In industrial automation safety protection, safety light curtains are considered the “first line of defense.” But what exactly can this “defense line” block? The key lies in its “detection resolution”—also known as the resolution.
If the resolution is chosen correctly, the equipment can operate safely without false stops. If it’s chosen incorrectly, it either fails to provide adequate protection or significantly reduces efficiency. So, how exactly is the detection resolution of a safety light curtain calculated, and how should it be selected? Today we’ll explain this core issue in a clear and simple way.
1. What is detection resolution (resolution)?
Detection resolution, also known as “light curtain resolution,” refers to the spacing between two infrared beams, i.e., the smallest object size that can be detected.
For example:
- A resolution of 14mm can detect objects the size of a finger.
- A resolution of 30mm can only detect a hand or an arm.
- A resolution of over 40mm is suitable for detecting a human body or large objects.
Simply put: the smaller the value, the more sensitive the detection and the finer the protection; the larger the value, the more suitable it is for protecting larger targets.
2. How is detection resolution calculated?
The resolution of a light curtain is not based on guesswork but is determined by structural parameters and application requirements. A common calculation is as follows:
Detection resolution ≈ Beam spacing = Detection height / (Number of beams – 1)
For example:
- A light curtain has a detection height of 420mm and 31 beams.
- Then the resolution is approximately 420 ÷ (31 – 1) = 14mm.
Of course, most light curtain products on the market have fixed resolutions (such as 14mm, 20mm, 30mm, 40mm). Users can directly match the model according to their application scenarios.
3. What scenarios are suitable for different resolutions?
According to national standards and actual applications, the general recommendations are as follows:
14mm–20mm (high resolution)
- Suitable scenarios: Prevent fingers and palms from entering dangerous areas, such as high-speed punch presses, laser processing, etc.
- Protection target: Small body parts, prevent hand clamping or cutting.
- Features: Low false alarm rate, suitable for high-speed movements.
30mm–40mm (medium resolution)
- Suitable scenarios: Prevent arms and upper body from approaching danger, such as robotic workstations, handling areas.
- Protection target: Whole hand or body nearing.
- Features: Wide application range, high cost-performance ratio.
Over 50mm (low resolution)
- Suitable scenarios: Detect human bodies or material crossing, such as automatic doors or goods passages.
- Protection target: Personnel approaching or intrusion detection.
- Features: Not suitable for precision applications, but good for large-area detection.
4. Other points to consider when selecting a model
- Installation distance: The smaller the resolution, the shorter the protective distance. It is generally recommended to use high-resolution light curtains within a 10cm–3m range.
- On-site interference: The higher the precision, the higher the environmental requirements. Attention should be paid to avoid dust, oil mist, or strong light interference.
- Beam alignment accuracy: High-resolution light curtains have more beams and require higher installation precision. Solid brackets or dedicated mounting accessories must be used.
