Interactive Tool · ISO 13855

Safety Light Curtain Minimum Distance Calculator

The ISO 13855 formula for presence-sensing safeguards is S = (K × T) + C, where S is the minimum safety distance, K is the approach speed constant, T is the total stop time of the machine plus the curtain response, and C is the intrusion distance based on detection resolution.

Use this calculator as a first-pass estimate during specification. Final safety distance calculation must be validated by a qualified safety engineer against the machine’s measured stop time and risk assessment.

1 · Detection Resolution (d) 2 · Approach Direction 3 · Machine Stop Time Tm (ms) 4 · Light Curtain Response Ts (ms)

ENT response time ranges from 6.0 to 30.8 ms depending on beam count.

Minimum Safety Distance (S)

Approach:

Total stop time T:

Intrusion constant C:

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Formula per ISO 13855. This is a first-pass estimate — final mounting distance must be validated by a qualified safety engineer.