Photoelectric Fork sensors SR31 Series

Datasensing SR31 Series

The SR31 Series offers a robust family of fork-type photo-electric sensors, engineered for precise object/gap detection through a slot, high-speed performance, and industrial-grade construction. With a nominal slot width of 30 mm, slot depth of 42 mm, switching frequency of up to 10 kHz, and response time as low as ~50 µs, this series delivers exceptional detection speed, compact footprint, and reliable performance in automation and packaging applications. 

Design & Functionality

• The sensors feature a metal housing (Zamak/metal alloy) with dimensions approx. 13×50×70 mm (slot 30×42 mm) designed for machine-side mounting in packaging, labelling or inspection equipment.
• Key operational highlights include:
  • Infrared LED emission for reliable contrast detection even on transparent substrates or web materials. 
  • Elevated switching frequency up to 10 kHz and response time down to ~50 µs, enabling reliable detection of fast-moving parts, gaps or labels. 
  • Setting via a multi-turn sensitivity trimmer, and selectable operating mode (Light-On / Dark-On) through wiring, providing flexibility in diverse applications. 
  • Output logic selectable between NPN or PNP, based on variant, with both output types available on cable version — allowing integration into different control architectures. 
• Mechanical and electrical details: Operating voltage range 10…30 V DC, no-load current ≤ 50 mA, load current up to 200 mA, slot width 30 mm, slot depth 42 mm, housing IP protection (metal frame) and operating temperature -10 °C to +60 °C.

Total Crossed Beams

(In this context, the term emphasises full detection coverage across the slot aperture rather than literal crossed optical beams.)

• The SR31 Series provides a complete detection zone across the slot aperture, meaning objects or gaps passing through the 30 mm wide by 42 mm deep slot will reliably be detected regardless of the exact pass-through position, reducing misses and increasing repeatability.
• This makes it particularly suited for label detection on transparent supports, control of material presence/continuity, detection of synchronisation pulses on toothed or holed wheels, or edge-guide detection in packaging machines. 

Beam Pitch Options

(Here interpreted as variant options of slot width/depth or output configuration rather than literal beam spacing.)

• Example variant: Slot width 30 mm, depth 42 mm (standard) with cable version offering both NPN/PNP output. 
• Example variant: Same mechanical slot but connector version (M8) with NPN or PNP output. 
• These variant options allow selection of the SR31 model that matches your mounting footprint, output logic, and sensor-controller integration — giving design flexibility.

Intrinsic Synchronism

• The emitter, detector and electronics are fully integrated in one compact housing — no external synchroniser or module needed — which simplifies wiring and reduces installation complexity in machine side or packaging lines.
• With built-in sensitivity adjustment trimmer and status LED indicator, the SR31 series supports fast commissioning, simple adjustment, and minimal maintenance overhead.

Operational Advantages

• High-speed detection: With switching up to 10 kHz and response time ~50 µs, the SR31 is capable of detecting fast moving labels, gaps or parts in high-throughput systems.
• Compact fork format: The 30 mm width and 42 mm depth slot in a small metal housing allows integration in front-space-limited installations while maintaining detection performance.
• Flexible output and logic: With selectable NPN/PNP output and Light/Dark mode, the sensor integrates into a wide variety of automation setups.
• Applications: Ideal for label detection on transparent supports, presence or continuity checking in packaging lines, synchronisation pulse detection on toothed wheels, edge-guide detection, printing or labelling systems where high speed, precise detection, and compact installation are required.