F31 650 nm Square Laser Photoelectric Switch
A laser switch you aim by eye: the visible red spot shows the exact detection point — diffuse up to 300 mm from one housing, or a through-beam pair spanning up to 50 m.
- Visible 650 nm red laser — see the spot, nail the alignment
- F31300 diffuse: potentiometer-adjustable detection point
- F3150M through-beam pair: up to 50 m range
- NPN / PNP × NO / NC — direct PLC integration
- 10–30 VDC, IP65, simple 3-wire hookup
Product Overview
Infrared photoelectric switches make you commission blind — you wave a target, watch an LED, and hope the beam is where you think it is. The F31 replaces that ritual with a 650 nm visible red laser: the detection point is a dot you can see, on the part you care about, from the moment power is applied.
The square-body family ships in two working modes. F31300 is diffuse-reflective — a single housing that emits and reads back its own laser, with an on-body VR potentiometer to set the trip point, adjustable up to 300 mm (the catalog table lists the range as 1–300 mm; the datasheet as 50–300 mm — confirm the near limit with the factory if it matters to you). F3150M is a through-beam matched pair rated to 50 m; the transmitter carries a green indicator LED and the receiver a yellow one, so the two ends never get mixed up on a long run.
Electrically it is deliberately boring: 3-wire hookup (brown V+, blue V−, black signal), 10–30 VDC, output in NPN or PNP with NO or NC action by suffix, inside an IP65 housing — a drop-in citizen of any standard 24 VDC control cabinet.
Two Variants, Two Reach Classes
Model Selection Table
| Variant | Detection | NPN NO | NPN NC | PNP NO | PNP NC |
|---|---|---|---|---|---|
| F31300 diffuse-reflective | Adjustable up to 300 mm* | F31300N1 | F31300N2 | F31300P1 | F31300P2 |
| F3150M through-beam pair | Up to 50 m | F3150MN1 | F3150MN2 | F3150MP1 | F3150MP2 |
* Catalog table: 1–300 mm adjustable; datasheet: 50–300 mm — confirm the near limit with the factory for sub-50 mm working distances. Through-beam units are supplied and used as matched transmitter/receiver pairs.
Technical Specifications
| Light source | 650 nm visible red laser |
|---|---|
| Variants | F31300 (diffuse-reflective) / F3150M (through-beam matched pair) |
| Detection distance | Diffuse: adjustable up to 300 mm (near limit — see note) · through-beam: up to 50 m |
| Output | NPN (N) or PNP (P); NO (1) or NC (2) |
| Wiring | 3-wire — brown V+, blue V−, black signal |
| Supply voltage | 10 – 30 VDC |
| Adjustment | On-body VR potentiometer (diffuse detection point) |
| Indicators | Through-beam pair: transmitter green LED, receiver yellow LED |
| Protection rating | IP65 |
| Laser safety class / response time / temp. range | Contact factory — not published |
General-purpose sensing component — not an IEC 61496-certified safety component; never use it alone for personnel protection.
Typical Applications
Small-Part Presence Checks
The visible spot lands exactly where you point it — ideal for confirming small components on assembly and packaging lines.
Long-Span Beam-Break Points
The F3150M pair covers up to 50 m: wide conveyors, gate openings and long-aisle object-passage detection.
Carton Counting & Gap Detection
NO/NC and NPN/PNP options drop straight into existing packaging-line PLC logic for counters and gates.
Commissioning-Friendly Retrofits
Technicians see the red spot during setup — no blind aiming, faster swaps in existing 24 VDC cabinets.
Frequently Asked Questions
What does a visible 650 nm laser spot change compared with an infrared photoelectric switch?
Alignment stops being guesswork. With infrared sensors you infer aim from the output LED; with the F31 you watch a red dot land on the target, so commissioning a narrow target — a pin, a label edge, a carton corner — takes seconds. On the through-beam pair, aiming emitter at receiver over tens of meters is equally a by-eye job.
What is the difference between F31300 and F3150M?
F31300 is diffuse-reflective: one housing emits and receives its own laser, detects the target's reflection, and its detection point is tuned with the on-body potentiometer, up to 300 mm. F3150M is a through-beam matched pair — transmitter (green indicator LED) and receiver (yellow indicator LED) face each other across up to 50 m and switch when the beam is broken.
How close to the sensor can the diffuse version detect?
Factory sources differ on the near limit: the catalog selection table states 1-300 mm adjustable, while the datasheet states 50-300 mm. If your application depends on detection closer than 50 mm, confirm the working distance with the factory before ordering.
How do I read the model suffixes?
N = NPN output, P = PNP output; 1 = normally-open, 2 = normally-closed. So F31300N1 is the diffuse NPN NO model, and F3150MP2 is the through-beam PNP NC pair. Choose N for sinking PLC input cards, P for sourcing cards.
How is it wired?
Standard 3-wire scheme: brown to V+, blue to V-, black is the signal output, on a 10-30 VDC supply. Active level and rest state follow the NPN/PNP and NO/NC variant you ordered.
Is the laser safe, and can it run in dusty or damp areas?
The published data covers the 650 nm wavelength but not a laser safety class, so do not assume a class — request the figure from the factory if your site requires it. The housing is IP65: dust-tight and resistant to water jets, fine for normal factory floors but not for immersion.
Can the F31 act as a safety device at a gate or opening?
No. Neither variant is an IEC 61496-certified safety component; they are detection sensors and must never stand in for a safety light curtain. For personnel protection at openings, use a certified device such as our DQC series.
What are the export purchasing terms?
Both variants are quoted factory-direct from Foshan. Small trial orders are normally accepted; MOQ, lead time, packing and available documents (dimensional drawings, wiring diagrams) are confirmed with your quotation — state model codes and quantities, e.g. F31300N1 x 50 + F3150MN1 x 10 pairs.
Specs reviewed by Engineer Cai, Senior Application Engineer. See certificates.