A20B-3300-0341 Fanuc PCB Board A20B33000341 A2OB-33OO-O34I

A20B-3300-0341 | FANUC LCD/MDI Display Driver and Graphics Module — 0i-B / 16i-B / 18i-B / 21i-B CNC / Plug-In Display Card

Display Driver + MDI Interface — Two Functions, One Module

The A20B-3300-0341 combines two operator interface functions in one plug-in module:

LCD display driver: The CNC generates its screen content — axis positions, programme listings, alarm messages, menus — as display data. The A20B-3300-0341 takes this data and drives the LCD panel with the correct video signals: timing (horizontal sync, vertical sync, pixel clock), color data (RGB), and backlight control commands. The LCD panel shows exactly what the CNC's display software has rendered.

MDI keyboard interface: MDI (Manual Data Input) is the CNC's keyboard for manual programme entry, parameter changes, and jog operation. The A20B-3300-0341 scans the MDI keyboard matrix, detects key presses, debounces the signals, and reports key codes to the CNC's main processor for action.

The combination of these two functions on one module simplifies the operator panel connection — one plug-in card handles the complete operator interface hardware layer.

Key Specifications

Graphics Processing — Beyond Simple Display

The "graphics module" designation confirms the A20B-3300-0341 handles more than just video signal timing. Graphics processing includes:

Character rendering: Converting ASCII/Unicode character codes from the CNC's display data into the pixel patterns displayed on screen — managing the character set font ROM and rendering each character at the correct screen position.

Graphical elements: CNC display screens include graphical components — axis position bargraphs, programme structure displays, alarm indicator graphics, and (in some configurations) basic tool path visualisation. The graphics module processes these elements.

Screen composition: Assembling the complete screen image from text, graphics, and background elements before driving the LCD panel.

Application Scenarios

16i-B display fault: A FANUC 16i-B CNC develops a display problem — partial screen corruption, random characters, or complete display loss while the CNC continues machining. The A20B-3300-0341 is identified. Replacement restores full LCD display and MDI keyboard function.

0i-B CNC display module spare: A production facility with 0i-B CNC machines holds one A20B-3300-0341 spare — it also covers their 18i-B and 21i-B machines, reducing the distinct spare parts they need to hold.

FAQ

Q1: Does A20B-3300-0341 failure stop the CNC from machining?

The display/MDI module handles the operator interface — screen display and keyboard input. If it fails, the CNC's machining functions (servo axes, PMC, programme execution) continue on the main CPU. The operator cannot see the screen or enter commands, making safe operation impossible. The CNC should be brought to a controlled stop at a safe position before addressing the fault.

Q2: Is A20B-3300-0341 plug-in compatible across all four CNC platforms (0i-B, 16i-B, 18i-B, 21i-B)?

The four platforms are described as sharing the same display module — all four use the same LCD/MDI display architecture. Whether the module physically plugs into identical connector positions on all four main board types is confirmed from the applicable FANUC hardware manuals. 

Q3: Does replacing A20B-3300-0341 require any display configuration?

The display module drives the LCD and scans the keyboard as defined by its hardware — no software configuration is needed for standard operation. After fitting the replacement, the CNC's display should restore immediately on power-up. For screens requiring specific display parameter adjustment (brightness, contrast on some LCD types), confirm from the applicable maintenance manual.

Q4: Is A20B-3300-0341 compatible with both colour and monochrome LCD displays?

The compatibility with the specific LCD type (colour or monochrome) depends on which display module variant is used on the specific CNC. The CNC's display unit specification (screen size, colour/monochrome, resolution) determines which module variant is installed. A20B-3300-0341 serves its defined display configuration — confirm from the installed module's label.

Q5: What is the difference between A20B-3300-0341 (display driver) and the GUI module A20B-3300-0551 (128MB)?

The A20B-3300-0341 is an LCD/MDI display driver — it handles the hardware interface between the CNC's display data and the physical LCD panel and keyboard. The A20B-3300-0551 GUI module is a higher-level graphics processor with 128MB DRAM, providing the display content generation for advanced graphical interfaces. For the 0i-B/16i-B/18i-B/21i-B platforms, the A20B-3300-0341 is the base display interface; the GUI module is an advanced display processing option for higher-tier platforms.