ST27 — Type 3 safety laser scanner, SIL 2 / PL d
5 m protective field · 276° · 100 ms
The only unit here with OSSD outputs and a published rating. Use this one when the scanner has to stop a machine to protect a person.
LiDAR Products
Grouped by the job the scanner does, because the three groups are not interchangeable: an avoidance scanner stops a vehicle, a navigation scanner tells it where it is, and mixing them up is the most expensive mistake on this page.
Certified safety scanner — for protecting people
Obstacle avoidance & zone detection — not for personnel protection
DLD05A3-3N / DLD20A5-5N — 5 m / 20 m obstacle-avoidance LiDAR
0.05–5 m / 0.05–20 m
270° scan, 15/30 Hz. The default pick for an AGV or AMR front scanner.
SDLD-05A — 14 m TOF laser radar
up to 14 m
Mid-range avoidance for larger vehicles and wider aisles.
DLDS2030A-5S — 20 m obstacle-avoidance scanning LiDAR
up to 20 m
Zone-based avoidance for machine cells and mobile platforms.
Perimeter & long-range detection
Navigation, mapping & measurement
DLD-50D — 50 m 2D TOF LiDAR for SLAM navigation & mapping
up to 50 m
Point-cloud output for a navigation stack — not a stopping device.
DLD-50G — diffuse-reflective 2D scanning LiDAR, no reflector needed
diffuse, no reflector
Works off the target's own surface, so no retro-reflective tape to install and maintain.
DLD50T8N / DLD50T8P — 50 m measuring LiDAR, NPN/PNP + Ethernet
up to 50 m
Switching output and point-cloud output in one unit — a PLC zone bit without a second sensor.
5JPTG / 10JPTG — 5 m and 10 m laser scanning ranging radar
5 m / 10 m
Compact ranging scanners for robotics and light automation.
Is Your LiDAR a Safety Device? Usually Not — and That Matters
A LiDAR that draws a zone and switches an output looks exactly like a safety laser scanner. The difference is not visible on the bench, and it is the single most expensive misunderstanding in this product category. Two things separate them:
- The output. A safety scanner has OSSD outputs — a pair of continuously test-pulsed channels. If the output stage fails, the failure is detected and the output goes safe. A perception LiDAR has an ordinary NPN or PNP transistor. If it fails shorted, it reports “clear” forever and nothing notices.
- The certificate. A safety scanner is type-examined to IEC 61496-3 and carries a stated Type, PL and SIL. Without that examination there is no basis for putting it in a circuit whose job is to stop a hazard.
Where DAIDISIKE stands, plainly: in this range only the ST27 is a certified safety component — Type 3 ESPE per IEC 61496, SIL 2, PL d, with OSSD outputs. Every other scanner on this page (DLD, SDLD, DLDS, JPTG) is a perception and obstacle-avoidance sensor with ordinary switching or Ethernet outputs and no Type, SIL or PL rating. They are the right tool for keeping a vehicle from bumping into things, for area monitoring and for navigation. They are not the right tool for protecting a person, and we would rather say so here than have it discovered during an audit.
The usual architecture on an AMR uses both: a certified scanner for the stop function, and a perception scanner for navigation and for the softer “slow down, something is ahead” behaviour that keeps the vehicle from nuisance-stopping all shift.
Sizing the Protective Field on a Moving Vehicle
On a fixed machine, ISO 13855 gives S = K × T + C with K = 1600 mm/s for a walking approach. On an AGV or AMR the vehicle is the thing that moves, so the protective field has to be at least as long as the distance the vehicle still covers after the scanner sees an obstruction:
L = v × (tscanner + tcontrol + tbrake) + v² / (2a) + Z
| Term | What it is | Where the figure comes from |
|---|---|---|
| v | Vehicle speed in the direction of travel | Maximum speed permitted for the field set that is active |
| tscanner | Scanner response time | 100 ms on the ST27. Rises if you increase multiple sampling — see below. |
| tcontrol | Safety controller and contactor reaction | From the relay or safety PLC datasheet |
| tbrake | Brake application delay before deceleration starts | Measured on the vehicle, loaded |
| v² / (2a) | Deceleration distance | a = achieved deceleration with the heaviest payload on the worst floor you have, not the empty-vehicle figure |
| Z | Allowances | Scanner measurement tolerance, plus ground-clearance and localisation allowances |
Worked example — 1.2 m/s AGV with an ST27
Take a vehicle running at 1.2 m/s, an ST27 at 100 ms, a safety controller adding 30 ms, a brake that takes 150 ms to bite, deceleration of 0.8 m/s² loaded, and 150 mm of combined allowance:
- Distance during response: 1.2 × (0.10 + 0.03 + 0.15) = 0.34 m
- Deceleration distance: 1.2² ÷ (2 × 0.8) = 0.90 m
- Allowances: 0.15 m
- Protective field length: ≈ 1.39 m — round up and verify by test
Now notice what happens when the fleet manager asks for more throughput. Deceleration distance scales with the square of speed, so at 2 m/s it is 2.50 m and the field needs ≈ 3.0 m; at 2.8 m/s it is 4.90 m and the total exceeds the ST27's 5 m protective-field range altogether. With this deceleration figure the practical ceiling is around 2.6 m/s.
The engineering consequence: when the required field will not fit the aisle, buying a longer-range scanner rarely helps — the limit is the vehicle, not the sensor. Improve deceleration, or switch to a slower field set before entering the tight area. Speed and field set have to be interlocked, which is exactly why the next section matters.
Six Ways Scanner Commissioning Goes Wrong
These are the failures that show up during acceptance testing or, worse, during an incident investigation. They are consistent with what the major scanner manufacturers publish, and none of them are exotic.
Mounting height and resolution do not match
To detect a leg, a scanner mounted at up to 300 mm works with 70 mm resolution. Mount it lower than 300 mm and the required resolution becomes 50 mm — because the beam plane now cuts the ankle rather than the calf. Dropping the scanner to clear a bumper and leaving resolution at 70 mm is one of the most common faults in the field, and the machine still passes a walk-through test with an adult, which is what makes it dangerous.
Multiple sampling turned up to stop nuisance trips
Multiple sampling sets how many consecutive scans must see an object before the output trips. The default is ×2. Raising it suppresses false trips from dust, insects and weld spatter — and adds directly to the response time, which lengthens every protective field you already calculated. Raise it and you must re-run the sizing; if you do not, you have quietly shortened the stopping margin.
Field-set switching done with a standard PLC
Switching between field sets — slow field in the aisle, long field in the open — is itself a safety function. It must be performed at the same PL/SIL as the scanner. Route it through an ordinary PLC output or a single unmonitored switch and the whole function degrades to roughly PL a–c, no matter what the scanner is rated at. The failure mode is specific and nasty: the vehicle runs at high speed with the short field active.
Reaching for range instead of robustness
Long-range scanners buy their range with angular resolution and detection robustness, which often has to be recovered by raising multiple sampling — which adds response time — which enlarges the field. The guidance from every manufacturer is the same: the protective field should be as large as required and as small as possible. A shorter, more robust scanner frequently ends up with a smaller footprint, fewer false trips and a lower price.
Blind spots designed in, then patched
A scanner sees a plane. Corners, forks, overhanging loads and the vehicle's own bodywork cast shadows in that plane. Two scanners at diagonally opposite corners with overlapping fields is the standard answer for a vehicle or a large cell. Deciding this after the chassis is built means mechanical patches and extra units.
Environment treated as an afterthought
Dust, steam, rain, snow and fog degrade an infrared scanner's availability, not its safety — it fails toward stopping, which is correct behaviour and terrible for production. If the area genuinely has these conditions, plan for the downtime, enclose the scanner, or move the detection task to a different technology rather than discovering it during the ramp-up.
The History of LiDAR Scanners: From Lab to Factory Floors and Robotics
Turning “seeing the world” into an engineering capability, LiDAR has traveled more than half a century — from research prototypes to must-have sensors for industrial automation, AGV/AMR navigation, robotic obstacle avoidance, perimeter security, and zone protection. This timeline explains how the technology got here — and answers a practical question buyers and operators care about most: can it stay stable on the line?
1) A Single Dot of Light (1960s–1980s): Measuring Distance Accurately
Time of Flight (TOF) made optical ranging practical: emit a laser pulse, measure the round-trip time Δt, and estimate distance as c·Δt/2. Early instruments were bulky and power-hungry, mostly for defense and science. Critical building blocks — semiconductor lasers, photodetectors (APD/SiPM), and pulse shaping — took shape. To turn point measurements into scans, engineers developed repeatable optical mechanisms: spinning mirrors, galvos, and polygon scanners.
Safety baseline: products follow IEC 60825-1 for laser eye safety; most industrial LiDARs target Class 1.
Keywords: laser ranging, TOF, pulsed laser, rotating mirror scanning, photodetection, IEC 60825-1
2) From Dot to Line (1990s–2000s): 2D LiDAR Hits the Line
A classic 2D LiDAR pairs a transmitter/receiver with a rotary or oscillating mechanism to build a polar point cloud. Early deployments focused on obstacle detection and zone protection: define protection/warning areas; if breached, output I/O to interlock a stop.
- Device maturity: 905 / 1550 nm sources plus narrow pulses improved range and SNR.
- Signal processing: DSP/FPGA-based echo discrimination strengthened immunity to glare and dust.
- Integration: interfaces evolved from relays to RS485/Modbus, CAN, and Ethernet for easy line-level integration.
Functional safety context: LiDARs used in protective functions are commonly engineered with the thinking of ISO 13849-1 (PL), IEC 61508 (SIL), and EN 62061 — risk assessment, redundancy, diagnostics, and verifiable interlocks.
Keywords: 2D LiDAR, scanning rangefinding, zone protection, perimeter security, RS485/Modbus, functional safety
3) From Line to Surface (2010s): 3D Point Clouds and SLAM
Narrow aisles, glass shelving, and harsh lighting can cause drift or loss when you only have 2D + odometry. The response was multi-beam / solid-state 3D LiDAR plus SLAM (front-end features, loop closure, back-end optimization). The ecosystem matured: ROS/SDK support, multi-sensor fusion (camera + LiDAR + IMU), and native PLC/IPC communications.
Mobile robot safety: ISO 3691-4 raised expectations for obstacle avoidance, speed limits, and emergency stops on AGV/AMR platforms.
Keywords: 3D LiDAR, point cloud, SLAM, AGV/AMR navigation, ROS, ISO 3691-4
4) Making “Lab Results” Production-Stable (2015–Today)
The real bar is not hitting spec once, but doing it every shift:
- Glare & reflectors: sunlight and stainless / glass can bury weak returns in noise.
- Dust / oil mist: scattering raises false positives; a dirty window attenuates signals.
- Vibration & temperature: mobile bases and press shops require rigid opto-mechanics and compensation.
- Deterministic interlock: “seeing” isn't enough; the stop chain must be verifiable.
Engineering answers buyers value:
- Echo processing: multi-echo, dynamic thresholds, adaptive gain — reliable on thin / black / glass-edge targets.
- High refresh + low end-to-end latency: ensures braking distance in fast motion.
- Flexible zoning: configurable polygon/fan Protection / Warning areas with instant I/O / 485 outputs.
- IP, anti-vibration, wide temperature: structure, sealing, and coatings for 24/7 duty.
- Interfaces & ecosystem: RS485/Modbus, digital I/O, Ethernet; quick coupling to PLC/IPC and safety light curtains.
- Maintainability: robust window materials / coatings, easy cleaning, firmware updates, parameter backup.
Keywords: glare immunity, low latency, high refresh rate, flexible zoning, IP rating, reliability, fast integration
5) Why Industry Relies on LiDAR (Proven Business Value)
- Industrial safety: in pressing, bending, palletizing, and AS/RS, intrusion detection and zone protection drive EHS compliance and reduce downtime.
- AGV/AMR: stable 2D / 3D point clouds enable SLAM, dynamic obstacle avoidance, and tight docking.
- Perimeter security & patrol: low false alarms with fast linkage in day / night and backlight.
- Semi-outdoor / high-reflectance sites: robust echo logic and proper protection ratings make the difference.
Keywords: industrial automation, AGV/AMR navigation, dynamic obstacle avoidance, perimeter security, EHS, zone protection, false-alarm rate
6) Buyer's Shortlist: A Practical Selection Table
| Focus | Pragmatic Check | Why It Matters |
|---|---|---|
| Range | Match 5 / 10 / 20 / 40 m… to obstacle size, speed, stopping distance | Rated range ≠ effective detect distance; reflectivity matters |
| Resolution & Repeatability | Millimeter-class? Edge / thin-object performance | Datasheet specs need robust echo processing to hold up on site |
| Refresh & End-to-End Latency | ≥ 20–30 Hz for fast motion; minimize total latency | Defines the “see → brake” reaction window |
| Interference Immunity | Glare, black surfaces, glass, reflective metals, dust / oil mist | Direct impact on false / missed alarms and maintenance load |
| Zoning Strategy | Multi-zone protection / warning, logs exportable | Supports EHS audits and traceability |
| Interfaces & Ecosystem | RS485/Modbus, digital I/O, Ethernet, ROS/SDK | Cuts gateway / dev costs; shortens commissioning |
| Environment Fit | IP rating, vibration, wide temp (e.g. −10–+50 °C), anti-soil | Determines real 24/7 uptime |
| Compliance & Safety | Laser Class 1; interlock path verifiable | Aligns with ISO 13849-1 / IEC 61508 practices |
7) What “Deliverable” Means on the Shop Floor
- Fast onboarding: power-up recognition, guided setup, and visual zone configuration.
- Usable data: exportable logs / alarms / statistics for traceability and OEE analysis.
- Maintainable: scratch-resistant / easy-clean windows, accessible spares, remote firmware, parameter backup / restore.
- System-ready: seamless with safety light curtains, door interlocks, and PLC / IPC — closing the loop from sense → interlock → stop.
Keywords: OEE, data traceability, maintainability, interlock loop, reduced downtime
8) Closing: Seeing Clearly — and Staying Steady
The story of LiDAR is the story of turning a beam of light into stable capabilities for safety, throughput, and data. Expect continued gains in echo logic, frame rates at lower power, and deeper fusion with vision and ultrasonics. For smart manufacturing and mobile robots, LiDAR will remain a primary viewpoint sensor.
Recommended Models (DAIDISIKE · Field-Proven)
For obstacle detection, zone protection, perimeter security, and AGV/AMR navigation, we provide multiple ranges, standard interfaces, and quick-integration options:
DLD05A3-3N / DLD20A5-5N (5 m / 20 m) — Obstacle-Avoidance LiDAR
Use cases: narrow-aisle AGV avoidance, station intrusion detection, near-field machine guarding.
Highlights: high refresh, low end-to-end latency, RS485/Modbus + digital I/O, dual Protection / Warning zones (polygon / fan).5JPTG / 10JPTG (5 m / 10 m) — Scanning Rangefinder Radar
Use cases: small mobile platforms, service robots, light-duty AMR.
Highlights: millimeter-class resolution, lightweight, integration-friendly power & interfaces, SDK / protocols for rapid development.DLD30T-5N (40 m) — Perimeter Security / Obstacle-Avoidance LiDAR
Use cases: campus / yard channels, semi-outdoor patrol, long-range zone protection.
Highlights: glare / reflector immunity, multi-zone configuration, industrial IP protection, exportable logs / alarms.
Essential Differences: Obstacle-Avoidance (Safety) vs. Navigation (SLAM / Mapping) LiDAR
One-line conclusion: An obstacle-avoidance (safety) LiDAR is built for people & machine safety and provides safety-rated outputs. A navigation LiDAR is built for mapping and localization, outputting point clouds / ranges to algorithms and does not perform safety stop functions. Their roles, interfaces, and compliance paths are entirely different and not interchangeable.
Keyword coverage for SEO: safety laser scanner, protective field / warning field, OSSD, safety Ethernet, PL / SIL, AOPDDR, SLAM, mapping, point cloud, angular resolution, scan rate, AMR / AGV, forklift retrofit, industrial safety guarding.
I. Side-by-Side Overview
| Dimension | Obstacle-Avoidance (Safety LiDAR) | Navigation (SLAM / Mapping LiDAR) |
|---|---|---|
| Primary purpose | Personnel / equipment safety: entering a protective or warning field triggers interlock, deceleration, or emergency stop | Build maps, localize, and plan paths; provide raw data to avoidance / planning algorithms |
| Output format | Dual-channel OSSD, safety Ethernet, zone status bits; on-board zone logic and self-diagnostics | Point cloud / range / intensity (Ethernet / serial); processed by upper-layer navigation stacks (e.g. ROS) |
| Compliance & safety level | Designed and assessed for safety applications (typical target: safety functions at PL d / SIL 2 level) | No safety-function rating; not used directly for safety stopping |
| Engineering metrics | Safety response time, fail-safe behavior, diagnostic coverage, zone switching, immunity to reflections / dust / high ambient light | Angular resolution, scan frequency, range, point-cloud consistency, drift & loop-closure robustness |
| System architecture | Interlocks directly with braking circuits / safety PLC; supports EDM / automatic reset interlocks | Algorithms compute motion commands; control layer issues speed / path after perception |
| Typical placement | Low-mounted / peripheral to cover human ingress risk zones | High or corner mount for complete environmental coverage |
| Typical applications | AMR / AGV safeguarding, forklift retrofits, hazardous-area perimeter guarding, machine guarding | SLAM mapping, localization, path planning, narrow-aisle traversal, global obstacle avoidance |
II. Why “Higher Resolution ≠ Safety”
- Safety is about predictable, provable stopping behavior, which requires redundancy, diagnostics, self-tests, and fail-to-safe design — not just measurement accuracy.
- Even with excellent angular resolution and dense clouds, a navigation LiDAR only improves perception; it does not provide safety interlocking or fail-safe behavior.
- Combining “safety + navigation” in one device raises risks for maintenance, software updates, and conformity assessment. In real projects, separation is usually recommended.
III. Reference Architecture for AMR / AGV
Front-zone safeguarding
Mount a safety LiDAR low at the front; configure protective / warning fields and speed zones; interlock directly with the braking chain to cover frontal and diagonal ingress.
Global perception
Mount a navigation LiDAR on the top or corners; feed point clouds to SLAM / localization and planning for corridors, turns, and narrow aisles.
Cooperation logic
Safety layer has the highest priority. The navigation layer handles speed / path only; once a safety trigger occurs, the vehicle must enter a safe state.
IV. Eight-Step Selection Method (Practical)
- Define the role: Do you need enforced stopping for people / zone entry? If yes, prioritize a safety LiDAR.
- Set speed & stopping distance: Use max speed, total system latency, and braking capability to size protective fields.
- Choose minimum detectable size (MDS): 50 / 70 / 90 mm typical; it drives resolution and mounting height.
- Assess environment: Strong backlight, black / transparent materials, dust / mist, vibration / thermal drift — these define power and filtering strategy.
- Interfaces & interlocks: Safety: OSSD / safety Ethernet, EDM, and reset method. Navigation: Ethernet, time sync, point-cloud format.
- Zones & switching: Safety requires multiple zones and speed-linked switching; navigation focuses on scan rate and angular resolution for dynamics.
- Mounting & occlusion: Avoid bumpers / forks; consider multi-sensor overlap; for glass scenes, use tilt angles or anti-glare film.
- Validation & checks: Verify “stops-in-time” at max speed; keep logs; set weekly / monthly checks, threshold reviews, and test-run records.
V. Common Pitfalls (Avoid These)
- Treating a “high-precision navigation unit” as a safety device — leads to no safety backing in audits.
- Testing only head-on triggers while ignoring diagonal / edge ingress — acceptance will fail.
- No treatment for reflections / multipath with glass / mirrors — causes false positives / negatives.
- No control of vibration / shift at the bracket — protective-field borders drift; no periodic re-verification.
- Coupling safety and navigation software updates — changes may silently affect safety behavior.
VI. FAQ (Quick Answers)
Q1: Can one LiDAR do both navigation and safety?
A: Not recommended. Goals, interfaces, and conformity differ. Engineering practice uses a separated scheme: safety LiDAR (interlocked stopping) + navigation LiDAR (mapping / localization) to reduce conformity and maintenance risks.
Q2: What about black objects or glass doors that are hard to detect?
A: Increase resolution or integration time; adjust incidence angle by 5–10°; apply anti-glare film or choose higher-power models; always validate with worst-case material samples.
Q3: How do I size protective vs warning fields?
A: Compute the minimum protective field from max speed, total system delay, and braking capability; keep a 20–40 % margin as a warning field for tuning and environmental drift.
Q4: Do I need re-acceptance after changing models?
A: If the sensor model or zone logic changes, re-test max-speed stopping and field borders, and archive parameters and logs to ensure the safety function is unaffected.
VII. Mapping to Product Selection (Example Logic)
- Safety tier: Focus on OSSD / safety Ethernet, number of zones, switch speed, response time, and environmental immunity. Suitable for AMR front / side human safeguarding and forklift retrofits.
- Navigation tier: Focus on angular resolution (e.g. ≤ 0.1°), scan rate (e.g. 20–100 Hz), range (e.g. 20–50 m), point-cloud consistency, and timing sync. Suitable for global mapping, narrow-aisle travel, and high-precision localization.
- Combined deployment: “Safety-first” strategy: when the safety layer triggers, decelerate / stop; the navigation layer only handles speed / path optimization.
Engineering tip (by DAIDISIKE): For AMR / AGV, forklifts, or HRC scenarios, define safety responsibilities first, then choose navigation sensors. Label “Safety vs Navigation” clearly with matching interfaces — this speeds customer understanding and reduces presales friction.