Pulse FANUC A860 Encoder A860-0370-T002 CE Certificated

Fanuc A860-0370-T002 | Alpha αA1000 Pulse Coder — 1,000,000P, CNC AC Servo Motor Encoder, Discontinued by Manufacturer

Overview

The Fanuc A860-0370-T002 is the T002 variant of Fanuc's αA1000 absolute pulse coder for large-frame alpha series AC servo motors.

Like all members of the A860-0370 encoder family, it delivers 1,000,000 ppr absolute serial position feedback — the high-resolution specification matched to the torque characteristics and operating speeds of motors in the α12 through α40 class. 

Fanuc has discontinued the A860-0370-T002, meaning it is no longer available through Fanuc's standard distribution channels as a new product. 

All replacement supply comes from the aftermarket: motor exchange programs, controlled surplus from machine decommissioning, and managed service inventories.

The T002 suffix distinguishes this variant's connector configuration or mechanical fitment from the T001 within the same A860-0370 family.

Both variants serve the same large alpha motor range, carry the same αA1000 1M ppr resolution, and are compatible with the same CNC controls and amplifiers. 

The physical difference lies in how the encoder connects to the motor-side feedback cable — the specific connector type that mates with the existing cable assembly in the machine determines which T-suffix variant is the correct replacement.

Understanding the discontinued status of this part has practical implications beyond just sourcing.

When a machine's documentation lists the A860-0370-T002 and that exact variant is unavailable, the service question becomes: can the T001 (or another T-suffix variant with equivalent feedback characteristics) be used with appropriate cable adaptation, and is the machine's production schedule tolerant of the additional work that adaptation requires? 

For many facilities, a working T001 with a cable adapter is preferable to an extended machine-down while waiting for T002-specific stock.

Key Specifications

Managing a Discontinued Encoder — Practical Considerations

When the OEM stops producing a specific encoder part number, procurement strategy shifts from reactive to proactive.

For a facility with multiple machines running Fanuc alpha motors that use the A860-0370-T002, the most effective approach is to conduct an audit: how many motors have this encoder, what is each motor's approximate age and operating hours, and what is the consequence of that motor failing tomorrow? 

The answers to these questions define how much spare encoder stock is appropriate to hold.

Service exchange programs offer an alternative to outright spare stock. Under a typical exchange program, a faulty A860-0370-T002 is shipped to a specialist service provider in exchange for a tested, warranted equivalent unit from their managed inventory.

This approach keeps capital tied up in spare inventory minimal while maintaining the ability to respond quickly to machine-down events — provided the exchange supplier maintains adequate stock of the variant required.

αA1000 Resolution in the Large Alpha Motor Context

The 1M ppr resolution of the αA1000 deserves some additional perspective compared to more modest encoder specifications.

At the α22/2000 motor's rated 2000rpm speed, the αA1000 generates 33.3 million absolute position updates per second.

In practical servo control terms, this means the velocity estimate computed by the servo amplifier from consecutive position samples is derived from a very dense data stream — position sample intervals are so short at rated speed that the velocity estimate noise is minimal, contributing to the smooth velocity regulation that makes these motors suitable for precision machining applications.

For comparison, a 64K (αA64) encoder on the same motor at 2000rpm would generate 2.13 million updates per second — still fast, but with a proportionally coarser velocity estimate per control cycle.

The choice of 1M ppr for large alpha motors reflects Fanuc's servo engineering judgment that the αA64 resolution available for smaller motors was not sufficient for optimal velocity control of high-inertia, high-torque large alpha motors at their rated operating conditions.

FAQ

Q1: Since the A860-0370-T002 is discontinued, what are the realistic options for machine operators?

Three main options exist.

First, source surplus T002 units from aftermarket specialists — availability varies, and tested exchange units with warranty are preferable to untested surplus. 

Second, use a T001 or other T-suffix A860-0370 variant with appropriate cable adaptation at the motor end, if the variant's connector can be accommodated by the motor's cable installation.

Third, contact a Fanuc-authorised service representative to determine whether Fanuc has issued an official replacement or cross-reference part number for the T002.

Option three is always worth checking before committing to aftermarket sourcing, as Fanuc sometimes maintains quiet cross-reference paths for discontinued encoder variants.

Q2: How does "discontinued by manufacturer" affect the warranty on a refurbished T002?

The manufacturer's warranty does not apply to discontinued products sourced from the aftermarket — that is implicit in the discontinued status.

The warranty coverage on a refurbished or surplus T002 comes from the service provider who supplies the unit, not from Fanuc. 

Reputable aftermarket encoder suppliers typically offer 3 to 12 months of warranty on refurbished units, backed by testing on a closed-loop test rig.

When evaluating a supplier, ask specifically about the test procedure: was the encoder mounted on a compatible alpha motor and driven at rated speed on a Fanuc-controlled test rig? That level of functional verification is substantially more meaningful than bench electrical testing alone.

Q3: What is the difference between T001 and T002 within the A860-0370 family?

Both the T001 and T002 are αA1000 1M ppr absolute encoders for the same large alpha motor range, compatible with the same CNC generation and amplifiers.

The T-suffix difference indicates a variation in connector type, cable configuration, or a minor mechanical fitment detail at the encoder-to-motor interface.

The functional encoder performance — resolution, protocol, absolute position capability — is identical. 

A service provider familiar with Fanuc alpha encoder variants can confirm which physical differences apply and advise on whether cable adaptation allows T001 stock to serve as a T002 replacement in a specific installation.

Q4: How should the absolute position reference be verified after installing a replacement T002?

After fitting the replacement encoder, power on the machine and perform a reference return on the affected axis. Jog the axis to its reference switch and execute the reference return command from the CNC operator panel.

The CNC will drive the axis to the reference switch, then creep to find the encoder's reference mark, and finally set the axis position to the machine zero coordinate.

Verify the position display shows the expected zero coordinate before moving any other axes or running programs. 

Check that the axis moves correctly in both directions without unexpected limit alarms. Run a simple positioning cycle (e.g., moving to a known offset and returning to zero) to confirm position repeatability before returning the machine to production.

Q5: Is there a risk of receiving a counterfeit A860-0370-T002 from low-cost suppliers, and how can this be identified?

Counterfeit Fanuc encoder components do exist in the market, particularly for popular encoder families.

Key indicators of a genuine unit include: the encoder body labelling should clearly show the full Fanuc part number with consistent font and print quality; the weight and housing finish should match original Fanuc units (lightweight plastic bodies with high-quality paint are a warning sign on what should be a precision metal-bodied encoder); and the serial communication output when the encoder is connected to a Fanuc amplifier should be recognised as a valid αA1000 encoder — counterfeit units often fail to generate a valid serial handshake, producing immediate encoder communication alarms.

Sourcing from established industrial automation specialists with verifiable track records in Fanuc parts supply is the best protection against counterfeit risk.