Compatibility

• CNC Series: FANUC 21i‑B (21i‑B standard, 21i‑B5, 21i‑B8)

• Applicable Systems: Milling, turning, and machining centers with 21i‑B controls

Key Specifications

• Processor: Intel Pentium MMX

• Onboard Memory: 16 MB DRAM (fixed, no expansion slots)

• Interfaces:

  • 1 × Ethernet (10/100 Mbps)

  • 2 × USB 1.1

  • Internal CNC bus (FANUC proprietary)

• Power: 5 V DC from CNC backplane

• Operating Temperature: 0 °C to +55 °C

• Humidity: 5%–95% RH (non‑condensing)

Main Functions

• System Core: Runs CNC system software, PMC logic, and motion control algorithms

• Motion Control: Executes interpolation, path planning, and axis synchronization

• Data Management: Stores user programs, parameters, tool offsets, and macro data

• Communication: Handles Ethernet (FTP, DNC) and USB (data backup/restore)

• Diagnostics: Onboard LEDs for power, reset, and error status

Features

• MMX Technology: Optimized for multimedia and real‑time motion processing

• Integrated Ethernet: Eliminates need for separate network card

• Compact Design: Single‑board CPU for 21i‑B series (small form factor)

Installation & Handling

• ESD Protection: Use anti‑static wrist strap at all times

• Power Off: Disconnect CNC power and wait 5 minutes before removal/installation

• Slot: Install in dedicated CPU slot (usually slot 0)

• Battery: Replace onboard backup battery every 2–3 years to prevent data loss

Troubleshooting

• Boot Failure: Check seating, backplane power, and battery voltage

• Ethernet Error: Verify cable, link LEDs, and network settings

• Data Loss: Check battery and perform parameter/program restore