How to read a FANUC part number before ordering a replacement
Every ordering mistake in this trade that does not involve money involves a number: a digit dropped, a suffix tidied away, a neighbour's number copied off the wrong label. A FANUC part number comes apart in three pieces — prefix, digit group, suffix — and a buyer can practise every check on real stocked numbers, because the stocked numbers are the examples that matter.
From the Spareaxis blog — guides for buyers of FANUC spare parts.
The prefix names the family
Start with the prefix, because it sorts the world. In this catalogue, A02B numbers are control and display units: the A02B-0319-B502 is a control, the A02B-0303-C084 is a display, and the prefix alone does not say which — position does, and position is the witness to trust. A06B is the drive and motor world: amplifiers like the A06B-6132-H002 and the motor A06B-0235-B202. A16B is a board — the A16B-3200-0219 is the catalogue's named example. A860 is the feedback shelf: encoders, pulse coders and one handwheel. A05B is the robot side, where the A05B-2256-C100 teach pendant lives.
Five prefixes, five shelves. A buyer who can sort a number into its shelf has already avoided the grossest class of error — asking the amplifier desk about a board — and has the frame the remaining digits hang on. Note what the prefix does not do: it never, by itself, identifies the part. Two units can share a prefix and a digit group and still be different parts, which is what the suffix is for.
The digit group names the line
The four digits after the prefix identify the line within the family. In the A06B amplifier shelf, the groups behave like a map: 6132, 6117 and 6320 are servo-side listings; 6140 is a spindle module; 6222 covers a matched pair; 6110 and 6250 are combined servo/spindle units. In the A860 family, 0309, 2005, 2000 and 0365 are motor feedback devices while 0203 is the handwheel — the same prefix, a different species, separated by its group.
The habit to build is reading the group as a neighbourhood, not an address. The group tells you which other numbers to compare against — the A06B table lists all nine amplifier groups side by side for exactly this purpose — and it tells you when a transcription looks wrong: a group that does not exist in the family's map is a digit misread, and it is cheaper to re-read the label than to ship against the guess.
The suffix completes the identity
After the final dash sits the suffix — H002, B500, T301, V501, C100 — and the suffix, not the prefix, decides which part the number names. A06B-6222-H015 is a servo amplifier module; A06B-6222-H022 is a spindle amplifier module. Same prefix, same group, different part, decided entirely by the suffix. Any system that truncates numbers — a spreadsheet that eats the suffix, a stores list that keeps only the group — will eventually order the wrong half of that pair.
Suffixes also carry the T and V distinction in the A860 family: most encoders there end in T-blocks, while the A860-0365-V501 ends in a V-block, and the V is not a typo to be corrected into a T. The rule is absolute: copy the number as printed, all of it, and let the label outrank every intermediate document. Where a mark follows the number, like the #0100 shown in the catalogue entry for the A06B-0235-B202 motor, quote that too and let the desk reconcile it.
Position beats pattern
A number divorced from the unit it was read off is half an identification. The A02B family proves it: controls and displays share the prefix, and while the named displays here end in C-blocks and the controls in B-blocks, that pattern is a hint, not a law. The reliable witnesses are physical: a number read from the main unit in the cabinet is a control; a number read from the back of the screen unit is a display; a number read from a board's printed face is a board, whatever prefix the paperwork claims.
In practice, one sentence in the inquiry performs this check: say where the number was read from. Label of the fitted unit, photograph of the label, machine paperwork, or a previous invoice are four different grades of evidence, and the desk weights them differently. The label wins; paperwork is reconciled against it; a number with no stated source gets the source question back.
A five-line checklist for any number
Five habits do the whole job. Read the number off the fitted unit, not off a document about the unit. Copy the suffix as printed, and say where a character is a guess. Name the unit's family and its position when you write. Keep any suffix marks that follow the number. And when two documents disagree about a number, send both readings — the desk would rather reconcile a conflict at the inquiry stage, when it costs a reply, than after a shipment, when it costs a machine-week.
Buyers who hold a number and want the catalogue's own record of it can find every named number from its family page in the catalogue. Buyers holding only a symptom have a different starting point — the repair desk — and the number can be hunted down from the machine side with the family pages as the map.
When the number alone is not enough
A part number narrows the field; it does not always close it. Marks printed after the number — a hash mark with digits, a letter added to the suffix, a revision state on the label — can separate two units that share the main number and differ in a way that matters to the control. That is why the desk asks for the whole label and not the number alone: the number says which shelf to walk to, and the marks say which box on the shelf.
Three companions travel well with any number sent for quotation. The first is the control generation, read from the control's own plate or its start screen, because the same family spans generations. The second is the unit's position — which axis, which slot, which cabinet — because position separates look-alike modules. The third is a plain description of the label as it survives: what is legible, what is damaged, and what was copied from a document instead of the unit itself. A number with its companions is answered once; a number without them is answered with questions.
A photograph of the label, described in the message, beats a careful transcription more often than buyers expect. Transcription errors cluster exactly where the number is hardest to read — the suffix letters and the marks after the dash — while a photograph preserves them for the desk to read directly. Where a camera cannot reach the label, transcribe it twice, once from the unit and once from any document that names it, and send both readings where they differ.
One number can sit on two shelves
The A06B-6200-H026 makes the point from the seller's own listings: the number appears among the servo amplifiers and again among the power supplies. A buyer who orders by number alone, without saying which of the two units is being replaced, has left the decisive fact out of the message. The unit's position settles it — a module feeding the drive chain from the supply side is one part; a module driving a motor is another — and position is information only the buyer at the machine can supply.
Treat every number, then, as a name that still needs its address: the cabinet, the slot and the unit it sits beside. Quoted with its address, a shared number orders as safely as a unique one.
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Send the part numbers you need, or the number of a unit you want assessed, with the machine each belongs to. One desk answers for the shelves and the bench.
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