Fanuc alarm SV0381: ABNORMAL PHASE (EXT)
αi/βi Servo (SV0xxx) · Fanuc 0i-D
What it means
The separate (external) detector reported abnormal position-phase data, detected as an alarm within the scale's output. Since the separate detector provides the fine position feedback in full-closed configurations, the axis position becomes unreliable when this occurs. Confirm the scale interface unit connections first; then involve the scale manufacturer, as many linear scales are not field-repairable.
Likely causes
- Linear scale head/read-head failure
- Scale tape contamination or physical damage
- Separate detector interface unit fault
- Interface cable damage
Triage note: Part numbers vary by scale manufacturer (Heidenhain/Mitutoyo/Fanuc); verify against the machine's full-closed configuration.
Need the part urgently?
Send us alarm SV0381 with your machine details — typical RFQ turnaround is 24–48h.