Robot Safety Scanners and Light Curtains: Practical Selection
Three common devices
| Device | Protects | Notes |
|---|---|---|
| Safety light curtain | A plane of access | Fast, precise, needs alignment |
| Safety laser scanner | A configurable area | Two zones: warning and stop |
| Safety mat / bumper | A floor area or contact | Robust, less flexible |
Selection depends on the stopping distance
The minimum distance between the hazard and the device comes from the machine's stopping time, the approach speed and the device's response time. Measure the real stopping time after installation: the calculated value from the datasheet is a starting point, not the answer.
Common mistakes
- Scanner fields drawn on a plan but never re-measured after commissioning.
- Muting that bypasses protection during normal operation without interlock logic.
- Devices wired into a standard PLC instead of a safety-rated channel.
- No record of the configuration file, so a controller replacement loses the settings.