FANUCPlug-In CPU Processor Card with Dual Check Safety for Series 16i / 18i / 20i / 21i CNC

Product Description

What this part is

A Fanuc A20B-3300-0260 CPU card — the plug-in central processor module for Series 16i, 18i, 20i and 21i CNC controls, built around a 486MMX-class processor and carrying Dual Check Safety. It mounts onto the control’s main motherboard (the A20B-8100-013x family of model A cards), not directly into a card rack.

This is a CPU-tier processor card, not an I/O card and not an expansion or option board. Supplied as a bare card.

Decoding the order code

A20B: Fanuc printed-circuit-board prefix. On the i-series controls A20B covers both the motherboards and the plug-in processor, axis and option cards that mount on them.

3300: The control generation group. A20B-3300 is the Fanuc Series 16i / 18i / 20i / 21i plug-in card group. Sibling numbers in the group cover other functions — A20B-3300-0121, for instance, is an axis control card for the same platform.

0260: The specific card, here the CPU with Dual Check Safety.

/11F: The board edition, or revision level. A revision suffix, not a different part number.

Dual Check Safety: what it actually does:
Dual Check Safety is Fanuc’s safety-rated cross-checking function. Two independent CPUs in the control monitor the commanded and actual speed and position of each motor and compare their results. A disagreement is detected at high speed and power is removed from the motor through two independent paths. That is what makes safe-speed and safe-position functions on the machine possible — a guard-open reduced-speed mode, for example, rather than a hard stop.

The practical consequence for a buyer: a machine specified with Dual Check Safety needs a DCS-equipped CPU card to restore the safety function, and conversely a DCS card on a machine not configured for it will alarm until the corresponding parameters and ladder are in place. Match the card to the machine’s safety specification, not just to the control series.

Published specifications

Function: Plug-in CNC central processor card with Dual Check Safety.

Processor: 486MMX-class CPU chipset.

Platform: Fanuc Series 16i, 18i, 20i, 21i CNC controls.

Mounting: Plugs onto the control motherboard, typically the A20B-8100-013x model A card.

Safety architecture: Two independent CPUs cross-checking speed and position, power removal via two independent paths.

Quantity and configuration

Sold as 1 piece — one bare CPU card. Scope of supply is the card itself. Dual Check Safety operation additionally depends on the machine’s own safety parameters and PMC ladder, which live in the control. New old stock, in an opened box.

Interchange guidance

Searchable forms of the same part number: A20B-3300-0260, A20B33000260, A20B 3300 0260, A20B-3300-0260/11F, A20B33000260 11F. Other editions of the same base number are the same card at a different revision level. Adjacent 3300-group numbers such as A20B-3300-0121 or A20B-3300-0360 are different cards — different function, not interchanges.