How does a measuring light curtain differ from a safety light curtain?
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- Issue Time
- Jul 2,2026
Measuring light curtains are designed for dimensional measurement and object profiling, while safety light curtains are designed to protect personnel by stopping hazardous machinery when a person enters a dangerous area. They serve fundamentally different purposes.
Key Differences
| Feature | Measuring Light Curtain | Safety Light Curtain |
|---|---|---|
| Primary Purpose | Dimension measurement, position detection, profiling | Personnel safety, machine stop on intrusion |
| Output Type | RS485/RS232, 4-20mA, 1-10V analog or digital measurement data | OSSD safety outputs (dual-channel), relay |
| Response Time | Typically 5-50ms depending on scan rate | Typically less than 20ms for safety stop |
| Resolution | High resolution (2.5mm, 10mm, 20mm beam spacing) | Finger (14mm), hand (30mm), body (50mm+) |
| Safety Certification | Not required (measurement device) | Required (SIL3, PL e, Type 4) |
| Output Data | Precise measurement data for object size/position | Binary ON/OFF state (safe/unsafe) |
When to Use Which
Use Measuring Light Curtain When
You need to measure part dimensions, detect object position, count items, profile shapes, or perform quality control inspections on a production line.
Use Safety Light Curtain When
You need to protect operators from hazardous machine motion, create a safety perimeter, or comply with machinery safety regulations (ISO 13849, IEC 62061).
Case Example
Scenario: An automotive parts assembly line requires both dimensional inspection and operator protection.
Solution: Install DADISICK DK-QL measuring light curtains (10mm beam spacing) at the inspection station to measure part dimensions. Separately install DADISICK safety light curtains around the robot cell to ensure operator safety. The two systems work independently — one measures, the other protects.