Overview
What are Photoelectric Sensors?
Photoelectric sensors are industrial detection devices that use a light transmitter (usually infrared or visible red LED/laser) and a photoelectric receiver to determine the presence, absence, or distance of an object. These sensors are essential for non-contact detection across automation lines, capable of sensing targets ranging from transparent glass to matte black plastics. At PALM Parts Solution, we provide a wide range of sensing technologies, including through-beam, retro-reflective, diffuse, and specialized background suppression (BGS) models.
Main Manufacturers
We maintain a comprehensive inventory of photoelectric sensors from leading global brands to ensure compatibility with existing control architectures:
- Allen-Bradley: Specializing in ruggedized sensors for the North American market, including the high-performance 871C and 42 series.
- Keyence: Known for high-precision fiber-optic and laser measurement sensors like the FS and LR series.
- Pepperl+Fuchs: A leader in industrial sensing, offering the modular R100 and R200 series for diverse mounting requirements.
- Omron: Providing the industry-standard E3Z and E3X series, favored for their reliability in high-speed packaging.
- Delta Electronics: Offering cost-effective, high-reliability sensing solutions for general-purpose automation.
Typical Applications
Photoelectric sensors are utilized in nearly every industrial vertical:
- Packaging & Bottling: Counting containers, detecting cap presence, and sensing transparent films.
- Material Handling: Detecting box positions on conveyors and preventing jams.
- Automotive Assembly: Part verification and positioning using high-accuracy laser sensors.
- Pharmaceuticals: Small part detection using fiber-optic sensors in cramped machine spaces.
Selection Guide
Choosing the right sensor depends on several technical variables:
- Sensing Range: Through-beam offers the longest range (up to 50m+), while diffuse is best for short-range detection (under 2m).
- Target Material: For transparent objects, use specialized retro-reflective sensors with coaxial pilarization (e.g., Omron E3Z-B).
- Environment: Select IP67/IP69K rated housings (like those from Pepperl+Fuchs) for washdown environments in food and beverage.
- Output Type: Match the sensor output (PNP vs. NPN) to your PLC’s input card requirements.
- Connectivity: Consider IO-Link enabled sensors for Industry 4.0 applications to monitor sensor health and signal strength in real-time.
7 products · Pepperl+Fuchs
Frequently asked questions
What are the main types of photoelectric sensors?
The three primary modes are Through-beam (separate emitter and receiver for long distances), Retro-reflective (single housing using a reflector), and Diffuse-reflective (detects light bouncing directly off the target). Each is suited to different detection ranges and target materials.
What is the difference between Light-ON and Dark-ON?
Dark-ON sensors trigger an output when the light beam is interrupted (blocked), whereas Light-ON sensors trigger an output when the light beam is received by the sensor. Most industrial sensors, like the Allen-Bradley 42JT or Pepperl+Fuchs R100 series, provide selectable outputs for both modes.
Why should I use Background Suppression (BGS) sensors?
Standard diffuse sensors can be "tricked" by bright backgrounds. Background Suppression (BGS) sensors use a triangulation method to detect objects at a specific distance, ignoring anything beyond that setpoint regardless of color or reflectivity. This is essential for detecting dark targets on conveyor belts.
How do photoelectric sensors connect to a PLC?
Standard photoelectric sensors use M8 or M12 quick-disconnect cables or flying leads. For data integration, look for IO-Link compatible models (standard in Omron E3Z-IO and Allen-Bradley 42JT series) which allow for remote parameterization and diagnostic monitoring via a PLC.
What are the common voltage and output ratings?
Standard photoelectric sensors are rated for 10-30V DC and provide either NPN or PNP transistor outputs. For older systems or specialized infrastructure, AC/DC universal voltage models are available, typically providing a relay contact output.