FANUC A860-0304-T112, also searched as A8600304T112, is a legacy 2500-pulse-per-revolution incremental pulse coder for position and speed feedback on compatible FANUC three-phase AC servo motors.

GE FANUC documentation identifies A290-0561-V502 as the later ordering number for the same encoder. Existing nameplates may still show A860-0304-T112; confirm both references before purchase.

A860-0304-T112 Product Specifications

2500P Incremental Servo Feedback

FANUC's legacy AC servo motors use an optical pulse coder coupled to the shaft. The 2500P specification means 2,500 A-phase pulses per revolution. It supplies relative feedback for servo speed and position control; the machine reference is established by the configured reference-return procedure.

A860-0304-T112 and A290-0561-V502

A290-0561-V502 is the documented later order reference for A860-0304-T112. GE FANUC explained that the same encoders received new A290 ordering numbers as old A860 stock was exhausted. This is an order-number cross-reference, not permission to substitute a different pulse count or detector type.

Compatibility, Testing and Installation

Confirm the complete A06B motor number, original encoder label, 2500P resolution, connector, cable, coupling or shaft interface, mounting and CNC/servo configuration. Do not select by housing appearance alone. REACO CNC checks the label, housing, connector, mechanical condition and feedback operation on a compatible FANUC test setup as applicable.

Installation should be completed by qualified personnel. Record the original alignment and machine reference position. After replacement, verify encoder alignment, the motor/encoder phase relationship and reference return using FANUC and machine-builder procedures.

Related resources: FANUC CNC and robot parts, FANUC servo motors and FANUC encoder and servo repair services.