DK-G Series Laser Displacement Sensor

Name: DK-G Series Laser Displacement Sensor
Brand: DAIDISIKE
SKU: dk-g-series-laser-displacement-sensor
Availability: InStock

Laser triangulation sensor: 30-400 mm reference distances, switching, analog, or RS485 output.

DK-G Series Laser Displacement Sensor - product photo

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Technical Specifications

Category	Laser displacement / distance measurement
Measuring principle	Laser triangulation
Laser source	Class 2, 655 nm red semiconductor laser, max. output 1 mW
Output types	NPN discrete switching output / Analog output (0-5 V or 4-20 mA) / RS485 Modbus RTU output
Operating voltage	12-24 VDC ±10% (pulsation P-P 10%)
Response time	1.5 / 5 / 10 ms, switchable
Protection rating	IP60
RS485 communication	Modbus RTU, 9600-115200 bps (RS485 variant only)
Switching output type	NPN open-collector, max. sink current 50 mA, applied voltage ≤30 VDC, residual voltage ≤1.5 V at 50 mA, leakage current ≤0.1 mA
Switching output logic	Selectable: ON while target detected / ON while target not detected, with automatic recovery after short-circuit
Measuring range — 30 mm reference	30 ±5 mm
Repeatability — 30 mm reference	10 μm
Beam diameter — 30 mm reference	about Φ50 μm
Measuring range — 50 mm reference	50 ±15 mm
Repeatability — 50 mm reference	30 μm
Beam diameter — 50 mm reference	about Φ70 μm
Measuring range — 100 mm reference	100 ±35 mm
Repeatability — 100 mm reference	70 μm
Beam diameter — 100 mm reference	about Φ200 μm
Measuring range — 200 mm reference	200 ±80 mm
Repeatability — 200 mm reference	200 μm
Beam diameter — 200 mm reference	about Φ300 μm
Measuring range — 400 mm reference	400 ±200 mm
Repeatability — 400 mm reference	400 μm (200-400 mm range) / 800 μm (400-600 mm range)
Beam diameter — 400 mm reference	about Φ500 μm
Housing material	Die-cast aluminum body with acrylic front cover plate
Operating temperature	-10°C to +40°C
Storage temperature	-20°C to +60°C
Operating humidity	35%-85% RH
Altitude	Under 2000 m
Ambient illumination	Below 3000 lx (incandescent-type light) on the illuminated surface
Weight	Approx. 35 g without cable; approx. 85 g with the supplied 5-core, 2 m composite cable
Cable	Supplied 5-core, 2 m composite cable
Applicable specifications	Comply with EMC instructions

Overview

DK-G is a laser triangulation displacement sensor: a red semiconductor laser (Class 2, 655 nm) projects a spot onto the target surface, and a CMOS receiving element detects how the reflected spot position shifts as the target moves closer or farther from the reference distance. The sensor converts that shift into a distance/displacement reading.

It suits machine builders and process engineers who need non-contact distance, thickness, position, or runout measurement in the 30-600 mm range, with a choice of simple on/off output, continuous analog output for PLC integration, or RS485 digital output for multi-sensor networks.

Features & Benefits

Three Output Tiers — Pay Only for the Interface You Need

Discrete NPN switching output (DK-G50N/100N/200N/400N; no discrete-switch variant at the 30 mm reference distance), analog output (DK-GxxNM, 0-5 V or 4-20 mA), and RS485 Modbus RTU output (DK-GxxN-RS485) are all offered across the same 30-400 mm distance lineup, so you only pay for the interface tier your application needs.

Five Reference Distances (30-400 mm) with Repeatability from 10 μm

Measuring range spans ±5 mm (30 mm reference) to ±200 mm (400 mm reference); repeatability runs from 10 μm at the 30 mm reference down to 400 μm (200-400 mm) or 800 μm (400-600 mm) at the 400 mm reference — near-range high precision through to longer-range coarse measurement in one series.

Switchable Response Time (1.5 / 5 / 10 ms)

A faster response setting suits high-speed moving targets; a slower setting improves reading stability on darker or low-reflectivity surfaces, giving you a speed/stability trade-off standard for laser triangulation sensors.

RS485 Modbus RTU for Digital, Drift-Free Readings and Multi-Drop Networking

The RS485 variant transmits the measured distance as digital data over Modbus RTU, avoiding the A/D conversion error and long-cable voltage drop inherent to analog transmission, and allows multiple sensors to be daisy-chained on one bus.

NPN Open-Collector Switching Output with Selectable Logic

The switching output is an NPN open-collector transistor (max. sink current 50 mA, applied voltage ≤30 VDC, residual voltage ≤1.5 V at 50 mA, leakage current ≤0.1 mA), and can be configured for "ON while target detected" or "ON while target not detected," with automatic recovery after a short-circuit condition.

Compact Aluminum Housing, IP60, -10°C to +40°C Operation

Body shell is die-cast aluminum with an acrylic front cover plate; the sensor is rated IP60 and specified for use at -10°C to +40°C (storage -20°C to +60°C), 35%-85% RH, under 2000 m altitude, weighing approx. 35 g without cable (approx. 85 g with the supplied 5-core, 2 m composite cable).

Applications

Multi-Point Board/Sheet Thickness or Flatness Measurement — RS485 daisy-chain lets several sensors share one bus for width-wise multi-point measurement without one analog cable per point.

Detecting the Presence of Thin, Flat Parts — A small beam diameter (from about Φ50 μm at the 30 mm reference) suits detecting small or thin targets, as shown in the official catalog's application case images.

Checking Bending/Deflection of Sheet Material — Continuous analog or digital output tracks deviation from a flat reference in real time, as shown in the official catalog's application case images.

Monitoring Remaining Material on a Reel / Coil Diameter — Pictured as a factory application case in the official catalog for tracking coil diameter or reel remaining material.

Position Feedback for Lifting Platforms or Feed Mechanisms — Analog output (0-5 V or 4-20 mA) feeds directly into a PLC's analog input for closed-loop position control.

Remote Level/Inventory Reporting via Modbus — The RS485 variant reports the distance value digitally, avoiding long analog cable runs to a control room's Modbus-based system.

Simple Presence/Limit Judgment on a Production Line — The discrete NPN switching output variant is the lowest-cost tier for pure go/no-go decisions.

Radial Runout Inspection of Rollers or Shafts — High repeatability (from 10 μm) and fast response (down to 1.5 ms) support runout-style measurement, a typical use case for triangulation displacement sensors.

Models & Ordering Information

NPN Discrete Switching Output

DK-G50NDK-G100NDK-G200NDK-G400N

No discrete-switch variant is offered at the 30 mm reference distance.

Analog Output (0-5 V or 4-20 mA)

DK-G30NMDK-G50NMDK-G100NMDK-G200NMDK-G400NM

Switching output on this variant is NPN open-collector.

RS485 Modbus RTU Output

DK-G30N-RS485DK-G50N-RS485DK-G100N-RS485DK-G200N-RS485DK-G400N-RS485

How to Select

Need only a go/no-go or limit judgment? Choose NPN switching output (DK-G50N / 100N / 200N / 400N); no discrete-switch model is offered at the 30 mm reference distance.
Need a continuous value into a PLC analog input? Choose analog output (DK-G30NM / 50NM / 100NM / 200NM / 400NM), 0-5 V or 4-20 mA.
Need digital readings, multi-sensor networking, or Modbus-based software integration? Choose RS485 output (DK-G30N-RS485 / 50N-RS485 / 100N-RS485 / 200N-RS485 / 400N-RS485).
Pick the reference distance that keeps your target's normal travel within its measuring range, centered as close as possible to the reference distance for best precision.
Shorter reference distances (30 mm, 50 mm) give the tightest repeatability and smallest beam spot, best for small or fine targets; longer reference distances (200 mm, 400 mm) trade precision for working distance and range.
Match response time to your target: use the fastest setting (1.5 ms) for high-speed moving targets, and a slower setting (5 / 10 ms) for improved reading stability on dark, matte, or low-reflectivity surfaces.
Check mechanical/environmental fit: all variants share the same aluminum housing, IP60 rating, 12-24 VDC ±10% supply, and -10°C to +40°C operating range — verify against your installation environment, since IP60 is not a washdown/outdoor rating.
The sensor cannot detect transparent objects or liquids, and cannot calculate range starting from zero distance; keep the detection angle perpendicular to the measured surface within 90°±15°.

When NOT to specify the DK-G — and what to use instead

The target sits more than 600 mm away, or the task is really a metre-scale distance/position measurement (e.g., crane travel, silo level over several metres).

Why not: DK-G's longest reference distance is 400 mm with a measuring range up to ±200 mm (600 mm maximum span) — the series has no metre-range option.

Use instead: a laser distance sensor built for metre-range ranging, such as DDA-Y/DDB-Y or DSK-CG

The target is transparent, a liquid, or cannot be mounted close to perpendicular to the beam.

Why not: per DK-G's own stated detection limitations, it cannot detect transparent objects or liquids, cannot calculate range starting from zero distance, and the detection angle must stay within 90°±15° of perpendicular.

Use instead: consulting the factory for an application-specific method for transparent/liquid targets rather than laser triangulation

The installation is outdoors, washdown, or otherwise exposed to significant water or heavy dust ingress.

Why not: DK-G carries an IP60 rating, which covers dust-tightness but no specified water-ingress protection — it is not a washdown or outdoor rating.

Use instead: confirming an IP-rated alternative with the factory, or housing the sensor in a protective enclosure

The project needs the tightest available repeatability at a longer standoff distance (e.g., 200-400 mm).

Why not: repeatability coarsens as reference distance grows — from 10 μm at the 30 mm reference to 400 μm (200-400 mm range) or 800 μm (400-600 mm range) at the 400 mm reference.

Use instead: the 30 mm or 50 mm reference-distance model, if the mounting space allows, for tighter repeatability

The application requires a personnel-safety function such as a guard interlock.

Why not: DK-G is a measurement sensor with standard NPN switching, analog, or RS485 outputs; no safety-rated certification is documented for it.

Use instead: a certified safety device such as a safety light curtain or safety laser scanner, not a displacement sensor

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.

Whether a PNP output version, or a pure switching-output model at the 30 mm reference distance, is currently orderable
RS485 communication protocol details (parity, register map, address range) beyond the general Modbus RTU description are not documented
Outline dimensions read from the catalog drawing are approximate and not yet confirmed against a factory CAD file
Certification documents (CE/RoHS, laser-safety standard reference) are not yet available
Linearity and temperature-coefficient specifications are not yet included in the primary parameter sheet

Frequently Asked Questions

What measuring principle does the DK-G series use?

DK-G uses laser triangulation: a Class 2, 655 nm red semiconductor laser (max. output 1 mW) projects a spot on the target, and a CMOS receiving element tracks how the reflected spot's position shifts as the target's distance from the reference point changes, converting that shift into a distance reading.

What output options are available?

Three tiers across the same distance lineup: NPN discrete switching output, analog output (0-5 V or 4-20 mA), and RS485 Modbus RTU digital output. The 30 mm reference distance is offered only in the analog and RS485 tiers, not as a discrete switching model.

What is the difference between "repeatability" and "resolution"?

Repeatability describes how consistently the sensor reproduces the same reading for the same target position under the same conditions; it is the specification DAIDISIKE documents for the DK-G series (from 10 μm at the 30 mm reference distance). Resolution describes the smallest detectable change in reading and is a different metric — the two should not be directly compared between sensor models unless both are stated on the same basis.

Can the DK-G sensor measure transparent objects or liquids?

No. Per the manufacturer's stated detection limitations, the sensor cannot detect transparent objects, cannot detect liquids, and cannot calculate range starting from zero distance. The detection angle should also be kept perpendicular to the measured surface within 90°±15°.

What is the IP rating and operating temperature range?

IP60, rated for use at -10°C to +40°C (storage -20°C to +60°C), 35%-85% RH, at altitudes under 2000 m, with ambient illumination below 3000 lx from incandescent-type sources on the illuminated surface.

What power supply and output current does the switching output support?

12-24 VDC ±10% supply (pulsation P-P 10%). The NPN switching output is open-collector, rated for a maximum sink current of 50 mA, applied voltage up to 30 VDC, residual voltage under 1.5 V at 50 mA, and leakage current under 0.1 mA.

Can multiple DK-G RS485 sensors share one communication bus?

Yes — the RS485 variant communicates over Modbus RTU (baud rate configurable in the 9600-115200 bps range per product documentation), which supports multiple sensors on a single multi-drop bus rather than one dedicated line per sensor.

How does response time affect the reading?

Response time is switchable at 1.5 / 5 / 10 ms. A faster setting is suited to fast-moving targets; a slower setting improves reading stability on darker or low-reflectivity surfaces — a standard speed/stability trade-off for laser triangulation sensors.

What is the sensor housing made of, and how much does it weigh?

The housing is die-cast aluminum with an acrylic front cover plate. Weight is approximately 35 g without cable, or approximately 85 g including the supplied 5-core, 2 m composite cable.

Can DAIDISIKE provide certification documents for the DK-G series?

Certification documents are available on request.

Works Well Together

On the same machine or line, DK-G is typically ordered together with: Laser Distance Sensors · Contact Displacement Sensors · Relay & Timer Modules

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