Omron E3Z-T81 — 15 m Through-Beam Sensor, PNP
SKU: E3Z-T81USD 18.00
E3Z-compact through-beam photoelectric sensor pair, 15 m sensing range, infrared LED, PNP output, pre-wired 2 m cable — emitter + receiver set for long-distance opaque-object detection.
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Product Overview
The E3Z-T81 2M is a compact through-beam photoelectric sensor pair from Omron's E3Z family — supplied as a matched emitter (E3Z-T81-L 2M) and receiver (E3Z-T81-D 2M), both in a tiny 20 × 11 × 31 mm rectangular housing with pre-wired 2 m PVC cable. Through-beam is the most reliable photoelectric principle: detection occurs when anything opaque interrupts the beam, so target colour, reflectivity, and surface finish don't matter. The 15 m rated sensing distance uses an infrared LED (870 nm) that the human eye cannot see — alignment is confirmed via the receiver's green stability LED, which lights when the beam is fully seated.
When through-beam is the right answer
Use through-beam when diffuse (E3FA-DP) or retro-reflective (E3FA-RP) sensors struggle.
E3Z-T81 vs E3Z-T86 and the through-beam wavelength family
The T81 is the pre-wired PNP variant of the 15 m family. Sibling options: T61 (NPN pre-wired), T62 (NPN, 30 m), T82 (PNP, 30 m), T66 (NPN M8 connector), T86 (PNP M8 connector), T67/T87 (M8 30 m). Pick T61 if your input card reads NPN (CP1W-ID211 in NPN source mode, CJ1W-ID211) and you don't need quick-disconnect; pick T86 if you need PNP with an M8 connector for the same 15 m range. For greater working distance with the same compact body, jump to the E3Z-T82 (30 m PNP pre-wired) — useful on long conveyors where emitter and receiver mount on opposite frames.
Key Features
- Compact through-beam sensor pair, 15 m rated distance
- 20 × 11 × 31 mm rectangular ABS plastic housing, M3 mount holes
- Infrared LED emitter — eye-safe, no visible alignment spot
- PNP Dark-ON / Light-ON selectable output
- Pre-wired 2 m PVC cable
- 12 mm minimum opaque object detection — sharp beam geometry
- 0.5 ms response time, 100 mA load current
- Reverse polarity, short-circuit, and surge-protected output
- SKU: E3Z-T81
- Series: E3Z
- Voltage: 12 TO 24 VDC
- I/O: 24 I/O
Best-Fit Applications
- Clear-bottle detection on beverage filling lines where diffuse sensors miss transparent PET
- Small parts counting on high-speed assembly conveyors
- Detect dark rubber gaskets or O-rings that fool diffuse sensors on automotive assembly lines
- Wrap-around label presence detection on cylindrical containers — emitter/receiver aimed across the gap
Buying Checklist
- Pick the E3Z-T81 for PNP pre-wired 15 m through-beam — works with any modern Omron PLC input card
- Pick the E3Z-T61 for NPN pre-wired if your input reads sinking signals
- Pick the E3Z-T82 for 30 m range in the same compact body
- Pick the E3Z-T86 for PNP M8 quick-disconnect connector at 15 m
- Pick the E3Z-T61A/T81A if you specifically need the narrow-beam 'A' variant for precise slot detection
- Pair with an E39-L104 L-shaped bracket for side-mounting on conveyor frames
Technical Specifications
| Model | E3Z-T81 2M (matched emitter + receiver pair) |
|---|---|
| Series | E3Z |
| Sensing Method | Through-beam (separate emitter and receiver) |
| Sensing Distance | 15 m (rated); usable 0 to 20 m with margin |
| Standard Sensing Object | Opaque, 12 mm diameter minimum |
| Light Source | Infrared LED (870 nm) |
| Directional Angle | ±3° receiver acceptance, ±5° emitter cone |
| Output Type | PNP open collector, Light-ON or Dark-ON selectable |
| Supply Voltage | 12 to 24 VDC ±10 % |
| Current Consumption | ≤ 20 mA (receiver); ≤ 15 mA (emitter) at 24 VDC |
| Load Current | ≤ 100 mA |
| Operating Temperature | -25 to +55 °C (no icing) |
| Body Dimensions | 20 (W) × 11 (H) × 31 (D) mm |
| Mounting | Two M3 screws (slots on rear), or optional E39-L104 mounting bracket |
| Compatible PLC Inputs | All Omron 24 VDC PNP-source inputs: CP1W-ID211, CJ1W-ID211, NX-ID5342 |
Resources & Downloads
FAQ for E3Z-T81
Why does my E3Z-T81 read distance only to 12 m in the field?
The rated 15 m assumes the receiver is operating near maximum gain with a clean lens and the emitter aimed directly at the receiver.
What's the difference between the E3Z-T81 and the E3Z-T86?
T81 is pre-wired 2 m PVC cable; T86 has an M8 4-pin quick-disconnect connector on a short pigtail. Both are PNP, both 15 m, both use the same matched emitter/receiver pair. Pick T81 when the sensor is fixed install and you want zero connector joints (failsafe for washdown). Pick T86 when you need to swap a faulty sensor in under a minute without re-stripping wires — useful for service loops in high-volume plants.
Can I use the E3Z-T81 to detect a transparent bottle?
Yes — through-beam is the most reliable photoelectric principle for transparent targets. The beam must be fully interrupted, and a PET or glass bottle passing through the 12 mm minimum beam width will block it long enough for the 0.5 ms response time to register.
Is the E3Z-T81 suitable for washdown environments?
Rated IP67 — handles temporary water immersion and high-pressure spray, but not IP69K for steam cleaning. For chemical CIP washdown (dairy, pharmaceutical, food processing) the ABS plastic lens will fog over time from alkaline cleaners. For those environments use the E3FB-T81 or E3RB-T81 with a metal housing and PMMA lens treated for chemical resistance, or upgrade to a hygienic-grade M18 stainless E3H2 sensor.
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