Robotics & Automation worked example

Light Curtain Safety Distance with hand approach speed k of 1,000 mm / sec: a worked example

Here is what the math looks like when conditions slip. We hold every other input steady and drop hand approach speed k to 1,000 mm / sec, then walk the calculation through step by step. Estimate ISO 13855 safety distance to a light curtain from hand approach speed, system stopping time, light curtain resolution intrusion, and a margin.

The inputs for this scenario

  • Hand approach speed K: 1,000 mm / sec (the input this scenario stresses; the baseline uses 2,000)
  • Total stopping time T (curtain to full stop): 0.3 sec (held at the documented default)
  • Depth-penetration allowance C (from resolution): 128 mm (held at the documented default)
  • Applied safety margin multiplier: 1.2 x (held at the documented default)

Working through the calculation

  • The calculation starts from the formula this tool documents: Base mounting distance = (hand approach speed K x overall system stopping time T) + intrusion C.
  • Required light curtain mounting distance works out to 46,080 mm at these inputs, and this is the headline figure for the scenario.
  • Base product works out to 38,400 value at these inputs.
  • Multiplier works out to 1.2 x at these inputs.
  • Factor A x B works out to 300 value at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where hand approach speed k sits at 2,000 mm / sec and the headline result is 92,160 mm, this scenario comes in 50% below the baseline at 46,080 mm.
  • The practical read: the gap between this scenario and the baseline is entirely attributable to hand approach speed k, so recovering it is worth quantifying in dollars before considering equipment or staffing changes. It is a design aid: the penetration factor C, hand speed K, and stop-time T must come from ISO 13855 and a validated stop-time test, and the layout must pass a formal risk assessment before production.

Results at a glance

  • Required light curtain mounting distance: 46,080 mm (headline result)
  • Base product: 38,400 value
  • Multiplier: 1.2 x
  • Factor A x B: 300 value

Run it with your numbers

  • To rerun this with your own numbers, open the live Light Curtain Safety Distance calculator, set hand approach speed k to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.