Photoelectric sensors use light beams to detect the presence or absence of objects. This technique is an ideal alternative to inductive proximity sensors when you need a long sensing distance or when the item you want to detect is not a metal. Our photoelectric sensors meet the needs of applications in many industries such as material handling, packaging, food processing and transportation. For specialized applications that require the use of non-standard connectors or cables, we can customize the sensor connection. The following small series introduces photoelectric sensors to measure the speed principle and the advantages of photoelectric sensors.
Photoelectric sensor speed measurement principle
Photoelectric speed sensor is a kind of electronic device that senses the change of intensity of received light according to the working principle of photodiode. When the light emitted by it is reflected or blocked by the target, the receiver will induce the corresponding electrical signal. It contains a modulated light source, an optical system composed of a photosensor, an amplifier, a switch, or an analog output device.
Photoelectric sensors consist of independent and relatively placed light emitters and light collectors. When the El mark passes between the light emitter and the light receiver and blocks light, the sensor outputs a signal. It is the most efficient and reliable detection device. The slot-shaped (u-shaped) photoelectric switch is a transmissive deformation, which has the advantage of no need to adjust the optical axis.
Photoelectric sensor advantages
1, less restrictions on the detection of objects. Since the principle of detection is light blocking and reflection caused by the detection of objects, the detection object is not limited to the metal like the proximity sensor, and it can detect almost all objects such as glass, plastic, wood, and liquid.
2, the response time is short. The light itself is high speed, and the circuit of the sensor is composed of electronic parts, so it does not include mechanical working time.
3, high resolution. The high resolution can be achieved by using advanced design techniques to focus the projected light beam at a small spot or by forming a special light receiving optical system. Can also detect small objects and high-precision position detection.
4, can achieve non-contact detection. The detection can be performed without mechanically contacting the detection object, and thus the detection object and the sensor are not damaged. Therefore, the sensor can be used for a long period of time.
5, can achieve color discrimination. The reflectivity and absorptivity of the light formed by the detection object differ depending on the combination of the wavelength of the light to be cast and the color of the detection object. With this property, the color of the detected object can be detected.
6, easy to adjust. In the type of projected visible light, the cast light beam is visible to the eye, facilitating the adjustment of the position of the detected object.
7, long detection distance. By maintaining a detection distance of 10 m or more in the radiation type, other detection methods can be realized.
Photoelectric sensor classification
1, trough photoelectric sensor
An optical transmitter and a receiver mounted face-to-face on both sides of a slot are slot-shaped optoelectronics. The light emitter emits infrared light or visible light, and the light receiver can receive light in the unimpeded condition. However, when the detected object passes through the slot, the light is blocked and the photoelectric switch is activated. A switch control signal is output, and the load current is cut off or turned on to complete one control action. The detection distance of the trough switch is generally only a few centimeters because of the limitation of the overall structure.
2, on-beam photoelectric sensor
If the light emitter and the light receiver are separated, the detection distance can be increased. A photoelectric switch composed of a light emitter and a light receiver is called a split-type photoelectric switch, or short-beam photoelectric switch. Its detection distance can reach several meters or even tens of meters. When in use, the light emitter and the light receiver are respectively installed on both sides of the path through which the detection object passes. When the detection object passes, the light path is blocked, and the light receiver operates to output a switch control signal.
3, reflective plate photoelectric switch
The light emitter and the light receiver are mounted in the same device, a reflector is installed in front of it, and a photoelectric reflection switch (or mirror reflection type) photoelectric switch that uses the principle of reflection to complete the photoelectric control is used. Under normal circumstances, the light emitted by the light emitter is reflected back by the reflector and received by the light receiver. Once the light path is blocked by the detection object and the light receiver does not receive light, the photoelectric switch activates and outputs a switch control signal.
4, diffuse reflective photoelectric switch
Its detector head is also equipped with a light emitter and a light receiver, but there is no reflector in front of it. The light emitter emitted by the light emitter is normally not found. When the detection object passes the light is blocked, and the light part is reflected back, the light receiver receives the light signal and outputs a switch signal.
Editor's summary: The principle of measuring the rotation speed of the photoelectric sensor and the advantages of the photoelectric sensor are introduced here. I hope to help everyone. If you want to know more about yourself, you can follow the information on this site.
Photoelectric sensor photoelectric sensor measuring speed
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