Fagor alarm 6000: Feedback alarm (parameter FBACKAL active)
CNC 8060/8065/8070 feedback alarm (analog axes) · Fagor 8060/8065/8070
What it means
Analog-axis feedback alarm at the CNC counter input. Differential TTL: broken A/B (or inverted) wire, input disconnected. Differential 1 Vpp sinusoidal additionally trips when amplitude >~1.45 Vpp or <~0.4 Vpp or A/B quadrature phase-shift is wrong.
Likely causes
- feedback cable conductor fracture (works cold, fails warm - classic thermal intermittent)
- connector contact corrosion at scale head
- scale head amplitude drift out of the 0.4-1.45 Vpp window
- counter/feedback input stage on COMPCI-side hardware failing
Triage note: Scope pins A-/A at the drive/CNC input: amplitude inside 0.4-1.45 Vpp and ~90 deg shift = healthy scale, suspect cable/input. TRIAGE NOTE: 'S100/S120' appear in some ask-lists but are NOT Fagor products (Siemens SINAMICS S120 is a drive); Fagor scales are S/SV, S2/SV2, LA/SA/GA series.
Replacement parts
We supply the following units for this alarm — tested, warranty-backed:
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EC-P-D
Feedback cable CNC-side · Primary suspect
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SP-1020 (1 Vpp) / SX-520 (TTL) - match interface
Legacy S-series linear scale · Common cause
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S2P-920 / S2X-320-5
Current-generation S2 scale · Common cause
Need the part urgently?
Send us alarm 6000 with your machine details — typical RFQ turnaround is 24–48h.