Fagor alarm 3717: Some pulses got lost (not counted)
CNC 8060/8065/8070 servo/feedback error · Fagor 8060/8065/8070
What it means
Encoder exceeded maximum permissible turning speed; counts were dropped, reference (home) is invalid and displayed positions unreliable.
Likely causes
- axis oversped (runaway, wrong gear ratio, Z-axis plummeting on brake loss)
- encoder frequency limit lower than application demands (cable-length derating)
- signal quality marginal at speed (shielding, cable capacitance)
Triage note: After ANY E3717 the machine reference is void - full home search mandatory. On vertical axes treat this as a safety event: verify the brake BEFORE restarting production.
Replacement parts
We supply the following units for this alarm — tested, warranty-backed:
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HP-1024-C5 (1 Vpp, 150 m reach)
Higher-frequency rotary encoder · Common cause
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SP-1024-R-C5-IP66
Solid-shaft rotary encoder · Common cause
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Brake/coil kit per axis OEM
Vertical-axis motor brake (root cause on plummets) · Common cause
Need the part urgently?
Send us alarm 3717 with your machine details — typical RFQ turnaround is 24–48h.