The Fanuc A860‑2020‑T301 encoder is designed for Fanuc Beta i / Alpha i servo‑motor platforms, where it mounts directly on the motor shaft end and interfaces with A860‑series servo amplifiers (e.g., 61xx‑series amps). It is used in CNC machining centers, turning machines, robotics, and automation cells to provide closed‑loop position and velocity feedback, enabling high‑precision milling, turning, and robot‑motion control. The unit is commonly specified as BiA128, and it is a key spare for Beta i / Alpha i motor assemblies when the original encoder fails or drifts out of accuracy.
Technically, the A860‑2020‑T301 is an absolute‑type pulsecoder, providing digital position and speed data to the servo amplifier without the need for reference‑run tracking. It supports high‑resolution incremental and absolute feedback, suitable for both positioning (PRC‑type) and velocity control, which makes it ideal for high‑duty, high‑cycle applications such as metal‑cutting spindle positioning, tool‑changer axes, and precision‑feed drives. The encoder is built to match Fanuc‑standard servo‑motor couplings and connectors, ensuring plug‑in compatibility and minimal setup once bolted to the motor end.
Mechanically, the A860‑2020‑T301 is a compact, lightweight pulsecoder with a shaft‑mount design and a motor‑end connector, typically weighing about 1 kg and compatible with small‑to‑medium Beta i AC servo motors. It is built for industrial environments, resisting vibration and temperature swings while maintaining low‑signal‑drift operation over long‑run cycles. Installation is straightforward: align the shaft with the motor’s output end, secure the encoder flange or clamp, and connect the factory‑matched feedback cable to the A860‑series servo amp; no special tools or calibration are required beyond standard Fanuc commissioning procedures.
