DD-301/401/302/402 Series Reflective Photoelectric Sensor (Wire-lead Type)

Name: DD-301/401/302/402 Series Reflective Photoelectric Sensor (Wire-lead Type)
Brand: DAIDISIKE
SKU: dd-301-401-302-402-series-reflective-photoelectric-sensor
Availability: InStock

Wire-lead NPN reflective sensor, 5mm range, horizontal/vertical mount, Light-ON/Dark-ON logic options.

DD-301/401/302/402 Series Reflective Photoelectric Sensor (Wire-lead Type) - product photo

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Technical Specifications

Model	DD-301 / DD-401 / DD-302 / DD-402 / DD-301A / DD-401A / DD-302B / DD-402B
Output type	NPN; DD-301/DD-302 = Dark-ON (blocked = ON), DD-401/DD-402 = Light-ON (reflected = ON)
Housing / orientation	DD-301/DD-401 = horizontal; DD-302/DD-402 = vertical
Detection method	Reflective (diffuse-reflective)
Detection distance	5mm (90% reflectance white paper)
Light source	GaAs infrared, 940nm
Supply voltage	DC5-24V ±10%
Switching frequency	500Hz or higher
Protection rating	IP50

Overview

This is a diffuse-reflective photoelectric sensor that emits a 940nm GaAs infrared beam and detects the light reflected back from the target object itself — no separate reflector or receiver unit is required. It is designed for equipment manufacturers who need a low-cost, easy-to-wire sensor to detect the presence of a small object (paper, card, part) at very close range (up to 5mm) inside a machine.

It suits OEM/board-level integrators building printers, financial equipment (ATMs/note counters), vending machines, small appliances, or general automation equipment where the sensor mounts internally in a dry environment. The series is available in horizontal or vertical sensing orientation and in Light-ON or Dark-ON output logic, runs on a DC5-24V ±10% supply, and uses NPN open-collector output, so a matching model can be selected without extra interface circuitry.

Features & Benefits

Horizontal and Vertical Sensing Orientations

DD-301/DD-401 are horizontal (side-sensing) versions and DD-302/DD-402 are vertical (top-sensing) versions, so the optical axis can be matched to the internal layout of your equipment without redesigning the mounting.

Wide 5-24 VDC Supply Range

The sensor accepts DC5-24V ±10%, so it can be wired directly to 5V logic-level control boards as well as 24V industrial supplies, without an added voltage regulator.

Light-ON and Dark-ON Output Versions Available

DD-401/DD-402 switch ON when light is received (Light-ON), while DD-301/DD-302 switch ON when the beam is blocked (Dark-ON), letting you pick the output polarity your controller expects without adding an external signal inverter.

500Hz+ Switching Frequency for Continuous Small-Object Detection

Combined with the 5mm close-range setting, the sensor is responsive enough for detecting a continuous stream of small objects such as paper sheets or feed parts passing at close range.

NPN Open-Collector Output for Standard Interfacing

All four base models use NPN output, a widely supported interface for PLC inputs and common control-board designs.

Wire-lead Construction for Straightforward OEM Assembly

Leads are brought out directly from the sensor body for soldering or terminal connection, simplifying wiring during high-volume equipment assembly compared to connector-style sensors.

Applications

Paper/Note Presence Detection Inside Printers and Financial Equipment — 5mm close-range reflective detection is suited to sensing thin paper/note media directly at close proximity without a separate reflector.

Card Presence Detection in Card Readers or Vending/Kiosk Equipment — Diffuse reflection off a card surface at short range falls within the sensor's rated 5mm detection distance.

Small Part or Component Presence Check on Internal Mechanisms — Close-range diffuse sensing with 500Hz+ response supports quick pass/fail checks as parts move into position.

Continuous Small-Object Counting on Feed Paths — 500Hz+ switching frequency allows the sensor to register successive close-passing objects reliably.

Board-Level (5V Logic) Embedded Detection in OEM Devices — The DC5-24V supply range lets the sensor connect directly to 5V control boards without a separate power-conditioning stage.

PLC-Integrated Detection in General Automation Equipment — NPN open-collector output at 24V is a standard PLC input interface, and the sensor also runs on 24V supplies.

Interior, Dust-Controlled Equipment Enclosures — IP50 rating provides dust protection appropriate for use inside an equipment housing, but is not intended for wet or washdown areas.

Models & Ordering Information

Horizontal (Side-sensing) Models

DD-301DD-401DD-301ADD-401A

DD-301/DD-301A are Dark-ON (output ON when blocked); DD-401/DD-401A are Light-ON (output ON when reflected light is received). All NPN output.

Vertical (Top-sensing) Models

DD-302DD-402DD-302BDD-402B

DD-302/DD-302B are Dark-ON (output ON when blocked); DD-402/DD-402B are Light-ON (output ON when reflected light is received). All NPN output.

How to Select

All base models are rated for a 5mm detection distance against a 90% reflectance white paper reference target; actual distance will vary with target color/reflectance, and this series is intended for close-range (≤5mm) detection rather than long-range sensing.
Choose DD-301/DD-401 for horizontal (side-sensing) mounting, where the object approaches from the side of the sensor body.
Choose DD-302/DD-402 for vertical (top-sensing) mounting, where the object approaches from above/below the sensor body.
Choose DD-401/DD-402 if your controller expects the output to switch ON when the sensor is receiving reflected light (Light-ON).
Choose DD-301/DD-302 if your controller expects the output to switch ON when the light path is blocked/no reflection is received (Dark-ON).
Confirm your available supply falls within DC5-24V ±10%; the same sensor works across this range, so no separate model is needed for 5V-logic vs 24V-industrial systems.
Confirm the mounting location is dry and free of splashing/washdown — the series is rated IP50 (dust-protected only, not water-protected).

📘 Need the full method? NPN vs PNP Sensor Outputs Explained

When NOT to specify the DD-301/401/302/402 — and what to use instead

Outdoor use, washdown, or any wet/splash-exposed mounting location

Why not: This series is rated IP50 - dust protection only, with no water protection stated.

Use instead: an IP65-rated sensor such as BGS-CX441/CX442 or the strip-beam DK-D461/D561

Target is more than 5 mm from the sensor face

Why not: The rated detection distance is 5 mm against a 90% reflectance white paper target - this is a very-close-range OEM/board-level sensor, not a general-purpose distance sensor.

Use instead: a longer-range background-suppression sensor (BGS-CX441/CX442, BX series) or a through-beam pair for gap detection

A PNP output is required

Why not: All base models (DD-301/401/302/402 and A/B variants) are documented as NPN open-collector output only.

Use instead: BGS-CX441/CX442 (NPN or PNP by order suffix) or the E3JK series (M1-M4 transistor logic includes PNP)

Needing to switch between Dark-ON and Light-ON logic on site without re-ordering

Why not: Output polarity is fixed by model number (DD-301/302 = Dark-ON, DD-401/402 = Light-ON) - there is no field-selectable control wire on this series.

Use instead: the BGS-CX441/CX442 or DK-D461/D561, which select N.O./N.C. logic via a control wire on site

Personnel guarding or any safety-related presence detection

Why not: No safety rating or safety certification is published for this series.

Use instead: a certified safety light curtain (e.g. DQC/DQA series) for personnel protection

Specifications we do not publish yet

We only publish a figure once we are confident it is true. The items below are still being validated through further testing and real-world customer feedback, so for now we would rather leave them open than guess. If one of them matters to your design, ask us for the latest validated status.

Minimum detectable object size
Hysteresis
MTBF
Operating and storage temperature range
Cable/lead termination type and length
Certification status (documents said to be available on request but not specified)

Frequently Asked Questions

What is the detection distance of the DD-301/401/302/402 series?

5mm, measured against a 90% reflectance white paper standard target. Detection distance will differ for targets with lower reflectance or different surface color.

What is the difference between DD-301 and DD-401?

Both are horizontal (side-sensing) NPN reflective photoelectric sensors with the same 5mm detection range, but DD-301 is Dark-ON (output switches ON when the light path is blocked) while DD-401 is Light-ON (output switches ON when reflected light is received).

What is the difference between the 301/401 pair and the 302/402 pair?

DD-301/DD-401 are horizontal (side-sensing) versions and DD-302/DD-402 are vertical (top-sensing) versions. The output-logic difference (Dark-ON vs Light-ON) is the same as described for the 301/401 pair.

Can this sensor run on a 5V logic board?

Yes. The rated supply range is DC5-24V ±10%, so it can be powered directly from a 5V logic-level board as well as a 24V industrial supply.

Is the output NPN or PNP?

All models in this series (DD-301, DD-401, DD-302, DD-402 and their A/B variants) use NPN open-collector output.

Is this sensor waterproof?

No. It is rated IP50, which provides dust protection but no water protection. It is intended for dry, indoor equipment interiors, not for wet or washdown environments.

What light source does this sensor use?

A GaAs infrared emitter with a 940nm wavelength.

What is the switching (response) frequency?

500Hz or higher, suitable for continuous detection of small objects passing at close range.

Is this a reflective sensor or does it need a separate reflector?

It is a diffuse-reflective (proximity) type — it detects light reflected directly off the target object itself and does not require a separate reflector or receiver unit.

How is the sensor wired — connector or leads?

It is a wire-lead (pre-wired) type; leads are brought out directly from the sensor body for soldering or terminal connection.

Can you provide certification documents for the DD-301/401/302/402 series?

Certification documents are available on request.