The FANUC SP9002 alarm indicates an excessive spindle speed deviation. The related amplifier alarm number is 02. This alarm occurs when the detected spindle motor speed cannot follow the commanded spindle speed.
In normal operation, the spindle motor feedback speed should closely follow the spindle command speed. If the detected speed is far away from the command speed, the CNC system may judge that the spindle cannot accelerate, decelerate, or rotate as required, and then generate the SP9002 alarm.
SP9002 may be caused by excessive cutting load, unreasonable acceleration/deceleration time constant, incorrect spindle motor parameters, speed detector parameter errors, output limit parameter problems, spindle motor wiring issues, motor winding faults, or spindle amplifier failure.
Quick Summary of FANUC SP9002 Alarm
| Alarm Code | SP9002 |
|---|---|
| Alarm Meaning | Excessive Spindle Speed Deviation |
| Amplifier Alarm No. | 02 |
| Main Cause | The detected spindle motor speed cannot follow the spindle command speed. |
| Key Parameter | P4082 acceleration/deceleration time constant |
| Related Parameters | P4028, P4029 output limit parameters; spindle motor-specific parameters; speed detector parameters |
| Key Check Items | Spindle load, cutting condition, acceleration/deceleration time, speed detector settings, motor code, motor parameters, power cable, motor winding, spindle amplifier |
What Does FANUC SP9002 Alarm Mean?
SP9002: Excessive Spindle Speed Deviation
The FANUC SP9002 alarm means that the spindle motor speed detection value is greatly different from the commanded spindle speed.
The CNC system sends a spindle speed command, and the spindle motor should accelerate or rotate according to that command. At the same time, the system monitors the actual spindle speed through the speed detector or feedback system. If the actual speed cannot follow the command speed within the required range, the system reports SP9002.
This alarm may appear during spindle acceleration, heavy cutting, or even no-load rotation. The troubleshooting direction depends on the operating condition when the alarm occurs.
First Check: When Does SP9002 Occur?
Before changing parameters or replacing parts, first confirm when the alarm appears. This helps identify whether the cause is related to acceleration setting, cutting load, motor parameter, wiring, or spindle amplifier hardware.
| Alarm Timing | Likely Check Direction |
|---|---|
| During spindle acceleration | Check acceleration/deceleration time constant P4082 and speed detector parameters. |
| During heavy cutting | Check cutting load, output limit parameters P4028/P4029, and spindle motor parameters. |
| During no-load spindle rotation | Check spindle motor power cable, motor winding, and spindle amplifier. |
Case 1: SP9002 Appears During Spindle Acceleration
If SP9002 appears while the spindle motor is accelerating, the spindle may not be able to reach the commanded speed within the expected time.
1. Check Acceleration/Deceleration Time Constant P4082
Confirm whether the spindle motor acceleration/deceleration time constant is reasonable.
If the acceleration time is too short, the spindle motor may not be able to follow the command speed quickly enough, especially when the spindle load is high or the motor/inertia condition is demanding.
Modify parameter P4082 to extend the acceleration/deceleration time, then test the spindle again.
2. Check Speed Detector Parameter Settings
Confirm whether the spindle motor speed detector parameters are set correctly.
If the speed detector parameters are incorrect, the CNC may receive an incorrect detected speed value. In this case, the system may judge that the detected speed deviates too far from the command speed, even if the motor is rotating normally.
Check the spindle motor parameter documentation and confirm the speed detector-related settings according to the actual spindle motor model.
Case 2: SP9002 Appears During Heavy Cutting
If SP9002 occurs during heavy cutting, the spindle may be overloaded and unable to maintain the commanded speed.
1. Check Whether the Cutting Load Exceeds Motor Capacity
Check whether the cutting load exceeds the maximum output power of the spindle motor.
Use the spindle load meter to confirm the load condition. If the load is too high, adjust the cutting depth, feed rate, spindle speed, tool condition, or machining process.
2. Check Output Limit Parameters P4028 and P4029
Incorrect spindle output limit parameters may restrict the spindle output and cause the motor to fail to follow the commanded speed.
Check whether parameters P4028 and P4029 match the machine and spindle motor specifications. If the output limit setting is too low or incorrect, the spindle may not have enough output during cutting.
3. Check Spindle Motor Model and Motor Code
Confirm the spindle motor model and motor code.
If the motor code or spindle motor-specific parameters are incorrect, the spindle amplifier may not control the motor correctly. This may lead to speed deviation, weak output, poor acceleration, or unstable spindle speed.
4. Reinitialize Spindle Motor Parameters If Needed
If the motor-specific parameters are suspected to be incorrect, reinitialize the spindle motor parameters according to the correct motor code and motor model.
After initialization, test whether the spindle can follow the command speed normally.
Case 3: SP9002 Appears During No-Load Rotation
If SP9002 appears even when the spindle is rotating without load, the problem is more likely related to wiring, motor hardware, or the spindle amplifier.
1. Check Spindle Motor Power Cable Connection
Check whether the spindle motor power cable is connected correctly.
Confirm the cable connection, terminal tightening, connector condition, and continuity of the motor power cable. A poor connection may prevent the motor from receiving correct output from the amplifier.
2. Check Motor Winding Continuity
Check whether the spindle motor winding is normal.
If the motor winding has an open circuit, poor continuity, or abnormal resistance, the motor may not rotate correctly or may fail to follow the command speed.
3. Replace the Spindle Amplifier for Testing
If the motor power cable and motor winding are both normal, but SP9002 still occurs during no-load rotation, the spindle amplifier may be faulty.
Replace the spindle amplifier for testing and confirm whether the alarm is cleared.
How to Troubleshoot FANUC SP9002 Alarm
When troubleshooting SP9002, compare the spindle command speed with the detected spindle speed and identify the working condition when the alarm appears.
You may need to check:
- Whether amplifier alarm number 02 is displayed
- Whether the alarm appears during acceleration, heavy cutting, or no-load rotation
- Whether the detected spindle speed is far from the command speed
- Whether acceleration/deceleration time constant P4082 is reasonable
- Whether the spindle speed detector parameters are correct
- Whether the cutting load exceeds the spindle motor maximum output power
- Whether the spindle load meter shows overload
- Whether output limit parameters P4028 and P4029 match the machine and motor specifications
- Whether the spindle motor model and motor code are correct
- Whether the spindle motor-specific parameters are correct
- Whether spindle motor parameter initialization is needed
- Whether the motor power cable connection is normal
- Whether the motor power cable has good continuity
- Whether the spindle motor winding is normal
- Whether the spindle amplifier needs to be replaced for testing
Recommended Solution
The correct solution for FANUC SP9002 depends on whether the alarm is caused by acceleration setting, load condition, parameter mismatch, wiring problem, motor fault, or spindle amplifier failure.
1. Confirm the Alarm Timing
First, confirm whether SP9002 appears during spindle acceleration, heavy cutting, or no-load rotation.
This step is important because the troubleshooting direction is different for each condition.
2. If the Alarm Appears During Acceleration, Adjust P4082
If SP9002 occurs during acceleration, check whether the acceleration/deceleration time constant is too short.
Modify parameter P4082 to extend the acceleration/deceleration time, then test whether the spindle speed can follow the command more smoothly.
3. Check Speed Detector Parameter Settings
Confirm whether the spindle motor speed detector parameters are set correctly.
If the detected speed value is incorrect because of wrong speed detector settings, correct the parameters according to the spindle motor parameter documentation and actual motor model.
4. If the Alarm Appears During Heavy Cutting, Check Load and Output Limit
If SP9002 appears during heavy cutting, check whether the cutting load exceeds the motor output capacity.
Also check whether output limit parameters P4028 and P4029 are consistent with the machine and spindle motor specifications.
5. Check Spindle Motor Code and Motor-Specific Parameters
Check the spindle motor model and confirm the correct motor code.
If the motor-specific parameters are incorrect, reinitialize the spindle motor parameters according to the correct motor code and motor model.
6. If the Alarm Appears with No Load, Check Power Cable and Motor Winding
If SP9002 occurs during no-load spindle rotation, check the spindle motor power cable first.
Confirm whether the power cable connection is correct and whether the cable has good continuity. Then check whether the spindle motor winding is normal.
7. Replace the Spindle Amplifier If Wiring and Motor Are Normal
If the motor power cable and motor winding are normal but SP9002 still occurs, replace the spindle amplifier for testing.
If your machine shows FANUC SP9002 excessive spindle speed deviation alarm, please contact REACO CNC directly. Our team can help check P4082, speed detector parameters, spindle load condition, output limit parameters P4028/P4029, spindle motor code, motor-specific parameters, power cable, motor winding, and spindle amplifier replacement options.
REACO CNC Support for FANUC SP9002 Alarm
REACO CNC provides support for FANUC CNC systems, spindle amplifiers, spindle motors, speed feedback systems, spindle parameters, and related CNC hardware problems.
We can help with:
- FANUC CNC alarm analysis
- FANUC SP9002 alarm troubleshooting
- Spindle speed deviation issue analysis
- Amplifier alarm No.02 checking
- Spindle command speed and detected speed comparison
- Acceleration/deceleration time constant P4082 checking
- Spindle speed detector parameter review
- Heavy cutting load analysis
- Output limit parameter P4028/P4029 checking
- Spindle motor code and motor-specific parameter checking
- Spindle power cable and motor winding checking support
- Spindle amplifier repair or replacement support
- Replacement FANUC CNC parts supply
If you are not sure whether the SP9002 alarm is caused by acceleration setting, heavy cutting load, incorrect speed detector parameter, wrong output limit parameter, spindle motor parameter error, power cable issue, motor winding fault, or spindle amplifier failure, you can send us the CNC system model, spindle amplifier model, spindle motor model, alarm screen, command speed, detected speed, load meter condition, and related parameter values. Our team will help check the possible cause.
FAQ About FANUC SP9002 Alarm
What is FANUC SP9002 alarm?
FANUC SP9002 alarm means excessive spindle speed deviation. The related amplifier alarm number is 02. It occurs when the detected spindle motor speed cannot follow the commanded spindle speed.
What causes FANUC SP9002 spindle speed deviation alarm?
The alarm may be caused by excessive cutting load, unreasonable acceleration/deceleration time constant, incorrect speed detector parameters, wrong output limit parameters, incorrect spindle motor parameters, power cable problems, motor winding faults, or spindle amplifier failure.
What should I check first when SP9002 appears?
First, confirm when the alarm occurs: during acceleration, heavy cutting, or no-load rotation. The troubleshooting direction depends on the alarm timing.
Which parameter is related to acceleration during SP9002 troubleshooting?
Parameter P4082 is related to spindle acceleration/deceleration time. Extending P4082 may help if SP9002 occurs during acceleration.
Can heavy cutting cause SP9002?
Yes. If the cutting load exceeds the spindle motor maximum output power, the spindle feedback speed may not follow the command speed and SP9002 may occur.
Which output limit parameters should be checked?
Parameters P4028 and P4029 should be checked to confirm whether the spindle output limit settings match the machine and motor specifications.
Can incorrect spindle motor parameters cause SP9002?
Yes. Incorrect motor code or spindle motor-specific parameters may cause poor spindle control, weak output, or incorrect speed feedback, resulting in SP9002.
What if SP9002 appears with no load?
If SP9002 appears during no-load rotation, check the spindle motor power cable connection, cable continuity, motor winding condition, and spindle amplifier.
How can I fix FANUC SP9002 alarm?
Confirm the alarm timing, adjust P4082 if the alarm occurs during acceleration, check speed detector parameters, reduce heavy cutting load, verify P4028/P4029, check motor code and spindle motor-specific parameters, inspect the power cable and motor winding, and replace the spindle amplifier if necessary.
Need Help with FANUC SP9002 Alarm?
If your CNC machine has a FANUC SP9002 excessive spindle speed deviation alarm, please contact REACO CNC. We can help analyze the alarm cause and provide suitable FANUC CNC repair, spindle speed feedback troubleshooting, P4082 parameter checking, load analysis, output limit parameter review, spindle motor parameter checking, or spindle amplifier replacement support.
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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