What are the detection modes of photoelectric sensors

The detection modes of photoelectric sensors are divided into the following categories: through-beam type, reflector type, polarized reflector type, direct-reflection type, wide beam type, focus type, fixed area type and adjustable area type. Among them, the direct-reverse type, wide beam type, focus type, fixed area type and adjustable area type are sometimes classified as "photoelectric proximity detection mode" (note: not to be confused with capacitive or inductive proximity switches). For fiber optic sensors, if you use a through-beam fiber, it is a through-beam detection mode; if you use a straight-and-reflex fiber, it is a proximity detection mode. Ultrasonic sensors have two detection modes: on-beam type and proximity type.

The transmitter and receiver of the through-beam detection mode are installed opposite each other, and the light of the transmitter is directly aligned with the receiver. When the measured object blocks the beam, the sensor output changes to indicate that the measured object is detected. Through-beam type is the earliest used photoelectric detection mode. Before the advent of modulated light, the alignment of the transmitter and receiver was a big problem. Today, for photoelectric sensors that use high-energy modulated light, it is very easy to align the transmitter and receiver. ,

In the reflective detection mode, a sensor itself has both a transmitter and a receiver. The transmitter emits light onto the reflector, and the reflected light returns to the receiver. When an object blocks the light beam, the measured object is detected.