FANUC SP9034 Alarm 34: Illegal Spindle Parameter and Troubleshooting

FANUC SP9034 means that the spindle amplifier detected parameter data outside the range that can be specified. The CNC displays SP9034 / SSPA:34 ILLEGAL PARAMETER, while the spindle amplifier displays alarm 34.

The correct action is to identify the invalid internal parameter number, map it to the applicable CNC spindle parameter, and restore the correct value from the exact motor parameter list or approved machine backup. On supported configurations, CNC diagnosis 720 provides the internal number. A value of 0 has a separate meaning: the motor model code used for initial parameter loading is incorrect.

For the surrounding spindle alarm numbers, see the FANUC Serial Spindle Alarm Codes SP9001–SP9033.

What Does FANUC SP9034 Mean?

SP9034 is a spindle parameter validation alarm. During spindle parameter initialization or adjustment, the spindle control checks whether the transferred data can be used by the installed spindle software. Alarm 34 is issued when a value is outside the specifiable range.

This description is narrower than a general “wrong parameter” message. The alarm does not by itself prove that the spindle motor, feedback cable, power wiring or spindle amplifier power section is defective. It indicates that the spindle control has rejected parameter data.

The main diagnostic task is therefore not to replace hardware. It is to answer two questions:

1. Is the motor model code used for automatic initialization incorrect?

2. If the motor code is not the problem, which internal spindle parameter F-xxx contains an unacceptable value?

The answer depends on the CNC generation and spindle system. Newer parameter manuals describe diagnosis 720 as the identification method for applicable configurations. Older α-series maintenance procedures instruct the technician to connect the specified spindle check board and read AL-34 / F-xxx. Use the procedure and diagnostic number documented for the exact CNC, amplifier and spindle software.

When SP9034 Commonly Appears

FANUC specifically discusses SP9034 during the initial setting or adjustment of spindle parameters. In practice, the same validation can be encountered after work that changes or restores the spindle configuration, such as:

• Initial commissioning of a spindle amplifier and motor

• Replacement of a spindle amplifier or control board

• Automatic spindle parameter initialization

• Manual entry of motor-specific parameters

• Restoration of a parameter backup from a different machine or configuration

• Spindle switching setup in which the main-side or sub-side motor code is incorrect

• Installation of an amplifier, motor or spindle software combination that has not been verified for the CNC

These events help establish where to begin, but they do not replace the internal error number. Record the complete alarm and diagnostic information before changing any value.

1. Record the CNC, Amplifier and Motor Information

Before initializing or editing parameters, record the complete installed configuration:

• CNC series and model

• CNC and spindle software series and edition, when available

• Complete spindle amplifier model, including every suffix

• Complete spindle motor model and specification

• Whether spindle switching or output switching is used

• Whether the alarm began after a replacement, parameter load or software change

• Existing parameter backup and its machine source

Do not select a motor code from physical appearance, motor output alone or a similar model number. FANUC motor codes and model-specific parameter tables must correspond to the exact motor and supported spindle system.

If the alarm began after fitting a newer αi-B or βi-B amplifier or motor to an older CNC, verify compatibility before repeatedly reloading parameters. Alarm 34 remains a parameter-range alarm, but an unsupported hardware/software combination may prevent the expected parameter set from being accepted.

2. Check CNC Diagnosis 720 on Applicable Systems

On the applicable CNC configuration, open the diagnosis screen and locate diagnosis 720 for the first spindle. The displayed value determines the next step.

Image caption: On supported FANUC controls, diagnosis 720 identifies the SP9034 parameter error. A displayed value of 0 directs the technician to the motor model code used for parameter initialization.

The image shows 0720 = 0 for spindle S1. It is an interface example, not proof that every SP9034 alarm has a motor-code error. Read the value on the affected machine.

Diagnosis numbering can vary with CNC generation, spindle number and installed functions. Do not assume that diagnosis 720 has the same role on an unrelated FANUC series without checking its parameter and maintenance manuals.

3. If Diagnosis 720 Equals 0, Verify the Motor Model Code

FANUC B-65280EN states that diagnosis 720 equal to 0 means there is an error in the motor model code used for initial parameter loading.

For the configurations covered by the cited parameter manual:

• Parameter 4133 is the spindle motor model code on the main side.

• Parameter 4309 is the motor model code on the sub side when spindle switching is used.

Parameter 4309 is not a second code that every machine must contain. It applies to the sub side of an applicable spindle-switching configuration. On a standard single-motor setup, the relevant motor-code parameter is normally the main-side entry documented for that CNC.

Compare the complete spindle motor model with the correct FANUC motor-code table. Then follow the automatic spindle parameter initialization procedure for the exact CNC and spindle series.

Do not guess the code or copy it from a motor with a similar rating. Also do not use a generic initialization code from another FANUC manual edition without confirming that the procedure applies to the installed motor category. Some manuals define special codes for motors without a dedicated model code, but those values and the required manual entries depend on the spindle series and control method.

Before initialization:

• Back up the existing CNC, PMC and spindle parameters.

• Preserve machine-builder orientation, gear ratio, switching and optional-function settings.

• Confirm whether automatic initialization loads only common motor data or whether additional model-by-model entries are required.

• Follow the specified power-off and power-on sequence.

Automatic initialization is not a harmless reset. It can replace spindle parameter data and should be performed only with the correct motor identification, parameter list and machine documentation.

4. If Diagnosis 720 Is Nonzero, Map the F-xxx Number

When diagnosis 720 is not 0, the displayed number is the internal data number of the parameter that caused SP9034. FANUC represents that number as F-xxx in Appendix A, “Spindle Parameter Table,” of the spindle parameter manual.

F-xxx is not necessarily the CNC parameter number that should be typed into the parameter screen. It is an internal spindle-software index. The Appendix A table maps that index to:

• The corresponding parameter number for each CNC series

• The applicable bit, when the item is bit-coded

• The standard initial setting

• The parameter description

• Applicable winding or control groups

• Parameter classification

• The detailed reference section

Image caption: Example English spindle parameter table showing how an internal F-xxx number maps to the actual CNC parameter and bit. This excerpt is not the complete SP9034 parameter list.

The example begins with internal numbers 0H, 0L, 1H, 1L, 2H, 2L and 3H and maps them to parameters 4000–4006 for the shown CNC columns. SP9034 can identify many other internal numbers. Always search the complete Appendix A table from the manual edition that applies to the installed spindle system.

English Table for the Supplied Parameter Example

This table is an English transcription of the supplied image. The complete B-65280EN table contains additional columns, internal numbers and spindle-series sections. Do not use this excerpt as a substitute for the full motor and spindle parameter manual.

5. Correct Only the Identified Parameter

After mapping F-xxx to the CNC parameter, compare the existing value with:

1. The exact motor-specific parameter list

2. The machine builder's approved parameter backup

3. The applicable FANUC B-65280EN explanation and allowable range

4. The hardware and functional configuration actually installed

Correct the confirmed parameter rather than changing a group of nearby values. A parameter with the same number may have different applicability or settings across spindle motor categories, control methods and CNC generations.

If the item is a bit parameter, change only the identified bit. Preserve the other bits unless the applicable documentation proves they are also incorrect.

After the correction, perform the specified CNC power cycle or spindle initialization step and confirm that SP9034 and amplifier alarm 34 are cleared. Then test the spindle with the machine builder's controlled no-load procedure before cutting.

6. Use a Spindle Check Board on Systems That Require It

FANUC B-65285EN/04 describes a spindle check-board procedure for alarm 34. The board displays AL-34 and F-xxx alternately. F-xxx identifies the parameter outside the permitted range, and the technician then uses B-65280EN to find the corresponding CNC parameter.

This procedure is especially relevant when the CNC diagnosis method described for another generation is unavailable or the applicable maintenance manual explicitly calls for the check board.

Use only the correct FANUC check board and connection procedure for the installed amplifier. Isolate power and observe the specified discharge time before connecting or removing service hardware. Do not connect an assumed board to a connector based only on appearance.

7. Verify Compatibility After Amplifier or Motor Replacement

If SP9034 began after installing a different amplifier, spindle motor or control board, verify the entire combination:

• Exact amplifier model and suffix

• Exact spindle motor model

• CNC series and spindle software

• Supported control method

• Sensor and spindle-switching configuration

• Motor code and model-specific parameter list

A parameter set taken from the removed unit may not be valid for a different amplifier or motor specification. Likewise, an automatically initialized motor parameter set may not contain every machine-specific orientation, gear, switching or optional-function value.

Do not select replacement hardware only by kW rating, current rating or connector arrangement. If compatibility cannot be confirmed, obtain the supported combination from FANUC or the machine builder before modifying further parameters.

If a tested replacement or repair is required, browse FANUC servo, spindle and power drives or send the complete model and suffix to REACO CNC for a compatibility check.

What Not to Do for SP9034

Avoid troubleshooting steps that are not supported by the alarm evidence:

• Do not replace the spindle motor because alarm 34 appears.

• Do not replace feedback or power cables without a separate alarm or test result.

• Do not increase a parameter beyond its documented range to force the alarm to clear.

• Do not initialize all spindle parameters before making a verified backup.

• Do not copy a parameter file from another machine merely because the CNC model is similar.

• Do not treat F-xxx as the CNC parameter number without mapping it in Appendix A.

• Do not enter 4309 on a machine that does not use the applicable spindle-switching sub side.

• Do not bypass machine safety or spindle interlocks during the retest.

SP9034 is intended to prevent the spindle control from operating with invalid data. Clearing the display without establishing why the value was rejected can create a second fault or unsafe spindle behavior.

Difference Between SP9034, SP9037 and SP9014

SP9034 can follow an incorrect motor or detector parameter load, but the alarm definition is the out-of-range data itself. SP9037 identifies a more specific speed-detector setting problem. SP9014 identifies a software/hardware mismatch rather than a parameter-range value.

For the related compatibility procedure, see the FANUC SP9014 spindle software mismatch guide.

FANUC SP9034 Diagnostic Table

Recommended Troubleshooting Order

1. Confirm SP9034 / SSPA:34 on the CNC and alarm 34 on the spindle amplifier.

2. Record the exact CNC, spindle software, amplifier, motor, sensor and switching configuration.

3. Back up all existing CNC, PMC and spindle parameters before making changes.

4. On supported systems, check the affected spindle's diagnosis value, including diagnosis 720 for the applicable first-spindle configuration.

5. If the value is 0, verify the exact motor code and check main-side parameter 4133 or sub-side parameter 4309 only where spindle switching applies.

6. If the value is nonzero, treat it as F-xxx and map it to the actual CNC parameter and bit using Appendix A of the correct B-65280EN edition.

7. If the applicable manual requires it, connect the specified spindle check board and read AL-34 / F-xxx.

8. Compare the identified value with the exact motor parameter list and approved machine backup.

9. Correct only the confirmed parameter or perform the documented initialization with the correct motor code.

10. Power cycle as specified, confirm the alarm is cleared, and complete a controlled no-load spindle test.

Technical References

• FANUC AC Servo Motor αis/αi Series, AC Spindle Motor αi Series, Servo Amplifier αi Series Maintenance Manual, B-65285EN/04, Alarm Code 34

• FANUC AC Spindle Motor αi/βi Series, Built-in Spindle Motor Bi Series Parameter Manual, B-65280EN, SP9034 identification and Appendix A spindle parameter table

• Applicable FANUC CNC maintenance and parameter manuals for the diagnosis screen and spindle-number assignment

• Machine-builder parameter backup, electrical documentation and spindle commissioning procedure

• Beijing FANUC SP9034 technical guidance, illegal spindle parameter

Always use the manual edition that applies to the exact CNC, spindle amplifier, spindle motor, spindle software, sensor, switching configuration and machine.

Need Help With FANUC SP9034 Alarm?

REACO CNC provides independent FANUC spindle parameter review, amplifier testing, repair, compatibility checking and replacement support. Send us the CNC alarm screen, diagnosis 720 value or check-board F-xxx display, complete CNC model, exact spindle amplifier and motor models with suffixes, and details of any recent parameter or hardware changes.

Visit the FANUC Technical Support Center for more FANUC alarm guides, or contact REACO CNC for assistance.

Reference Source: Beijing FANUC. This article is based on FANUC technical documentation. The correct diagnostic number, motor-code parameter, F-xxx mapping, initialization and commissioning procedure depend on the exact CNC and spindle configuration.