Types of Photoelectric Sensors
– Self-contained photoelectric sensors contain optics, electronics, and require a power source.
– They perform modulation, demodulation, amplification, and output switching.
– Some self-contained sensors have built-in control timers or counters.
– Technological progress has made self-contained sensors smaller.
– Remote photoelectric sensors only contain optical components, with circuitry located elsewhere.
Sensing Modes of Photoelectric Sensors
– Through-beam arrangement: receiver detects when the light beam is blocked.
– Retroreflective arrangement: receiver detects when the beam fails to reach it after bouncing off a reflector.
– Proximity-sensing (diffused) arrangement: receiver detects when the transmitted radiation reflects off the object.
– Some photo-eyes have light operate and dark operate modes.
– The detecting range of a photoelectric sensor is its field of view.
Difference Between Sensing Modes
– Through-beam: most accurate with longest sensing range, very reliable.
– Through-beam requires installation of emitter and receiver at two points.
– Through-beam may not detect translucent objects and can have false triggers when misaligned.
– Advantages and disadvantages of other sensing modes are not provided in the content.
Use of Fibre Optics in Photoelectric Sensors
– Fibre optics can be used with both remote and self-contained sensors.
– They are passive mechanical sensing components.
– Fibre optics have no electrical circuitry or moving parts.
– They can safely transmit light into and out of hostile environments.
– No further information is provided about the benefits or drawbacks of using fibre optics.
Additional Resources
– Wikimedia Commons has media related to photoelectric sensors.
– A selection guide for photoelectric sensors is available in PDF format on automationdirect.com.
– No additional information is provided about the content of the PDF or its relevance.
– No other external links or resources are mentioned in the content.Sources: https://en.wikipedia.org/wiki/Photoelectric_sensor
