The M3, M4, M5, and M6 series are ultra-miniature laser through-beam sensors engineered for high-precision detection in space-constrained installations. Operating on the classic through-beam principle with separate transmitter and receiver units, these sensors utilize a 650 nm red visible laser source. They achieve an impressive 20 meter sensing range while maintaining an exceptionally small spot size (Standard 1.5 mm, customizable down to 0.3 mm for some models), enabling precise long-range detection. Constructed with stainless steel housing and featuring an IP55 protection rating, they guarantee reliable performance in harsh industrial environments. Their ultra-compact threaded body design (M3/M4/M5/M6) makes them the ideal solution for automation applications where space is at a premium.
This series operates on the through-beam photoelectric sensing principle. The transmitter emits a modulated, collimated red laser beam. The photodetector inside the receiver is specifically tuned to detect this unique light signal. When an object passes between the transmitter and receiver, interrupting the laser beam, the receiver's output state changes, generating a switch control signal. This principle makes the sensor highly immune to the target's color, material, or surface reflectivity, ensuring extremely stable and reliable detection.
| Parameter | M3×20 Model | M4×20 Model | M4×18-TZ Model | M5×24 Model | M6×26 Model | M6×20-TZ Model |
|---|---|---|---|---|---|---|
| Thread Size | M3×0.5 | M4×0.7 | M4×0.7 | M5×0.8 | M6×1.0 | M6×1.0 |
| Sensing Distance | 20 m | 20 m | 20 m | 20 m | 20 m | 20 m |
| Standard Target | 100×100 mm White Paper | 100×100 mm White Paper | 100×100 mm White Paper | 100×100 mm White Paper | 100×100 mm White Paper | 100×100 mm White Paper |
| Light Source | 650 nm Red Laser | 650 nm Red Laser | 650 nm Red Laser | 650 nm Red Laser | 650 nm Red Laser | 650 nm Red Laser |
| Spot Size (at 2 m) | ~Φ5 mm | ~Φ5 mm (Customizable) | ~Φ1.5 mm (Customizable) | ~Φ1.5 mm (Customizable) | ~Φ1.5 mm | ~Φ1.5 mm (Customizable) |
| Housing Material | Stainless Steel | Stainless Steel | Stainless Steel | Stainless Steel | Stainless Steel | Stainless Steel |
| Output Configuration | NPN/PNP NO/NC | NPN/PNP NO/NC | NPN/PNP NO/NC | NPN/PNP NO/NC | NPN/PNP NO/NC | NPN/PNP NO/NC |
| Operating Voltage | 10–30 V DC | 10–30 V DC | 10–30 V DC | 10–30 V DC | 10–30 V DC | 10–30 V DC |
| No-load Current | <10 mA | <10 mA | <10 mA | <10 mA | <10 mA | <10 mA |
| Max. Load Current | 150 mA | 150 mA | 150 mA | 150 mA | 150 mA | 150 mA |
| Leakage Current | <0.01 mA | <0.01 mA | <0.01 mA | <0.01 mA | <0.01 mA | <0.01 mA |
| Voltage Drop | <1.5 V | <1.5 V | <1.5 V | <1.5 V | <1.5 V | <1.5 V |
| Switching Frequency | 100 Hz | 100 Hz | 100 Hz | 100 Hz | 100 Hz | 100 Hz |
| Response Time | 5 ms | 5 ms | 5 ms | 5 ms | 5 ms | 5 ms |
| Switching Hysteresis | <15% Sr | <15% Sr | <15% Sr | <15% Sr | <15% Sr | <15% Sr |
| Repeat Accuracy | <5% Sr | <5% Sr | <5% Sr | <5% Sr | <5% Sr | <5% Sr |
| Protection Rating | IP55 | IP55 | IP55 | IP55 | IP55 | IP55 |
| Operating Temperature | 0 °C ~ +55 °C | 0 °C ~ +55 °C | 0 °C ~ +55 °C | 0 °C ~ +55 °C | 0 °C ~ +55 °C | 0 °C ~ +55 °C |
| Short-Circuit Protection | Yes | Yes | Yes | Yes | Yes | Yes |
| Overcurrent Protection | 180 mA | 180 mA | 180 mA | 180 mA | 180 mA | 180 mA |
| Connection | Φ3.0 mm PVC Cable | Φ3.0 mm PVC Cable | Φ3.0 mm PVC Cable | Φ3.0 mm PVC Cable | Φ3.0 mm PVC Cable | Φ3.0 mm PVC Cable |
| Cable Specification | 3×0.15 mm² | 3×0.15 mm² | 3×0.15 mm² | 3×0.15 mm² | 3×0.15 mm² | 3×0.15 mm² |
| Front-end Connection | Tx: 2-core wire Rx: Fiber optic | Tx: 2-core wire Rx: Fiber optic | Tx: 2-core wire Rx: Fiber optic | Tx: 2-core wire Rx: Fiber optic | Tx: 2-core wire Rx: Fiber optic | Tx: 2-core wire Rx: Fiber optic |
| LED Indicator | Tx: Green Rx: Yellow | Tx: Green Rx: Yellow | Tx: Green Rx: Yellow | Tx: Green Rx: Yellow | Tx: Green Rx: Yellow | Tx: Green Rx: Yellow |
| Certification | CE, RoHS | CE, RoHS | CE, RoHS | CE, RoHS | CE, RoHS | CE, RoHS |
It is a pair of separate transmitter and receiver units. The transmitter emits a modulated 650 nm red visible laser beam that the receiver detects. When an object breaks the beam between them, the output switches. Because it relies on beam interruption rather than reflection, detection is largely immune to target color, material and surface reflectivity, giving very stable non-contact sensing.
All variants reach up to a 20 m sensing distance against a 100×100 mm white-paper target. The visible red laser keeps a tight spot — about Φ5 mm on the M3/M4 and down to roughly Φ1.5 mm on the M4-TZ, M5 and M6 models (some customizable). The small spot allows precise detection of tiny parts and thin materials at long range.
These sensors ship with NPN/PNP and NO/NC configurations. PNP (sourcing) is the default for most modern PLCs, while NPN (sinking) suits some Asian control systems. NO conducts when the beam is clear; NC conducts when the beam is broken. Operating voltage is 10–30 V DC with short-circuit and overcurrent protection built in.
Each unit uses a stainless-steel threaded body (M3×0.5 to M6×1.0) with an IP55 protection rating, suited to dusty and lightly washed-down industrial settings. The operating temperature range is 0 °C to +55 °C. The compact threaded design fits space-constrained machinery, SMT lines, robotics end-effectors and precision assembly stations.
They excel in micro-electronics and semiconductor SMT equipment for PCB and component positioning, in precision instruments and medical assembly for part counting and presence verification, in robotics for grip confirmation, and in textile and light machinery for broken-yarn or thin-film edge detection. The 20 m range and tiny spot make them ideal where space is tight and accuracy is critical.
Specs reviewed by Engineer Cai, Senior Application Engineer. CE & RoHS compliant — see certificates.