1 PC Used Fanuc A20B-3300-0102 Board In Good Condition A20B33000102 A2OB-33OO-O1O2

FANUC A20B-3300-0102 | RISC CPU Card (PowerPC) — Series 16i / 18i / 21i High-Speed Machining Functions

Why a CNC Needs a Separate RISC Processor

The A20B-3300-0102 is a secondary processor card — a dedicated high-speed computing module that adds to the 16i/18i/21i CNC's processing capability without replacing the main CPU. Understanding its role requires understanding what the main CNC CPU handles and what it cannot handle alone at production speed.

The main CNC CPU runs the core CNC functions: system software execution, PMC ladder, I/O management, display. These tasks are manageable on a general-purpose processor with deterministic scheduling. What the main CPU cannot handle without saturation is the numerically intensive real-time computation that advanced machining functions require — tasks measured in microseconds, running continuously while the main CPU is doing everything else simultaneously.

The A20B-3300-0102 carries a PowerPC RISC processor specifically for this parallel computation role. RISC architecture executes each instruction in fewer clock cycles than CISC processors, and the PowerPC's floating-point performance was the leading embedded processor choice for deterministic real-time computation at the time of the 16i/18i/21i generation's development

Key Specifications

Functions the RISC Card Enables

The advanced machining functions that require this card are grouped around high-speed and high-precision processing:

AI Contour Control (AICC) / AI Advanced Preview Control — look-ahead processing that pre-reads upcoming programme blocks and calculates optimised tool paths in real time. Analysing many blocks ahead simultaneously requires dedicated computation that cannot burden the main CPU.

High-speed small-block processing — complex die and mould programmes from CAM systems producing thousands of very short blocks per second. Processing these at full speed requires the additional throughput the RISC card provides.

NURBS interpolation — direct mathematical evaluation of spline curve data at each interpolation step, rather than receiving pre-linearised data from the CAM system.

Advanced servo feed-forward algorithms — high-precision servo control algorithms that reduce positional lag during direction changes and contour transitions, improving surface finish on complex parts.

FAQ

Q1: A 16i-B has the -0101 installed. Does replacing it with the -0102 require parameter changes?

No changes are required. The A20B-3300-0102 is a direct hardware replacement for the -0101. The CNC system software does not distinguish between the two revisions. Install in the same position — RISC-dependent functions operate identically. No parameter modifications, software uploads, or reconfiguration needed.

Q2: The 16i-B runs normally but alarms specifically during AI contour control. Is the RISC card at fault?

An alarm that occurs only during AICC or other RISC-dependent functions — while normal block-by-block machining runs without issue — is a strong indicator the RISC card is the fault source. The main CPU handles standard machining; the RISC card is the additional resource AICC depends on. If a substitute card is available for temporary installation, that is the fastest diagnostic confirmation.

Q3: Is a RISC card from a Series 18i-A machine compatible with a Series 16i-B?

The A20B-3300-0101/0102 family is used across both model A and model B generations, but the physical installation path differs between them — the connector arrangement and riser configuration differ between model A and model B main boards. Before substituting a card from a different machine, confirm the board revision and connector arrangement match the target machine's hardware. Confirm with a FANUC-specialised supplier with both machines' hardware part numbers.

Q4: The machine has the RISC card installed but AICC is not working. Is the card faulty?

Not necessarily. AI contour control requires both the hardware (this RISC card) and the software option licensed and enabled in the CNC's FROM. If the AICC option is not shown as available in the CNC's function menu, the issue is software licensing, not hardware. Check the option status before assuming a hardware fault.

Q5: Can the A20B-3300-0102 be repaired at component level?

The PowerPC processor itself is not practically repairable at component level. Peripheral component failures — voltage regulators, clock oscillators, memory ICs, coupling capacitors — are sometimes repairable by qualified specialists with the correct test equipment. In most cases board-level replacement is the practical maintenance path. Refurbished -0102 units are accessible through specialist FANUC spare parts suppliers.