Omron E3T-ST21 2M Photoelectric Sensor
The Omron E3T-ST21 2M Photoelectric Sensor is an ultracompact through-beam with NPN output, 300 mm sensing distance, and red light source (650 nm) for precise object detection. Operating on 12–24 VDC power supply, it is part of the Omron industrial range under the Omron Photoelectric Sensors category and the Omron E3T Series. It ensures stable performance with 30 mA current consumption, Light-ON operation, open-collector control output, 1 ms response time, and IP67 protection. The sensor includes a 2 m pre-wired cable supporting reliable and easy integration in compact industrial setups.
| Brand | Omron |
| Product | Photoelectric Sensors |
| Model Number | E3T-ST21 2M |
Omron E3T-ST21 2M Photoelectric Sensor – Technical Specifications
| Specification | Value |
|---|---|
| Sensing Method | Through-beam |
| Sensing Distance | 300 mm |
| Standard Sensing Object | Opaque, 2-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 |
Engineered for high-performance automation, the Omron E3T-ST21 2M features a Photoelectric Sensor with a 300 mm sensing distance, making it suitable for detecting small opaque objects as small as 2 mm in diameter. It is powered by a 12 to 24 VDC supply and incorporates a red LED light source (650 nm), delivering precise operation with a fast 1 ms response time. The sensor is configured with an NPN open-collector output and comes with a 2-meter pre-wired cable for easy integration into control systems.
This model supports a Light-ON operation mode and includes dual visual indicators: an orange operation indicator and a green stability indicator for convenient diagnostics. Designed to operate reliably in harsh conditions, it features IP67 protection, robust resistance to shock (1,000 m/s²) and vibration (up to 300 m/s²), and a wide ambient temperature range of −25 to 55°C. Its durable body is made of PBT and denatured polyarylate, ensuring long-term performance in industrial environments where dust, moisture, and temperature fluctuations are common.
Trusted by OEMs and system integrators worldwide, the Omron E3T-ST21 2M photoelectric sensor combines compact design with rugged reliability.
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