Omron E3T-ST31 2M Photoelectric Sensor
Omron E3T-ST31 2M is an ultracompact through-beam photoelectric sensor for sensing opaque targets across a distance of up to 2 m. Its 650 nm red LED establishes the optical path between the emitter and receiver, while the NPN open-collector output transfers the switching state to compatible control equipment. Light-ON operation defines the output behavior, and the sensor responds within 1 ms. It operates from 12 to 24 VDC and includes a 2 m pre-wired cable. Current consumption is 10 mA maximum for the emitter and 20 mA maximum for the receiver. Within the E3T Series, the E3T-ST31 2M provides the 2 m Light-ON configuration. Related long-range through-beam sensors are available across Omron Sensors.
| Brand | Omron |
| Product | Photoelectric Sensors |
| Model Number | E3T-ST31 2M |
Omron E3T-ST31 2M Photoelectric Sensor – Technical Specifications
| Specification | Value |
|---|---|
| Sensing Method | Through-beam |
| Sensing Distance | 2 m |
| Standard Sensing Object | Opaque, 3-mm dia. min. |
| Light Source | Red LED (650 nm) |
| Power Supply Voltage | 12 to 24 VDC , ripple (p-p) 10% max. |
| Output Configuration | NPN |
| Connection Method | Pre-wired 2 M cable |
| Current Consumption | 30 mA max. (Emitter 10 mA max., Receiver 20 mA max.) |
| Control Output | Load power supply voltage: 26.4 VDC max. Load current: 50 mA max. (residual voltage: 2 V max. for load current of 10 to 50 mA, 1 V max. for load current of less than 10 mA) Open-collector output |
| Operation Mode | Light-ON |
| Response Time | Operate or reset: 1 ms max. |
| Indicators | Operation indicator (orange), Stability indicator (green) |
| Ambient Illumination | Incandescent lamp: 5,000 lx max., Sunlight: 10,000 lx max. |
| Ambient Temperature Range | Operating: −25 to 55°C Storage: −40 to 70°C (with no icing or condensation) |
| Ambient Humidity Range | Operating: 35% to 85% Storage: 35% to 95% (with no condensation) |
| Insulation Resistance | 20 MΩ min. at 500 VDC |
| Dielectric Strength | AC1,000V, 50/60 Hz for 1 min. |
| Vibration Resistance | 10 to 2,000 Hz, 1.5-mm double amplitude or 300 m/s2 for 0.5 hours each in X, Y, and Z directions |
| Shock Resistance | 1,000 m/s2 3 times each in X, Y, and Z directions |
| Protection Circuits | Power supply and control output reverse polarity protection, Output short-circuit protection |
| Degree Of Protection | IEC 60529 IP67 |
| Material | PBT (polybutylene terephthalate), Denatured polyarylate |
| Weight | Approx. 40 g |
The Omron E3T-ST31 2M Photoelectric Sensor uses through-beam sensing across a maximum distance of 2 m for opaque targets as small as 3 mm in diameter. A 650 nm red LED establishes the optical path between the emitter and receiver. The NPN open-collector output supports a load supply voltage of up to 26.4 VDC and a load current of up to 50 mA. Light-ON operation determines the switching behavior, while operate or reset time is specified at 1 ms maximum. The sensor operates from 12 to 24 VDC and includes a 2 m pre-wired cable. Total current consumption is 30 mA maximum, consisting of 10 mA maximum for the emitter and 20 mA maximum for the receiver. Orange operation and green stability indicators provide visual status information.
For an Omron through-beam sensor requiring NPN output, Light-ON logic, and a 2 m sensing distance, the relevant model is the E3T-ST31. Ambient-light resistance is specified at 5,000 lx under incandescent light and 10,000 lx under sunlight. Operating temperature extends from -25 to 55°C, while storage covers -40 to 70°C without icing or condensation. Power-supply and control-output reverse-polarity protection and output short-circuit protection are included. PBT and denatured polyarylate are listed as construction materials. The specification also matches searches for an Omron 2 m through-beam sensor and Omron NPN photoelectric sensor. For the corresponding Dark-ON version with the same 2 m sensing distance and 2 m cable, see the E3T-ST32 2M.
