Omron E3T-ST21M 5M Through-Beam Photoelectric Sensor
Omron E3T-ST21M 5M is an ultracompact M3-mounting through-beam photoelectric sensor intended for 300 mm object sensing in restricted installation spaces. A red LED establishes the beam between the emitter and receiver, while the built-in amplifier evaluates the optical change when a target interrupts that path. Its NPN output interfaces with compatible machine-control circuitry, and Light-ON operation determines the stated switching behavior. The unit operates from 12 to 24 VDC and includes a 5 m pre-wired cable for longer wiring runs. Maximum current consumption is 30 mA, including 10 mA for the emitter and 20 mA for the receiver. Within the E3T Series, the E3T-ST21M 5M provides the extended-cable M3 version. Related M3 through-beam sensors can be explored across Omron Automation Sensors.
| Brand | Omron |
| Product | Photoelectric Sensors |
| Model Number | E3T-ST21M 5M |
Omron E3T-ST21M 5M Photoelectric Sensor - Technical Specifications
| Specification | Value |
|---|---|
| Sensing Method | Through-beam |
| Shape | Square type |
| Sensing Distance | 300mm |
| Power Supply Voltage | 12 to 24 VDC |
| Output Configuration | NPN |
| Connection Method | Pre-wired cable length 5m |
| Current Consumption | 30 mA max. (Emitter 10 mA max., Receiver 20 mA max.) |
| Light Source (Wavelength) | Red LED |
| Operation Mode | Light-ON |
| Response Time | 1 ms max. |
| Degree Of Protection | IP67 |
| Material | Polybutylene terephthalate |
| Material Lens | Denatured Polyarylate |
| Weight | 40g |
The Omron E3T-ST21M 5M Photoelectric Sensor uses an M3-mounting through-beam arrangement for sensing targets over a 300 mm distance. Its red LED establishes the beam between the emitter and receiver, and the integrated amplifier processes the optical change when that beam is interrupted. The NPN output then supplies the switching state to compatible control equipment. Light-ON operation provides the stated switching logic, while response time is specified at 1 ms maximum. Operating voltage is 12 to 24 VDC, and a 5 m pre-wired cable provides additional wiring length. Total current consumption is 30 mA maximum, including 10 mA maximum for the emitter and 20 mA maximum for the receiver.
For an Omron M3 photoelectric sensor requiring NPN output with a 5 m connection cable, the relevant model is the E3T-ST21M. The compact square form supports closely spaced machine layouts, while the separate emitter and receiver establish a defined through-beam sensing path. PBT and denatured polyarylate are listed as construction materials, and the supplied specification states IP67 protection. The configuration also suits searches for an Omron 300 mm NPN sensor and Omron ultracompact through-beam sensor. For the Dark-ON M3 version with the same 300 mm distance and 5 m pre-wired cable, see the E3T-ST22M 5M. The choice between these versions depends primarily on the required output behavior.
