1-pv sensor working principle
Pv sensors are controlled by converting changes in light intensity into changes in telecommunications numbers. In general, pv sensors consist of three components: transmitters, receivers and detection circuits. The transmitter is directed at the target launching beams, which are generally derived from semiconductor light sources, leds, laser diodes and infrared-launched diodes. The beam is launched without interruption or changes the pulse width. The receiver consists of pv diodes, pv triodes, and pv batteries. In front of the receiver, there are optical elements such as lenses and radiums. Behind it is the detection circuit, which filters out a valid signal and applies it。
2-pv sensor structural analysis
Optical sensors typically consist of three components: senders, receivers and detection circuits. The launcher was accompanied by a calibration lens, which directed the light focus towards the receiver, which came out of the cable and brought the device to a vacuum tube amplifier. There is a small incandescent light inside the metal cylinder, and these small and strong incandescent sensors are the prototype of today's pv sensors。
The receivers consist of pv diodes, pv triodes and pv batteries. The optically sensitive diode is now the most common sensor. Pv sensor photo-sensitization diodes have the same external shape as the general diodes, except for a window with glass on their casings to allow for light-raying, a larger area of pn to increase light area, light-sensitized diodes working in a reverse biased working state, and being associated with load resistance, which, in the absence of light, is, like the general diodes, a very small dark current of the reverse current called the light-sensitized diodes; when there is light, the stream is activated, creating an electron-empty, known as the photovoltaic stream。
In addition, the pv sensors also have transmitters and optical fibres in their structural components. Angular reflector is a well-structured launcher, consisting of a small trigonometric reflector, capable of enabling the beam to accurately return from the reflector. It can change the launch angle in the range of 0 to 25 with the beam coming almost from a line of fire and returning from it after reflection。
3-photo sensor classification
Dirt reflector type: generic or energy type (8), focus type (-8-h), function type with background inhibition (-8-h), function type with background analysis (-8-hw)
Responder plate type: general (-6), rivimetric filter function type (54, -55), transparent detection function type (54-g), foreground inhibition function type (54-v)
Opposite type
Slot
Fibre-optic sensor: plastic fibre-optic, glass fibre-optic
Colour-marked sensors, colour sensors, fluorescent sensors
Light communications
Laser ranging: triangular reflection rationale, phase differential rationale, time differential rationale
Raster
Explosive/explosive
4 optical sensor applications
Dust and dust monitor
Preventing industrial soot pollution is one of the important tasks of environmental protection. In order to eliminate industrial soot pollution, it is necessary to first know the emissions of soot and soot sources must be monitored, automatically displayed and over-specified. The fumes in the flue are measured by the changes in the size of the transport process through light in the flue. If there is an increase in pyrotechnic turbidity, the light from the source is absorbed and rereflected by dust particles, and the light reaching the light detector is reduced, so that the strength and weakness of the output signal of the light detector can reflect changes in the pyrotechnicity。
Barcode scan pen
When a scanned pen moves on a bar code, if a black line is encountered, the light of the luminous diode will be absorbed by the black line and the luminous triode will not receive the reflecting light, be highly resistant and be in a state of closure. When encountered with a white interval, the light from the luminous diodes was reflected to the basic poles of the light-sensitive triodes, which produced light currents and guided them. After the entire bar code has been scanned, the light-sensitized tripolar tube transforms the bar code into a single electrical pulse signal, which is magnified, shaped into a pulse column, then processed by a computer to complete the identification of bar code information。
Product counter
The product, while running on the conveyor belt, continuously shields the light source from the light-to-pv sensor circuit, which produces a single pulse signal. Every time the product is shaded, the pv sensor circuit produces a pulse signal, so the number of pulses produced represents the number of products, and the pulse counts the circuits and shows them。
Optical smoke alarm
When there is no smoke, the light-lined transmission from the luminous diodes does not receive the signal. No output, and when there is smoke, the light from the luminous diode is reflected by the smoke particles, allowing the triode to receive the light, signal output and alert。
Measuring velocity
On the rotation axis of the electric motors, black and white colours are painted, reflecting and non-reflective light are rotated, the photo-sensor is displaced from each other to receive the reflecting signal of the light, and output a broken telecommunications signal, re-magnifiers and whole circuits are magnified by the integer output signal, and finally the electronic digital monitor is able to output the rate of rotation of the electric generator
Optical cell applications for pv detection and automatic control
When pvs are used as pv detection, their underlying principles are the same as the photo-sensitive diodes, but their basic structure and manufacturing processes are not identical. As the pv works without additional voltage; the pv is highly efficient, spectrally wide, with good frequency characteristics and low noise, it has been used extensively for photoreading, pv coupling, raster ranging, laser straightness, film resonance, ultraviolet light monitors and gas turbine shut-off protection。
Ii. Diversion sensors
The shift sensor, also known as the linear sensor, is a metallic sensor linear device that converts various measurements of physics to electricity. Small moves are commonly detected by mutations, electrons, differential transformers, vortex, hall sensors, and large shifts are commonly measured by sensor-syncs, rasters, flasks, magnets, etc。
Offset sensor
1-place transfer sensor working principles
Converts the mechanical position to the electrical resistance or voltage output in relation to the linear or random function of the element. Normal straight-line and circular-level units can be used as straight and agular transposition sensors, respectively. However, the electrons designed to achieve the measurement shift require a definite relationship between the shift and the resistance change. An electric brush of the slot transfer sensor is connected to the object being detected. The shift of the object causes resistance changes at the point-to-place end. The variation in the barrier reflects the value of the shift, while the increase or decrease in the barrier indicates the direction of the shift. The power voltage is usually applied to the electrical level to convert resistance changes to voltage output. Wire-to-wire level units vary because of the stairwell of electrical resistance when their brush moves and their output properties are also stairwelled. If this shift sensor is used as a position shift feedback element in the server system, an excessive step-to-step voltage causes system convulsion. Therefore, the electrical resistance value should be minimised in the generation of the level units. Another major element of the electrons. Disadvantages: wear and tear. Advantages: simple structure, high output signal, ease of use, low cost。
2 signal processing
In practical application, the mode of resolution has two directions, i. E., a positive-and-negative point after the selection of one direction, so the direction of the molse stripe signal is not determined by a photoelectric element. In order to discern, two morse stripes with a gill/2 phase are required. As illustrated in figure 2, two photoelectric elements were placed at a distance of 1/4 stripes, with u01 and u02 telecommunications numbers for two phase differential gills/2, and two square signals u01 ' and u02 ' after plasticization. The direction of the raster can be determined by means of a circuit resolution, as the raster is moving towards u01 at u02 90 degrees forward and u02 at reverse movement at u01 90 degrees forward. As the precision requirements for measurement are increased, the requirements are no longer met by fencing distances and appropriate measures are required to disaggregate the morse stripes. The breakdown is a number of pulses sent over a period of time during which the mole stripe signal changes to reduce the pulse equivalent. An increase in the accuracy of the measurements could be achieved by sending an n-pulse over a period of time, each of which would be equivalent to 1/n of the original grid distance. As the frequency of pulses increased by a factor of n, it is also referred to as n-frequency. Two types of breakdown are commonly used: one: direct. The placement of two pvs at a distance of one quarter of the mole strip gives us a telecommunications signal of 90o for two phases and 90o for four in turn. Similarly, the placement of four 1/4 stripe-spaced photoelectric elements between twomore stripes allows for the acquisition of a communication signal of 90o of the four phase differentials, with a four-fold breakdown. Second: breakdown of circuits。
3 main categories
Line shift sensor
The function of a straight-level shift sensor is to convert a straight-line mechanical shift into a telecommunications number. In order to achieve this effect, variable resistance slides are usually set at the fixed part of the sensor and different resistance values are measured by the shift of slides on the slides. The sensor's slide tracks are connected to a steady state current voltage, which allows a flow of small currents through micro-ampe, which is proportional to the length of the slide move. Use of the sensor as a subpressor minimizes the requirement for accuracy of the total barrier to the slide track, as changes in the barrier caused by temperature change do not affect the measurement results。
Angle transfer sensor
Angle transfer sensors are used for barrier treatment: an angle sensor is used to control the indirectly detectable barrier of your wheel. The principle is very simple: if the motor angle sensors work and the gears don't turn, it means your machine is blocked by obstacles. The technology is very simple and very effective; the only requirement is that the wheel of movement cannot slide (or slide too many times) on the floor, otherwise you will not be able to detect the barrier. This problem can be avoided by connecting an empty gear to the motor, which is driven not by the motor, but by the movement of the device: in driving the wheel, if the inert wheel stops, it means you've encountered the barrier。
Hole point transfer sensor
Its measurement principle is to keep the currents of incentives in the hol (see semiconductor magnetic sensitivity elements) constant and to move them in a magnetic field with an even gradient, where the shift is proportional to the output of the hol message. The greater the magnetic field gradient, the more sensitive it is; the more evenly the gradient changes, the closer the holler is to linear. Figure 2 shows three magnetic systems that generate gradient magnetic fields: a system with narrow linear ranges, with z = 0 degrees, and b system with z
Optical pv transfer sensor
It measures the location or geometry of the object according to the amount of light flux blocked by the object. It is characterized by non-contact measurements and allows continuous measurements. The pv transfer sensor is often used to continuously measure the diameter of the line material or as a remote position sensor in the frame edge control system。
Four, please
Marked resistance value: the barrier value indicated above the electrical level. Repeat precision: the smaller the parameter, the better. Resolution: the minimum digit of which the transposition sensor is capable of feedback. This parameter is as small as possible. Allowed error: the percentage difference in the nominal barrier to the actual barrier relative to the nominal barrier is called the resistance deviation, which indicates the accuracy of the level. The permitted error is generally within 20%, as the general shift sensor is used in a depressive manner and the size of the specific resistance does not affect the sensor's data collection. Linear precision: linear error. The smaller the parameter, the better. Life: the conductive plastic shift sensor is over 2 million times。
Iii. Ultrasound sensors
Ultrasound sensors are sensors that convert ultrasound signals to other energy signals (usually telecommunications). The ultrasound is a mechanical wave with a vibration frequency greater than 20 khz. It is characterized by high frequency, wave length, small rounding phenomena, in particular good orientation, capable of being radio-dependent。
Ultrasound sensor
Component 1
The commonly used ultrasound sensor consists of a voltage chip, capable of both launching and receiving ultrasound. Small power ultrasound probes are often detected. It has a number of different structures, ranging from direct probes (vertical waves), tilt probes (crosswaves), surface wave probes (surface wave), rampo probes (rampo), double probes (one probe, one probe receiving), etc。
2 performance indicators
The core of the ultrasound is a pressure ultrasound sensor chip in its plastic or metal jacket. There are many kinds of materials that make up the chip. The size of the chip, such as diameter and thickness, also varies, so each probe has different performances, and we have to know its performance in advance. The main performance indicators for ultrasound sensors include:
Working frequency
The working frequency is the resonance frequency of the voltage chip. When the frequency of the communication voltage at both ends of it is equal to the resonance of the chip, the output is the largest energy and the highest sensitivity。
Working temperature
Because the density of the voltage material is generally high and, in particular, because of the low power of ultrasound probes used for diagnostic purposes, the working temperature is low and can work long hours without failure. Medical ultrasounds have high temperatures and require separate refrigeration equipment。
Sensitivity
Much depends on making the chip itself. The coupling coefficient is high and the sensitivity is high; on the contrary, the sensitivity is low。
Pointing sex
Scope of ultrasound sensor detection。
3. Rationale
People are able to hear sound as a result of the vibration of the object, whose frequency is within 20hz-20khz, which exceeds 20khz called ultrasound, which is less than 20hz called infrasound. The frequency of ultrasound is commonly several dozen khz-two dozen mhz. Ultrasound is a mechanical oscillation in a flexible medium in two forms: horizontal oscillation (crosswave) and vertical oscillation (vertical wave). In industry, vertical oscillations are used mainly. Ultrasonic waves can be transmitted in gases, liquids and solids at different rates. In addition, it has refractions and reflections, and declines in transmission. Transmitting ultrasonic waves in air at a lower frequency, typically in the case of dozens of khzs, and at a higher frequency in solids and liquids。
4 specific applications
1. Ultrasound sensors can detect container status. An ultrasound sensor is installed at the top of a plastic smelting tank or plastic particle room, which allows for an analysis of the container's state, such as full, empty or semi-full, when the sound waves are sent inside the container. Ultrasound sensors may be used to detect transparent objects, liquids, any surface rough, smooth, light-rich materials and irregular objects. Not applicable to outdoors, hot environments or pressure tanks and foam objects. Iii. Ultrasound sensors can be used in food processing plants to achieve a closed ring control system for plastic packaging testing. New technologies can be used to detect humid rings, such as bottling machines, noise environments, extremely volatile temperatures, etc. 4. Ultrasound sensors can be used to detect liquid levels, detect transparent objects and materials, control tension and measure distance, mainly for packaging, bottling, equipment handling of materials for the inspection of coal, plastic processing and the automobile industry. Hypersound sensors can be used for process monitoring to improve product quality, detect defects, determine availability and other aspects。
