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DQM Measuring Light Curtain (Switching Output)

Switching-output measuring light curtain: any interrupted beam triggers direct NPN/PNP output, no controller needed.

DQM Measuring Light Curtain (Switching Output) - product photo🔍 Click to enlarge · 1/7

Technical Specifications

Output typeSwitching (discrete) output — NPN normally-closed (order code A), PNP normally-closed (B), NPN normally-open (C), PNP normally-open (D); output switches state when any single beam across the full detection height is interrupted. Wired via 5-wire or 7-wire cable; no external controller required.
Beam spacing2.5 / 5 / 10 / 20 / 40 / 80 mm (order code K); DQM does not offer the 1.25 mm spacing available on DQL.
Protection height (by spacing)2.5mm: 77.5-797.5mm (32-320 beams); 5mm: 75-1595mm (16-320 beams); 10mm: 70-3990mm (8-400 beams — the catalog's own table prints the last three rows' height column as 4950/4970/4990mm, inconsistent with the model-number suffixes and the height formula; see dataGaps); 20mm: 60-3980mm (4-200 beams); 40mm: 120-3960mm (4-100 beams); 80mm: 240-3920mm (4-50 beams).
Sensing (transmitter-receiver) distance0.3-3m for most configurations (order code A); narrows to 0.3-2m and then 0.3-1.3m at the highest beam counts within the 2.5mm-spacing tier specifically (0.3-2m up to 96 beams, 0.3-1.3m from 104 beams up, per the model table); 0.3-6m (code B) also selectable. Exact breakpoints for other spacing tiers beyond what the model table shows are not confirmed.
Response time0.5 ms, as explicitly stated in the catalog directly beneath the DQM wiring diagrams (p.47). A separate general DQL/DQM feature-page bullet also cites “up to 5ms” and “<=15ms” in the same sentence — see dataGaps for this inconsistency.
Ingress protectionIP65 default; IP68 (DQMF waterproof-enclosure variant, F code immediately after DQM)
Detection/measurement accuracySet directly by the selected beam spacing (finest 2.5mm); catalog does not publish a separate accuracy multiplier
AccessoriesStandard: DQLMR-06 right-angle end-mount bracket (two-end mounting), DQCA-02 T-slot screws. Optional: DQCA-01 stainless-steel tube bracket, DQCA-03 raised/male nut, DQCA-05 side right-angle bracket (side-face mounting)

Overview

DQM belongs to Daidisike's light-grid product family and is the switching-output counterpart to the DQL analog measuring light curtain: where DQL reports position or size via analog voltage/current or RS485, DQM answers a simple yes/no question - "is anything in the field?" - through a direct NPN/PNP switching signal. It is a detection/measurement device, not a safety device: it carries no personnel-safety rating and must not be used as machine-guarding equipment.

It suits machine builders and line integrators who need a full-height object-presence signal wired straight into a PLC input, without programming an analog channel or a communication bus. Any single beam interrupted across the full detection height switches the output, and the series is offered in six beam-spacing options from 2.5 mm up to 80 mm, so the sensing field can be matched to the actual opening or workpiece size.

Features & Benefits

Full-height sensing beats single-point detection

Any one of the beams across the entire detection height being interrupted switches the output, so objects that vary in size, position, or falling trajectory are still reliably caught, whereas a single-point photoelectric sensor can miss anything that doesn't line up with its one beam.

NPN/PNP and NO/NC selectable for direct PLC compatibility

Switching output is available as NPN or PNP transistor output, with normally-open or normally-closed logic selectable, so the same product family connects directly to sinking-input and sourcing-input PLCs without an interposing relay.

2.5 mm fine beam spacing for small parts

The finest available spacing is 2.5 mm, from model DQM32/2.5-77.5, letting the light curtain catch small screws, stamped parts, or thin sheet-like objects that would fall between the beams of a coarser-pitch grid.

Six beam-spacing options for precise specification

Beam spacing is offered at 2.5, 5, 10, 20, 40 or 80 mm, with detection heights spanning from 60 mm upward per spacing tier, so the sensing field can be matched to the actual opening or workpiece size instead of over-specifying.

Direct switching output, no external controller required

DQM outputs the switching signal directly through standard 5-wire or 7-wire cabling, with no separate controller unit and no communication protocol to configure, which shortens commissioning time and lets maintenance staff swap a unit without bus-configuration knowledge.

Shares mounting accessories with the DQL series

DQM uses the same accessory range as DQL: end-mount bracket DQLMR-06 as standard, plus optional side-mount and corner brackets DQCA-01/02/03/05, so lines that run both DQL and DQM keep a common spare-parts inventory.

IP68 waterproof variant available (DQMF)

For washdown or wet-environment installations, the DQMF variant is documented as rated IP68, an option not present on every switching light curtain in this class.

Applications

Object presence / pass-through detection on conveyors — Full-height switching detection covers objects at different positions across the conveyor width, since interrupting any one beam produces an output.
Part ejection verification after stamping or die-cutting — Ejected parts land at unpredictable positions and angles, so a full-height detection zone confirms part ejection more reliably than a single-point sensor.
Small-part drop-through / fall detection with fine beam spacing — The 2.5 mm beam-spacing tier is built for small screws and small stamped parts that would otherwise pass undetected between coarser-pitch beams.
Packaging line fill-level / arrival confirmation — The direct switching signal can trigger the next station's action immediately, without an analog-signal processing step.
Entry/exit or passage triggering for counting, print-marking, or photo events — Any beam interruption produces an immediate ON output, making it suitable as a trigger source for downstream actions such as counters, print marking, or photo triggers.
Infeed opening oversize / foreign-object detection — The multiple protection-height options can cover the full opening height of an infeed, so oversized objects interrupt additional beams beyond the normal profile.
Mixed DQL/DQM production lines needing shared spares — Because DQM shares DQLMR-06 and the DQCA mounting accessories with DQL, lines running both series can simplify spare-parts purchasing.
Washdown or wet-area object detection (DQMF) — The DQMF variant is documented as IP68-rated, suiting installations that need protection from washdown or wet conditions.

Models & Ordering Information

559 standard models across 6 beam-pitch options. Select the pitch your risk assessment calls for, then the protective height that covers the opening.

DQM Measuring Light Curtain (Switching Output) — 2.5 mm beam pitch, 37 standard models
ModelBeam pitch K (mm)Number of beams NProtective height H (mm)
DQM32/2.5-77.52.53277.5
DQM40/2.5-97.52.54097.5
DQM48/2.5-117.52.548117.5
DQM56/2.5-137.52.556137.5
DQM64/2.5-157.52.564157.5
DQM72/2.5-177.52.572177.5
DQM80/2.5-197.52.580197.5
DQM88/2.5-217.52.588217.5
DQM96/2.5-237.52.596237.5
DQM104/2.5-257.52.5104257.5
DQM112/2.5-277.52.5112277.5
DQM120/2.5-297.52.5120297.5
DQM128/2.5-317.52.5128317.5
DQM136/2.5-337.52.5136337.5
DQM144/2.5-357.52.5144357.5
DQM152/2.5-377.52.5152377.5
DQM160/2.5-397.52.5160397.5
DQM168/2.5-417.52.5168417.5
DQM176/2.5-437.52.5176437.5
DQM184/2.5-457.52.5184457.5
DQM192/2.5-477.52.5192477.5
DQM200/2.5-497.52.5200497.5
DQM208/2.5-517.52.5208517.5
DQM216/2.5-537.52.5216537.5
DQM224/2.5-557.52.5224557.5
DQM232/2.5-577.52.5232577.5
DQM240/2.5-597.52.5240597.5
DQM248/2.5-617.52.5248617.5
DQM256/2.5-637.52.5256637.5
DQM264/2.5-657.52.5264657.5
DQM272/2.5-677.52.5272677.5
DQM280/2.5-697.52.5280697.5
DQM288/2.5-717.52.5288717.5
DQM296/2.5-737.52.5296737.5
DQM304/2.5-757.52.5304757.5
DQM312/2.5-777.52.5312777.5
DQM320/2.5-797.52.5320797.5

37 standard models at 2.5 mm pitch · 559 across the series. Protective height is derived as H = (N − 1) × K. Intermediate beam counts can usually be built to order — send the opening height you need to cover.

Waterproof variant

DQMF (F suffix denotes the IP68 waterproof version of any model above)

How to read the DQL/DQM model code

D Q L(M) [F] [beams] / [pitch] - [height] [output] [signal] [baud] [mode] [upload] [interval] [distance]
DQM = switching output selected; DQL = analog/RS-485 output selected (same physical platform — per the catalog: choosing switching output gives DQM, choosing analog voltage/current or RS485 output gives DQL). F (optional) = IP68 waterproof enclosure (model prefix DQMF); default blank = IP65. [beams] = beam count, 2-digit (04, 06, 08 ... 400). [pitch] after "/" = 2.5/5/10/20/40/80mm (DQM has no 1.25mm option). [height] after "-" = protected height in mm. [output] = A (NPN NC), B (PNP NC), C (NPN NO), D (PNP NO). [signal]/[baud]/[mode]/[upload] positions in the shared code apply to the DQL analog/serial variant, not DQM. [distance] = A (0.3-3m) or B (0.3-6m). Catalog example (from the shared decode key): QL08/40-280ARF21 = 8 beams, 40mm pitch, 280mm protected height, NPN normally-closed RS485 output, 9600bps, passive transmission, full-status upload, 3m sensing distance — the equivalent DQM part number would read, e.g., DQM08/40-280A (switching, NPN NC, 3m sensing distance).

How to Select

  1. Select beam spacing by detection precision / minimum target size: the smaller and thinner the target, the finer the spacing needed, from 2.5mm (small screws, thin sheets) up to 80mm (coarse detection of large objects at lowest beam count and cost).
  2. Select protection height by installation opening: determine the actual height range to cover first, then pick the closest sufficient protection height within the chosen spacing tier's model list, rather than over-specifying.
  3. Select NPN vs PNP by PLC input type: PNP for European-style sourcing-input PLCs (e.g. Siemens), NPN for Japanese-style sinking-input PLCs (e.g. Mitsubishi, Omron).
  4. Select NO vs NC by required signal logic, depending on whether fail-safe behavior on wire break or power loss is prioritized.
  5. Confirm the field cable specification against the wiring type: standard is 5-wire or 7-wire, so confirm which wiring format the chosen model uses before ordering cable.
  6. Select the IP68 waterproof version (DQMF) for washdown, wet, or dusty environments; use the default version for normal indoor installations.
  7. If analog position, size, or contour data is needed rather than a simple presence signal, select the DQL series instead - DQM outputs only an ON/OFF presence signal.
  8. For accessories, the standard end-mount bracket is DQLMR-06; add DQCA-01/02/03/05 when side-mount or corner-mount fixing is required (shared with the DQL series).

📘 Need the full method? How to Choose a Safety Light Curtain

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

You need to protect a person from a hazardous machine motion

Why not: DQM is a measuring/detection light curtain. It sits under a catalog section headed “安全光幕” (safety light curtain) that also cites IEC 61496 and TÜV/UL certification, but no Category, PFHd/MTTFd, or Type-4 architecture data is published for this series anywhere in the catalog, and every worked DQL/DQM application example (part-ejection detection, conveyor presence, screw counting) is a measuring or counting task, never personnel guarding.

Use instead: A DAIDISIKE safety light curtain series actually designed and documented for personnel protection — DQC, DQA or DQT4 — paired with a DA31 or DQSRN safety relay module, or an ST27 safety component, as the application requires.

Need position, size, or profile data, not just a presence signal

Why not: DQM only switches an output ON/OFF when a beam is interrupted; it carries no analog or serial interface to report which beam, how many, or a bitmap.

Use instead: The DQL series (analog voltage/current or RS-485/RS-232 Modbus RTU output), built on the same mounting platform and accessories.

Detecting an object smaller than the selected beam spacing

Why not: DQM's finest spacing is 2.5mm; unlike DQL, it has no 1.25mm option. An object narrower than the chosen pitch can pass between two beams undetected.

Use instead: Select the finest available DQM spacing (2.5mm), or move to the DQL series with its 1.25mm option if finer resolution is required.

Transmitter-receiver span beyond the standard 0.3-3m order code

Why not: The DQM model tables list 0.3-3m as the sensing distance for nearly every configuration (narrowing further at very high beam counts in the 2.5mm tier); the 0.3-6m code and any longer special-order range are not detailed with confirmed figures for DQM.

Use instead: Confirm sensing-distance requirements beyond 3m with the factory before specifying.

Washdown, high-pressure spray, or continuously wet installation

Why not: The default DQM enclosure is IP65; only the DQMF variant is rated IP68.

Use instead: Order the DQMF IP68 waterproof variant for wet measuring/detection applications, or the DQR waterproof safety light curtain series if the task is actually personnel guarding in a wet area.

Application requires a confirmed operating-temperature or humidity rating

Why not: Pages 44-47 of the catalog do not publish an operating-temperature or humidity figure specific to DQM.

Use instead: Confirm the operating environment range with the factory before specifying for hot, cold, or humid installations.

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.

  • No machine-safety rating (Type / Category / PL / PFHd) is published for DQM and we do not claim one. Treat DQM as a measuring light curtain, not a protective device — for safeguarding people use a safety light curtain such as DQC, DQA or DQT4
  • The 10mm-spacing model table's last three rows (beam counts 396/398/400) print protection heights as 4950/4970/4990mm, inconsistent with their own model-number suffixes (...-4950/...-4970/...-3990) and with the height formula height=(beams-1)x10mm (which gives 3950/3970/3990mm, matching the equivalent DQL rows). The correct top-end height figures need confirming.
  • Response time: the catalog states 0.5ms specifically for DQM (p.47) but a separate general DQL/DQM feature-page bullet cites “up to 5ms” and “<=15ms” in the same sentence. Which figure is authoritative, and whether it varies by beam spacing/count, needs confirming.
  • Exact sensing-distance breakpoints (where the range narrows from 0.3-3m to 0.3-2m or 0.3-1.3m at high beam counts) are only confirmed from the printed 2.5mm-spacing table; equivalent breakpoints for the 5/10/20/40/80mm tiers are not confirmed beyond the “0.3-3m” figure shown.
  • Overall housing cross-section dimensions are not given directly for DQM in these catalog pages.
  • Whether any TUV/UL certificate covers a DQM configuration, and its number and scope
  • Operating temperature and humidity range for DQM is not stated on pages 44-47 of the catalog.

Frequently Asked Questions

What does "switching output" mean on the DQM light curtain?
It means the DQM outputs a simple ON/OFF (discrete) signal - as soon as any single beam across the detection height is interrupted, the output switches state. It does not report the position or size of the object; for that, the analog/RS485 DQL series is used instead.
Is the DQM light curtain a safety device?
No. DQM is a measurement/detection light curtain, not a safety light curtain, and it carries no personnel-safety certification such as Type 4, PLe, or SIL3. It must not be used as machine guarding or personnel-protection equipment. The catalog's DQL/DQM feature page does cite IEC 61496 and TUV/UL certification, but this appears to be boilerplate carried over from the safety-curtain product line rather than a genuine rating for this measuring series; we are confirming with the factory before citing any certification for DQM.
What is the finest beam spacing available on DQM?
2.5 mm, starting from model DQM32/2.5-77.5, intended for detecting small parts that could pass undetected through coarser-pitch beam spacing.
Can DQM connect directly to both NPN and PNP PLC inputs?
Yes. The switching output is available as NPN (sinking) or PNP (sourcing) transistor output, with normally-open (NO) or normally-closed (NC) logic selectable, covering both Japanese-style sinking and European-style sourcing PLC input conventions.
Does DQM require an external controller?
No. DQM outputs the switching signal directly through standard 5-wire or 7-wire cabling; no separate controller unit or communication protocol configuration is needed.
What beam spacing options does DQM offer?
Six spacing options: 2.5, 5, 10, 20, 40, and 80 mm, each covering a different range of protection heights as listed in the model table.
Is there a waterproof version of DQM?
Yes, the DQMF variant is documented as IP68-rated for washdown or wet-environment installations.
What is the difference between DQM and DQL?
Per the manufacturer's catalog: choosing switching output gives the DQM series; choosing analog voltage/current or RS485 output gives the DQL series. DQM answers only "is something present," while DQL also reports position/size data.
What accessories does DQM use for mounting?
DQM shares its accessory range with DQL: end-mount bracket DQLMR-06 as standard, plus optional accessories DQCA-01, DQCA-02, DQCA-03, and DQCA-05.
What is the maximum protection height available on DQM?
Maximum height varies by beam-spacing tier - for example, the 20mm spacing tier extends up to 3980mm (model DQM200/20-3980). Consult the model list for the exact figure at your chosen spacing.

Works Well Together

On the same machine or line, DQM is typically ordered together with: Safety Light Curtains · Photoelectric Sensors · Relay & Timer Modules

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Optocoupler-isolated input amplifier that turns a low-voltage signal into a 250V AC / 10A relay output.

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