FaultResolve
Back to Search Directory
Search this section

Search Fanuc Alpha-i Servo Spindle Amplifier

Search other Fanuc Alpha-i Servo Spindle Amplifier alarms without going back to the model list.

Search all database

Code SP0035: Gear ratio parameter error

Issue Description & Safety Warning

The Fanuc Alpha-i Servo Spindle Amplifier has triggered a critical Gear ratio parameter error alarm. Immediate attention from a qualified operator or maintenance technician is required to prevent secondary damage to the equipment or spoiled parts during the manufacturing cycle. Always ensure standard safety and LOTO procedures are followed before accessing electrical cabinets.

Official Troubleshooting Steps

Amplifier LED display: 35 Also shown as: SP0035 (15i), SP9035 (30i/31i/32i), SP9035 (0i-D) Cause: There is a large difference between the motor speed calculated from the position coder and the motor speed estimated with the spindle software. (1) If an alarm is issued when a rotation command is entered (a) Error in the position coder setting parameter Correctly specify the bits representing the relationships between the direction of position coder rotation and that of spindle rotation and between the direction of spindle rotation and that of motor rotation. FS15i FS16i Description 3000#0 4000#0 Spindle and spindle motor rotation directions 3001#4 4001#4 Spindle sensor (position coder) mounting direction (b) Invalid gear ratio parameter setting Check to see if an incorrect gear ratio has been specified. This value is used to convert the position coder speed to the motor speed. Be sure to specify the correct value. FS15i FS16i Description 3056 to 3059 4056 to 4059 Spindle-motor gear ratio data (c) Clutch/gear signal error Make sure that the entered clutch/gear signals (CTH1A, CTH2A) are correct with respect to the actually selected gear. FS15i FS16i #7 #6 #5 #4 #3 #2 #1 #0 First spindle G227 G070 CTH1A CTH2A Second spindle G235 G074 CTH1B CTH2B (d) Belt slippage between the spindle and spindle motor Make adjustments so that no belt slippage will occur between the spindle and spindle motor. (2) If an alarm is issued during a cutting operation An overload has occurred to decrease the motor speed. Review the cutting condition. 4.REPLACING AMPLIFIER COMPONENTS

Source: Fanuc αi Servo/Spindle Amplifier Maintenance Manual (B-65285EN/04) — Part II Troubleshooting

Last reviewed: 2026-07-01 · Verified against the manufacturer’s official documentation.

About Fanuc Alpha-i Servo Spindle Amplifier Alarms

Fanuc controllers include extensive self-diagnostics that flag or halt the machine when a fault is detected. Error code SP0035 on the Alpha-i Servo Spindle Amplifier identifies one specific fault condition — its documented cause and the official corrective steps are listed above, sourced from Fanuc's service documentation. Always confirm against the manual for your exact machine configuration and follow LOTO procedures before servicing.

Complete Alarm List: 135 Fanuc Alpha-i Servo Spindle Amplifier codes.

Have a better solution?

Help the industrial community by sharing your repair experience for code SP0035.

Manual conversion service

Need a searchable reference for more Fanuc Alpha-i Servo Spindle Amplifier manuals?

We structure equipment manuals into searchable code, title, cause, solution, safety note, and source-reference data. Send a PDF and example searched codes when you need public pages, private search, or structured exports.

Convert PDF fault-code charts and manuals into clean data.
Build public SEO pages or private internal search tools.
Prioritize updates around codes and manuals people search for.
Request manual conversion Email PDFs to manuals.errordb@gmail.com
Advertisement

Space reserved for Google AdSense / Industrial Affiliate Links

Monetization target for 2026

Related Fanuc Alpha-i Servo Spindle Amplifier Codes