Optical axis pitch is the distance between two adjacent infrared beams in a safety light curtain or area sensor. It determines the minimum object size that can be reliably detected. A smaller pitch provides higher detection resolution. The DPR-1220-NPN-NC uses a 20 mm optical axis pitch.

Protection height should match the machine opening or the area that needs to be protected. First measure the actual machine opening, then select a protection height that provides adequate coverage. The DPR-1220-NPN-NC provides a 220 mm protection height, suitable for mid-size machine openings and personnel protection applications.

Beam spacing (also called resolution or optical axis pitch) determines the minimum detectable object size:

• 10 mm — detects small objects such as fingers or small parts
• 20 mm — suitable for hand detection and general safety applications
• 30 mm — medium detection for larger objects
• 40 mm — suitable for body detection and general presence detection

The DPR-1220-NPN-NC uses a 20 mm pitch.

Detection distance refers to the maximum distance between the transmitter and receiver within which the sensor can reliably detect beam interruption (for the DPR-1220-NPN-NC, this is 0.2–3 m). Safety distance is a separate concept — it is the minimum installation distance from the hazardous area, calculated based on machine stopping time, sensor response time, approach speed and applicable safety standards.

For a machine opening around 380 mm, consider the DPR Series models with protection height that provides adequate coverage. The DPR-1620-NPN-NC offers 16 beams and a 300 mm protection height, and the DPR series can be evaluated for models with appropriate coverage. Contact DAPPRA Automation for model selection support based on your specific machine dimensions.

All DPR Series models with the “20” in their model number use a 20 mm optical axis pitch. The correct model depends on the required protection height:

• DPR-0620-NPN-NC — 6 beams, 100 mm protection height
• DPR-0820-NPN-NC — 8 beams, 140 mm protection height
• DPR-1220-NPN-NC — 12 beams, 220 mm protection height
• DPR-1620-NPN-NC — 16 beams, 300 mm protection height

Yes. Because area sensors use multiple parallel infrared beams, objects entering the detection area at different heights can be detected as long as they interrupt one or more beams. The DPR-1220-NPN-NC has 12 beams across a 220 mm protection height, allowing detection of objects positioned at various points within the detection field.