DD / DDOF Single-Sided Area Light Curtain

Name: DD / DDOF Single-Sided Area Light Curtain
Brand: DAIDISIKE
SKU: dd-diffuse-reflection-area-light-curtain
Availability: InStock

One housing, no far-side receiver: order DD for diffuse sensing to 2000 mm, or DDOF for per-beam TOF ranging to 4000 mm with zero dead zone and one-key distance teaching. 48 standard models, 4-50 beams.

▶ Watch it in action: Diffuse-Reflection Light Curtain for Part Counting & Edge Detection

DD single-sided area light curtain mounted on one side of a roller conveyor detecting passing cartons, no receiver on the far side

🔍 Click to enlarge · 1/13

Technical Specifications

Series structure	Two order prefixes on one mechanical platform: DDOF = TOF time-of-flight type (per-beam distance ranging); DD = diffuse reflection type (returned-energy sensing). Same housing, tiers, wiring and mounting for both.
Mounting principle	Emitter and receiver integrated in a single housing; installs and wires on one side only - no far-side receiver, reflector or alignment
Maximum sensing distance	DDOF: up to 4000 mm with no dead zone. DD: up to 2000 mm, dead zone possible.
Background suppression	DDOF only: each beam axis ranges independently and reports only targets inside the taught distance window - background colour and target reflectivity do not shift the trigger point, and distance attenuation on dark targets is small
Distance setting	DDOF: one-key distance teaching. DD: steps 1-9 matched to working distance (hold 1 s to save, auto-save after 30 s) plus self-learning at default step 0 (2 s press, fixed backgrounds only)
Beam pitch	40 mm, fixed across all 48 standard models
Beam count / tiers	4-50 beams in even steps - 24 standard tiers per series; any even count in between to order
Detection height H	H = beam count x 40 mm: 160 mm (4 beams) to 2000 mm (50 beams), per the 2026-08 factory table
Overall length L	L = H + 49 mm: 209 mm to 2049 mm (verified against every row of the factory table)
Housing	35 x 35 mm aluminium extrusion cross-section with T-slot mounting channel; 12 mm end caps top and bottom
Dead lengths on the housing	Top: half a beam pitch (20 mm). Bottom (cable-exit end): half a pitch + 25 mm (45 mm). Plan the critical detection edge away from the cable end.
Output	NPN and PNP transistor outputs both fitted on separate wires; connect the polarity your PLC input needs and insulate the other
Output logic	Normally-open ex-factory; normally-closed stored via the power-on button routine (cut power, hold the button, re-power while holding, let go at the red LED)
Wiring / wire colours	Brown = +24 V; Blue = 0 V; Black = NPN signal; White = PNP signal (2026-08 factory wiring diagram); pigtail cable termination
Indicators	Power shows on the green LED, signal on the red; the built-in digital readout displays the live step number
Intended use (factory statement)	Area and object detection only. Not a safety component: must not be used for personnel safety protection - applies to DD and DDOF equally.

Overview

This page covers one purchasing decision with two answers. The DD / DDOF family is a reflective area light curtain that puts the emitter and the receiver in the same 35 x 35 mm housing, so the whole sensor bolts to one side of the opening and nothing at all is mounted opposite it. What you must decide at order time is the sensing engine inside: the DD prefix buys the diffuse version, the DDOF prefix buys the time-of-flight version, and the two are otherwise identical twins - same 24-tier height table, same mounting holes, same wiring, same price logic of paying only for the beams you need.

Here is the buying rule our sales engineers actually use. Count how many of these apply to your line: targets change colour or gloss between production runs; the surface behind the detection field moves or varies; the span to cover is longer than 2000 mm; a dead zone at the sensing limit would miss product. Zero items - order DD and save the difference. One or more - order DDOF, because the time-of-flight version prices in exactly those four problems: it ranges every beam individually, triggers only inside a distance window you teach with one key press, reaches 4000 mm, and has no dead zone.

Sizing is a one-line calculation you can do while reading this. Detection height H = beam count x 40 mm, and the housing adds 49 mm on top of H. The 24 standard tiers run from 4 beams (160 mm of coverage, 209 mm housing) to 50 beams (2000 mm of coverage, 2049 mm housing) in even steps, under either prefix - DDOF2040 and DD2040 both put 20 beams across an 800 mm field. Between-tier beam counts are a normal custom order, not a special project.

Two commitments before you specify. First, every number on this page comes from the manufacturer's 2026-08 selection sheet; where that sheet is silent - response time, ingress rating, supply tolerance - we say so below instead of guessing, and we will put the confirmed figures in writing against your order number. Second, this family is an object-detection instrument. It counts, positions, and monitors areas; it is not certified to IEC 61496 or ISO 13849 and must never be the device that stops a machine to protect a person. That job belongs to a certified safety light curtain such as the DQT4.

Key Facts — DD at a glance

Order code is the whole decision: the DDOF prefix buys per-beam time-of-flight ranging (4000 mm, no dead zone, distance window taught with one key), the DD prefix buys diffuse energy sensing (2000 mm, dead zone possible, steps 1-9) - everything mechanical is shared between them.
48 standard models in total: DDOF0440 through DDOF5040 and DD0440 through DD5040, each series in 24 even-beam tiers from 4 to 50 beams at the fixed 40 mm pitch.
Height mathematics printed on the 2026-08 factory sheet: detection height H = beam count x 40 mm (160-2000 mm), overall housing length L = H + 49 mm (209-2049 mm) - the 49 mm being two 12 mm end caps plus the mounting allowance.
The DDOF's background suppression is geometric, not optical trickery: each beam measures the distance to whatever reflects it, and anything outside the taught window - including the wall behind the line - is simply not reported.
Colour independence is the DDOF's second dividend: a black rubber tote and a white carton read as the same distance, so product changeovers stop being sensor-retuning events.
Both series ship with BOTH transistor polarities on separate wires - black carries NPN, white carries PNP - so one stock unit wires into either a sinking or a sourcing PLC input; the unused wire is simply insulated.
Output logic leaves the factory normally-open; switching to normally-closed is a documented power-on button procedure (hold the button while powering up, release when the red LED lights), not a wiring change.
The housing keeps two dead lengths you must plan around: half a pitch (20 mm) at the top end and half a pitch plus 25 mm (45 mm) at the bottom cable-exit end - point the cable end away from the critical detection edge.
DD tuning is two-layer: match steps 1-9 to the working distance (hold 1 s to save, or auto-save after 30 s), or press 2 s at the default step 0 to let the unit self-learn a fixed background; self-learning is explicitly not for backgrounds that move or change brightness.
The 2026-08 factory sheet publishes no response time, no IP rating, no supply tolerance and no temperature range for this family - we list those as open items below rather than inventing figures, and confirm them in writing per order.
The factory sheet limits both prefixes to area and object detection and expressly rules safety-protection duty out; no IEC 61496, ISO 13849 PL or IEC 62061 SIL credential exists anywhere in this family.

Features & Benefits

One order-code letter group decides everything hard

Most area-sensor mis-purchases trace to one cause: an energy-based sensor sent into a distance-based problem. This family makes the fix a prefix. Same bracket, same holes, same cable colours - a line that outgrows its DD (new black totes, a moved background wall, a wider span) upgrades to the DDOF tier-for-tier without touching the mechanical installation.

4000 mm and zero dead zone on the DDOF

Doubling the reach of the diffuse version matters most at doorways, wide conveyors and pallet lanes where the sensor must sit well back. Just as valuable: the DDOF has no dead zone, so there is no near-field band where product slips past undetected - a real failure mode on energy-based sensors positioned close to the material path.

Teach the window once, survive every changeover

The DDOF's working distance is taught with a single key press, and because judgment is by measured distance, next week's product in a different colour or film does not move the trigger point. On lines that change SKUs daily, this is the difference between a sensor you commission once and a sensor someone re-tunes every Monday.

Nothing to install on the far side - literally nothing

No receiver column, no reflector panel, no far-side conduit run, no beam alignment session with two technicians and a radio. For retrofits, open edges, walls and one-sided door frames, the second-side work simply does not exist on the bill of labour.

Both PLC polarities in the same cable

Black wire NPN, white wire PNP, both live on every unit. Panel builders stock one part number for Japanese-style sinking inputs and European sourcing inputs alike, and the commissioning tech connects whichever wire the input card wants.

A height tier every 80 mm, and custom counts between

24 standard tiers per series mean the next size up is never far away, and any even beam count between 4 and 50 is a routine custom order. You pay for the field height you need instead of rounding up to a distant catalogue size.

DD steps 1-9 plus self-learning for the simple cases

Where the background is a fixed baffle and the product is consistent, the DD's nine intensity steps and its 2-second self-learning routine cover commissioning without instruments - and the live step number stays visible on the built-in digital display for anyone auditing the setting later.

Priced and documented like a component, not a project

Factory-direct pricing, a published English selection manual compiled from the 2026-08 factory sheet, and open declaration of which parameters the factory has not printed - so your engineering file contains data, not marketing.

Applications

Carton and tote counting on busy conveyors — Mounted on the frame's accessible side, the beam field counts or confirms passage regardless of package height variation. Uniform brown cartons against a fixed guide rail: DD does it economically. Mixed streams with black totes and shrink-wrap: specify DDOF so the count does not drift with product colour.

Doorway and lane presence for AGVs and forklifts — One column beside the opening covers a 2-4 m lane with the DDOF's 4000 mm reach, and the distance window ignores traffic beyond the lane. Tyres, films and metal pallets all range identically - the classic failure case for energy-based sensing, solved by ordering the right prefix.

Stack height and overtravel watch at palletizers — A 20-40 beam tier (800-1600 mm of field) watches whether the stack has arrived, overshot, or leaned into the clearance envelope. Moving pallets behind the field argue for DDOF - and remember: a person-entry stop at the same station is bought as a certified safety curtain, never as this instrument.

Drop detection at chutes and hoppers — A falling part crosses the field for milliseconds at an unpredictable height - exactly what a continuous 40 mm-pitch array catches and a single-point photo-eye misses. Size the tier to the full drop window, keeping the 45 mm cable-end dead zone away from the busiest edge.

Feed-opening material presence on packaging machines — Within 2000 mm of a fixed machine frame, the DD tier matching the opening height is the economical pick. If the line runs metallized or transparent film whose reflectivity jumps roll to roll, either sample-test the DD first or specify DDOF and stop worrying about the material.

Moving-background posts: lifts, shutters, auto doors — A platform or door that changes the background position defeats both DD self-learning and manual step tuning - the factory sheet says so plainly. This is not a tuning challenge to accept; it is a DDOF specification line: teach the window to end before the moving element and the problem is designed out.

Models & Ordering Information

DDOF series - TOF time-of-flight type (4000 mm, no dead zone)

DDOF0440DDOF0640DDOF0840DDOF1040DDOF1240DDOF1440DDOF1640DDOF1840DDOF2040DDOF2240DDOF2440DDOF2640DDOF2840DDOF3040DDOF3240DDOF3440DDOF3640DDOF3840DDOF4040DDOF4240DDOF4440DDOF4640DDOF4840DDOF5040

Read as DDOF + beam count (2 digits) + 40 mm pitch. DDOF2040 = time-of-flight type, 20 beams, detection height 800 mm, overall length 849 mm. Per-beam distance ranging, background suppression, one-key distance teaching, up to 4000 mm with no dead zone.

DD series - diffuse reflection type (2000 mm)

DD0440DD0640DD0840DD1040DD1240DD1440DD1640DD1840DD2040DD2240DD2440DD2640DD2840DD3040DD3240DD3440DD3640DD3840DD4040DD4240DD4440DD4640DD4840DD5040

Same tier table under the DD prefix: energy-based diffuse sensing to 2000 mm (dead zone possible), distance matched via steps 1-9 or self-learning. Choose DD when targets are consistent, the background is fixed, and cost decides.

Downloads

DD / DDOF Area Light Grid - English Selection ManualCompares the two engines, prints every tier of both series, walks the height mathematics with the dead lengths, documents the four-wire hookup and how to store NC output, covers steps and self-learning, and closes with scenario-driven picks plus the usage boundary.0.18 MB

How to Select

Step 1 - Choose the prefix with four questions: do target colours or finishes vary? does the background move or change? is the span over 2000 mm? is a dead zone unacceptable? Any yes = DDOF; all no = DD. This single choice outweighs every other line on the order.
Step 2 - Convert the height to cover into a beam count: divide the field height by 40 mm and round up to the next even number between 4 and 50. Check H = beams x 40 covers the zone and L = H + 49 fits the mounting space including cable-exit clearance.
Step 3 - Place the dead lengths deliberately: the top of the housing loses 20 mm and the cable end loses 45 mm of sensing. Orient the cable end toward the less critical edge of the field before drilling anything.
Step 4 - Wire the polarity your PLC wants: black wire for NPN (sinking) inputs, white wire for PNP (sourcing) inputs, insulate the unused one. If the output participates in any interlock logic, switch to normally-closed with the power-on button procedure so a cut cable reads as blocked rather than clear.
Step 5 - Commission by type: DDOF - teach the distance window with one key press so it ends before the background. DD - step through 1-9 against the real target and save (1 s hold), or self-learn at step 0 only where the background is truly fixed.
Step 6 - Close the open parameters in writing: response time, IP rating, supply tolerance and temperature range are not printed on the factory sheet. Have us confirm them for your model and quantity before the design freezes - and if any part of the requirement is protecting a person, stop here: that requirement moves to a certified device, which is exactly what the DQT4 line is for.

📘 Need the full method? How to Choose a Safety Light Curtain · Type 2 vs Type 4 Safety Light Curtains

When NOT to specify the DD — and what to use instead

The requirement is stopping hazardous machine motion when a person or body part enters - press brakes, robot cells, any guarded danger zone

Why not: The factory sheet limits the whole family - DD and DDOF alike - to area detection and states it must not be used for safety protection. No IEC 61496 Type, ISO 13849 PL or IEC 62061 SIL rating exists for either series, and the DDOF's stronger detection does not substitute for certification.

Use instead: A certified through-beam safety light curtain - DQT4 for stated Type 4 architecture, or DQC/DQA - wired through a safety relay.

A DD (diffuse) model is being considered for black, glossy, transparent or colour-varying targets

Why not: Energy-based sensing reads dark and specular surfaces as weak returns and bright backgrounds as strong ones; detection then depends on the product's finish and the week's SKU mix.

Use instead: The DDOF prefix of this same family - per-beam distance ranging is colour-independent. For transparent film specifically, sample-test first or consider a through-beam arrangement.

The span to cover exceeds 4 metres

Why not: 4000 mm is the DDOF's ceiling and 2000 mm the DD's; neither is a long-range curtain.

Use instead: A long-distance through-beam light curtain such as the DQA series (selectable ranges to 40 m).

The design file requires a confirmed IP rating, response time or temperature range before sign-off

Why not: None of these is printed on the 2026-08 factory sheet for this family; assuming values is how sensors end up failing acceptance audits.

Use instead: Written factory confirmation via us before freezing the design - or a series whose datasheet publishes the full environmental table.

The controller needs a volt-free relay contact

Why not: This family documents transistor outputs only (NPN + PNP); no relay output version is listed.

Use instead: An interposing relay module driven by the transistor output, or a series with a documented relay option.

Full selection table - all 24 tiers, both series

H = beam count x 40 mm; L = H + 49 mm. Values from the 2026-08 factory selection sheet, identical for both prefixes. Any even beam count in between is available to order.

Beams	DDOF model (TOF)	DD model (diffuse)	Detection height H (mm)	Overall length L (mm)
4	DDOF0440	DD0440	160	209
6	DDOF0640	DD0640	240	289
8	DDOF0840	DD0840	320	369
10	DDOF1040	DD1040	400	449
12	DDOF1240	DD1240	480	529
14	DDOF1440	DD1440	560	609
16	DDOF1640	DD1640	640	689
18	DDOF1840	DD1840	720	769
20	DDOF2040	DD2040	800	849
22	DDOF2240	DD2240	880	929
24	DDOF2440	DD2440	960	1009
26	DDOF2640	DD2640	1040	1089
28	DDOF2840	DD2840	1120	1169
30	DDOF3040	DD3040	1200	1249
32	DDOF3240	DD3240	1280	1329
34	DDOF3440	DD3440	1360	1409
36	DDOF3640	DD3640	1440	1489
38	DDOF3840	DD3840	1520	1569
40	DDOF4040	DD4040	1600	1649
42	DDOF4240	DD4240	1680	1729
44	DDOF4440	DD4440	1760	1809
46	DDOF4640	DD4640	1840	1889
48	DDOF4840	DD4840	1920	1969
50	DDOF5040	DD5040	2000	2049

2026-08 factory selection sheet

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.

Response time is not published on the 2026-08 factory sheet.
Supply-voltage tolerance and current draw are not published (the wiring diagram labels +24 V and 0 V only).
IP ingress-protection rating is not published for this family.
Operating and storage temperature ranges are not published.
Cable length and housing material grade are not published (cross-section and end-cap dimensions are).
Minimum detectable object size is not published; it depends on pitch and the set distance - state your smallest target in the inquiry.
Output load rating of the transistor outputs is not published - confirm before driving anything heavier than a PLC input.
No safety certification (IEC 61496 / ISO 13849 / IEC 62061) exists for this family - by design, as it is an area-detection instrument; do not request or expect an ESPE certificate for it.

Frequently Asked Questions

How do I order the TOF version - is it a suffix or a different series?

It is the model prefix. DDOF0440 through DDOF5040 are the time-of-flight models; DD0440 through DD5040 are the diffuse models. The digits mean the same in both: beam count (two digits) then the fixed 40 mm pitch. So DDOF2040 and DD2040 are the same 20-beam, 800 mm-field instrument with different sensing engines inside.

In one sentence each, when do I buy DD and when do I buy DDOF?

Buy DD when the product is consistent, the background is bolted down, and 2000 mm is enough - it is the economical choice for tame applications. Buy DDOF when anything varies (target colour, background position, span beyond 2000 mm) or when a dead zone would miss product - the TOF engine makes those variables irrelevant instead of tunable.

Are the DDOF and DD mechanically interchangeable on the same bracket?

Yes. Both series share the 35 x 35 mm cross-section, the same tier table, the same end caps and the same mounting holes. A DD2040 that has run out of headroom can be replaced by a DDOF2040 without re-drilling or re-routing - only the sensing engine changes.

What exactly does the background suppression on the DDOF do?

Every beam measures the distance to whatever reflects it. You teach the sensor a distance window with one key press; only reflections from inside that window count as detection. The wall, the far conveyor, passing traffic beyond the lane - all sit outside the window and are ignored. Because the judgment is distance, not brightness, the target's colour and the background's finish stop mattering.

How tall a field can one unit cover, and what if my height is between tiers?

Standard tiers cover 160 mm (4 beams) to 2000 mm (50 beams) of detection height, in 80 mm increments (2 beams at a time). The housing is always 49 mm longer than the field. Heights between tiers are handled by custom even beam counts - a routine order, not a special build.

Is the output NPN or PNP - and what do I do with the wire I don't use?

Both. Black carries the NPN signal and white carries the PNP signal on every unit, alongside brown +24 V and blue 0 V. Connect the wire that matches your input card and insulate the unused one - do not leave it floating against the panel.

How do I get normally-closed output, and why would I want it?

Kill the power first, hold the adjustment button down, restore power with the button still pressed, and let go the moment the red LED comes on - the unit stores the normally-closed setting from then on (ex-factory it ships normally-open). NC is worth specifying whenever the signal feeds interlock logic: a severed cable or lost supply then reads as 'blocked', which fails toward attention instead of toward silence.

Can I use the self-learning mode at a doorway or on a lifting platform?

No - and the factory sheet says so explicitly. Self-learning memorizes a fixed background; a door that opens or a platform that travels changes that background and defeats the learned setting. Moving-background posts are precisely what the DDOF's taught distance window exists for.

What response time does this series have?

The 2026-08 factory sheet does not publish a response time, and we will not invent one. If your application times a falling or fast-moving object, tell us the speed and we will confirm suitability with the factory in writing before you order.

Is this an IP65 sensor? Can it go outdoors or in washdown areas?

The factory sheet publishes no ingress-protection rating for this family, so no IP figure should appear in your design file without written confirmation from us. For explicitly washdown-rated sensing, ask about series designed for that duty instead.

Can the DDOF, with its better detection, be used as a safety device?

No. The factory statement - area detection only, not for safety protection - covers the whole family, DDOF included. Superior detection performance is not a safety certification: neither series carries IEC 61496, ISO 13849 PL or IEC 62061 SIL credentials, and neither may be the device that stops a machine to protect a person. For that duty specify a certified curtain such as the DQT4 with a safety relay.

What documentation ships with an export order?

The English selection manual on this page travels with the quotation, and certification documents for the company and product line are available on request. Open parameters (response time, IP, supply tolerance, temperature) are confirmed in writing per order so your engineering file is complete before the goods ship.