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| Place of Origin | JAPAN |
| Brand Name | FANUC |
| Certification | CE ROHS |
| Model Number | A20B-3300-0102 |
Part Number: A20B-3300-0102
Manufacturer: FANUC Corporation (Japan)
Product Category: PCB — RISC CPU Module (High-Performance Processing Card)
Series: A20B-3300 — FANUC i-series CNC processing module family
Replaces: A20B-3300-0101
Processor Architecture: PowerPC RISC
The FANUC A20B-3300-0102 is a RISC CPU card — a high-performance secondary processor module for FANUC Series 16i, 18i, and 21i CNC controllers.
It carries a PowerPC RISC processor and installs as an add-on board in the CNC control unit, supplementing the main CPU module with dedicated high-speed computation capacity for advanced machining functions.
The A20B-3300-0102 is the direct replacement for the earlier A20B-3300-0101 RISC board. The -0102 represents an updated revision of the same functional module — same interface, same operational purpose, same system compatibility — with component or design improvements made by FANUC during the product's production lifetime.
For any 16i/18i/21i CNC that carried the -0101 board and requires replacement, the -0102 is the correct current substitute.
Understanding why a CNC needs a RISC CPU card requires understanding the separation between the main CNC processor and the RISC board's role.
The main CNC CPU (from the A20B-3300-03xx family for the 16i-B/18i-B, or the A20B-3300-0260 for the model A generation) handles the core CNC functions: executing the CNC system software, running the PMC ladder, managing I/O, driving the display.
The RISC card handles the numerically intensive real-time computation tasks that high-speed machining functions require — tasks where execution time is measured in microseconds and where the computational load would saturate the main CPU if handled there.
| Parameter | Value |
|---|---|
| Processor | PowerPC RISC architecture |
| Compatible CNC | FANUC Series 16i, 18i, 21i (model A and B generation) |
| Function | Secondary high-speed RISC co-processor for advanced machining |
| Replaces | A20B-3300-0101 (direct replacement) |
| Installation | Option slot / riser on main control board |
| Board Designation | RISC BOARD CPU (PCB-CPU CARD STANDARD FOR RISC BOARD) |
| Series | A20B-3300 |
| Status | Available — refurbished, tested |
| Origin | Japan |
The PowerPC processor that the A20B-3300-0102 carries is a RISC (Reduced Instruction Set Computer) architecture processor. RISC processors execute a simpler set of instructions compared to CISC (Complex Instruction Set Computer) processors like the x86 family, but execute each instruction in fewer clock cycles.
For the type of computation required by advanced CNC functions — trigonometric interpolation, spline calculation, look-ahead processing, servo feed-forward algorithms — the RISC architecture's efficient numerical processing provides substantial throughput advantages.
FANUC selected the PowerPC architecture for this role because it was, at the time of the 16i/18i/21i controller generation's development, the leading high-performance embedded processor architecture.
PowerPC was used in aerospace, automotive control, and industrial applications where deterministic real-time performance and computational throughput were requirements.
Its combination of floating-point performance and deterministic execution timing suited the real-time requirements of CNC machining function execution precisely.
The A20B-3300-0102 is the updated revision of this processing module.
The -0102 incorporates component updates relative to the -0101 while maintaining full compatibility with the 16i/18i/21i system software and the functions the RISC card enables.
The advanced CNC functions that require the A20B-3300-0102 RISC card are grouped around high-speed and high-precision machining:
AI Contour Control (AICC) / AI Advanced Preview Control. These functions use look-ahead processing to pre-read upcoming programme blocks and calculate smoothly optimised tool paths in real time.
The look-ahead computation — analysing many blocks ahead while simultaneously executing the current block — requires dedicated high-throughput processing.
The RISC card handles this computation without affecting the main CNC system's real-time scheduling.
High-speed small-block processing. Complex die and mould programmes, particularly those generated by CAM systems using fine-tolerance interpolation, produce thousands of very short programme blocks per second. Processing these blocks at full speed without losing programme flow requires the additional computation capacity the RISC card provides.
NURBS interpolation. Where the CNC interprets NURBS (Non-Uniform Rational B-Spline) curve data directly from the NC programme rather than receiving pre-linearised point data from the CAM system, the mathematical evaluation of the spline curve at each interpolation step is handled by the RISC processor.
Advanced servo feed-forward algorithms. Certain high-precision servo control algorithms that reduce positional lag during direction changes and contour transitions are computed by the RISC card, improving surface finish and dimensional accuracy on complex contoured parts.
The A20B-3300-0101 is the predecessor of the A20B-3300-0102. FANUC's numbering convention for module revisions follows a consistent pattern: when a module is revised — typically due to component obsolescence, manufacturing improvement, or minor design refinement — the last digit of the part number increments.
The -0102 replaces the -0101 as the standard product with full backward compatibility.
For a maintenance technician ordering a replacement RISC card for a machine that has the -0101 installed, the -0102 is the correct part to order. Installation is identical.
System software compatibility is identical. No parameter changes or software updates are required when substituting the -0102 for the -0101.
The practical implication for the secondary market is that -0101 units are increasingly less available as the installed base ages and boards are consumed by service needs.
The -0102, as the current revision, has higher availability in the refurbished market.
Q1: A 16i-B machine has the A20B-3300-0101 installed. Does replacing it with the -0102 require any CNC parameter changes or software updates?
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 the -0102 in the same position as the -0101, and the RISC-dependent functions will operate identically.
No parameter modifications, software uploads, or reconfiguration are needed.
Q2: The 16i-B runs fine for normal machining but shows an alarm specifically during AI contour control operation. Is the RISC card likely at fault?
An alarm that appears specifically during AI contour control or other RISC-dependent functions, but not during normal block-by-block machining, is a strong indicator that the RISC card is the fault source.
The main CPU handles normal machining; the RISC card is the additional processing resource that AI contour control depends on.
If normal operation is unaffected and the fault occurs only when functions that require the RISC card are activated, the card itself should be suspected.
If a substitute unit is available for temporary installation, this is the fastest diagnostic confirmation.
Q3: Is the RISC card from a Series 18i-A machine compatible with a Series 16i-B machine?
The RISC board family (A20B-3300-0101/0102) is used across both the model A (16i-A, 18i-A, 21i-A) and model B (16i-B, 18i-B, 21i-B) controller generations, but the physical installation path differs between generations.
The model A generation installs the RISC board via a specific riser arrangement on the model A main board. The model B generation installs option boards differently.
Before substituting a RISC card from one machine into another, confirm that the specific board revision and connector arrangement match the target machine's hardware configuration. When in doubt, contact a FANUC-specialised supplier with the source and target machine's hardware part numbers for compatibility confirmation.
Q4: The machine has the RISC card installed but AI contour control is not working. Is the card definitely faulty?
Not necessarily. The AI contour control and related RISC-dependent functions require both the hardware (the RISC card) and the software option enabled in the CNC's FROM.
If the option software is not licensed and enabled on this specific machine, the RISC-dependent functions will not appear in the CNC's function menu regardless of whether the RISC card is installed and functioning.
Check the option status first — if the AICC option is not shown as available, the issue is software licensing, not hardware.
Q5: Can the A20B-3300-0102 RISC card be repaired at component level after failure?
The PowerPC processor on the RISC card is a highly integrated device — component-level repair of the processor itself is not practically achievable.
Failure of peripheral components (voltage regulators, clock oscillators, memory ICs, coupling capacitors) is sometimes repairable by a qualified specialist with access to the correct test equipment and the ability to verify the board's function after repair. In most cases, board-level replacement is the correct maintenance path.
The -0102's status as the current revision means refurbished units are accessible through the specialist FANUC spare parts market.
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