Omron E3T-SR42 2M Photoelectric Sensor
Omron E3T-SR42 2M is an ultrathin retro-reflective photoelectric sensor designed for object sensing up to 200 mm with the specified reflector arrangement. A 650 nm red LED establishes the optical path, while the NPN open-collector output transfers the switching state to compatible control circuitry. Dark-ON operation is specified, and operate or reset time is 1 ms max. The sensor operates from 12 to 24 VDC, consumes 20 mA max., and includes a 2 m pre-wired cable. The stated target requirement is an opaque object with a minimum diameter of 27 mm. Within the E3T Series, the E3T-SR42 2M provides the Dark-ON NPN option. Related retro-reflective photoelectric sensors are available across Omron Sensing Range.

| Brand | Omron |
| Product | Photoelectric Sensors |
| Model Number | E3T-SR42 2M |
Omron E3T-SR42 2M Photoelectric Sensor – Technical Specifications
| Specification | Value |
|---|---|
| Sensing Method | Retroreflective |
| Sensing Distance | 200 mm [30 mm] |
| Standard Sensing Object | Opaque, 27-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 | 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 | Dark-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 | 1,000m/s2 3 times each in X, Y, and Z directions |
| Protection Circuits | Power supply and control output reverse polarity protection, Output short-circuit protection, Mutual interference prevention |
| Degree Of Protection | IEC 60529 IP67 |
| Material | PBT (polybutylene terephthalate), Denatured polyarylate, Methacrylc resin |
The Omron E3T-SR42 2M Photoelectric Sensor uses retro-reflective sensing across a maximum 200 mm distance with the specified reflector arrangement. A 650 nm red LED establishes the optical path, while the NPN open-collector output transfers the switching state to compatible control equipment. Dark-ON operation is specified, and operate or reset time is 1 ms max. The sensor operates from 12 to 24 VDC and consumes 20 mA max. A 2 m pre-wired cable provides the electrical connection. The stated target is an opaque object with a minimum diameter of 27 mm. Orange operation and green stability indicators provide visual operating information during setup.
For an Omron NPN retro reflective photoelectric sensor requiring Dark-ON operation and 200 mm sensing, the corresponding model is the E3T-SR42. Output load current is specified at 50 mA max., with load supply voltage up to 26.4 VDC. Operating temperature extends from -25 to 55°C, while storage extends from -40 to 70°C without icing or condensation. Reverse-polarity protection, output short-circuit protection, and mutual-interference prevention are specified. PBT, denatured polyarylate, and methacrylic resin are listed among the materials. For a related Light-ON retro-reflective E3T model, see E3T-SR41 2M.

