Optical Slot Sensor

Optical slot sensor, also known as a U-type photoelectric switch, determines the strength and distance of the induced reception signal and uses light as the medium to detect the position of an object by receiving and converting infrared light between the emitting body and the receiving body.

1. Use simple wire leads (standard wire length 2M), which can be extended arbitrarily;
2. Variable dimming type that is not affected by external light interference;
3. 5MM slot width with various shapes, suitable for various installation occasions, marking detection, liquid level detection and other applications;
4. All designed products can have waterproof, oil-proof, dustproof and other functions;
5. comes standard with soft wire;

1. Mechanical Positioning and Limit Control: Origin and Limit Detection: Commonly used in 3D printers, CNC engraving machines, automated robotic arms, and automated production lines to detect the absolute zero point (zeroing) or travel boundaries of moving parts, preventing mechanisms from exceeding safe limits. Fixture and Pallet Positioning: Detects whether pallets and mechanical fixtures on the production line have moved to the designated workstation, confirming safety before proceeding to the next step.

2. Object Counting and Flow Monitoring: Production Line Counting: When packaging boxes, parts, etc., on a conveyor belt pass through sensor grooves, the light is blocked, generating pulses, thus achieving accurate counting. Mechanical Coin/Label Detection: Widely used in vending machines, game machine coin channels, or label color mark and paper edge detection in printers and packaging machines.

3. Rotational Speed ​​Measurement and Angle Measurement: Encoder Speed ​​Measurement: Works with a perforated disc (code disk) or gear. When the gear rotates through a U-shaped groove, the on/off state of the light beam is converted into a pulse signal. The real-time speed of the motor can be obtained by calculating the pulse frequency.

4. Component Presence and Status Identification for Error Prevention and Omission Prevention: Detects whether holes in assembled parts on the production line have been successfully drilled and whether any screws or small components are missing. Label Missing Detection: In the labeling machine, it detects whether any labels are missing from the backing paper.

Do not use Optical Slot Sensor in the following locations: 

Locations exposed to direct sunlight
Locations with high temperatures or condensation
Locations exposed to corrosive gases
Locations subject to vibration or shock exceeding the rated range

Shelf Life: The warranty period is one year from the date the product is shipped to the purchaser's designated location.

Warranty Coverage:

The following are not covered by the warranty:
1: Failure to follow the operating instructions
2: Failure caused by modifications or repairs not performed by personnel

Q：How to judge the quality of Optical Slot Sensor?

I. Appearance and Structure (Quick Initial Inspection)

Shell and Tank: No cracks, deformation, or burrs; good parallelism on both sides of the U-shaped groove, no misalignment (optical path misalignment will lead to missed/false detections).

Optical Window: Transparent PC material, light transmittance ≥95%; no scratches, oil stains, or dust, otherwise the light signal will be attenuated.

Pin/Wiring: No oxidation, bending, or detachment; gold-plated pins offer better oxidation resistance; wire cores are undamaged and firmly crimped.

Indicator Lights: Uniform illumination, no flickering; clear indication of light exposure/blockage status (red/green LED).

Material and Workmanship: Flame-retardant ABS (UL94 V-0) shell, impact resistance ≥1000G; uniform sealant, no excess sealant/bubbles.

Bottom Line of Acceptance: No deformation of the tank, clean window, intact pins, and normal indication.

II. Electrical Performance (Multimeter + Power Supply, Required)

1. Transmitter (Infrared LED)

Analog Multimeter R×1k range: Forward resistance 10kΩ–50kΩ (voltage drop 1.1–1.6V), reverse resistance **∞**; abnormal readings indicate aging/breakdown of the transmitter.

Digital Multimeter Diode range: Forward voltage drop 1.2–1.5V, no reading in reverse.

2. Receiver (Phototransistor)

Dark state (no light): collector-emitter resistance **∞**; low resistance indicates leakage damage.

Bright state (transmitter powered on): Resistance rapidly drops to several hundred Ω–several kΩ; no change indicates receiver failure.

3. Power-on Function Test (5–24V DC)

Power supply: Voltage within ±10% of rated value, current 10–20mA (commonly ≤15mA for micro-sized units).

Output:
Unobstructed: LED lights up when light is incident, output is high (NPN) / low (PNP).

Obstructed: LED turns off when light is blocked, output toggles; crisp action, no jitter.

Load Capacity: Output drive ≥100mA, can directly drive PLC/relay; no overheating or abnormal voltage drop.

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