What are the applications of photoelectric sensors?

sensor_152540238296">photoelectric sensors have the advantages of high accuracy, fast response time, and non-contact. The application range is very wide, the working principle of the photoelectric sensor is based on the photoelectric effect. The photoelectric effect refers to the phenomenon that when light is irradiated on certain substances, the electrons of the substances absorb the energy of photons and the corresponding electrical effect occurs. For the introduction of the photoelectric effect, please go to F&C Jiejun Sensing Technology. In recent years, with the development of photoelectric technology, photoelectric sensors have multiplied a series of products, and their varieties and output are increasing, and are widely used in various industrial automation equipment and daily life. The following are some examples of industrial and life applications of photoelectric sensors.

The role of photoelectric sensors in counting machines

One of the essential components of a bill counting machine is a photoelectric sensor. The counter of the bill counting machine adopts non-contact infrared photoelectric detection technology, which has the advantages of simple structure, high precision, and fast response time.

The counter of the banknote counting machine uses two sets of infrared photoelectric sensors. Each sensor consists of an infrared light-emitting diode and a photosensitive transistor that receives infrared light, with a proper distance between them.

When no banknotes pass, the receiving tube is illuminated by light and conductive, the output is 0. When a banknote passes instantly, blocking the infrared light, the receiving tube luminous flux is insufficient, the output is 1. After the banknote passes, the receiving tube receives infrared light again and is conductive. This produces a pulse signal at the output of this part of the circuit, and these signals are shaped and amplified by the subsequent circuit and fed into the microcontroller, which drives the execution motor and completes the counting and display accordingly. The reason why the bill counting machine uses two sets of photoelectric sensors is to detect the integrity of the banknotes and to avoid residual coins from being counted.

The photoelectric sensors are used to detect the counting of the banknotes and then to accumulate the number of banknotes, and finally the liquid crystal and external display part visually display the number of banknotes to the user and automatically alert the user in case of abnormalities.

The photoelectric sensor in the barcode scanning pen application

When the scanning pen head moves on the barcode, if it encounters a black line, the light from the light-emitting diode will be absorbed by the black line, and the light-sensitive transistor will not receive the reflected light and will be high impedance and in a cut-off state. When encountering white intervals, the light emitted by the light-emitting diode is reflected in the base of the photosensitive transistor, the photosensitive transistor produces photocurrent and conduct. After the whole barcode is scanned, the photo-sensitive transistor deforms the barcode into an electrical pulse signal, which is amplified and shaped to form a pulse column, and then processed by the computer to complete the identification of the barcode information.

Photoelectric sensors in photoelectric smoke alarm applications

When there is no smoke, the light emitted by the light-emitting diode propagates in a straight line, and the phototransistor does not receive a signal. There is no output, when there is smoke, the light emitted by the light-emitting diode is refracted by the smoke particles, so that the triode receives the light, there is a signal output and an alarm is issued.

The photoelectric sensor in measuring speed application

The rotating shaft of the motor is painted with two colors of black and white, and when it rotates, the reflected light and non-reflected light appear alternately, and the photoelectric sensor intermittently receives the reflected signal of light accordingly and outputs the intermittent electric signal, then the square wave signal is output by the amplifier and shaping circuit to amplify and shape, and finally the speed of the motor is output by the electronic digital display.

The photoelectric sensor in product counter application

When the product is running on the conveyor belt, it continuously blocks the light path from the light source to the photoelectric sensor, so that the photoelectric pulse circuit generates one electrical pulse signal. Each time a product blocks the light, the photoelectric sensor circuit generates a pulse signal, so the number of pulses output represents the number of products, which are counted by the counting circuit and displayed by the display circuit.

Photoelectric sensors in photoelectric detection and automatic control applications

When photocell is used for photoelectric detection, its basic principle is the same as that of the photodiode, but their basic structure and manufacturing process are not the same. As the photoelectric cell works without applied voltage; has high photoelectric conversion efficiency, wide spectral range, good frequency characteristics, low noise, etc., it has been widely used in the photoelectric readout, photoelectric coupling, grating ranging, laser collimation, film return sound, ultraviolet monitor and gas turbine flameout protection device, etc.

Photoelectric sensors in laser weapons applications

Since optoelectronic sensors are particularly sensitive to infrared radiation, visible light, or both, they become easier targets for laser attacks. In addition, the electronic system and the sensor itself are also very vulnerable to laser-generated thermal noise and electromagnetic noise interference and can not work properly. Laser weapons on the battlefield attack optoelectronic sensors in the following ways: the appropriate energy of the laser beam will be the sensor "blind" so that it can not detect or continue to track the target that has been detected. Alternatively, if the sensor is guiding a weapon toward a target, blinding will cause it to lose its target. In summary, sensors have become the preferred target for low-energy laser weapons due to their increasingly important role on the battlefield and their vulnerability to laser attacks.

Photoelectric sensors in soot and dust turbidity monitor applications

Preventing industrial soot and dust pollution is one of the important tasks of environmental protection. To eliminate industrial fume and dust pollution, it is necessary to first understand the dust emissions, therefore it is necessary to monitor the dust sources and automatically display and exceed the emission standards. Flue gas turbidity is used to detect changes in the transmission of light through the flue. If the flue turbidity increases, the light emitted by the light source increases the absorption and refraction of the soot particles, the light detector reaches the light detector, and the intensity of the light detector output signal can reflect the change in flue turbidity.

Other applications of photoelectric sensors

The use of photoelectric switches can also be used for production statistics on the product assembly line, detection of whether the assembly parts are in place, and the quality of the assembly, such as whether the cap is pressed on when filling, whether the logo is missed, and whether the feeding mechanism breaks the material.

In addition, the presence and width of fabric can be detected using reflective photoelectric sensors. The sagging of the fabric is detected using the masking photoelectric sensor and the result can be used to adjust the tension of the fabric in the transfer. Empty boxes with missing products can be detected using the reflective photoelectric sensor mounted on the frame and the empty boxes can be pushed out using the cylinder.