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Omron / Sentech E3T-C (M5/M6 miniature) machine vision sensor
Omron / SentechPhotoelectric sensors
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Omron / Sentech E3T-C Miniature Photoelectric Sensor (M5/M6 Housing)

E3T-C

The E3T-C family covers axial and radial M5 through-beam sensors (1 m and 500 mm sensing distances) and axial M6 diffuse-reflective sensors (3 to 50 mm), each available with NPN or PNP open-collector output. Light sources are red LED (630 nm axial / 625 nm radial) for through-beam models and infrared LED (870 nm) for diffuse-reflective models, with a maximum response time of 0.5 ms. All models run on 12 to 24 VDC, are pre-wired with a 2 m cable, use a SUS303 stainless-steel case, and carry an IP65 degree of protection. Operating temperature range is -25 to +55 degC with reverse-polarity and output short-circuit protection built in.

Brand
Omron / Sentech
Sensor type
Photoelectric sensor
Sensing method
Through-beam (M5) and diffuse-reflective (M6) variants
Light source
Red LED 630 nm (axial through-beam) / 625 nm (radial); Infrared LED 870 nm (diffuse-reflective)
Range / distance
1 m (axial through-beam); 500 mm (radial through-beam); 3 to 50 mm (diffuse-reflective)
Response time
0.5 ms max. (operate or reset)
Output type
NPN or PNP open-collector (load current 80 mA max., residual voltage 1 V max.)
Supply voltage
12 to 24 VDC +/-10%, ripple 10% max. (26.4 VDC max.)
Connection
Pre-wired, 2 m standard cable length
Housing material
SUS303 stainless-steel case; polysulfone display window/lens (through-beam), epoxy window (diffuse)
Dimensions
M6 diffuse body approx. 29.1 mm long x 11 mm dia.; M5 through-beam body approx. 26.2 mm (axial) / 27.2 mm (radial) x 10 mm dia.
Weight
Approx. 60 g (through-beam) / Approx. 40 g (diffuse-reflective), packed state
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Technical overview

The Omron E3T-C is a family of miniature self-contained photoelectric sensors with the amplifier built into the head, packaged in slim cylindrical stainless-steel (SUS303) bodies of roughly 10 mm (M5) and 11 mm (M6) diameter. It splits into two sensing principles. The M5 through-beam variants use a separate emitter and receiver facing each other across the gap; the beam is broken when an object passes between them, giving a clean, position-independent detection over 1 m (axial) or 500 mm (radial). The M6 diffuse-reflective variant integrates emitter and receiver in one body and detects light bounced back off the target itself, working at very short range from 3 to 50 mm where you only have access from one side. Through-beam models use a visible red LED (630 nm axial, 625 nm radial) that makes alignment easy to eyeball, while the diffuse model uses an 870 nm infrared LED. With a 0.5 ms maximum response time, the E3T-C is fast enough to gate fairly quick part flow on a conveyor or to trigger a camera as a leading edge passes.

Electrically the family is straightforward to design in. Every model runs on 12 to 24 VDC (plus/minus 10 percent, 26.4 VDC max) and provides an open-collector switching output available in either NPN or PNP polarity, so you pick the variant that matches your PLC or vision controller input common. The output is rated 80 mA max load current with 1 V max residual voltage, which is enough to drive a digital input or a small relay/indicator directly but not a heavy load. Reverse-polarity protection on the supply and short-circuit protection on the output make the device tolerant of wiring mistakes during commissioning. All units ship pre-wired with a 2 m cable rather than a connector, so the cable length and routing are fixed at the head and you plan for the full lead at installation.

Mechanically the E3T-C is built for tight, washdown-adjacent placements. The SUS303 stainless case with IP65 sealing (IEC 60529) resists dust and low-pressure water jets, and the operating range of -25 to +55 degC covers typical factory and light cold-environment use. The bodies are genuinely small (M6 diffuse about 29.1 mm long, M5 through-beam about 26.2 mm axial or 27.2 mm radial) and light (roughly 40 to 60 g), which is what lets them fit into nests, fixtures and the narrow guide rails of packaging and small-parts handling lines where a standard 18 mm barrel sensor will not go. In a vision context the E3T-C is not an imaging device; it is the discrete presence/trigger element that tells the camera or controller when a part is in position, or a simple go/no-go gauge of presence rather than a dimensional measurement.

Best for

  • Triggering a machine-vision camera or strobe as the leading edge of a part breaks the through-beam on a conveyor or indexing line
  • Tight-space presence detection in packaging and small-parts assembly where only a 10-11 mm cylindrical body will fit
  • Part-present / nest-occupied confirmation in fixtures using the M6 diffuse-reflective model at 3 to 50 mm working distance
  • Object counting and gap detection in logistics sortation, using the M5 through-beam for position-independent, reliable break detection
  • Edge or label presence checks on electronics and automotive subassemblies needing IP65 sealing in a stainless body

Selection notes

  • Choose the sensing method by access and target: M5 through-beam (1 m axial / 500 mm radial) for the most reliable, color-independent break detection when you can mount both emitter and receiver; M6 diffuse-reflective (3 to 50 mm) when you only have one-sided access, accepting that range is short and reflectivity-dependent.
  • Match output polarity to your input common before ordering: the open-collector output is NPN or PNP and cannot be reconfigured, and it is limited to 80 mA / 1 V residual, so drive a logic input or small load only, not a contactor.
  • The fixed 2 m pre-wired cable sets your routing budget; there is no M8/M12 connector option here, so plan junction-box termination and avoid cutting the lead short below what the run needs.
  • Confirm the IP65 rating and -25 to +55 degC range suit the cell: IP65 handles dust and water jets but is not rated for continuous immersion or high-pressure washdown, and very cold or hot zones fall outside spec.
  • If you are using the sensor as a camera trigger, budget for its 0.5 ms max response plus PLC/vision latency against your line speed; for the diffuse model, verify the 870 nm IR beam and short standoff give a stable signal on dark or specular targets before committing the layout.

Specifications: General
BrandOmron / Sentech
Sensor typePhotoelectric sensor

Specifications: Performance
Range / distance1 m (axial through-beam); 500 mm (radial through-beam); 3 to 50 mm (diffuse-reflective)
Response time0.5 ms max. (operate or reset)

Specifications: Interface
ConnectionPre-wired, 2 m standard cable length

Specifications: Electrical
Supply voltage12 to 24 VDC +/-10%, ripple 10% max. (26.4 VDC max.)

Specifications: Environment
Operating temperatureOperating: -25 to +55 degC; Storage: -30 to +70 degC (no icing or condensation)
IP ratingIP65 (IEC 60529)

Specifications: Sensing
Sensing methodThrough-beam (M5) and diffuse-reflective (M6) variants
Light sourceRed LED 630 nm (axial through-beam) / 625 nm (radial); Infrared LED 870 nm (diffuse-reflective)

Specifications: Output
Output typeNPN or PNP open-collector (load current 80 mA max., residual voltage 1 V max.)

Specifications: Mechanical
Housing materialSUS303 stainless-steel case; polysulfone display window/lens (through-beam), epoxy window (diffuse)
DimensionsM6 diffuse body approx. 29.1 mm long x 11 mm dia.; M5 through-beam body approx. 26.2 mm (axial) / 27.2 mm (radial) x 10 mm dia.
WeightApprox. 60 g (through-beam) / Approx. 40 g (diffuse-reflective), packed state

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