Photoelectric Sensor
Photoelectric sensors detect objects with light rather than contact — diffuse, retro-reflective and through-beam types for conveyors, packaging machines and assembly lines. Industrypapa stocks the Datalogic S3N, S5N, S100, S300, S8, S45, S60 and TL ranges alongside Micro Detectors QMR sensors, all quoted with GST invoice and delivered pan-India.
The three sensing modes, and when to use each
Diffuse (proximity)
Emitter and receiver in one housing; the sensor sees light bounced back off the object itself. Nothing to mount on the far side, so it is the quickest to install — but the range is the shortest and a dark or matt target reflects far less than a shiny pale one. Best for short, well-controlled gaps.
Retro-reflective
The sensor faces a reflector across the gap and triggers when the returned beam is broken. Longer range than diffuse, and largely indifferent to the colour of the object, because the sensor is watching the reflector rather than the target. The usual choice on conveyors.
Through-beam
Separate emitter and receiver facing one another. The longest range and the most tolerant of dust, mist, condensation and wash-down, because the beam only has to cross the gap once. The cost is wiring and aligning both sides of the machine.
Special optics
Beyond the three basic modes there are laser versions for very small targets, fibre-optic heads for cramped or hot positions, polarised retro-reflective versions for shiny objects, and contrast versions that read printed marks.
Photoelectric sensor series stocked at Industrypapa
| Series | Format | Examples in stock |
|---|---|---|
| S3N / S3Z | M18 miniature barrel, DC, cable or M12 | S3N-PR-5-T51-P, S3Z-PR-5-B01-PL, S3N-PH-5-M01-P |
| S5N | M18 barrel, the widest choice of optics including laser and fibre | S5N-PA-5-C01-PP, S5N-MA-5-W03-NN |
| S100 | Compact rectangular housing for tight machine positions | S100-PR-5-B10-PK, S100-PR-2-T10-PH, S100-PR-2-C00-NK |
| S300 | M18 barrel available in AC and relay-output versions | S300-PA-1-G00-EX, S300-PA-1-F01-RX, S300-PA-2-B01-OC |
| S45 | Miniature rectangular housing, M12 connection | S45-PR-5-M03-PH, S45-PH-5-M03-PH, S45-PR-5-T53-PH |
| S6 / S60 / S62 / S65 | Rectangular housings, several sizes and output options | S60-PA-5-T51-PP, S62-PA-5-B01-PP, S65-PA-5-M13-OO |
| S8 | Rectangular housing including the W03 contrast versions | S8-PR-5-B01-PP, S8-PR-5-T51-PP, S8-MR-5-W03-PP |
| S67 | Distance measuring and analogue output versions | S67-MH-5-Y03-1 |
| TL46 / TL50 / TLU / TLµ | Contrast and colour mark sensors for packaging registration | TL46-W-815, TL50-W-815, TLµ-011, TLU-355 |
| LD46 | Luminescence sensor for UV-visible marks | LD46-UL-735 |
| QMR (Micro Detectors) | Rectangular photoelectric sensors, alternative to the S-series | QMR7/OP-0F, QMRN/0P-0A, QMRHD/0P-0F |
| MLSI / MR (Tri-Tronics) | Tri-Tronics photoelectric heads | 20140 MLSI, 20144 MR |
Reading the part number before you order
The code is read left to right. The first block fixes the housing family and therefore the size and mounting — S3N and S5N are M18 barrels, S100 and S8 are rectangular blocks. The middle blocks set the optical function and supply type. The final block is the output and connection: codes ending in PP, PK and PH are PNP, while NN, NK and NH are NPN, and the same block tells you whether the sensor comes with a fly lead or an M12 plug.
One letter changes the sensing mode, so ordering from a half-remembered code is the most common cause of a wrong delivery. Send us the complete code from the sensor body or a photograph of the label and we will confirm it, or quote the current equivalent if the series has moved on.
Specifying a photoelectric sensor
- Sensing distance with a margin — rated ranges assume a clean lens and a good target.
- Target properties — colour, finish, transparency and whether it is shiny enough to need polarised optics.
- Housing and mounting — M18 barrel is easiest to retrofit; rectangular blocks give a better beam in tight guards.
- Output type — PNP or NPN, NO or NC, and whether the PLC card matches.
- Supply voltage — the majority are 10–30 V DC, but the S300 family also covers AC and relay output.
- Connection — fly lead or M12 plug, and the cable length you need.
- Environment — dust, wash-down and vibration usually push the choice towards through-beam or a stainless option.
- Response time — a fast conveyor or a small target needs the quicker versions.
Buying photoelectric sensors in India
Industrypapa supplies photoelectric sensors to OEMs, machine builders, packaging, food, pharma and automotive plants and to maintenance teams across India. Stocked parts ship the same or next working day and anything not held is quoted with a firm lead time. All orders are invoiced with GST and delivered pan-India, and we are happy to work from a bill of materials, a machine manual extract or a photo of the old sensor.
Related ranges: Datalogic sensors, contrast sensors, inductive proximity sensors, ultrasonic sensors, slot sensors, fibre optic cables and Pepperl+Fuchs sensors. For anything not shown, send us the part number.
Frequently asked questions
What is a photoelectric sensor?
A non-contact sensor that detects an object by the light it interrupts or reflects. It uses an LED or laser emitter and a photodetector, and switches an output when the received light crosses a threshold.
Which type gives the longest range?
Through-beam, by a wide margin, followed by retro-reflective and then diffuse. Through-beam is also the most reliable in dusty or wet conditions.
Will a diffuse sensor detect a black object?
Often, but at a much reduced distance, because a matt black surface returns very little light. If the target range varies in colour, a retro-reflective or through-beam arrangement is the safer specification.
Can you supply the reflectors and cables as well?
Yes — reflectors, M12 connector cables, mounting brackets and fibre-optic cables are all supplied alongside the sensors so the installation arrives complete.
