30/40 mm hand protection · 3–6 m range
Typical ranges and response time, with sizing tips. This guide explains how to select and deploy 30 mm / 40 mm safety light curtains for hand protection across 3–6 m working distances. It provides a selection matrix, ISO 13855 quick calculator with the correct C term for hand resolutions, mounting/alignment notes, and acceptance records.
1) Where 30/40 mm are the right choice
Use cases
- General machine guarding where hand access is credible but finger access is unlikely.
- Conveyors, robot loading zones, press lines with wider openings, packaging cells.
- Installations needing longer range (3–6 m) with robust tolerance to contamination.
Engineering characteristics
- Lower beam density vs 10–14 mm → easier alignment, better immunity to dirt/oil mist.
- Typical response time: ≤ 14–22 ms depending on height and model family.
- ISO 13855 adds C = 8×(d−14) (mm): for 30 mm → 128 mm, for 40 mm → 208 mm.
2) Selection matrix (3–6 m working distances)
| Model class | Resolution | Protective height (typ.) | Working range | Response time | Notes |
|---|---|---|---|---|---|
| Hand Compact | 30 mm | 300–900 mm | 0.5–4 m | ≤ 16 ms | Short cells, stands near the tool |
| Hand Standard | 30/40 mm | 420–1200 mm | 1–6 m | ≤ 18–20 ms | General purpose; best price/performance |
| Extended range | 40 mm | 600–1500 mm | 2–8 m* | ≤ 22 ms | *Use with model families supporting long range |
| Window-protected | 30/40 mm | 420–1200 mm | 0.8–5 m | +1–2 ms | Welding/oil mist; schedule cleaning |
Values are class references. Always check your device datasheet and apply worst-case figures in risk calculations.
3) ISO 13855 quick calculator (hand resolutions)
Stop + ESPE + logic + others
C term (auto): 128 mm
Formula: S = K×T + C + margin, where C = 8×(d−14) (mm) for hand resolutions (d > 14 mm).
4) Mounting & alignment (best practice)
Mechanical
- Use rigid brackets; avoid long cantilevering. Verify frame squareness.
- Keep mirror-like surfaces ≥ 300 mm away or tilt by 3–5° to reject reflections.
- Cable routing: separate from power by ≥ 200 mm, cross at 90°; single-point shield grounding.
Alignment routine
- Coarse align (spirit level), then power on and read indicators.
- Maximize horizontally → vertically; torque fasteners while watching stability.
- Run rod tests representative of hand access (e.g., 30/40 mm bars) at corners/center.
5) Acceptance & periodic verification
| Item | Test | Expected | Result | Notes |
|---|---|---|---|---|
| Resolution check | 30/40 mm bar at multiple points | Detection each attempt | ||
| OSSD coherence | Block/unblock beams | Both channels switch together | ||
| EDM | Hold K1/K2 contactor | Reset inhibited | ||
| Reset logic | Edge or two-stage | No hold-to-reset | ||
| Safety distance | Compute S | Installed S ≥ calculated |
CSV template (copy)
Machine/Line,Location,Resolution,Height,Range,Ttotal(ms),K(mm/s),C(mm),Margin(mm),S(mm),Date,By,Notes
,,,,30/40 mm,,2000,,,
6) Troubleshooting
| Symptom | Probable cause | Fix |
|---|---|---|
| False trips at long range | Parallel power cables, strong light, reflections | Re-route cables; add shrouds/filters; change incident angle; increase separation |
| Intermittent misses | Vibration/misalignment | Stiffen mounts; re-align; verify torque and frame squareness |
| Cannot achieve S distance | Stop time underestimated | Measure actual stop-time; re-calc S; move curtain/upgrade stop path |
7) FAQ
30 mm or 40 mm — which should I choose?
30 mm offers tighter detection and slightly shorter S but is more sensitive to contamination; 40 mm is more tolerant and often reaches longer ranges. Use the calculator to compare S values for your T.
How do ranges relate to response time?
Range is mostly optical power/receiver sensitivity; response time scales with beam count and scanning, not range. Always confirm both in the datasheet.
Do I still need test rods for hand protection?
Yes. Use bars matching the specified resolution (30/40 mm) at corners/center and record results.