Fanuc alarm SP9027: PULSECODER DISCONNECTED
spindle alarm (serial spindle, alpha i) · Fanuc 0i-D
What it means
The position coder signal was disconnected during operation. The spindle feedback device stopped delivering valid pulses, so speed control and orientation become impossible and the amplifier trips.
Likely causes
- Broken, chafed or unseated feedback cable
- Failed built-in motor sensor or external position coder
- Contaminated/damaged sensor coupling
Triage note: Inspect cabling thoroughly before condemning the sensor.
Replacement parts
We supply the following units for this alarm — tested, warranty-backed:
- View part →
A860-2000-T301
alpha i built-in motor sensor (Mi coder) · Common cause
Need the part urgently?
Send us alarm SP9027 with your machine details — typical RFQ turnaround is 24–48h.