AGV/AMR: safety scanner vs industrial LiDAR
Aisles, obstacle avoidance & speed monitoring. This engineering guide separates the certified personnel-stop function from navigation, measurement and ordinary obstacle avoidance, then shows what to verify before selecting either sensor class.
Quick answer: Choose a certified safety laser scanner when detecting a person must trigger a safety-rated stop. DAIDISIKE ST27 is the confirmed Type 3, PL d and SIL 2 model with dual PNP OSSD outputs. Choose an industrial LiDAR for mapping, localization, measurement or ordinary obstacle avoidance. DLD, SDLD, DLDS and JPTG products are perception sensors, not substitutes for ST27 in a personnel-protection safety function.
1) Clear roles: safety vs navigation
ST27 safety laser scanner (certified)
- Monitors protective fields whose OSSD state requests the validated safety stop, plus warning fields for a designed response.
- Confirmed Type 3, PL d and SIL 2 with dual PNP OSSD outputs.
- Use only inside a validated safety function with the required field selection, logic and final elements.
Industrial LiDAR (perception)
- Depending on the model, supplies ranging data or ordinary switching zones for navigation, measurement and obstacle avoidance.
- Uses ordinary Ethernet, serial or NPN/PNP signals; these are not dual OSSD safety outputs.
- DLD, SDLD, DLDS and JPTG models may complement, but must not replace, ST27 in a personnel-protection function.
To compare the safety-rated model with the available perception products, review the industrial LiDAR scanner and safety-scanner range by function first, then verify the exact model documentation.
2) Quick decision table
| Question | Prefer safety scanner | Prefer industrial LiDAR |
|---|---|---|
| Need certified stop on human entry? | Yes — use protective field OSSD | No — use it for navigation, measurement or ordinary avoidance |
| Safety-rated, speed-dependent field switching? | Yes — when field selection and the complete stop path are validated | May request ordinary slow-down; not a personnel-safety stop |
| Global mapping & localization? | Do not assume; check the exact model and interface | Yes — choose a model with the required ranging data and interface |
| Evidence to verify before selection | Type / PL / SIL, OSSD behavior, response time and safety manual | Working range, scan angle, resolution, interface and environment |
| DAIDISIKE product boundary | ST27: confirmed Type 3, PL d and SIL 2 | DLD / SDLD / DLDS / JPTG: navigation, measurement or ordinary avoidance only |
3) Common field patterns to evaluate
A. Forward travel
- Front scanner: Protective short field; Warning long field.
- Add rear or side coverage where the risk assessment and vehicle swept path require it.
- Select sets from validated speed, steering and direction signals.
B. Station docking
- Size the docking field for the validated reduced speed, stopping distance and swept path.
- Interlock station light curtains or doors through the safety logic where the risk assessment requires it.
- Apply the validated restart or reset method after the monitored area clears.
C. Reverse or tug mode
- Rear scanner becomes primary; trailer swing area covered.
- Wide side warning fields; validated reduced-speed mode where required.
- Fork/arm attachments add separate field sets.
4) Preliminary stopping-distance worksheet
Vehicle mass m (kg) = ?
Max speed v_max (m/s) = ?
System response time T (s) = sensor + controller + brake delay
Deceleration a_safe (m/s²) = measured under full load
Safety margin M (m) = tire slip, slope, floor
Braking distance: D_brake = v^2 / (2 × a_safe)
Total stopping distance: D_total = v × T + D_brake + M
Use this only as a first-pass engineering check. Apply the relevant standard,
manufacturer instructions and risk-assessment allowances, then verify the
selected protective field by an approach test under worst-case conditions.Record measured worst-case delays and braking under full load and expected floor conditions. This worksheet helps expose missing inputs; it does not replace the applicable standard, scanner manual, risk assessment or validation test.
5) Wiring baseline (scanner + controller)
// Certified safety scanner (ST27 example)
OSSD1 ─────► IN_CH_A (Safety controller)
OSSD2 ─────► IN_CH_B (Safety controller)
Field set ◄─ Validated speed / steering / direction selection
Diagnostics ► Engineering interface (not the safety output)
// Validated final safe state — application dependent
Safety outputs ─► STO / safe brake / K1-K2 contactors as designed
Feedback ─► Safety logic where final-element monitoring is required
// DLD / SDLD / DLDS / JPTG industrial LiDAR (non-safety)
Ethernet / serial / ordinary NPN-PNP outputs ─► Nav or motion controller
These signals may support navigation or ordinary avoidance; they are not OSSD.Implement the safety function with the selected safety-rated controller and validated configuration. Ordinary PLC/navigation code may provide supervisory information but cannot replace the required safety-related control function.
6) Commissioning & periodic tests
Commissioning checklist
- Verify OSSD dual-channel behavior and the required final-element feedback or safe-drive diagnostics.
- Measure response time T; log field screenshots and parameter seals.
- Validate mode switching (speed, steer, reverse, dock).
- Navigation: confirm obstacle avoidance yields bounded jerk and no dead-locks.
Periodic tests at the documented interval
- Approach tests at each speed band: warning→stop distances met.
- Blind-spot checks (pallet corners, low obstacles).
- Re-measure braking distance under max payload and worst floor.
Test log (CSV copy)
Item,Test,Expected,Actual,Result,Notes
1,OSSD coherence,Channels drop together,,,
2,Final-element feedback,Fault prevents restart where monitoring is required,,,
3,Mode switching,Correct fields vs speed/steer/reverse,,,
4,Approach test,Validated stop before contact with required separation,,,
5,Nav avoidance,No dead-lock; bounded jerk,,,
7) Common mistakes & fast fixes
| Mistake | Symptom | Fix |
|---|---|---|
| Using nav LiDAR as the safety device | No certified stop; unknown latency | Use a validated safety-scanner function; keep ordinary LiDAR for non-safety navigation, measurement and avoidance |
| Single-channel OSSD | Hidden single fault | Follow the validated dual-channel circuit and the scanner safety manual |
| No parameter sealing/logs | Audit failure; unsafe changes | Seal configs; export and archive parameter sets |
| Underestimating stopping distance | Overrun into hazard | Measure T and a_safe loaded; add margin M for floors/slopes |
8) Frequently asked engineering questions
Do I need both a safety scanner and a navigation LiDAR on an AMR?
Many AGV/AMR platforms use both, but the risk assessment and exact sensor capabilities decide the architecture. A certified safety scanner such as ST27 provides the personnel-protection detection and OSSD stop signal. An industrial LiDAR can provide mapping, measurement, localization or ordinary obstacle avoidance. DLD, SDLD, DLDS and JPTG models are not substitutes for the ST27 in a personnel-protection safety function.
How should I size speed-dependent protective fields?
Start with the vehicle's maximum speed, the measured worst-case response time of the complete safety chain, braking performance under the maximum payload and worst expected floor condition, and the applicable allowances from the risk assessment and standards. Select each field through validated safety-related signals, then prove the stopping result by an approach test. A preliminary braking formula is not a compliance calculation by itself.
Which DAIDISIKE scanner is intended for a safety-rated personnel stop?
ST27 is the confirmed DAIDISIKE safety laser scanner: Type 3, Performance Level d and SIL 2, with dual PNP OSSD outputs. DLD, SDLD, DLDS and JPTG scanners are for navigation, measurement or ordinary obstacle avoidance and do not carry the ST27 personnel-protection rating.
What records should be kept after commissioning?
Keep the risk assessment, circuit and field-set revisions, measured response and braking results, approach-test records for every operating mode, configuration exports, change authorization and the periodic inspection log. Record the exact scanner model and certificate or manual revision used in the validation.
9) Verification references
- IEC 61496-3:2025 — official IEC scope for AOPDDR electro-sensitive protective equipment that detects people as part of a safety-related system.
- ISO 3691-4:2023 — official ISO scope and verification requirements for driverless industrial trucks, including AGVs and AMRs.
- ISO 13849-1:2023 — official ISO methodology for designing and integrating the complete safety-related control system.
- ISO 13855:2024 — official ISO requirements for positioning and dimensioning safeguards relative to human approach.
Product boundary used here: DAIDISIKE ST27 documentation and confirmed certificate set support Type 3, PL d and SIL 2. No certificate number is inferred or published on this page.