A20B-3300-0390 Fanuc PCB Board A20B33000390 A2OB-33OO-O39O

A20B-3300-0390 | FANUC 8-Axis FSSB Servo Control Card — C5410A / Series 16i-B and R-J3iB / Single-Channel Fibre-Optic Servo Bus

8 Axes on One FSSB Channel — High-Density Servo Control

The A20B-3300-0390 places 8 servo axis channels on a single FSSB fibre-optic connection. This is the card's defining characteristic — not just the axis count, but the density of control achieved through one communication channel.

The FSSB (Fibre-optic Servo Serial Bus) daisy-chains multiple servo drives from a single fibre cable originating at the servo control card. The A20B-3300-0390 manages all the timing and data exchange for 8 drives in this daisy chain — transmitting position commands to each drive and receiving encoder feedback from each drive within the FSSB cycle time.

For a Series 16i-MB machining centre with 8 controlled axes — or an R-J3iB robot with 6 joint axes plus external axes — this card provides the complete FSSB servo interface from one slot.

Key Specifications

A20B-3300-039x — The Servo Card Family

The 039x range is the C5410A servo card family, with different axis counts:

Application Scenarios

Series 16i-MB 8-axis machining centre servo fault: A FANUC 16i-MB machining centre with 8 controlled axes (X, Y, Z, A, B plus tool changer and pallet axes) develops FSSB communication alarms on multiple axes. The A20B-3300-0390 is identified as the fault. Replacement restores all 8-axis FSSB communication.

R-J3iB robot servo card fault: A FANUC R-J3iB robot controller develops joint servo alarms. The A20B-3300-0390 8-axis servo card is the identified fault. Replacement restores all robot joint drives.

FAQ

Q1: What does "1 channel FSSB" mean for the A20B-3300-0390?

"1 channel" means the 8 axes all share a single FSSB fibre-optic daisy chain originating from this card. All 8 drives connect in series — each passes the fibre cable to the next. The C5410A on the card manages the complete 8-drive communication in each FSSB cycle. This is distinct from multi-channel FSSB cards where axis groups are on separate fibre chains.

Q2: What is the difference between A20B-3300-0390 (8-axis) and A20B-3300-0391 (6-axis)?

Both use the C5410A ASIC and single-channel FSSB — they are the same servo card family differing only in axis count. The 8-axis variant serves machines or robots with more controlled joints. The 6-axis variant serves standard 6-joint robot bodies or 6-axis CNC configurations. The two are not interchangeable even though they share the same ASIC.

Q3: Does replacing A20B-3300-0390 require servo parameter changes?

No. All servo axis parameters (gains, motor type, encoder type, acceleration limits) reside in the CNC's or robot controller's main SRAM. After fitting the replacement A20B-3300-0390, the system reloads all axis parameters automatically. Verify correct servo response at low speed on all 8 axes before resuming full-speed operation.

Q4: What environmental conditions does the A20B-3300-0390 operate in?

IP20 protection guards against fingers and similar-sized objects entering the card's electronics — adequate for installation in a sealed controller cabinet. Operating temperature range is 0–60°C, accommodating industrial environments without additional cooling. The CE certification confirms compliance with European safety, EMC, and environmental directives.