Fanuc alarm SP9043: PC DISCONNECT IN DIFFERENTIAL SPEED MODE
spindle alarm (serial spindle, alpha i) · Fanuc 0i-D
What it means
The position coder signal was lost while operating in differential speed mode, where the spindle head rotates slower than the motor according to the gear ratio. Feedback from the spindle-side coder is mandatory in this mode to compute true spindle speed.
Likely causes
- Disconnection of the differential-mode position coder (JY8-type feed)
- Cable damage near moving spindle-head components
- Wrong differential mode configuration after gear change work
Replacement parts
We supply the following units for this alarm — tested, warranty-backed:
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A860-0360-B101
Position coder (spindle encoder) · Check if others ruled out
Need the part urgently?
Send us alarm SP9043 with your machine details — typical RFQ turnaround is 24–48h.