Omron E3RB-RN21 Photoelectric Sensor
Omron E3RB-RN21 is an NPN retro-reflective photoelectric sensor designed for object sensing from 0.1 to 3 m when used with the E39-R1S reflector. Its red LED establishes the optical path between the sensor and reflector, while the NPN output transfers the switching state to compatible control circuitry. The sensor operates from 10 to 30 VDC and uses an M12 connector for detachable electrical connection. Light-ON or Dark-ON operation can be selected according to the required control logic, and response time is specified at 0.5 ms. Its M18 radial body uses nickel-plated brass. Within the E3RB Series, the E3RB-RN21 provides the NPN retro-reflective option. Related 3 m retro-reflective sensors are available across Omron Industrial Products.
| Brand | Omron |
| Product | Photoelectric Sensors |
| Model Number | E3RB-RN21 |
Omron E3RB-RN21 Photoelectric Sensor – Technical Specifications
| Specification | Value |
|---|---|
| Sensing Method | Retro-reflective |
| Shape | Cylindrical radial |
| Sensing Distance | 0.1 to 3 m (with E39-R1S) |
| Power Supply Voltage | 10 to 30 VDC |
| Output Configuration | NPN |
| Connection Method | M12 Connector |
| Light Source (Wavelength) | Red LED |
| Thread Size | M18 |
| Length | 61 mm |
| Operation Mode | Light-ON/Dark-ON |
| Response Time | 0.5ms |
| Degree Of Protection | IP67/IP69K |
| Material Housing | Brass, nickel plated |
| Features | M.S.R. |
The Omron E3RB-RN21 Photoelectric Sensor uses retro-reflective sensing across a range of 0.1 to 3 m when used with the E39-R1S reflector. Its red LED establishes the optical path toward the reflector, while the NPN output transfers the switching state to compatible PLC inputs and machine-control circuitry. The sensor operates from 10 to 30 VDC and consumes up to 25 mA. An M12 connector provides detachable electrical connection, while Light-ON or Dark-ON operation can be selected according to the required control logic. Response time is specified at 0.5 ms. Its cylindrical radial M18 body measures approximately 61 mm in length and uses nickel-plated brass, providing a threaded metal mounting format for industrial equipment.
For an Omron NPN retro reflective photoelectric sensor requiring 0.1 to 3 m sensing and M12 connection, the relevant model is the E3RB-RN21. The supplied information also identifies MSR for this configuration. Its radial optical arrangement supports side-facing sensing from the cylindrical housing, while IP67 and IP69K ratings are listed for environmental protection. The specification also suits searches for an Omron 3 m NPN sensor and Omron M18 retro reflective sensor. The 0.5 ms response supports presence and position sensing where rapid output changes are required. For the corresponding E3RB retro-reflective model with PNP output and the same 0.1 to 3 m sensing range, see E3RB-RP21.
