Fanuc A16B-3200-0429 Main Control Board for CNC Machine Tools

Product Overview

The Fanuc A16B-3200-0429 is a main control circuit board (also referred to as a control PCB or motherboard) used in Fanuc computer numerical control systems. This board serves as the central control unit within the CNC rack, integrating the processor, memory, I/O interfaces, and communication circuits necessary for controlling machine tool axes, spindle, and auxiliary functions. It is commonly used in Fanuc Series 16i, 18i, 21i, and other compatible controls. The A16B-3200-0429 is designed for high reliability in metal-cutting environments, with robust power regulation and noise immunity.

Key Features of Fanuc A16B-3200-0429

The board features a 32-bit high-speed RISC CPU dedicated to real-time CNC tasks such as interpolation, servo control, and PLC execution. It includes flash memory for system software (executable ROM) and battery-backed SRAM for part program storage, offsets, and parameters. The board provides interfaces for connecting to the servo bus (FSSB), I/O Link, and the CNC operator panel. It also includes a PMC (Programmable Machine Controller) function for machine logic control, reducing the need for an external PLC.

The A16B-3200-0429 includes diagnostic LEDs for power, CPU activity, and communication status. It is built on a multilayer PCB with conformal coating to resist dust and humidity. The board has edge connectors for plugging into a Fanuc backplane, as well as header connectors for field wiring of I/O (if populated). The board operates from a 24 V DC input supplied by the CNC power unit. It supports up to 4 axes of servo control (expandable) and a wide range of spindle drives. The board is field-replaceable with proper ESD precautions.

Technical Specifications

• Manufacturer: Fanuc Corporation

• Part Number: A16B-3200-0429

• Product Type: Main Control Board (CNC Motherboard)

• Compatible Controls: Fanuc Series 16i, 18i, 21i (check hardware compatibility)

• Processor: 32-bit RISC

• Memory: Flash ROM (system), SRAM (user data, battery-backed)

• Servo Interface: FSSB (Fanuc Serial Servo Bus)

• I/O Interface: I/O Link (for remote I/O units)

• Communication Ports: RS-232 (programming), Ethernet (optional on some variants)

• PMC Function: Built-in ladder logic execution

• Diagnostic LEDs: Power, CPU run, alarm indicators

• Power Supply: 24 V DC (from CNC power unit)

• Operating Temperature: 0 to +45 °C

• Storage Temperature: -20 to +60 °C

• Dimensions: Standard Fanuc 1-slot Eurocard (approx. 260 mm x 180 mm)

• Certifications: CE, FCC

Functional Description

The A16B-3200-0429 executes the CNC system software stored in flash ROM. It reads part program commands from memory, decodes G-codes, performs trajectory planning, and sends position commands to the servo drives via FSSB. The board also executes the ladder logic (PMC) that handles machine peripheral signals such as limit switches, coolant, and tool changer. It monitors feedback from encoders and scales to ensure accuracy. The battery-backed SRAM retains all user data when power is off. In the event of a fatal error, the board sets an alarm and stops machine motion. The board can be diagnosed using Fanuc’s boot-up routines and external display.

Applications

This control board is used as a replacement or spare part in Fanuc CNC-controlled machine tools including vertical/horizontal machining centers, CNC lathes, grinding machines, and laser cutters.