Fanuc alarm SP9039: 1-ROT CS SIGNAL DETECT ERROR
spindle alarm (serial spindle, alpha i) · Fanuc 0i-D
What it means
The one-revolution signal from the Cs contour control position coder was detected incorrectly. During Cs-mode initialization the amplifier expects a clean single mark per revolution; a distorted or noisy one-rot signal breaks positioning integrity.
Likely causes
- Dirty or damaged coder disk one-rotation mark
- Signal amplitude out of spec due to sensor gap or aging electronics
- Noise coupled into the coder cable
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 SP9039 with your machine details — typical RFQ turnaround is 24–48h.