Photoelectric switches are fundamental components in modern industrial automation, offering non-contact detection capabilities for a wide range of applications. Among the diverse models available, the L36/LV36-Ex/40b/116 photoelectric switch stands out as a robust and versatile solution designed for demanding environments. This guide provides a detailed overview of its specifications, operational principles, key advantages, and practical implementation scenarios to assist engineers and system integrators in making informed decisions.
The L36/LV36-Ex/40b/116 is a member of the cylindrical photoelectric sensor family, typically characterized by an 18mm diameter threaded barrel housing. The "Ex" designation signifies that this model is engineered for use in explosive or hazardous atmospheres, complying with intrinsic safety or explosion-proof standards such as ATEX, IECEx, or similar regional certifications. This makes it suitable for industries like oil and gas, chemical processing, mining, and grain handling, where the presence of flammable gases, vapors, or dust necessitates specialized equipment.
Operating on the principle of modulated infrared light, the switch functions by emitting a light beam from its transmitter. The receiver then detects either the presence or absence of this beam. The specific operating mode—be it through-beam, retro-reflective, or diffuse reflective—depends on the variant and configuration. The "40b" and "116" codes often refer to specific sensing ranges, connection types, or output configurations. For instance, a common interpretation is a sensing distance of up to 4 meters for diffuse reflection models and a cable or connector type denoted by "116." The output is typically a solid-state transistor (PNP or NPN) or a relay, providing a clear signal for PLCs, controllers, or other logic systems.
Key technical features of the L36/LV36-Ex/40b/116 include high immunity to ambient light interference, achieved through modulated LED technology. This ensures stable operation even in environments with strong artificial lighting or sunlight. The housing is usually constructed from nickel-plated brass or stainless steel, offering high resistance to corrosion, impacts, and vibrations. Many models are rated with IP67 or higher ingress protection, allowing them to withstand washdowns, dust, and temporary immersion. The integrated circuitry often includes protection against reverse polarity, short-circuits, and overloads, enhancing reliability and longevity.
A primary advantage of this photoelectric switch is its versatility. It can detect a vast array of objects regardless of material—metal, plastic, wood, glass, or liquid—provided there is a contrast in reflectivity or opacity. Common applications include object detection on conveyor belts, bottle counting in packaging lines, level sensing in silos or tanks, edge guiding in web processing, and position verification in automated machinery. In hazardous areas, it performs critical safety functions like detecting the presence of personnel or equipment in zoned areas or monitoring valve positions.
When selecting and installing the L36/LV36-Ex/40b/116, several factors must be considered. First, verify the exact required specifications: the necessary sensing range, the type of output (e.g., normally open/closed), the supply voltage (commonly 10-30V DC), and the required certification for the specific hazardous area classification (e.g., Zone 1, Zone 21). Installation requires careful alignment of the emitter and receiver for through-beam types, while diffuse sensors need consideration of the target object's color, size, and surface texture, as these affect the effective sensing distance. Mounting should be secure to minimize misalignment from vibration. Regular maintenance involves keeping the lens clean from dirt, dust, or condensation to prevent false triggers or loss of signal.
In comparison to standard photoelectric sensors, the explosion-proof variant involves additional considerations. The housing is designed to contain any potential ignition source, and electrical parameters are limited to prevent sparking. Installation must follow the manufacturer's guidelines and relevant safety codes, which may stipulate specific cable glands, conduit entries, and grounding practices. Despite these requirements, the L36/LV36-Ex models provide an essential link for automation in sectors where safety is paramount, enabling efficient and reliable operation without compromising on protection standards.
In conclusion, the L36/LV36-Ex/40b/116 photoelectric switch represents a critical intersection of sensing technology and safety engineering. Its robust design, reliable performance in harsh conditions, and compliance with explosion-proof standards make it an indispensable tool for industrial automation professionals. By understanding its capabilities and proper application guidelines, users can leverage this sensor to enhance system efficiency, safety, and productivity across numerous challenging industrial settings.
