How do you calculate robot safety distance?

Multiply the approach speed K by the total stopping time T, add the intrusion allowance C, then apply your margin. At 1,600 mm/s, 0.35 s and 128 mm, the base distance is 560 + 128 = 688 mm, and 825.6 mm with a 1.2 margin, the Robot Safety Distance calculator's own example.

What goes into the stopping time T?

Everything from the moment a person is detected to the moment the hazard stops: the safeguard's own response time, the safety controller's response, and the robot's measured stopping time at its worst speed and payload. The workbook adds the three, so 20 + 20 + 420 ms is 0.46 s.

What approach speed K and intrusion allowance C should I use?

The values ISO 13855 sets for the approach, the device's detection capability and how it is mounted. They are inputs in the workbook, not choices it makes; the example uses 1,600 mm/s for K and allowances from 0 to 1,200 mm that are invented for the example.

What is the robot stop limit column?

The longest robot stopping time the installed distance allows: (installed distance / margin - C) / K x 1,000, less the device and controller response. If a stop test comes in above it, that safeguard is too close. In the example the palletiser's exit curtain allows 366 ms against the 420 ms measured.

Does the workbook replace a risk assessment?

No. It applies the S = K x T + C form to your figures. Reaching over or around a safeguard, the standard's minimum distances and alternative K rules, and the validation of the safety function are not modelled.

Does the workbook use macros?

No. It is a plain .xlsx with ordinary formulas, tables and native charts. The Verify sheet re-checks the formulas against fixed test safeguards and shows Self-check: PASS.

Safety and People

Robot Safety Distance Excel Template

Safety distance S = (approach speed K × stopping time T + intrusion allowance C) × your margin, the ISO 13855 form. Give every light curtain, area scanner and safety mat around your robot cells a row and see whether it sits far enough out, the clearance, and the longest robot stop its installed distance allows.

Free, and a plain .xlsx with no macros to enable. A CSV with live formulas and a printed how-to guide come with it.

Overview

This robot safety distance template is a working Excel workbook for machine safety engineers, robot integrators and maintenance teams. Each light curtain, area scanner or safety mat is one row with its robot, the approach speed K and intrusion allowance C you take from ISO 13855, the device and safety controller response times, your margin and the distance it is installed at. The robot's measured stopping time comes from one list on Setup, so a new stop test updates every safeguard on that robot. It ships with seven safeguards on four robot cells of a fictional fabricator, so every tile and chart is filled in when you open it.

In the example the palletiser was retested after a payload increase and now stops in 420 ms. With 40 ms of device and controller response, T is 0.46 s: 736 mm of reaction travel plus 850 mm of intrusion allowance is 1,586 mm, and 1,903 mm with a 1.2 margin. Its exit light curtain sits at 1,800 mm, 103 mm too close; at that distance the robot would have to stop within 366 ms. The machine tending cell is within limits but tight: its rear mat allows a 246 ms robot stop against the 240 ms measured.

The workbook does the arithmetic of the ISO 13855 form; the standard, the device manual and a measured stop test decide K, C and T, and a risk assessment decides the guarding. The download is a plain .xlsx with no macros. A CSV with live formulas is also included for other tools; the dashboard, charts, dropdowns and self-check are in the .xlsx.

What this template includes

Setup sheet with the robots and their measured stopping time and test date, and the safeguard device types
Safeguards table, one row per device: robot, approach speed K, device and safety controller response, intrusion allowance C, margin and installed distance, with a Check column
Per safeguard: total stopping time T, reaction travel, base and required distance, the distance the margin adds, clearance, a status in words and the longest robot stopping time the installed distance allows
Dashboard with four tiles (safeguards, closer than required, smallest clearance, longest stopping time), what makes up each required distance, installed against required distance, and the safeguard table
Method sheet with every formula, and a Verify sheet that re-checks the formulas against an independent reference and the Robot Safety Distance calculator (Self-check: PASS)
CSV with live formulas for the Safeguards table; the dashboard, charts, dropdowns and self-check are in the .xlsx

Suggested use case

Use it to position safeguards on a new robot cell, to audit existing guarding after a stop test, or to see which safeguards a longer robot stop, a heavier payload or a slower safety controller would put too close.

How to use it

On Setup, list your robots with their measured stopping time and the date of the stop test, and the device types you use.
On Safeguards, give each light curtain, scanner or mat a row: robot, approach speed K, device and controller response, intrusion allowance C, margin and the installed distance.
Fix anything the Check column names.
Open the Dashboard: safeguards closer than required, the clearance of each, and what makes up each required distance.

Frequently Asked Questions

How do you calculate robot safety distance?: Multiply the approach speed K by the total stopping time T, add the intrusion allowance C, then apply your margin. At 1,600 mm/s, 0.35 s and 128 mm, the base distance is 560 + 128 = 688 mm, and 825.6 mm with a 1.2 margin, the Robot Safety Distance calculator's own example.
What goes into the stopping time T?: Everything from the moment a person is detected to the moment the hazard stops: the safeguard's own response time, the safety controller's response, and the robot's measured stopping time at its worst speed and payload. The workbook adds the three, so 20 + 20 + 420 ms is 0.46 s.
What approach speed K and intrusion allowance C should I use?: The values ISO 13855 sets for the approach, the device's detection capability and how it is mounted. They are inputs in the workbook, not choices it makes; the example uses 1,600 mm/s for K and allowances from 0 to 1,200 mm that are invented for the example.
What is the robot stop limit column?: The longest robot stopping time the installed distance allows: (installed distance / margin - C) / K x 1,000, less the device and controller response. If a stop test comes in above it, that safeguard is too close. In the example the palletiser's exit curtain allows 366 ms against the 420 ms measured.
Does the workbook replace a risk assessment?: No. It applies the S = K x T + C form to your figures. Reaching over or around a safeguard, the standard's minimum distances and alternative K rules, and the validation of the safety function are not modelled.
Does the workbook use macros?: No. It is a plain .xlsx with ordinary formulas, tables and native charts. The Verify sheet re-checks the formulas against fixed test safeguards and shows Self-check: PASS.