SP0141

Sensor One-Rotation Signal Undetected

Fanuc · A20B-2101-0390 αi series AC Servo Motor and Spindle

What does SP0141 mean?

No absolute position is established within 5 turns immediately after communication between the spindle amplifier and sensor is started. This indicates a failure to detect the absolute reference mark.

Repair Steps

  1. 1

    Verify the proper connection and alignment of the spindle sensor (e.g., αi position coder, αiBZ sensor, αiCZ sensor).

  2. 2

    Ensure the sensor ring is not deformed or damaged, particularly the Z-phase generation section.

  3. 3

    Check for mechanical backlash between the spindle and detector, as this can affect one-rotation signal detection.

  4. 4

    If the sensor head was moved, perform the procedure applicable when the sensor head is moved after conduction (Section 11.1.1.6 or 11.2.3.9).

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Verified technical data. Last updated: March 2026
Source: Fanuc A20B-2101-0390 αi series AC Servo Motor and Spindle