A20B-3300-0478 Fanuc PCB Board A20B33000478 A2OB-33OO-O478

A20B-3300-0478 | FANUC FSSB Servo Add-On Module — 30i / 31i / 32i / R-30i / Fibre-Optic Servo Expansion / DSP Multi-Axis

FSSB Add-On — Expanding Servo Axis Capacity

The Series 30i/31i/32i is FANUC's highest-capability CNC platform — designed for machines with the most demanding axis count requirements. The A20B-3300-0478 is a servo add-on module that extends the FS30i system's FSSB servo axis capacity beyond what the base main board alone provides.

The need for this add-on module arises from the 30i/31i/32i's application profile. A FANUC Series 30i CNC can theoretically manage up to 32 servo axes across multiple paths. The base FSSB channels on the main board serve a defined number of axes. For configurations that push beyond this base capacity — multi-path machining systems, robot applications with many joints, complex compound machine tools — the A20B-3300-0478 provides additional FSSB channels.

Key Specifications

R-30i Compatibility — Robot and CNC on the Same Platform

The R-30i is FANUC's robot controller for the Arc Mate, LR-Mate, and many other FANUC industrial robot families. The fact that A20B-3300-0478 serves both the 30i CNC and the R-30i robot controller reflects the shared hardware architecture of FANUC's flagship platforms.

Both the FS30i CNC and the R-30i robot use the same FSSB architecture for servo axis control:

• In the CNC: FSSB connects to Alpha-i SVM servo drives for machine tool axes
• In the robot: FSSB connects to the robot's joint servo drives

A single A20B-3300-0478 module can serve either application — providing FSSB axis expansion for a 30i machining centre or a FANUC industrial robot using the R-30i controller.

Application Scenarios

30i CNC high-axis-count machining system: A FANUC Series 30i CNC controls a 9-axis compound machining centre — more axes than the base main board's FSSB channels can serve. The A20B-3300-0478 provides the additional FSSB channels needed for the extended axis count.

R-30i robot servo module fault: A FANUC industrial robot controlled by the R-30i develops FSSB communication faults on one or more joint axes. The A20B-3300-0478 servo add-on module is identified as the fault. Replacement restores full FSSB communication to all joint drives.

FAQ

Q1: How does the A20B-3300-0478 physically connect to the 30i main board?

The A20B-3300-0478 is a plug-in module that installs horizontally onto the 30i/R-30i main CPU board — similar to how an option card plugs into a main board. It draws its power and control signals through the board-to-board connector and provides its FSSB fibre-optic connectors for servo drive chain connections.

Q2: What servo drives connect to A20B-3300-0478?

The A20B-3300-0478 provides FSSB fibre-optic outputs that connect to FANUC Alpha-i servo drive modules (A06B-6114 αis series, A06B-6096 Alpha SVM series, etc.) in daisy-chain topology. Each FSSB channel from the add-on module can service multiple drives connected in series.

Q3: Does replacing A20B-3300-0478 require servo parameter changes?

No. All servo parameters for the axes served by this add-on module reside in the CNC's or robot controller's main SRAM. After fitting the replacement, the system re-establishes FSSB communication with all connected drives and applies the existing parameters automatically.

Q4: Is A20B-3300-0478 interchangeable between the CNC (30i) and robot (R-30i) applications?

The hardware module is confirmed for both 30i/31i/32i CNC and R-30i robot controllers. However, the specific configuration (FSSB channel count, software settings) may differ between CNC and robot applications. Confirm from the applicable maintenance manual that the same module variant is correct for both applications before cross-substituting.

Q5: What is the difference between A20B-3300-0478 and the Axis Cards (A20B-3300-063x)?

The A20B-3300-063x Axis Cards (0635/0638) are the base axis control modules for lower-end FANUC CNC platforms (0i-D and related). The A20B-3300-0478 is a servo add-on expansion module specifically for the FS30i and R-30i platforms — which already have base FSSB channels on the main board and require this add-on for extended axis counts. They serve different CNC platform tiers.