Maintenance teams planning replacements for E3T-SL21M-2M frequently review Omron SMPS 24V 10A, E3Z D61 2M and Omron Sensors to prevent downtime, checking availability and compatibility with existing systems.
Omron E3T-SL21M 2M Photoelectric Sensor
The Omron E3T-SL21M 2M Photoelectric Sensor is an ultracompact photoelectric sensor with built-in amplifier offering limited reflective detection, 5–30 mm sensing distance, and NPN output with Light-ON operation. It uses a red LED (650 nm) light source and operates on 12–24 VDC with 20 mA current consumption. Part of the Omron industrial range, it comes under the Omron Photoelectric Sensors category and the Omron E3T Series. Equipped with a 2 m pre-wired cable, open-collector output, 1 ms response time, and IP67 protection, it ensures precise, durable performance for compact sensing applications.

| Brand | Omron |
| Product Type | Photoelectric Sensor |
| Model Number | E3T-SL21M 2M |
Omron E3T-SL21M 2M Photoelectric Sensor – Technical Specifications
| Specification | Value |
|---|---|
| Sensing Method | Limitedreflective |
| Sensing Distance | 5 to 30 mm (50 × 50 mm white paper) |
| Standard Sensing Object | 0.15-mm dia. (sensing distance 10 mm) |
| 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 | 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 | 1,000 VAC, 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 |
| Weight | Approx. 20 g |
The Omron E3T-SL21M 2M operates on a 12 to 24 VDC power supply and uses a red LED (650 nm) for close-range object detection. With a sensing range of 5 to 30 mm, it can reliably detect non-glossy objects as small as 0.15 mm in diameter at a 10 mm distance. This model features NPN open-collector output and supports Light-ON mode, delivering fast 1 ms response time for high-speed automation environments.
It includes an operation indicator and a stability indicator to assist with real-time status monitoring. The pre-wired 2-meter cable allows for quick integration into control panels and tight machinery layouts. With a maximum current consumption of 20 mA, the sensor is highly energy-efficient. Built-in reverse polarity protection and short-circuit protection ensure safe and reliable operation even in fluctuating industrial power conditions.
The sensor’s enclosure, made of PBT and denatured polyarylate, provides excellent resistance against environmental stress. Rated IP67 as per IEC 60529, the Omron E3T-SL21M 2M Photoelectric Sensor is protected from dust, water, and mechanical impact. It can withstand vibrations up to 2,000 Hz and shocks up to 1,000 m/s², making it a reliable component in challenging automation environments.




