Part of the Omron Photoelectric Sensors series — see the full model table, lifecycle status and replacement parts.
Omron E3FA-RN21 — M18 Retro Reflective Sensor, NPN, M12
SKU: E3FA-RN21USD 16.00
E3FA M18 retro-reflective photoelectric sensor, NPN, polarized red LED with M.S.R. for transparent-bottle detection. 0.1-4 m, M12, IP67.
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Product Overview
The Omron E3FA-RN21 is an M18 cylindrical retro-reflective photoelectric sensor with a built-in amplifier. manufactured by Omron Corporation. Hengyixin Automation ships this sensor from our Xiamen warehouse with a 30-day DOA return window and a datasheet PDF included in the box.
Pick it when the line needs object detection at 0.1 to 4 m via a single M18 sensor + E39-R1 reflector, with reliable reading of shiny or transparent bottles and reflective film. The sensor runs at 0.1 to 4 m on white-paper targets (100 mm minimum sensing distance, 4 m max with the E39-R1S 40 x 60 mm reflector).
The E3FA-RN21 ships from Xiamen with full datasheet documentation. The pre-wired 2 m cable variant is the E3FA-RN11; the PNP (sourcing) twin in the same M12 connector body is the E3FA-RP21.
Key Features
- 0.5 ms or less response time
- 10 to 30 VDC supply at 25 mA max
- M18 threaded flush-mount ABS plastic body, 45 mm length
- NPN open-collector output, 100 mA max at 30 VDC, Light-ON / Dark-ON selectable by wiring
- SKU: E3FA-RN21
- Series: E3FA-series compact cylindrical retro-reflective photoelectric sensor with built-in amplifier
- Voltage: 10 TO 30 VDC
Best-Fit Applications
- Replace a worn-out diffuse-reflective sensor on a washdown-light station where the ABS plastic IP67 body is acceptable
- Quick-disconnect build with an XS2F / XS2W M12 4-pin cordset routed to a CJ / CP1 / NX digital input card
- Detect PET bottles on a beverage conveyor where the M.S.R. filter rejects shiny reflections from the bottle surface
Buying Checklist
- Pick the E3FA-RN11 instead for the pre-wired 2 m cable variant (no M12 connector required)
- Pick the E3FA-RP21 instead for the PNP (sourcing) twin in the same M12 connector body
- Pick the E3FB-RN11 / E3FB-RP11 instead for an IP69K stainless steel retro-reflective sensor in food / beverage washdown
Technical Specifications
| Series | E3FA-series compact cylindrical retro-reflective photoelectric sensor with built-in amplifier |
|---|---|
| Model | E3FA-RN21 |
| Sensing Principle | Retro-reflective with M.S.R. (Mirror Surface Rejection) function, M18 threaded body |
| Sensing Range | 0.1 to 4 m (100 mm minimum distance, 4 m max with E39-R1S reflector) |
| Light Source | Polarized red 624 nm LED with M.S.R. function |
| Output Type | NPN open-collector, 100 mA max at 30 VDC |
| Output Mode | Light-ON / Dark-ON selectable by wiring |
| Response Time | 0.5 ms or less |
| Supply Voltage | 10 to 30 VDC at 25 mA max |
| Connector | M12 4-pin connector on rear face (suffix -21 = M12 connector variant) |
| Protection Rating | IP67 and IP69K |
| Operating Temperature | -40 to +55 degrees Celsius; ABS plastic housing, 45 mm length |
Manufacturer documentation
Omron's own product page, where the manufacturer's current specification and lifecycle information are published. We are an independent distributor and cannot mirror those documents; the link goes to Omron's site.
FAQ for E3FA-RN21
What does M.S.R. mean on the E3FA-RN21?
M.S.R. = Mirror Surface Rejection. The sensor uses a polarized red 624 nm LED plus a polarizing filter so the receiver only sees light that has been depolarized by the target object (true diffuse reflection) and ignores the bright first-surface mirror reflection from glass or shiny labels. The result: reliable detection of clear PET bottles, shrink-wrapped packs, and reflective film without false triggers.
Is the E3FA-RN21 rated IP69K?
Omron lists IP67 and IP69K for the E3FA-RN21 (IEC IP67, DIN 40050-9 IP69K), so it suits high-pressure, high-temperature washdown as well as the E3FB stainless line stainless steel sensor line (E3FB-RN11 NPN / E3FB-RP11 PNP). For a washdown-grade retro-reflective sensor in a food / beverage plant, pick the E3FB-RN11 or E3FB-RP11 with the matching E39-RB reflector.
What is the difference between E3FA-RN11 and E3FA-RN21?
Wiring. The E3FA-RN11 ships with a pre-attached 2 m oil-resistant PVC cable pigtail -- no M12 connector needed. The E3FA-RN21 (this SKU) ships with an M12 4-pin connector on the rear face; the field cable is attached with a separate XS2F / XS2W M12 4-pin cordset. Both sensors are otherwise identical: NPN retro-reflective, 0.1 to 4 m range, M18 ABS body, IP67.
Which reflector should I use with the E3FA-RN21?
The E39-R1S (40 x 60 mm ABS / acrylic rectangle) is the standard pick and reaches the full 4 m range. The E39-R7 round 84 mm reflector reaches about 1 m and is a low-cost tube-fitting option. The E39-R40 large 84.5 x 84.5 mm reflector reaches about 1.5 m and is the right pick when the target is more than 200 mm away and the reflector is mounted on a wide conveyor side. For tape-style applications on small parts, the E39-RS1 / RS25 / RS50 reflective tape works in place of a rigid reflector.
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