Fanuc alarm SP9047: POSITION CODER SIGNAL ABNORMAL
spindle alarm (serial spindle, alpha i) · Fanuc 0i-D
What it means
The A/B-phase waveform of the position coder is faulty: pulse trains are distorted, missing edges or mutually inconsistent. The amplifier validates quadrature relationships continuously and trips when they fail.
Likely causes
- Degraded coder LED/detector giving weak A or B channel
- Oil-contaminated coder disk
- Shielding failure letting noise corrupt quadrature signals
Replacement parts
We supply the following units for this alarm — tested, warranty-backed:
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A860-0360-B101
Position coder (spindle encoder) · Common cause
Need the part urgently?
Send us alarm SP9047 with your machine details — typical RFQ turnaround is 24–48h.