Fanuc spindle alarm E1 means the one-rotation signal of the serial sensor was not generated within five rotations after power-on — the amplifier turned the spindle, waited five revs for the Z reference, and gave up. Fanuc's triage: at first start, all causes (a)–(c) apply; on a machine that has been operating normally, (b) and (c).
The three causes
- (a) Parameter setting error (first start): an invalid number of sensor teeth makes the amplifier's calculated rotation count disagree with reality — it looks for the Z signal in the wrong place and times out. Check the sensor-setting parameters per the start-up section of B-65280EN — the first suspect after restores and amplifier swaps.
- (b) Sensor adjustment defective: the sensor signal (gap/amplitude on adjustable types) is out of spec, so the reference pulse never forms cleanly — adjust per the ‘Detectors’ section of B-65282EN. The classic origin: spindle mechanical work that disturbed the sensor mounting.
- (c) The detection circuit is abnormal: adjustment impossible or signal absent with parameters correct → replace the sensor.
Tip: ‘Within five rotations’ is the useful detail — the spindle turns, speed control works, and then E1 lands: exactly the ‘speed fine, reference missing’ signature of the whole Z-signal family (AL-42, AL-86). After spindle work → adjustment. After parameter work → teeth count. Neither → the sensor.
Related guides
- Fanuc spindle alarm E0 (pulse count out of range)
- Fanuc spindle alarm 42 (position coder Z missing)
- Fanuc spindle alarm d9 (sensor inner circuit)
E1 blocking orientation on a serial-sensor spindle? JJ Automation adjusts and replaces spindle sensors, verifies parameters, and repairs amplifier receiver stages at component level. On-site service in NCR. WhatsApp us or call +91 88022 12394.