Fanuc Membrane Keysheet Keypad Keyboard Fanuc A02B-0321-B500 A02B0321B500 AO2B-O321-B5OO

A02B-0321-B500 | FANUC CNC Controller — 8.4" LCD / 3-Axis / 512KB / Ethernet / USB / βi Servo / Linear & Circular Interpolation

FANUC CNC — Precision Control for 3-Axis Machining

The A02B-0321-B500 is a FANUC CNC controller designed for machine tool axis control. At its core is the ability to coordinate up to three axes simultaneously — driving servo systems to produce precise cutting paths defined by the machining programme.

The controller interprets G-code programmes, resolves the tool path geometry, and outputs position commands to the connected servo drives. Linear and circular interpolation — the two fundamental CNC motion types — are both supported. Linear interpolation drives the tool in a straight line between two points at a defined feedrate. Circular interpolation drives the tool along an arc defined by radius and endpoint. Together, these two motion types cover the full range of standard 2.5D milling and turning profiles.

Key Specifications

USB and Ethernet Connectivity

The two data interfaces serve different operational needs:

USB: Direct programme transfer from a USB memory stick or connected PC. Programmes can be loaded, saved, or transferred without network infrastructure. Useful for job-shop environments where programmes are prepared on an office PC and brought to the machine on a USB drive.

Ethernet: Network connection for DNC (Direct Numerical Control) operations — streaming programmes from a programme management server — and for remote monitoring of machine status. In production environments with multiple machines, Ethernet connectivity allows centralised programme management.

Application Scenarios

Vertical machining centre: A 3-axis vertical machining centre uses the A02B-0321-B500 as its CNC unit. The controller runs X, Y, and Z axes via three βi series servo amplifiers. Programmes are loaded via Ethernet from a DNC server, and the machine operator adjusts feedrate during first-off machining using the override controls.

CNC lathe (Z + X + C axes): A turning centre uses the A02B-0321-B500 for Z (longitudinal), X (cross), and C (spindle) axis control. Linear interpolation handles straight turning; circular interpolation produces tapered and radius transitions in a single programme block.

CNC retrofit: An older machine tool with a failed CNC unit is retrofitted with the A02B-0321-B500. The 24V DC power supply requirement, compact physical size, and βi series compatibility make it suitable for retrofit installations where the machine's existing servo system is retained.

FAQ

Q1: What is the maximum programme length the A02B-0321-B500 can store in 512KB?

512KB of CNC programme memory stores approximately 512,000 characters of programme code. A typical machining centre programme with 100 blocks of G-code uses roughly 1,000 to 5,000 characters. 512KB accommodates anywhere from 100 to 500 typical programmes simultaneously, or one very long contouring programme loaded via DNC for direct execution from the controller's memory.

Q2: Can the A02B-0321-B500 control 4 or more axes?

The A02B-0321-B500 is specified for up to 3 controlled axes. Adding a 4th axis requires a CNC controller variant rated for the additional axis channel. If the machine requires a 4th or 5th axis, verify the specific A02B variant's axis count before ordering.

Q3: What encoder types does the A02B-0321-B500 support?

The controller supports incremental encoders, which are standard on FANUC βi series servo motors. Incremental encoders provide position feedback relative to a reference point established at power-up (home position). If the application requires absolute position retention across power cycles without homing, an absolute encoder option must be specified with the servo motor selection.

Q4: Is the Ethernet port used for machine network integration or programme transfer only?

The Ethernet interface supports both programme transfer and network integration. For programme transfer, the controller can receive programmes from a DNC server over the Ethernet connection — programmes are streamed to the CNC in real time or stored to the CNC memory. For network integration, machine status, alarm data, and production counts can be accessed by connected PC or MES systems using FANUC's open communication functions. The specific network protocol capabilities depend on the CNC software options installed.

Q5: What is the feedrate override function and who controls it?

Feedrate override is a real-time operator adjustment of the programmed cutting feedrate, applied via a rotary switch or jog dial on the machine control panel. At 100%, the controller executes the feedrate commanded in the G-code programme exactly. At 50%, the tool moves at half the programmed speed. At 150%, it moves at 1.5× the programmed speed. Override is a temporary operator adjustment — it does not modify the programme. The A02B-0321-B500 supports 0% to 150% override in 10% steps.