Maintenance teams planning replacements for E3RB-RN21 frequently review Omron Photoelectric Sensor, E3Z D61 2M and Omron Sensors to prevent downtime, checking availability and compatibility with existing systems.
Omron E3RB-RN21 Photoelectric Sensor
The Omron E3RB-RN21 Photoelectric Sensor offers Cylindrical radial, Retro-reflective, 0.1 to 3 m (with E39-R1S) sensing distance, NPN Output, M12 Connector, Red LED Light source, 10 to 30 VDC Power supply voltage, Light-ON/Dark-ON mode. Manufactured by Omron under the Omron Photoelectric Sensors category, this model belongs to the Omron E3RB Series.
| Brand | Omron |
| Product Type | Photoelectric Sensors |
| Model Number | E3RB-RN21 |
Omron E3RB-RN21 Photoelectric Sensor β Technical Specifications
| Specification | Value |
|---|---|
| Shape | Cylindrical radial |
| Sensing Method | Retro-reflective |
| Sensing Distance | 0.1 to 3 m (with E39-R1S) |
| Light Source Wavelength | Red LED |
| Connection Method | M12 Connector |
| Power Supply Voltage | 10 to 30 VDC |
| Output Configuration | NPN |
| Power Consumption | 25 mA max. |
| Operation Mode | Light-ON/Dark-ON |
| Thread Size | M18 |
| Length | 61 mm |
| Response Time | 0.5ms |
| Degree of Protection | IP67/IP69K |
| Material Housing | Brass, nickel plated |
| Features | M.S.R. |
Omron is globally known for producing high-performance automation components, and the Omron E3RB-RN21 stands as a reliable example of this legacy. Designed for rugged industrial settings, this photoelectric sensor offers long-lasting durability, accurate object detection, and stable performance even in challenging environments. Its robust M18 brass housing and threaded design make it ideal for easy and secure mounting in machines and panels.
The Omron E3RB-RN21 uses a retro-reflective sensing method and operates at distances from 0.1 to 3 meters using a compatible reflector like the E39-R1S. With a red LED light source, it delivers reliable detection while resisting interference thanks to its Mutual Interference Prevention (M.S.R.) feature. The sensor runs on 10 to 30 VDC and supports NPN output with both Light-ON and Dark-ON modes. It includes an M12 connector for quick setup, a 0.5 ms response time, and low power consumption under 25 mA. Its IP67/IP69K rating ensures protection against dust, water jets, and high-pressure washdowns.
Engineers prefer the E3RB-RN21 in packaging lines, conveyor systems, and presence detection tasks that require strong reflective performance. Its M18 x 61 mm cylindrical body allows for compact installation, while the nickel-plated brass housing withstands vibration, oil, and harsh factory conditions. The clear model structure and integration in global machine designs make Omron E3RB-RN21 a trusted part of automation solutions.

