Catalog Number Highlighting: Why Reviewers Ask for It

Open any manufacturer datasheet and count the part numbers on it. A typical relay datasheet covers the whole family: two coil voltages, four contact arrangements, three terminal styles, every combination with its own catalog number. Forty part numbers on one PDF is normal. You are supplying exactly one of them.

The reviewing engineer's job is to verify that the one you're supplying meets the spec. An unmarked datasheet hands them a puzzle: which of these forty is it? Some reviewers solve the puzzle. The experienced ones don't try; they stamp the package Revise and Resubmit with a comment like "identify products being furnished" and send it back. You just lost two to four weeks of schedule to a missing highlighter stroke.

That's the whole case. Highlighting is cheap, its absence is expensive, and reviewers notice it immediately because it's the first thing that tells them whether checking your package will be easy or miserable.

What good highlighting looks like

Mark the complete catalog number, everywhere it appears. If the ordering table builds the number from a base plus suffix codes, mark the full assembled string, and mark each selected option in the options table too. The options are precisely where compliance lives: an unmarked lens code or coil voltage is an unanswered question about whether you met the spec.

Mark the row, not the general vicinity. In a selection table, the sweep should pin down one row unambiguously. A halo that plausibly covers two rows is worse than nothing, because now the reviewer has to guess which one you meant, and a wrong guess creates a comment either way.

One item, one color, when a datasheet serves several tags. A shared datasheet is good practice, since nobody wants twelve copies of the same relay PDF. But when tags CR-101 and CR-204 both live on that sheet with different part numbers, give each its own highlight color and say so on the sheet or the schedule. The reviewer should never have to work out which mark belongs to which tag.

Mark the values the spec constrains, not just the number. If the spec demands a 24 VDC coil or a NEMA 4X rating, a mark on the row of the ratings table that proves it turns a compliance question into a glance. This is the difference between a package the reviewer checks and a package the reviewer confirms.

Stay legible in grayscale and to color-deficient readers. Packages get printed, copied, and reviewed by people who can't tell red from green. Yellow on white survives everything; red and green marks on the same page are a gamble. If you use multiple colors, vary something else too: a label, an underline style, an arrow.

The process that makes it stick

Highlighting by hand is a mechanical pass, so treat it like one:

1. Print or pull up the equipment schedule. It's the master list of catalog numbers.
2. Work datasheet by datasheet. Search the PDF for the catalog number; mark every hit, including the ordering table and options.
3. Check the spec section for constrained characteristics on that item (where those hide), and mark where the datasheet states them.
4. Tick the line on the schedule. An unticked line at the end means a missing datasheet or a wrong catalog number, and either one is exactly what you want to find before the reviewer does.

On a 60-item package this is an afternoon. It's also the afternoon most likely to catch a real mistake: the wrong-voltage variant that got quoted, the discontinued part number that carried over from the last job's schedule. Every integrator I know has caught at least one of those with a highlighter, which is cheaper than catching it in the panel shop.

The mistake that undoes all of it

Highlighting a datasheet for the wrong part. It happens when the schedule says one catalog number and the quote or the purchase order says another, and the person highlighting works from the wrong list. The marks look diligent, the package looks thorough, and the panel gets built with a part the engineer never saw. Keep one list. Whatever document you consider the single source of truth for what's being supplied, highlight from that one, and make sure purchasing buys from it too.

Highlighting is one piece of the larger assembly job; the full structure is in what goes in a control system submittal package.

Disclosure: I build Submittal Kit, which finds and marks catalog numbers on datasheets automatically and gives each item its own color, with a person reviewing every mark. The manual process above is exactly what it automates.