensure the dynamic braking resistor is intact and its connections are secure.
    • Measure the resistor’s value and compare it with the specifications.
  5. Replace Faulty Components:
    • Replace the relay or driver components if faults are detected.
    • Ensure replacement parts are genuine and match the original specifications.
  6. Reset and Test:
    • After repairs, reset the system and perform operational tests to confirm the alarm is cleared and the DB relay functions correctly.

3. General Troubleshooting Techniques

LED Indicators

  • Check the LED status on the servo amplifier front panel. LED patterns often provide diagnostic information about the amplifier’s status and errors.

Error Codes

  • Refer to the system’s maintenance manual for detailed descriptions of error codes.
  • FANUC manuals, such as the GFZ-65195EN/01, provide comprehensive troubleshooting steps for each alarm code.

Electrical Checks

  • Measure power supply voltages to ensure they are within specified ranges.
  • Inspect connectors, cables, and PCB traces for continuity and integrity.

Parameter Verification

  • Confirm that the servo parameters are set correctly. Incorrect parameters can lead to operational issues and alarms.

4. Preventive Maintenance Tips

  1. Regular Battery Replacement:
    • Schedule periodic checks and replacements for the encoder battery to avoid position loss.
  2. Keep Components Clean:
    • Clean the servo amplifier and surrounding areas to prevent dust and debris accumulation.
  3. Inspect Wiring:
    • Regularly inspect cables and connectors for wear, corrosion, or loose connections.
  4. Follow Manufacturer Guidelines:
    • Always adhere to FANUC’s maintenance and operational guidelines for optimal system performance.

Conclusion

By understanding the causes and systematic repair methods for alarms like “NEED REF RETURN” and “DB RELAY FAILURE,” maintenance engineers can ensure minimal downtime and enhanced reliability of FANUC servo systems. Regular preventive maintenance further helps in avoiding recurring issues and extending the life of these critical components.

FANUC servo systems, widely used in industrial automation, are renowned for their reliability and precision. However, like any sophisticated equipment, they can experience faults that require systematic diagnosis and repair. This guide focuses on two common faults: “NEED REF RETURN” (Absolute Pulse Coder Alarm) and “DB RELAY FAILURE” (Dynamic Brake Relay Issue), along with general troubleshooting techniques.


1. “NEED REF RETURN” Alarm

Fault Description

The “NEED REF RETURN” alarm indicates that the absolute position data of the encoder is lost or the axis requires a reference return operation. This typically happens when:

  • The encoder battery voltage is low or the battery has failed.
  • The system loses its absolute position data due to a power interruption or improper initialization.

Repair Process

  1. Check the Encoder Battery:
    • Replace the battery if its voltage is below the specified threshold (typically 3.6V for FANUC systems).
    • Ensure the battery is replaced with the power ON to prevent loss of encoder data.
  2. Perform Reference Return:
    • Access the machine’s control interface and initiate the reference return operation for the affected axes.
    • Follow the machine tool builder’s specific procedures for homing operations.
  3. Inspect Encoder Wiring:
    • Verify that the encoder cables are securely connected and free from damage.
    • Check for continuity and signal integrity using a multimeter or oscilloscope if necessary.
  4. Reset the Alarm:
    • Once the reference return is completed, reset the alarm via the machine control panel.

2. “DB RELAY FAILURE” Alarm

Fault Description

The “DB RELAY FAILURE” alarm indicates an issue with the Dynamic Brake (DB) relay, responsible for safely braking the motor during stop or emergency stop conditions. Possible causes include:

  • A malfunctioning DB relay (burnt coil or damaged contacts).
  • Faults in the relay driver circuit.
  • Open or damaged connections in the DB circuit.

Repair Process

  1. Visual Inspection:
    • Open the servo amplifier and inspect the relay for signs of burning, discoloration, or physical damage.
    • Check the PCB for any visible defects such as burnt traces or damaged components.
  2. Test the DB Relay:
    • Use a multimeter to measure the resistance of the relay coil. A functional relay typically has a specific resistance value (e.g., tens to hundreds of ohms). If open or short-circuited, the relay needs replacement.
    • Inspect the relay contacts for proper operation and absence of welding or pitting.
  3. Inspect the Driver Circuit:
    • Check the transistors or ICs driving the DB relay for shorts or open circuits.
    • Use an oscilloscope to verify the control signal to the relay during operation.
  4. Verify DB Resistor and Wiring:
    • Ensure the dynamic braking resistor is intact and its connections are secure.
    • Measure the resistor’s value and compare it with the specifications.
  5. Replace Faulty Components:
    • Replace the relay or driver components if faults are detected.
    • Ensure replacement parts are genuine and match the original specifications.
  6. Reset and Test:
    • After repairs, reset the system and perform operational tests to confirm the alarm is cleared and the DB relay functions correctly.

3. General Troubleshooting Techniques

LED Indicators

  • Check the LED status on the servo amplifier front panel. LED patterns often provide diagnostic information about the amplifier’s status and errors.

Error Codes

  • Refer to the system’s maintenance manual for detailed descriptions of error codes.
  • FANUC manuals, such as the GFZ-65195EN/01, provide comprehensive troubleshooting steps for each alarm code.

Electrical Checks

  • Measure power supply voltages to ensure they are within specified ranges.
  • Inspect connectors, cables, and PCB traces for continuity and integrity.

Parameter Verification

  • Confirm that the servo parameters are set correctly. Incorrect parameters can lead to operational issues and alarms.

4. Preventive Maintenance Tips

  1. Regular Battery Replacement:
    • Schedule periodic checks and replacements for the encoder battery to avoid position loss.
  2. Keep Components Clean:
    • Clean the servo amplifier and surrounding areas to prevent dust and debris accumulation.
  3. Inspect Wiring:
    • Regularly inspect cables and connectors for wear, corrosion, or loose connections.
  4. Follow Manufacturer Guidelines:
    • Always adhere to FANUC’s maintenance and operational guidelines for optimal system performance.

Conclusion

By understanding the causes and systematic repair methods for alarms like “NEED REF RETURN” and “DB RELAY FAILURE,” maintenance engineers can ensure minimal downtime and enhanced reliability of FANUC servo systems. Regular preventive maintenance further helps in avoiding recurring issues and extending the life of these critical components.