This page covers FANUC SP alarms related to serial spindle communication, spindle control faults, spindle amplifier errors, spindle-side initialization problems, and spindle parameter setting failures. These alarms are especially important in service and repair work because they often point to communication instability between the CNC and spindle amplifier, spindle control hardware problems, incorrect spindle parameter allocation, or failure in spindle-side initialization.
These alarm references apply to FANUC Series 0i-Model D and FANUC Series 0i Mate-Model D.
In practical maintenance work, this group of spindle alarms is often more serious than routine spindle deviation alarms because it can affect spindle control availability, communication reliability, amplifier response, and even machine startup behavior. At REACO CNC, we supply FANUC CNC parts, FANUC robot parts, Mitsubishi automation parts, and repair services for customers worldwide.
What These FANUC SP Alarms Usually Indicate
This section of the FANUC alarm list mainly relates to spindle control architecture rather than ordinary spindle load or position deviation alone. In practical terms, these alarms may appear when the CNC cannot complete spindle initialization correctly, when serial spindle communication becomes unstable, when the spindle amplifier cannot respond as expected, or when the spindle control side detects hardware or parameter-related abnormalities.
Some of these alarms point to communication timing, sequence, timeout, or data exchange problems. Others indicate that the spindle amplifier, spindle-side SIC-LSI, or CNC-side spindle control logic has encountered an abnormal condition. Because these alarms can affect spindle availability at a deeper control level, they usually require more than simple reset-and-restart handling.
Common Causes of FANUC Serial Spindle Communication and Control Errors
Typical causes include unstable communication between the CNC and serial spindle amplifier, incorrect spindle amplifier number assignment, timeout during spindle communication, communication sequence errors, spindle-side control hardware abnormalities, failed spindle parameter reading, failed parameter auto-setting, or illegal spindle motor allocation.
In field service, these alarms may also appear after spindle amplifier replacement, spindle parameter restoration, control-side hardware work, noise-related communication problems, or mismatch between configured spindle structure and the actual machine hardware. Some alarms explicitly point to possible hardware faults, while others require broader checking of communication path, spindle assignment, and initialization state before replacing parts.
Full FANUC SP Alarm List: Serial Spindle Communication and Control Errors
Table 1. General Spindle Control Errors
| Alarm Code | Alarm Message | Full Technical Content |
|---|---|---|
| SP1969 | Spindle control error | An error occurred in spindle control on the CNC side. Contact FANUC with details of the condition when the alarm occurred, including system configuration, operation at the time of occurrence, and frequency of occurrence. |
| SP1970 | Spindle control error | Spindle initialization on the CNC side did not complete. Check the connection status between the CNC and the spindle amplifier. If the problem cannot be solved, contact FANUC with details of the condition when the alarm occurred. |
| SP1971 | Spindle control error | An error occurred in spindle control on the CNC side. Contact FANUC with details of the condition when the alarm occurred. |
| SP1972 | Spindle control error | [M] Check whether gear 4 was selected during rigid tapping. If the problem cannot be solved, contact FANUC with details of the condition when the alarm occurred. [T] Contact FANUC with details of the condition when the alarm occurred. |
| SP1988 | Spindle control error | An error occurred in spindle control on the CNC side. Contact FANUC with details of the condition when the alarm occurred. |
| SP1999 | Spindle control error | An error occurred in spindle control on the CNC side. Contact FANUC with details of the condition when the alarm occurred. |
Table 2. Serial Spindle Communication Errors
| Alarm Code | Alarm Message | Full Technical Content |
|---|---|---|
| SP1976 | Serial spindle communication error | The amplifier number could not be set for the serial spindle amplifier. |
| SP1977 | Serial spindle communication error | An error occurred in serial spindle communication. Possible causes include failure of the hardware used for serial spindle control or the effect of electrical noise. |
| SP1978 | Serial spindle communication error | A timeout was detected in communication with the serial spindle amplifier. |
| SP1979 | Serial spindle communication error | The communication sequence with the serial spindle amplifier was incorrect. |
| SP1989 | Spindle control error | An error occurred in serial spindle communication. Possible causes include failure of the hardware used for serial spindle control or the effect of electrical noise. |
Table 3. Spindle Amplifier and SIC-LSI Related Errors
| Alarm Code | Alarm Message | Full Technical Content |
|---|---|---|
| SP1980 | Serial spindle amplifier error | Fault in the SIC-LSI on the serial spindle amplifier side. |
| SP1981 | Serial spindle amplifier error | An error occurred while writing data to the SIC-LSI on the serial spindle amplifier side. |
| SP1982 | Serial spindle amplifier error | An error occurred while reading data from the SIC-LSI on the serial spindle amplifier side. |
| SP1983 | Serial spindle amplifier error | The alarm on the spindle amplifier side could not be cleared. Possible causes include failure of the hardware used for serial spindle control or the effect of electrical noise. |
| SP1984 | Serial spindle amplifier error | An error occurred during re-initialization of the spindle amplifier. Possible causes include failure of the hardware used for serial spindle control or the effect of electrical noise. |
| SP1987 | Serial spindle control error | Fault in the SIC-LSI on the CNC side. |
Table 4. Parameter Reading, Auto Setting and Allocation Errors
| Alarm Code | Alarm Message | Full Technical Content |
|---|---|---|
| SP1985 | Automatic parameter setting failed | Automatic parameter setting failed. |
| SP1986 | Serial spindle control error | An error occurred while reading spindle parameters. Possible causes include failure of the hardware used for serial spindle control or the effect of electrical noise. |
| SP1996 | Spindle parameter setting error | Illegal spindle motor allocation, or the number of spindles exceeds the system maximum. Check parameters (No.3701#1, #4, #5, 3716, 3717). |
Table 5. Analog Spindle Control Error
| Alarm Code | Alarm Message | Full Technical Content |
|---|---|---|
| SP1975 | Analog spindle control error | An abnormality in the position coder was detected in the analog spindle system. |
Practical Inspection Notes
When this group of SP alarms appears, the first step is usually to determine whether the problem is centered on communication, spindle amplifier initialization, spindle-side control hardware, or parameter structure. In many cases, repeated alarms in this category are not caused by normal spindle load fluctuation but by a deeper control or communication issue.
For serial spindle communication alarms, practical checks usually include the communication path between the CNC and spindle amplifier, amplifier number assignment, cable condition, electrical noise environment, and whether the spindle amplifier is completing initialization correctly. For spindle control errors on the CNC side, it is often important to review recent hardware replacement, spindle parameter changes, control board work, and the exact machine condition when the alarm occurs. For SIC-LSI related alarms, the source may be spindle-amplifier-side hardware or CNC-side control hardware depending on the code.
REACO CNC Support
REACO CNC supplies FANUC CNC parts, FANUC robot parts, Mitsubishi automation parts, and repair services for customers worldwide. If your machine is showing FANUC spindle alarms related to serial spindle communication, spindle amplifier control, parameter reading, or spindle-side initialization, we can support your spare parts sourcing and industrial repair requirements.
With 34 years of industry experience, REACO CNC supports global customers with worldwide shipping, tested industrial parts, and practical repair solutions for FANUC and Mitsubishi systems.
FAQ
What does a FANUC serial spindle communication alarm usually mean?
It usually means the CNC detected a communication problem with the serial spindle amplifier, such as timeout, sequence error, amplifier number setting failure, or communication instability.
What can cause SP1977 or SP1989?
These alarms may be related to hardware faults in the serial spindle control system or the effects of electrical noise on communication.
What does SP1996 indicate?
It indicates illegal spindle motor allocation or that the number of configured spindles exceeds the system maximum. The related spindle parameters should be checked.
Are SIC-LSI related alarms always caused by the spindle amplifier?
Not always. Some SIC-LSI alarms point to the spindle amplifier side, while others point to the CNC side, depending on the alarm code.
Which machines does this reference apply to?
These alarm references apply to FANUC Series 0i-Model D and FANUC Series 0i Mate-Model D.
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.
Related Pages
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