Fanuc alarm SV0304: APC ALARM: PARITY ERROR
servo APC alarm (absolute pulse coder) · Fanuc 0i-D
What it means
A parity error was detected in serial data received from the absolute position detector, so machine position could not be established. Parity errors indicate individual bits were flipped in transit, typically caused by marginal signal levels, a failing cable, or degrading encoder electronics. Isolate by swapping the cable between axes if the alarm follows, and check connector seating at both ends.
Likely causes
- Intermittent or damaged feedback cable
- Absolute pulse coder electronics degradation
- Poor grounding/shielding causing electrical noise
- Servo interface module fault
Replacement parts
We supply the following units for this alarm — tested, warranty-backed:
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A860-2000-T301
pulse-coder · Common cause
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A860-2070-T301
pulse-coder · Common cause
Need the part urgently?
Send us alarm SV0304 with your machine details — typical RFQ turnaround is 24–48h.