Photoelectric switch application and precautions - Solutions - Huaqiang Electronic Network

Photocoupler

1. Input power supply voltage fluctuations should be considered when operating in DC input mode. Typically, the fluctuation range is ±10%. Ensure that the power source is stable to avoid unexpected behavior of the photoelectric switch. 2. Proper wiring is essential. Cables should not exceed specified lengths and must be shielded against noise. For safety, high-voltage lines, power cables, and photoelectric sensor wires should never be placed in the same conduit or cable tray. This can lead to interference or damage due to electromagnetic induction. Always separate these wiring types. 3. Response time is critical. Choose a photoelectric switch with sufficient response speed based on the size and movement speed of the object being detected. For through-beam types, consider the beam thickness and calculate the full beam time before installation. 4. Sensitivity settings are important, especially in harsh environments. For through-beam models, allow at least four times the set distance. For reflective types, allow 1.5–2 times the set distance to ensure reliable operation. 5. Protection features vary. Most DC-powered photoelectric switches include reverse polarity protection. Transistor outputs often have overcurrent and short-circuit protection, either in temporary or self-locking modes. Be sure to understand the specific protection mechanism of your model. 6. Anti-vibration and impact resistance: While most photoelectric switches can handle vibrations up to 2000 beats per minute, it’s best to avoid using them in high-vibration environments. If incandescent bulbs are used as light sources, ensure the mounting structure is vibration-resistant. 7. Interference from ambient light: Infrared photoelectric switches can resist up to 3,000 Lux from incandescent lights and 10,000 Lux from sunlight. However, direct sunlight may still cause issues. Use optical filters or choose high-intensity models (up to 100,000 Lux) for strong ambient light. Adjust sensitivity carefully to reduce false triggers. 8. Prevent mutual interference: Cross the transmitter and receiver, increase group spacing, or use different frequency models. Reflective types require proper separation based on the product's beam angle and detection range. 9. Mirror surface effects: When detecting shiny or metallic surfaces, install the emitter and receiver at a 10–20° angle to avoid direct reflection and prevent false triggering. 10. Background interference: Smooth, reflective backgrounds can cause instability. Use distance-limited sensors, paint the background matte black, or make it rough and dark to reduce unwanted reflections. 11. Self-diagnosis function: Many modern photoelectric switches include stability indicators. If the green LED flickers or turns off, it may signal misalignment, dirt, or environmental issues. Regular checks help maintain performance. 12. Countertop interference: A partial beam reflected from the table can cause instability. Keep the sensor away from the surface and add a visor if necessary. 13. Mirror surface maintenance: Clean lenses and reflectors regularly with soft cloths. Avoid chemical cleaners, which can damage the optics. Dust buildup reduces light transmission and affects performance. 14. Temperature considerations: The standard operating temperature is -20°C to 55°C. Extreme temperatures may require cooling (air, water, or electric) or heating to prevent frost or ice buildup. Consult technical support if you’re working in extreme conditions. 15. Optical axis calibration: To ensure accurate alignment, leave extra space when setting the detection distance. Expand the optical system if needed, and ensure secure mounting. For narrow-angle sensors, fine-tune and mechanically fix after adjustment. 16. Signal-to-noise ratio (S/N): A high S/N ratio ensures reliable detection. Maximize incoming light during detection and minimize it during shading for consistent ON/OFF transitions. 17. Other potential issues: Avoid installing photoelectric switches in dusty, corrosive, or wet environments. Do not place them in direct sunlight without shading. Ensure the ambient temperature stays within the device’s operating range and provide shock absorption in high-vibration areas. These guidelines cover key considerations for optimal performance and reliability of photoelectric switches in various applications.