FANUC A860-0301-T004 Incremental Pulse Coder 4000 PPR for Servo Motor

FANUC A860-0301-T004 Incremental Pulse Coder 4000 PPR for Servo Motor Feedback

A860-0301-T004 is the FANUC incremental pulse coder, 4000 pulses per revolution, from the A860-0301 series of separate encoder units. It is a bolt-on feedback unit that mounts on the rear of a FANUC servo motor and drives the position loop through a keyed 10 mm shaft. The A860-0301 series is the incremental type: within the series the T suffix is what separates the resolution, with T001 at 2000 PPR, T003 at 3000 PPR and T004 at 4000 PPR. It is not an absolute encoder, so it needs a battery-backed absolute position reference elsewhere in the drive to recover its zero after power-up. Send us the part number on your unit and the motor nameplate, and we confirm the match before you order.

Specifications

Weight and packing dimensions are stated against the article number we quote. Send us the part number on your existing coder and the motor nameplate, and we confirm the match before you quote.

Industrial Applications

• FANUC α series and alpha i series servo motors — the A860-0301 series is a separate pulse coder unit, mounted on the motor rear rather than integrated into the motor body.
• CNC and machine tool axes — the ball screw pulse coder configuration is designed for ball screw driven linear axes, where the encoder feeds back the actual screw position rather than the motor command.
• Robot joint axes on FANUC controllers that use a separate feedback unit, where a failed coder takes the whole axis offline.
• Machine tending, welding and handling cells where servo hunting or a position drift on one axis stops the cycle.
• Retrofit and repair work on ageing Fanuc spindles and servo axes, as a bolt-on part that avoids replacing the complete motor.

Design Purpose

• Close the position loop with incremental feedback, reporting shaft angle and speed back to the amplifier so the drive can correct the axis in real time.
• Mount on the rear of the motor as a separate unit, so a damaged coder is exchanged without replacing the whole motor.
• Couple to the motor shaft through a keyed spigot so the encoder reads the true shaft position and not a belt or gear train approximation.
• Give 4000 counts per revolution, so the drive sees finer position resolution than the lower 2000P and 3000P variants in the same series.

Common Failure Modes

• Position count loss or a position deviation alarm on one axis — the classic sign of a coder that is no longer counting cleanly.
• Servo hunting or a motor that vibrates at standstill — contaminated or damaged optical elements inside the coder produce a noisy signal that the drive reacts to.
• Absolute position lost after power-up — an incremental coder holds no absolute position of its own, so the machine needs its battery-backed reference restored before the axis will move.
• Intermittent faults that only appear after the machine has been running — heat and vibration inside the motor housing are the usual triggers.
• Damage from coolant, cutting fluid or oil ingress into the motor rear, which is where this unit lives.
• A fault that turns out to be the feedback cable or the amplifier rather than the coder — a damaged cable or a failing amplifier produces the same symptoms, so check the cable and connector pins before ordering a new coder.

Why Choose Us

• Genuine FANUC part, supplied against part number A860-0301-T004 and matched on the T suffix.
• We confirm the part number, the resolution and the motor type before dispatch, so the coder you receive matches the axis it goes back on.
• New original or used original available — the condition is confirmed with you before you order.
• Photos of the actual unit and of the label, provided on request.
• Support with part-number identification across the A860-0301 resolution variants and the other A860 encoder types, because an incremental coder and an absolute coder are not interchangeable on the same drive.
• Packed for export with the encoder and its shaft protected in transit; ships worldwide from Shanghai.

Related Products

• FANUC Servo Motors & Encoders — the rest of the FANUC servo motor and encoder range, including the other A860 coder types and the motor families these feedback units fit.
• FANUC Sensors & Cooling Fans — the FANUC sensing and cooling range.
• FANUC Robot Cables — FANUC robot cabling, including the feedback cables that run to the motor rear.

Request a quote for current pricing and lead time – send us the part number on your existing coder and the motor nameplate, and we confirm the match before you order.