Sensors on a Sorting Conveyor Line: What to Specify Before t

Sensors on a Sorting Conveyor Line: What to Specify Before the Quote, and What an Independent Sourcing Desk Verifies Before Shipping

The question buyers actually send is «Какие датчики нужны для конвейера с сортировкой?», and the honest short answer is: pin the eight parameters that decide function, not the marketing family. For a sorting conveyor those are normally sensing distance, mounting diameter, output type, supply voltage, IP rating, response time, ambient temperature window and connector or cable. The role of an independent industrial automation distributor here is line-by-line sourcing across brands, marking and datasheet verification before dispatch, and a written condition per line — new surplus, refurbished or used. No functional-safety or certification conclusion is offered; Russia and CIS dispatch is arranged under the quotation terms only.

A 2018 sorting line, twelve detection points, three sensor families

A panel shop in Russia (Urals region) rebuilt a 2018-era sorting conveyor for a postal hub. The original build sheet listed twelve detection points: bar-code read at the infeed, height check before the diverter, six metal-detection checks before each reject gate, a transparent-bottle detector on one lane, and a final end-of-line confirmation. Three sensor families sat on that line: diffuse-reflective photoelectric for the bottle check, through-beam photoelectric for the diverter trigger, inductive proximity for the metal flaps. The buyer's original BOM mixed a Sick reference with two older references from a different brand, all of them surface-mount M12 or M18.

The first RFQ came in as twelve lines with the bare description "photoelectric, M12, PNP, NO". That description matches several hundred part numbers across at least four brands. Before any quote is realistic, the buyer has to add the eight parameters above. Without them, two distinct detection points can collapse into one part number on paper and diverge mechanically on the panel.

What the spec sheet has to pin down — and what it usually does not

For a sorting conveyor, the eight parameters below decide function. Marketing copy usually skips at least three of them.

Sensing distance / range. Diffuse-reflective units have a nominal range measured against a 100×100 mm white card; the real range against a glossy parcel or a black rubber tire can be 30–60% of that figure. Through-beam units have a clean range, but the optics must clear the conveyor's vibration envelope.
Mounting diameter and form factor. M12, M18, M30 and rectangular block form factors are not interchangeable on the existing bracket. The mounting thread pitch matters more than the headline diameter on a retrofit.
Output type. PNP (sourcing) versus NPN (sinking), normally-open versus normally-closed, plus whether the line is two-wire, three-wire or four-wire. Mixing PNP and NPN on a single conveyor's I/O card is a wiring fault, not a sensor fault.
Supply voltage. 10–30 V DC covers most modern sensors. Some older 24 V AC units still float around on legacy lines; the supply window has to be pinned.
IP degree of protection. IP67 is the de-facto floor for a wet conveyor area; IP65 is acceptable for a dry packaging hall; IP69K matters only in food-and-beverage wash-down. Going one rating down saves almost no money; going one rating up is sometimes impossible in a tight housing.
Response time. Sorting conveyors typically need ≤1 ms; high-speed diverters want ≤0.5 ms. Specifying this on paper filters out inductive sensors that look correct on the form factor but cannot keep up with the line.
Ambient operating temperature. Cold-store conveyors need a low-temperature rating that you do not see on the headline datasheet. Heat near a furnace infeed needs the upper end pinned, not assumed.
Connector and cable. M8 3-pin, M12 4-pin, PVC cable, PUR cable, fixed cable length, plug-and-lead length. Two lines that read "M12 connector" on paper can be M12 3-pin and M12 4-pin, and the difference surfaces at installation.

Datasheets typically understate three of these for sorting lines: sensing range against non-white targets, response time under LED de-rating, and the connector pin-out when an adapter cable is in use. The desk asks for these explicitly because the supplier datasheet is usually silent.

Three families you actually meet on a sorting conveyor, and what each is asked to do

A typical sorting conveyor leans on three sensor families. Each does one job and stays out of the other two's lane.

Photoelectric — diffuse, retro-reflective, through-beam. Diffuse-reflective reads the part itself, useful for transparent or oddly-shaped objects where a reflector is not practical. Retro-reflective pairs the sensor with a reflector across the belt; cleaner on a long reach but adds one mounting point. Through-beam uses a separate emitter and receiver; the most stable on a high-speed diverter trigger because the optical path is sealed against stray reflections from the parcel itself.

Inductive proximity — for metal only. Six of the twelve detection points on the postal-hub line were inductive, one at each reject gate. Inductive sensors see only metal at a short range; on a sorting conveyor they confirm a metal actuator flag, a metal flap position, or a metal guide rail. They will not see a cardboard box.

Laser distance / time-of-flight — for height, profile or dimension. Where the conveyor sorts by parcel height or by stack count, a laser distance sensor (or a small time-of-flight module) gives millimetre-level readings to the PLC. The optical head is more expensive than M12 photoelectric, and the optical window has to be kept clean — a planning note for the maintenance schedule, not a sourcing question.

These three families do not substitute for one another. A photoelectric sensor will not give a 0.5 ms metal-presence signal; an inductive sensor will not see a transparent bottle. Mixing the families across a single BOM is normal; substituting one family for another is not. The desk treats any same-family swap (for example a Sick ZL2-P2428 against a Sick ZL2-N2415 — different sub-family, different sensing principle) as a documented comparison rather than a like-for-like replacement, and flags the axes the desk cannot verify in-house as unknown rather than guessed. Where the buyer is sourcing into the Moscow or Russian-regions market, the per-line condition is recorded on the quotation so customs paperwork can be built from the same source.

How the desk handles the lines before they ship

For each line on the conveyor sensor BOM, the desk runs a fixed verification sequence before the unit is dispatched. When a part number shows in stock at the time the quote is built, lead time reflects that position; when the part is to be sourced fresh, the lead time is re-confirmed per order rather than carried over from a previous quote. The Sick ZL2-N2415 series and the ZL2-P2438 series, for example, sit alongside the ZL2-P2428 in the catalog and can be cross-referenced for fit on a like-for-like mounting bracket when the buyer's BOM allows it.

First, the marking on the housing is read against the part number on the quote. The Sick ZL2-P2428 series and the BCG05-K1KM01PP encoder family that show in the catalog, for example, share the same overall form factor as several look-alike parts from other vendors — the marking is the only reliable read at the bench.

Second, the line's specifications are checked against the manufacturer's published datasheet for the revision on the unit. A photoelectric sensor marked as the current revision will have a different sensing-range de-rating curve than an earlier revision of the same part number; the quote is updated to reflect the actual unit, not the catalogue summary.

Third, the condition of the line is stated up front and on the quote itself, not left as a lot-level comment. New surplus is documented as such, with original packaging and a date code where available. Refurbished is sold only with a bench-test record, a written list of what was tested, and a per-unit warranty as stated on the quotation. Used is sold as removed-from-service, with no test claim beyond a power-on check unless the quotation states otherwise. The three labels are not interchangeable.

Fourth, the desk takes a pre-dispatch photograph of the marking, the connector and, where relevant, a power-on indication. The buyer sees the photo before the unit ships. For testable lines, a short video of the bench response is also part of the record.

Fifth, the lines are consolidated into a single consignment where the buyer's readiness times allow. A short-notice replacement line and a planned-refurbishment line can ship together or separately, depending on what the buyer confirms at quote time.

Where the desk stops

A sorting conveyor sensor package is a sourcing scope, not an engineering scope. The desk does not write the PLC program that reads the sensors, does not wire the conveyor, and does not commission the diverter. Lines that sit on a safety-rated function (cat-3 / PL d light curtain, muting sensor pair, emergency-stop loop) are flagged as engineering-review items and are not substituted by the desk under any circumstance. Lines that touch a certification scope (ATEX zone, EAC-requiring machinery list, a Notified Body decision on the host machine) are also flagged — the importer or the original manufacturer of the host equipment owns the compliance question, and the desk's only role is to source the line as specified.

The desk does not own a calibration laboratory. When a buyer's spec requires a third-party test certificate (a calibration chart, a vibration profile, an EMC report), the desk can arrange shipment to an independent laboratory on the buyer's instruction, but the test plan, the pass criteria and the report are owned by the laboratory and the buyer.

When it makes sense to send the line list to a desk like ours

A short list of detection points on a single brand, with a single ready-to-ship date and a single delivery address, does not need a desk. A 30-line list with mixed brands, mixed quantities (some 2 pcs, some 50 pcs), mixed condition preferences (new on the diverter, refurbished acceptable on the height check, used acceptable on the metal-flap sensors) and mixed readiness windows is exactly the case a desk was built for. The buyer's first message in that case is the line list plus the eight parameters above; from there, the desk works each line separately and reports what it actually found, not what the brochure said was available.

By the aoctrl sourcing desk. Data through September 2026.

Data Notes

The catalog references in this article (Sick ZL2-P2428 family and the BCG05-K1KM01PP encoder) reflect catalog scores returned by the desk's own query against the live aoctrl product database on the date above; they are not a stock statement and they are not a quotation. The condition vocabulary — new surplus, refurbished, used — is used per line on the quotation, and the labels are not interchangeable; new surplus lines ship with original packaging and a date code where available, refurbished lines ship with a bench-test record from the seller who performed the work, used lines carry no test claim beyond a power-on check unless the quotation states more. The desk is an independent distributor, not an authorized channel partner for the brands named; verify any safety, certification or functional claims with the original equipment documentation and your own qualification process.

FAQ

What sensing distance should I specify for a sorting conveyor?

Give the real working distance against the worst-case target (a glossy parcel, a transparent bottle, a black rubber tire) — not the headline "maximum range" from the datasheet, which is measured against a 100×100 mm white card and is typically 30–60% higher than the working figure. The desk reads this against the published de-rating curve when the line is sourced.

How do I handle the lines that differ only in cable length?

Treat cable length as a separate line item, not as a variant of the sensor line. Two sensors that share the part number but differ on the cable (2 m, 5 m, 10 m, with or without a connector) are not interchangeable on the quote; the desk sources each as its own line, with its own price and lead time per the catalogue.

Can the desk match a Sick catalog reference we already have?

Yes. If the line is a current Sick reference such as the ZL2-P2428 family or a BCG05-K1KM01PP encoder, send the full part number and the marking photo. The desk checks the marking against the catalogue entry and reports the actual revision on the unit, not the catalogue summary. Out-of-revision units are flagged on the quote.

What if my line is just "photoelectric sensor, M12, PNP, NO"?

The desk will not guess. That description matches several hundred part numbers across at least four brands. The desk comes back with a clarifying question covering the eight parameters — sensing range, output, mounting thread, supply, IP rating, response time, ambient temperature, connector — and quotes against the pinned line. The cost of one extra round-trip is much lower than the cost of receiving twelve parts that do not fit.

Do you refurbish sorting conveyor sensors in-house?

No. Refurbished lines are sourced as refurbished units, not rebuilt in-house. Each refurbished line arrives with a bench-test record written by the seller who performed the work; the desk does not re-label used units as refurbished and does not add a test claim to a lot that did not have one.

How is condition stated on the quote line?

Every line carries its own condition: new surplus, refurbished or used. The label is per line, not per lot. New surplus lines are sold with original packaging and a date code where available; refurbished lines are sold with a bench-test record and a per-unit warranty as written on the quotation; used lines are sold as removed-from-service with a power-on check only unless the quotation states more.

What about safety-rated sensors on the conveyor?

The desk sources safety-rated sensors as specified, never as a substitute. A light curtain, a muting sensor pair or any sensor sitting on an emergency-stop loop is a buyer-engineering decision; the desk does not cross-reference, replace or recommend on those lines and flags them on the quote when they appear.